JP2018193550A - Durable silica grout and ground improvement method using durable silica grout - Google Patents

Abstract

To realize quantitative evaluation on durability by integrating injection material, construction method, management method, and the like and to provide reliable durable ground improvement corresponding to the purpose of injection.SOLUTION: Provided is durable silica grout having a pH of 1 to 10, which is used in a durable ground improvement method where ground improvement is performed by injecting a silica injection liquid into the ground, where the silica injection liquid contains as active ingredients any one or a plurality of silica colloid or liquid glass and, as a reactant, any one or a plurality of acid or salt and, when the silica injection liquid is constituted of colloid, water glass, and an acid, the silica grout is selected from compositions having a ratio of silica concentration due to the silica colloid to silica concentration due to water glass of 100:0 to 0:100, a silica concentration of 0.4 to 30 wt%, a silica mole ratio of 3.0 to 100, and a gel time of flash setting to 10000 minutes. A formulation which satisfies durability corresponding to the purpose of injection is selected from the above ranges.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a durable silica grout and a durable silica ground improvement method using the durable silica grout, and more particularly, a durable ground using a non-alkaline silica grout containing silica sol, silica colloid or water glass as an active ingredient. It relates to the grout for injection and the durable ground injection method, and more particularly to the ground improvement method used for prevention of liquefaction of soft ground, long-term excavation work, reinforcement work for foundation ground, etc. and the management method using the Internet system . In particular, the present invention elucidates the relevance of technologies that have been partially studied in the past, and by integrating them and integrating them, it became possible for the first time to improve the ground to maintain durability satisfying a predetermined injection purpose. It is.

In recent years, there has been an increasing social demand for chemical injection methods for seismic reinforcement such as earthquake and liquefaction countermeasures and permanent reinforcement of foundations.
Conventionally, since chemical injection has been used for temporary injection work such as excavation work, it should have been completed without trouble and stopped and solidified during excavation.

  However, in the permanent injection work in the earthquake-proofing work for earthquakes that do not know when it comes frequently, such as earthquakes that frequently occur in recent years, a predetermined improvement effect has been required for chemical injection over a long period of time. Also, even if it is not seismic reinforcement, the construction will be large, and as the construction over a long period of time after injecting and excavation, and construction that requires heavy load or water pressure in deep underground development, etc. The ground improvement effect is required to maintain a predetermined effect for a long time.

  In addition, if the solidification and water-stopping around the excavation area are permanent even in temporary construction, there will be less reinforcement and leakage of the underground structure after construction, and maintenance costs will be greatly reduced. Furthermore, in recent years, as social demands such as waste disposal by underground burial, underground storage of liquefied gas and construction of permanent water barriers increase, during the service period required for chemical injection or permanently If technology that can achieve water-stopping becomes possible, its usefulness is immeasurable.

The durability and construction methods of silica grout have been elucidated in the past, but all have been limited to partial development, and the entire technology has been developed to form a durable ground that integrates these. There wasn't.
Patent Document 1 relates to a blending design method using on-site collected soil in consideration of the durability period, and Patent Document 2 shortens the gelation by increasing the pH as the gelation time of the injected solution penetrates into the ground. Patent Document 3 is related to estimation of the strength of the injected ground by analyzing the amount of silica before and after the injection ground, and Patent Document 4 is based on the relationship between the gelation time in the soil and the injection time. It is a ground improvement method related to setting.
These are technologies developed by the present applicant to form durable ground by injecting silica grout into the ground, but they correspond to the ground conditions, construction conditions, and environmental conditions to be applied in actual construction. And how to choose injection method, injection design, injection material and injection material prescription has not been established.
The present invention uses silica grout in which the chemical reaction between the ground during injection and after gelation under various ground conditions continues to affect the durability, the target ground conditions, construction conditions, environmental conditions Corresponding to a predetermined improved soil effect or the like in the endurance period required for the purpose of infusion, an injection method for maintaining the predetermined infusion effect during the endurance period without departing from the infusion material from the predetermined infusion region, and The present invention has been completed by paying attention to the need for integrated integration technology including selection of injection design, selection of durable silica grout injection material and prescription, confirmation of effects, and construction management.

  Unlike other physical ground improvements, the chemical solution injection has an extremely rational feature that allows the chemical solution to penetrate into the gaps while leaving the existing soil particles intact. On the other hand, it is easy to construct easily due to its simplicity. In addition, chemical injection is a technology that applies a chemical reaction of silica. The result of the chemical reaction varies depending on the reaction conditions, and the characteristics of the gelled product may change over time.

  In addition, there are many factors affecting the durability in the case of chemical injection that requires osmotic consolidation in an economically wide range under various ground conditions, as will be described later. There are many factors for obtaining durability in this way, and these factors are related to each other. Changing one factor to the positive side changes the other factor to the negative side. It is difficult to improve.

  Therefore, in order to maintain the predetermined durability effect corresponding to the target injection purpose during the service period, or to select the injection material for obtaining the predetermined effect permanently, and in the blending setting, the reliability Selection of the composition of an injection material, formulation and gelling time setting method and injection management to ensure penetration and consolidation without departing from the predetermined injection area, injection design and injection method setting, predetermined after construction Establishing an injection technology that integrates these technologies, such as quality control for achieving the above effects, has become extremely important.

The biggest challenge in wide-area ground improvement that requires a permanent consolidation effect, such as liquefaction countermeasures and foundation reinforcement work, is economical.
A. The durable solution-type injection material must be non-alkaline silica grout from which the alkali of water glass, which is a deterioration factor, has been removed.
B. Even if the injection material itself is excellent in durability, it is necessary to widen the injection hole interval and consolidate a wide area for economic reasons. Then, it is easy to dilute and diffuse in the ground, or to deviate from the injection region or the ground surface. In this case, an unimproved portion may occur in the predetermined injection region, and a phenomenon in which the predetermined strength cannot be obtained in the predetermined injection region may occur.
C. To obtain a wide range of permeability, it must be an acidic silica grout with a long gel time. In silica grout, in the acidic region, the gelation time varies greatly with a slight change in pH, so it is virtually impossible to control the size of the solidified body with the gel time under various ground conditions. This is because the injection ground is more neutral than the pH of the acidic silica injection solution, and the pH of the injection solution in the soil shifts to the neutral side due to the reaction with the composition in the soil, and the gelation time is shortened. .
D. Gel volume shrinkage (sinelysis) after gelation leads to an increase in the strength of consolidated soil over time, but excessive volume shrinkage results in a decrease in strength. Therefore, selection of silica grout suitable for a predetermined injection purpose and evaluation of durability become problems.
E. In the temporary injection to which general chemical injection is applied, the injection range per stage is usually about 1m in diameter as long as the predetermined solidification is maintained until excavation, but durable ground improvement using durable grout Is required to have a wide range of permeation-solidifying properties with a diameter of about 1.5 to 4.0 m and durability for a predetermined strength.
This is a particularly big issue.
The present invention solves the above problems.

  As inventions related to the design method of the durable ground improvement method using silica grout containing water glass, silica colloid and acid as active ingredients, there are already inventions described in Patent Documents 1 to 4 etc. by the present inventor.

However, it can be firmly consolidated in a wide range of specified areas under the choice of composition and concentration of the injection material that satisfies the endurance purpose and the improvement effect required for the specific silica grout and the various ground conditions. Therefore, the reliable ground improvement that can obtain the predetermined ground improvement effect is unclear.

The present invention is a further development of the above invention,
(1) Clarification of durability and penetration characteristics of silica grout requiring durability, and formulation of silica grout corresponding to durability purpose, ground conditions, construction conditions, environmental conditions, quality control, and durability period of durable silica grout Durable silica grout that integrates and enables a durable ground improvement method. (Claims 1 to 16)
(2) Setting of formulation based on gelation time in soil for solidifying to a predetermined area (claims 8-9)
(3) Durable silica grout that provides durability according to the purpose of injection during the durability period. (Claim 10)
(4) Durable grout that can provide durability over time of homogel and sand gel with silica grout and durability over time of consolidated ground (Claims 11 to 13)
(5) A durable silica grout in which the above relationship is clarified and quantitative evaluation of durability, durability period and durability level is introduced, and a predetermined improvement effect can be expected in the durability period corresponding to the injection purpose. (Claims 14 to 16)
(6) Incorporation of an injection management system to ensure that the injection solution penetrates and consolidates into the specified injection area without deviating for a variety of ground conditions and injection purposes, and maintains the durability improvement effect. By doing so, it was possible to improve the durability ground using the durable grout that was previously ambiguous. (Claims 17 to 25)
(7) Furthermore, in order to ensure the quality control of the durable ground improvement, in addition to the injection control at the time of construction and the quality control of the consolidated ground (claims 22-25), the application of an information management system via the Internet Made possible. (Claims 26 and 27)
(8) Finally, a durable ground improvement method that integrates these is completed. (Claims 28-33)

Japanese Patent No. 5156828 Japanese Patent No. 4097664 Japanese Patent No. 4486564 Japanese Patent No. 4437481

  Conventionally, in the case of durable ground improvement, it is known to inject durable silica grout by removing alkali that causes deterioration of water glass grout, but durability by injecting durable silica grout into the ground Durable ground improvement technology that forms the ground has not yet been established. The reason for this is that even if it is said to be durable, it is unclear what has been said to be durable and how the period of durability has been captured. The specific method was unclear.

  Durability improvement is not only for the durability of the chemical itself, but also that the injected ground is required to maintain the specified improvement effect during the service period. It is required to obtain solidification, but when a wide range of injection is performed under heterogeneous and diverse ground conditions, it may not be solidified in a predetermined injection region or a predetermined strength may not be obtained. Can happen. This is because the characteristics of the gelation of silica grout that satisfies the injection purpose by reliably infiltrating and consolidating into a predetermined injection region with a long injection hole interval under such conditions, and its formulation and construction method were unclear. .

  In addition, there are many factors affecting the durability, and the durability period for the injection purpose and the method for confirming the improvement effect to be maintained were unknown. The durability of the injected ground depends on the chemical reaction of the injected material and the solid material injected into the ground, and the chemical reaction differs depending on the ground conditions and construction conditions, and the chemical solidified material. The physical properties of can change over time. As long as the durability is related to the physical properties of the consolidated body over time, such a concept has been unclear in the past although the physical properties in the durability should correspond to the durability period for which durability is required. Durability should mean that the improvement effect satisfying the injection purpose is maintained during the service period of the improved ground, but there was no clear idea of the service period.

  As described above, the flow and gelation characteristics of the injection liquid and the durability characteristics of the solidified product, such as the purpose of injection, the formulation of the injection material, the flow and gelation characteristics of the injection liquid, the durability characteristics of the gelled material, and the durability characteristics of the injection ground Since the relationship between the durability period and the improvement effect was unclear, it was impossible to quantitatively evaluate the durability improvement effect during the service period. For this reason, it has been difficult to establish a durable grout blending design that can maintain a predetermined improvement effect corresponding to the injection purpose under various ground conditions and to maintain the ground improvement technology using it.

Furthermore, as a result of injecting such a silica solution into the ground, it was difficult to verify whether or not the predetermined injection purpose was achieved. The reason is that the durability of the injected ground is influenced by many conditions described below, and they influence each other, so if you try to meet the durability requirements only partially, other requirements will not be met, It has been difficult to design injections that can improve the overall injection purpose. Furthermore, since durability against natural disasters such as earthquakes is targeted for a long period of more than 50 to 100 years, it is difficult to estimate the durability of the durability effect.
For these reasons, the conventional durable ground improvement has been easily qualitatively evaluated, and quantitative evaluation has been difficult.

  The inventor developed these mutually related elemental technologies by elucidating the durability mechanism through indoor long-term durability tests including over 30 years of accelerated tests, field demonstration studies, and follow-up surveys after large earthquakes of the injected ground. However, paying attention to the fact that durable ground improvement is the sustainability of the prescribed improvement effect during the period when durability is required, the gelation time of the infusion solution is determined in consideration of the composition and concentration of the injected solution and the penetration and solidification characteristics in the ground. The injections mentioned at the beginning, such as the construction method to ensure solidification in a predetermined area with the injection hole interval and large injection hole interval in the injection method to be applied, etc. Durable ground improvement method using reliable non-alkaline silica solution corresponding to the purpose of injection at the time of injection design so that quantitative evaluation of durability can be performed by integrating materials, construction methods, management methods, etc. Those that made it possible.

Factors affecting the durability of silica grout and injected ground (1) Type and composition of injected material.
(2) Ground conditions: soil particle size and particle size distribution, density, chemical composition, hydraulic conductivity.
(3) Groundwater conditions: dynamic water gradient, movement of groundwater, dilution with groundwater.
(4) Environmental conditions:
(A) Influence on groundwater use (fish, algae).
(B) Influence on underground structures such as concrete.
(5) Injection conditions: Injection hole interval, penetration distance, injection rate (injection rate per minute), type and composition of injection material, and gelation time (corresponding to a wide range of penetration and consolidation required for improvement of durable ground GT ₀ : Gelation time in air or compounding solution gelation time, pH (pH ₀ : formulation solution pH), soil gelation time in injection ground (GT _S ) and soil pH (pH _S )), formulation solution Change in soil gelation time (GT _S0 ) and soil pH (pH _S0 ) or soil infiltration time (pH _S ) and soil gelation time (GT _S ) when mixed with soil, predetermined amount Changes in pH (pH _Sf ) and gelation time (GT _Sf ), silica concentration of the injected solution, and silica concentration of the injected solution in the soil at the time of injection (or penetration at a predetermined distance).
(6) Durability conditions: Durability such as strength that satisfies the injection purpose. Durability period required to maintain a predetermined strength.

The present invention relates to the following contents.
(1) Silica grout with excellent durability (composition and durability) (Claims 1 to 16)
(2) Silica grout that permeates and consolidates in a predetermined injection region (especially gelation time in soil, injection time, composition for obtaining permeation solidification in the predetermined region, and setting of gel time) (Claims 8, 9, 17, and 22) , 23, 25)
(3) Silica grout that maintains a predetermined durability effect in consideration of the durability period (long-term change in strength and durability period) (Claims 10 to 15)
(4) Ground improvement method using durable silica grout that maintains the prescribed injection effect corresponding to the purpose of injection, ground conditions, environmental conditions, and durability period (factors affecting durability and durability) (Claim 10- twenty five)
(5) Ground improvement method using durable silica grout to obtain a predetermined improvement effect predicted from the long-term durability characteristics of homogel and sand gel (Claims 10 to 13)
(6) Durable ground improvement method by blending design method using on-site collected soil (Claim 22)
(7) Ground improvement method using durable silica grout to confirm the infiltration solidification property and the improvement effect of the injected ground from the injected material and the silica content of the ground before and after the injection (claim 22)
(8) Durability improvement method that maintains the predetermined effect corresponding to the durability period by integrating the durability factors related to the silicidation depending on the chemical reaction under various ground conditions and the elemental technologies that compose it. (Claims 26-33)
(9) Injection management method (Claims 17, 22 to 32)

Further, the following matters are included in the explanation items related to the present invention.
1. Development of durable silica grout that lasts for the purpose of injection and that permeates and consolidates into a specific area (Claims 1 to 16)
2. Durability and duration to meet the purpose of injection (claims 10-16)
(1) What is durability? (Claims 10 to 25)
(2) What is durability strength? (Claims 10-16, 20)
(3) Types of endurance strength (Claims 10 and 14)
(4) Setting the strength of durable silica grout (Claims 4-7, 10-16, 18-22)
(5) Durability of silica gel: silica leaching, volume change and strength (claims 10 to 16)
(6) Strength change and durability of consolidated soil (Claims 10-16, 18-22)
3. Improvement in durability (1) Characteristics of changes in durability of each injection material over time and improvement in reduction of durability strength (Claims 3-18, 22-25)
(2) Addition of fine particle silica (Claims 6 and 18)
(3) Homogenization of heterogeneous ground by primary injection prior to injection of durable grout (Claim 18)
4). Durability evaluation method (claims 10-16, 19, 20)
(1) Durability Evaluation Items (2) Durability Evaluation Elements (3) Durability Evaluation Judgment (4) Durability Level as Durability Evaluation Durable ground improvement method using durable silica grout (Claims 17 to 33)
(1) Durable silica ground improvement method that applies the composition of silica solution and silica concentration according to the purpose and duration of injection (claims 1 to 20)
(2) Durable silica ground improvement method in which the silica grout that has penetrated into the predetermined injection area stays and solidifies (Claims 1-9, 17, 18, 23-25)
(3) Durable silica ground improvement method that provides durability corresponding to durability conditions and ground conditions (Claims 7 to 25)
(4) Durable silica ground improvement method enabling improvement of durability (Claims 5-9, 18, 22-25)
(5) Environmental conservation durability silica ground improvement method (Claims 2, 4, 7, 14, 25, 27, 28, 30, 31)
6). Durable silica ground improvement method by durability evaluation method (Claims 10-16, 19-21)
7). 7. Durable silica ground improvement method using ground silicidation evaluation method using on-site collected soil (claims 22 and 25). Durable silica ground improvement method using durable silica grout by blending design method (Claims 19-22, 25)
9. Durable silica ground improvement method by durable silica grout using durable silica ground improvement effect estimation method (claims 12-22)
10. Durable silica ground improvement method that integrates elemental technologies (Claims 17 to 33)
11. Quality management of Internet information management system and durable ground improvement method (claims 17, 26-32)

  The present inventor has conducted research on long-term durability by injecting a chemical solution over 30 years, and has been researching and developing silica grout having excellent durability and a durability injection technology using the same. In addition, the gelation mechanism, durability principle, and characteristics of durability over time were clarified.

As a result of the long-term durability test of the chemical solution injection, it was found that the non-alkaline silica solution can be a durable silica grout in the following points.
(1) The amorphous silica solution precipitates the contained silica in an acidic to weakly alkaline region (non-alkaline region pH: 1 to 10). (Fig. 3, Fig. 4)
(2) In the non-alkaline region, silica leaching from the silica gel is negligibly small. (Fig. 32, Fig. 33)
(3) Non-alkaline silica gel is dehydrated over a long period of time, and the gel volume is reduced and the strength is increased (sinelysis). (Fig. 44, Fig. 45, Fig. 46, Fig. 57 (a))
(4) The strength of the soil consolidated with silica gel depends on the strength of the gel and the state of the ground, but if the gel shrinks excessively, the strength tends to decrease. However, the higher the silica concentration, the lower the strength reduction. (Figure 34, Figure 35, Figure 36, Figure 49, Figure 53, Figure 54)
(5) As the colloidal silica content increases in the composition of the silica solution, the shrinkage of the gel is reduced and the durability of the consolidated sand is improved. (Figure 34 (b), Figure 35 (b), Figure 36, Figure 37, Figure 38, Figure 42, Figure 53, Figure 54)

  For this reason, the present inventors clarified the durability period corresponding to the purpose of injection and what the durability is, and the durability during the endurance period in the construction and the characteristic that the permeation consolidation is surely obtained in the predetermined injection region. We have developed a durable grout that we have, and we have endeavored to develop a ground improvement method that uses the durable grout to confirm that the durable ground after construction has achieved its intended purpose.

  In particular, even if the ground improvement is excellent, even if the injected material itself is excellent in durability, the ground durability cannot be obtained if the injected solution does not deviate into the injection region of the injected soil. . For this reason, the mechanism by which the gelation characteristics of durable silica solutions can be effectively utilized for penetration and consolidation in the ground is elucidated, and the composition, formulation and construction of silica grout corresponding to the ground conditions, injection purpose and construction method We have developed a technique for infiltration and consolidation without deviating from a predetermined injection region in which the following (1) to (3) consisting of management are integrated.

(1) Silica grout that has excellent gelation characteristics based on the gelation time in the soil that is excellent in durability and penetration consolidation, and that penetrates and solidifies in a predetermined area corresponding to the injection method and ground conditions to be applied. Composition and formulation. (Claims 1-7)
(2) A construction management method for grasping in real time by visualizing that silica grout that has penetrated and consolidated into a predetermined area is injected into the predetermined area. (Claims 22 and 25)
(3) Ground silicification confirmation method by silica amount analysis to confirm that a predetermined improvement effect is obtained by infiltration and consolidation in a predetermined region. (Claims 22 and 25)
In addition, the durability of the silica grout gel corresponding to the service period and the durability improvement corresponding to the ground conditions, the improvement effect of the injection ground and the understanding of the improvement effect, and the development of technology that integrates environmental conservation This makes it possible to solve the above problems. (Claims 8-19, 26-33)

  The present invention clarifies the requirements related to each other in the above-mentioned durable ground improvement construction method, develops elemental technologies constituting the requirements, and provides a durable ground improvement construction method integrating these. (FIGS. 79 and 81) (Claims 26 to 33)

1) In order to obtain long-term durability in which a grout using a silica solution can solve the above-mentioned problems, a silica solution from which alkali, which is a deterioration factor of silica gel, has been removed is used, and a wide range without deviating from a predetermined injection region. There is a need for a composition that has osmotic gelling properties with osmotic consolidation properties and that the consolidated ground maintains the required durability for a predetermined period of time.

[Composition of durable silica grout that provides durability according to the purpose of injection]
Therefore, the silica solution of the present invention is a silica grout having a pH of 1 to 10 used in a durable ground improvement method for improving the ground by injecting a silica injection solution into the ground. One or more of water glass or one or more of acid or salt is used as an active ingredient, and the silica injection liquid is caused by the silica colloid The ratio of silica concentration to silica concentration due to water glass is 100
: 0 to 0: 100, silica concentration is 0.4 to 40 wt%, silica molar ratio is selected from 2.0 to 100, and the prescription that provides durability according to the injection purpose is selected within the above range A durable silica grout (FIG. 3, FIG. 4, FIG. 37) is used (claim 1).

  Silica grout in this region has long gelation time and excellent permeability, and its silica gel and consolidated soil have very little silica leaching, and the long-term consolidated property of consolidated sand is excellent. It can be regarded as a grout. However, since the gel shrinkage is related to the strength change of the consolidated sand, the strength change property of the sand gel must be a silica grout that maintains a predetermined strength during the durability period (FIG. 37).

  More specifically, the durable silica grout is a durable silica grout characterized by being selected from the following composition and silica concentration as the main agent (claims 1 to 4).

(1) A silica injection solution containing one or more of “silica colloid”, “water glass” or “acidic silica sol” as an active ingredient, and an acid, salt, or Either an acid or a salt is added as an additive, and the mixture is used as an injection material having a silica injection molar ratio of 2.0 to 100 and a pH of 1.0 to 10.
(2) The silica composition of the silica injection solution and the silica concentration are within the range.
0.4% ≦ SiO ₂ · T ≦ 40%
0 ≤ SiO ₂ · S ≤ 40%
0 ≤ SiO ₂ · C ≤ 40%
However,
Silica concentration caused by silica colloid is SiO ₂ · C (%)
The silica concentration resulting from the water glass or silica sol is SiO ₂ · S (%)
The total silica concentration in the silica injection solution is SiO ₂ · T (%) (= SiO ₂ · C (%) + SiO ₂ · S (%
))
And

(3) The silica concentration and composition of the silica injection solution is 0.4% or more of the limit concentration at which the silica in the water glass is precipitated in the acidic solution and gels the entire silica solution, In the gelation time curve, select the gelation time within the range of 10000 minutes from the instantaneous setting (Figure 3, Figure 4, Table 1).
The gelation time is adjusted by pH, silica composition, silica concentration and composition ratio, pH and acid, and salt type and concentration.

(4) It is injected while reducing the deviation from the predetermined injection region by managing the gelation time for osmotic consolidation in the predetermined region and the predetermined amount of osmotic injection at each stage.

3, FIG. 4, FIG. 5, FIG. 6, and FIG. 8 show the relationship between the pH of the durable silica grout and the gelation time in the present invention.
In FIG. 3, the S line is an example of a curve of pH and gelation time of water glass and acid (or salt). The C line is an example of a silica colloid and a salt or salt + acid. The D line shows an example of the gelation line of composite silica consisting of silica colloid, water glass and acid (+ salt), the range is above the S line and the gelation time is 10,000 minutes beyond the C line. The upper limit. The slanted line indicates the range of durable silica grout in which the composition satisfying the predetermined durability and the silica concentration and the gel time that permeates and consolidates into the predetermined injection region can be selected in the durability period according to the injection purpose and construction conditions.
FIG. 4 shows an example of the gel time, pH and silica concentration of a non-alkaline silica solution.

Furthermore, since the silica injection liquid of the present invention is a silica grout (pH 1 to 10) used for the durable ground improvement method for improving the ground by pouring into the ground, the characteristics of the long-term change of the sand gel as described above. It must be a silica grout that maintains a predetermined strength during the endurance period. For this reason, an example of the change in strength over time corresponding to the time axis of the endurance period of FIG. 3 can be shown in FIG.

That is, in FIG. 37, the silica grout includes “silica colloid grout (C line)”, “acidic silica grout (S line) containing water glass and acid as active ingredients” and “colloid, water glass and acid as active ingredients. The range surrounded by the maximum line and the minimum line of the strength over time of “composite silica grout (D line)” is the application range E, and the strength that satisfies the durability within the application range E within the endurance period according to the purpose of injection. It is a durable silica grout characterized by selecting the composition obtained and the silica concentration. Specifically, the durable silica grout has a time-dependent MIN intensity line with a minimum silica concentration of 0.4% and a time-dependent MAX intensity line with a maximum silica concentration of 40% (claims 3 and 10).

In a composite silica grout containing water glass + colloid + acid as active ingredients, the silica solution has a non-alkali region, and by adjusting the amount of colloid, the gelation time is adjusted and the amount of gel shrinkage is reduced. It is possible to obtain a durable silica grout with no strength reduction, and by increasing the amount of water glass, it is possible to obtain a durable silica grout with a rapid strength development and high sand gel strength (Claim 6, FIG. 36, FIG. 37, FIG. 49, FIG. 52, FIG. 53). (Claims 2, 4, and 5)

In the acidic silica solution, although the silica concentration of the solid soil by the silica colloid is high, the strength is low and the development of the strength is slow. For low concentrations, the strength can be increased and the onset of strength can be accelerated. In addition, from FIGS. 35 to 37, FIG. 49, FIG. 53, and FIG. That is, an active composite silica grout (FIG. 39), which is a silica grout that enables a ground improvement method in which a predetermined improvement effect within the durability period is maintained, can be used. (Claims 3, 4, 14, 16)

  By mixing colloidal silica, water glass, and acid to form an acidic silica solution (acidic composite silica solution), gel shrinkage and strength reduction are suppressed, and intermediate physical properties of both are expressed. The larger the silica colloid ratio with respect to the total amount of silica in the silica solution having the silica content due to the colloidal silica and the silica content due to the water glass, the smaller the initial strength, but the smaller the shrinkage rate and the less the strength decrease. When the silica colloid is 10% or more of the total silica amount, the shrinkage is reduced and the strength converges at a substantially constant value. On the other hand, in silica sol, when the silica concentration is 10% or more, the shrinkage is reduced, the decrease in strength is reduced, and the strength converges to a substantially constant value. When the colloid in the total silica is 10% or less, the strength increases in the long term as the water glass ratio in the silica solution increases. When the silica concentration in the total silica solution increases, the decrease in strength decreases even if shrinkage occurs. The intensity converges to a constant value in the long term (FIGS. 49 (a), 53 and 54). (Claims 4, 14, 16)

In addition, non-alkaline silica grout is almost completely deposited in the injected ground, and it will contribute to the consolidation of the ground, so even if the consolidated soil decreases over time, the convergence strength should be set by taking into account the decrease Can do.
In the field, when durable silica grout is injected into the ground, the strength of the ground after consolidation is affected by the density and particle size of the ground sand in addition to the volume change and strength increase of the gel. A durable ground can be formed by adjusting the silica concentration and composition according to the injection purpose, the durable purpose, the durable period, and the ground conditions. (Claims 8, 10, 11, 14, 16, 18, 22)

  When the soil soil particle size is large and the sand density is low, or on the ground with large voids, the shrinkage in the sand gap due to the volume change of the gel affects the long-term strength. Acidic composite silica using both silica colloid and water glass takes an intermediate value depending on the ratio of colloid and water glass, but an appropriate ratio can be used according to the purpose of injection, the purpose of durability, and the ground conditions (Fig. 36). , FIG. 37, FIGS. 39-54). (Claims 2, 3, 4, 5, 16)

  From Table 5, Fig. 3, Fig. 5, Fig. 6 and Fig. 30, silica sol (water glass grout in the acidic region) has a fast gelation time, and the gelation time tends to fluctuate due to a slight change in pH. It can be seen that silica has a slow gelation time, a long gelation time, and is easy to adjust the gelation time.

  That is, it can be seen that both the active silica colloid and the active composite silica are excellent in wide-range penetrability in the near-neutral region where the gelation time can be easily adjusted in the neutral region from weakly acidic to weakly alkaline compared to the silica sol. . (Figure 3, Figure 23, Figure 24, Figure 26, Figure 27)

In the case of non-alkaline silica in FIG. 3, the silica solution having a silica concentration of 0.4% is gelled while the total amount of silica is precipitated and the entire mixture is contained. However, the silica concentration that maintained the degree of self-removal from the container was 1%. Table 1 shows the caking properties of homogels and sand gels with low concentration silica.

Therefore, the silica concentration, composition and gelation time of the silica injection solution of the present invention are within the range where the silica concentration is 40% as the upper limit and 0.4% as the lower limit, as shown in FIGS. The gel time has a lower limit of the instantaneous setting region (usually 30 seconds to several seconds) and an upper limit of 10,000 minutes, which is the maximum value of the injection time per stage (Claims 1, 2, and 3).

In the non-alkaline silica injection liquid in the present invention, the silica colloid is one or more kinds of silica colloid or precipitated silica or silica fine particles obtained by ion exchange method, ion exchange membrane method, metal silica method, and water glass is molar. It is selected from one or more kinds of silicates having a ratio of 3.0 to 5.0, or acidic silica solutions containing water glass and acid as active ingredients. In the durable silica grout, the silica concentration of the silica injection solution is 0.4 to 40 wt%, and various acids, salts, and alkalis can be used as a reactant in addition to sulfuric acid. In particular, when a phosphoric acid compound and / or sequestering material (including organic acid) is selected as the active ingredient, a concrete structure is formed to form a hydroxyapatite crystal structure on the concrete surface and protect the concrete from sulfuric acid. Excellent environmental safety in ground improvement in the surrounding area. (Fig. 59) (Claims 1 to 4)

When sulfuric acid and phosphoric acid are used as the acid, the ratio of phosphoric acid in the acid is 75% sulfuric acid, and the phosphoric acid is 15% to 50% by volume of the total acid amount when converted to 75% phosphoric acid. Even if it is high, the gelation time can be easily adjusted (FIG. 31), and an excellent effect on the safety of concrete can be obtained. (FIG. 59) Of course, only phosphoric acid may be used, but the amount of phosphoric acid increases with the same pH, resulting in an increase in reaction products.
Therefore, it is desirable to use only sulfuric acid, use only phosphoric acid, use phosphoric acid and sulfuric acid together and adjust the ratio according to the environment (claims 2, 4, and 14).

As described above, the gelation time is adjusted by using sulfuric acid, phosphoric acid or a mixed acid as the acid, and the salt is selected from monovalent or polyvalent metal salts, or those using a sequestering agent (claims). 6, 7, 60, 68).

The following compounds can be raised as the sequestering agent. Tetrapolyphosphate, hexametaphosphate (especially sodium salt is good), tripolyphosphate, pyrophosphate, acid hexametaphosphate, acid pyrophosphate and other condensed phosphates, ethylenediaminetetraacetic acid, nitrilotriacetic acid, gluconic acid, Examples thereof include tartaric acid, citric acid, and salts thereof, and practically preferred are condensed phosphates.
Examples of phosphoric acid compounds include phosphoric acid, various acidic phosphates, neutral phosphates, and basic phosphates. In this way, a durable ground in the vicinity of the concrete structure can be formed by selecting a composition according to the environmental conditions. Durable silica containing these materials exhibits the effects of FIG. 59 and protects the concrete in the soil (claims 2, 8, 10, 14).

In addition to the sequestering agent, various salts such as carbonates, bicarbonates, aluminum salts, chlorides, aluminates and the like can be added as additives. (Claims 1, 2, 4
)

Various salts for adjusting the gel time (monovalent alkali metal salts, aluminum salts such as aluminum sulfate and polyaluminum chloride, alkaline earth metal salts such as Ca and Mg, sequestering agents, sodium hexametaphosphate, sodium phosphate, etc. Phosphate, etc.) and alkali can be used, especially when adjustment of the gelation time and workability, and a long penetration distance are required, use a combination of phosphoric acid and sulfuric acid to increase the gelation reaction rate. Can be adjusted. (The reaction of phosphoric acid is slower than that of sulfuric acid) Therefore, it is possible to increase the permeation distance with a long gelation time, and it is possible to take a long gelation time in a pH region close to the neutral region (Fig. 30, 31). These are, in particular soil gel time (GT _S) and soil pH (pH _S) and penetration distance and aerial gel time of the silica concentration considering the liquid combination (GT ₀₎ or aerial pH of (pH ₀₎ It is useful for adjustment and composition setting (Claims 2 to 7) (Tables 11, 12, and FIGS. 82 to 84). The acidic reactant in the present invention is an inorganic acid such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, an organic acid such as formic acid, acetic acid, succinic acid, etc .; aluminum chloride, aluminum sulfate, 1 calcium phosphate, 1 sodium phosphate, hydrogen sulfate Acids such as sodium, aluminum sulfate and aluminum chloride; aldehydes such as esters, amides and glyoxal, etc., which are substances that hydrolyze in the presence of alkali to form acid groups, but are not limited to these. Not what you want.

In the present invention, a strength enhancer such as chloride or carbonate or a gelling time adjuster can be used in combination.
For example, chloride, chlorate, sulfate, aluminate, carbonate, bicarbonate, bisulfate, bisulfite, silophate, silicate, phosphate, hydrogen phosphate, pyrophosphate Of course, inorganic salts such as salts, dichromates and permanganates, arbitrary organic salts, alcohols, other metal oxides, calcium silicates and the like are not limited to these examples. (Claims 1, 2, and 4)

The above composition will be further described below.
-Active silica colloid: Silica colloid is a weakly alkaline, or silica colloid produced from metal silica or precipitated silica, which has been increased in size by ion-exchange treatment of water glass (Table 5). A silica solution exhibiting acidity to weak alkalinity, which is provided with reactivity by adding salt or acid thereto, is called active silica colloid.

・ Silica sol: Non-alkaline acidic silica solution containing water glass and acid (+ salt) as active ingredients (
Fig. 3, Fig. 5, Fig. 6, Fig. 35, Fig. 36).
Active composite silica: Non-alkaline composite silica solution containing silica colloid, water glass and acid as active ingredients or non-alkaline composite silica solution composed of acidic silica solution and colloid (Fig. 3,
7-10, FIG. 30, FIG. 36, FIG. 37, FIG. 39).

Here, the active composite silica refers to non-alkaline composite silica composed of large silica particles caused by colloid and small silica particles caused by water glass or silica sol. Usually, the diameter of silica particles caused by water glass is 0.1 nm, the particle diameter of acidic silica sol obtained by neutralizing the alkali of water glass with acid is 1 nm, the particle diameter of colloid is 5-100 nm, usually 5-20 nm It is. The active composite silica is referred to as active composite silica because it is given its own reactivity (Table 5 (a)).

  In the active composite silica, the amount of silica due to the colloid in the silica solution is preferably 10% by weight to 50% by weight in the total amount of silica. Since the colloid contains almost no alkali, the amount of silica due to the water glass increases, so the acid amount for removing the alkali in the water glass must be increased in order to bring the silica solution to a non-alkaline pH. (Figure 3, Figure 4, Figure 30, Figure 31). When sulfuric acid is used as the acid, it is difficult to adjust the gelation time because the pH changes abruptly. Therefore, it is common to use a strong acid with a stable gelation time and a long gelation time (Figs. 3-6, (Figure 30). For this reason, a large amount of sulfuric acid is required. (Claims 2 and 4)

On the other hand, silica solutions containing colloids have less water glass, and therefore less alkali, so non-alkaline silica grout can be formed even if the amount of acid is small, and colloids are weakly alkaline (pH 9 to 10). It is possible to obtain a blend in which the amount of sulfuric acid is reduced in the vicinity of acidity to neutrality and the gelation time is easily adjusted. (Claims 2 and 4)

  In addition, since the acid active composite silica has a lower amount of acid as the ratio of the colloid amount increases, the pH in the soil tends to maintain a neutral value when injected into the ground (FIGS. 8, 9, 23, and 30). , FIG. 31). Accordingly, it is possible to obtain a silica grout that is less likely to deviate from the injection target in a predetermined region by adjusting the optimum gelation time in accordance with the ground conditions, construction conditions, and environmental conditions. Thus, a silica solution that obtains a predetermined durability to be consolidated in a predetermined region by adjusting the total amount of silica, the ratio of colloid and water glass, and the ratio of sulfuric acid and phosphoric acid can be blended (claim 2, Four).

As described above, the ratio of silica grout colloid, water glass, and acid and the composition of the composition are such that the ratio of water glass to colloid is related to the pH and gelation time of the injection solution, and the ratio of colloid is larger at all concentrations of silica. It becomes close to the neutral region and becomes strongly acidic when the water glass is large. When sulfuric acid and phosphoric acid are used in combination, the neutralization reaction between water glass and phosphoric acid is slower than that of sulfuric acid, so that the gel time can be easily adjusted near neutrality. Moreover, it becomes easy to apply a long gelation time near neutrality. For this reason, by adjusting the ratio of colloid and water glass and the ratio of sulfuric acid and phosphoric acid, it is easy to adjust the gelation time between weakly acidic to neutral, increasing the injection hole interval and consolidating a wide range. be able to. (Claims 2, 4, and 8) Further, as the ratio of phosphoric acid increases, a protective effect on concrete is produced. In the above, in the case of composite silica, the ratio of colloid in the total silica can be 10 to 100%, and the ratio of phosphoric acid to the total acid (sulfuric acid + phosphoric acid) can be 15 to 100%. (Claims 3, 4, 6, 8)

The silica of silica grout is water glass as the main ingredient, and the pH of the injection solution is neutral by increasing the colloid content as silica or increasing the ratio of phosphoric acid or phosphoric acid as acid compared to when sulfuric acid is used as the reactant. (FIGS. 30 and 31) (around pH 2.5 to 5) and gels around a pH almost neutral (FIG. 9 (b)). In addition, if the ground contains a lot of Ca or cement is mixed, GTs will be greatly shortened (Fig. 9 (a), Fig. 10). GTs is the gel time in the soil, but the gel time (GTs) is shortened if the pH (pHs) of the soil injection solution increases while being injected into the ground (Fig. 7, Fig. 9 (a), Fig. 10). However, when the pH of the consolidated soil poured and solidified with an acidic silica solution is measured, it is almost neutral (Figs. 6 and 9 (b)) (Claims 4 to 5).

In the present invention, the minimum silica concentration is 0.4%. The gel itself is self-supporting at a silica concentration of 1%. At 0.4%, the gel does not stand by itself, but the entire amount of silica in the silica grout precipitates.
(table 1)
Therefore, if microbubbles are mixed into the solution using a 0.4 to 3% dilute silica solution, the microbubbles are adsorbed and fixed with silica between the soil particles while containing the microbubbles. It does not deviate to the ground surface for a long time. Silica solutions with a silica concentration lower than 2% have low strength for consolidation purposes. However, it is effective when used in combination with microbubbles. It is already known that microbubble liquid is effective as a desaturation method. However, there was a possibility that bubbles would escape into the air over the long term. In order to prevent this, the microbubble liquid containing the low-concentration silica and the silica having a concentration lower than 2% can maintain the function of preventing the liquefaction of microbubbles by simply fixing the microbubble in the ground with silica. In this case, the strength of the microbubbles can be expressed more effectively because the strength of the silica bubbles alone is low and the strength is so low that it is difficult to stand on its own. (Table 1) (Claims 1, 2, and 7).

Moreover, since silica gel is weak, the increase in excess pore water pressure can be reduced and liquefaction can be prevented without losing the function of shrinking microbubbles against earthquake motion. In addition, powders such as powdered silica and bentonite (Table 6) are mixed into such a thin silica solution to fill coarse voids, preventing the influence of groundwater and reducing gel shrinkage. Economic ground improvement becomes possible. In addition, if bentonite and microbubbles are mixed in a thin silica solution and injected, bentonite does not escape and the strength of bentonite is weak, so the function of shrinking microbubbles against earthquake motion is not lost and liquefaction is prevented. Can do. In addition, such a thin silica solution can take a long gelation time in the neutral region, so it is excellent from the environment, and it is economically mixed to prevent the liquefaction by increasing the density of the ground. (Claim 63).
In addition, silica colloids with a silica concentration of 15 to 30 wt% are so small that the leaching of silica is negligible and has excellent durability and water pressure resistance. Therefore, water injection for rock injection, containment of waste and harmful substances, storage of liquefied gas, etc. It can be used to construct a water pressure resistant water stop zone. (FIGS. 32-34, 35 (b), 36-38, 44 (c), 49 (c), 54 (f), 55, 56) (Claims 3, 6, 7, 16)
38 (a) and 38 (b) show the difference in long-term water stopping properties between the silica colloid grout and the silica sol grout. Silica sol system has large shrinkage compared to silica colloid system with little shrinkage over time. Is found to be reduced. In this way, the shrinkage of the gel (active silica colloid containing colloid or active composite silica grout) and (silica sol grout) affects the reduction in strength and water stoppage. It makes a difference.

[Silica grout that reduces the deviation from the injection area and enables ground improvement according to the injection purpose with a predetermined injection composition]
Even if the durability of the durable silica grout is excellent, the improvement of the durability ground is required to maintain the effect that the ground injected under various ground conditions satisfies the durability purpose during the durability period. The present applicant has developed a ground improvement method for obtaining penetration solidification properties while reducing deviation from a predetermined injection region by utilizing the characteristics of the durable silica grout. (Claims 4-8, 17, 18, 22)
Deviation prevention by the composition is described below.
Even if a predetermined amount of injectable material with excellent durability is injected into the ground, the injected solution splits out of the injection region in a pulse shape (Fig. 16 (a)), or if it flows down downward, it is durable. Sexual ground is not formed (Fig. 16 (b)). In order to be able to inject into a predetermined region, first, the injection ground must be a ground through which chemicals can be injected. Figures 1 (a) and 1 (b) are grounds that may be liquefied, and are the targets for injecting chemicals at liquefaction countermeasures. Fig. 2 shows the ground improved by liquefaction measures. In order to infiltrate between soil particles, in the ground of Table 2, the intersoil particle infiltration injection area shown in Fig. 2, at least in the infiltration / split injection area, the injection rate per minute (injection speed) within the limit speed between soil particles, and the upper limit pressure is It must be injected with the injection pressure taking into account the amount of soil loaded on the injection site and the upper load of the building, etc., as the upper limit pressure.

When the injection solution deviates outside the injection range through a rough soil layer, or when the injection rate is high and splits and continues to deviate outside the injection range, the phenomenon shown in FIG. 16 (a) occurs. In addition, after the injection of a predetermined injection amount, gelation does not occur, and on the ground having a high water permeability, a phenomenon occurs in which it flows downward and is not consolidated into a predetermined region (FIG. 16 (b)). In such a case, it is possible to inject a liquid mixture that exhibits the gelation behavior corresponding to the flow characteristics and the injection method of the injection solution for reducing the deviation to the predetermined region by the present inventor and osmosis and consolidating. is necessary.

The results of research on the flow gelation characteristics of durable silica grout to satisfy such purposes are shown below (Table 11, Table 12, FIGS. 3 to 31, Claims 1 to 23).
From the laboratory experiment conducted by the present applicant and the field test using various injection methods, the gel time of the non-alkaline silica injection injected into the ground and the behavior of its fluidity were found to be as follows. In the acidic silica solution, the gel time of the blended solution fluctuates rapidly with changes in pH. Moreover, when it enters the ground, it reacts with the pH of the ground and reaction components, the pH changes during injection, and the underground gel time changes (FIGS. 4, 6, 7, 9, 10, and 17 to 17). Figure 28). For this reason, it has been found that it is virtually impossible to adjust the consolidation range of the acidic silica solution by gel time. Moreover, the predetermined penetration and consolidation is further impossible in a wide area such as 1.5 to 4 m. Therefore the present inventors injection time (H), corresponding to the injection fluid injection rate injected by the following procedure by concept soil gelation time (GTs ₀₎ to set the blend solution was basic (GT ₀₎ It was possible to form a consolidated body. (Claims 5-9, 17, 18, 22)

(1) Relatively homogeneous ground: As a result of research on the gelation characteristics of silica grout in such an acidic region, if a predetermined amount is injected into a homogeneous ground, even if it does not gel at the time of injection of a predetermined injection solution The injected solution moves in the neutral direction in the ground and sooner or later gels there. This is because the gelation of the acidic silica solution is accelerated in the ground where the pH is higher than that, and the silica content in the acidic silica solution is surely deposited even if diluted with groundwater. (FIG. 4, FIG. 5, Table 1, FIG. 17 (a), (e)) (Claims 5-9, 17).

(2) In the case of heterogeneous ground: The injection range can be expanded while suppressing the dilution of the silica concentration while preventing the deviation by allowing the gel to penetrate in the semi-gel state while proceeding with the gelation in the ground (Fig. 17 (b) ), (C), (d)). This is because the acidic silica solution is surely gelled at a low concentration and with a long gelation time, and the gel itself is weaker than the gel in the alkaline region. (Claims 5-8, 17)

From the above, the acidic silica solution can be gelled reliably on the neutral ground without setting a strict gel time as long as the gelation is sufficiently long. It can be seen that the gel time should be set. It was found that this guideline should be determined based on the gelation time in the soil (GTs ₀ ) and injection time (H) that can be reliably set or measured. From experiments, it was found that H ≧ GTs ₀ and H ≦ GTs ₀ were applied depending on the ground conditions and injection conditions, and these could be used together depending on the ground conditions and construction method. This will be specifically described below. (Claim 5
~ 8, 17) (Table 4, Table 11, Table 12, Figures 82-84)

(1) The injection distance is usually 1.0m in the temporary injection, but in the permanent injection, the injection amount per stage is large because it is usually 1.5m or more because of the need for economy by mass injection (Table 4, Tables). 11, Table 12, Fig. 84), when injected at a rate that is within the injectable limit of permeation between soil particles (Fig. 15), the injection rate varies depending on the injection method (Figs. 82-84), but the injection time becomes longer (Table 11). , 12). The reaction between the injected solution and the soil proceeds and the gelation time in the soil is shortened (FIGS. 6, 7, 9 (a), and 10). On the other hand, as the permeation distance becomes longer, when the infusion solution is diluted with groundwater, the gelation time is extended and the strength tends to decrease (FIGS. 4 and 23 to 27).

(2) Generally, the pH of the ground is 4.5 to 8.5 (Fig. 9 (a), Fig. 10), and the pH of the non-alkaline silica grout solution (Figs. 3, 4, 6, 7, 9 (a) )), The gel time in the soil of the injected solution is promoted (FIGS. 6, 7, 9 (a), and 10).

(3) In the case of Toyoura sand, the soil pH is almost neutral, so the soil gel time (GT _S ) is almost the same as the chemical air gel time (GT ₀ ) (see Toyoura sand in Figure 7). . In homogeneous ground, the smaller the difference between the injection time (H) and the gelation time in the soil (GT _S0 ), the more likely the shape becomes a predetermined consolidated body.

(4) Since the soil mixed with shells contains Ca, the gel time in the soil is greatly reduced.
That is, the gel time in the soil is also affected by the soil properties (FIGS. 7, 9 (a), and 10).

From the above, it has been found that the following method may be mainly used to infiltrate and solidify the injection region with certainty.
(A) In general injection target ground is in the order of ^{k = 10 0 ~10 5 cm /} sec, in particular ^{k = a.10 -2 ~b.10 -4 cm,} pH is Lord around 6 to 8.5 (Table 2, Fig. 1 and Fig. 2) First, it must be injected at a low injection rate and within the limit pressure (Fig. 15) that can penetrate between soil particles. Soil pH ₀ with the pH of the liquid combination (pH ₀₎ is a blend of more acidic than the pH of the soil infusate rises, soil gelation time (GT _S) is aerial gel time (pH ₀ ). If the ground contains Ca and reaction components, gelation time will be shortened. (Claims 4-8, 17)

(B) Since the actual ground is not homogeneous, there may be a rough layer with high water permeability or a layer with low water permeability.
When water permeability is large or inhomogeneous ground conditions or groundwater conditions are affected, the injected solution may deviate from or flow down from the target area, or the injected solution may dilute into the groundwater and extend gel time (Fig. 16). (b)). As a result of the inventor's many years of research, acidic silica grout has a pH during injection.
Moves in the neutral direction and gelation proceeds. By setting the gelation time in the soil (GT _S0 ) shorter than the injection time (H) for heterogeneous and diverse ground using acidic silica liquid, instantaneous setting ≦ GT ₀ ≦ 10000 minutes) (GT ₀ ≥ H ≥ GT _S0 ), the solidification area expands while infiltrating between soil particles without becoming a vegetal shape, regardless of dilution with groundwater or inhomogeneity of the ground. I understood. (Claims 5, 7, 8), (Fig. 17 (a) (b) (c) (d))

This is because the injection time (H) of silica grout in the acidic region is longer than the gelation time in soil (GT _S0 )
It was found that the injection range can be expanded and the predetermined region can be securely consolidated while the pH of the injection is increased and the gelation time is shortened and the injection solution is about to gelate while being held in the injection region. Figure 17). To widen the injection hole interval, the injection volume per stage becomes large (Tables 11 and 12).
). In order to permeate and consolidate a large amount of injection into a predetermined region without deviating from the target of injection, the injection time per stage must be shortened and the infiltration injection must be performed. For this reason, the columnar permeation injection method is a method in which the length of one stage is increased and the soil particles are infiltrated in a short time. (Fig. 82, Fig. 83, Table 12)
On the other hand, the multi-point simultaneous injection method can shorten the injection time by shortening the length of one stage to reduce the injection amount per stage. (Fig. 83 (a), Fig. 84 (b), Table 12)

(C) In the ground where the ground conditions are relatively homogeneous, the acidic silica injection material was retained in a predetermined region even if it did not result in gelation at the time when a predetermined amount of injection was completed if it was on the neutral side from the pH of the injection solution. It turned out that it gelled as it is (GT ₀ > GTs ₀ > H) (Table 11, Table 12, FIG. 17 (e), FIG. 84 (a)). Permeates and solidifies almost based on permeation theory. Such osmotic solidification uses non-alkaline silica grout, and is caused by the interaction with soil. By effectively combining stage length, number of stages, injection speed, injection time, gelation time in the soil and compounding recipe corresponding to multi-point injection, the semi-gel silica grout that precedes the ground is followed. It has been found that the silica silica grout can be penetrated and gelled in a predetermined region by using a phenomenon in which the silica grout solidifies while pushing over or over the outer peripheral portion. (Table 12 (b), * 2, * 3)
* 2 and * 3, GTs ₀ is smaller than H, but solidifies while getting over as shown in Fig. 17 (b).

Figures 83 (a), (b), and (c) are the grounds of the particle size distribution of Figure 84 (d), although they were injected under ground conditions consisting of various soil layers as shown in Figure 84 (e). First, it was found that by the injection with the air gel time GT ₀ , the soil gel time GT _S0 and the injection time H shown in Table 12 (b), the infiltration and consolidation were performed without deviating outside the predetermined injection region. This is similar to the phenomenon that the magma that continues from one to the next, overcoming it, loses its fluidity as the temperature of the magma ejected on the ground cools (Fig. 17 (b), (c) , (D))
So we named it the Magma Action Method. Table 12 will be described below.

Table 12 shows an example of the results of analyzing the examples. In order to infiltrate and consolidate into a predetermined region from these, the ground condition or injection hole is defined as air gelation time GT ₀ , soil gelation time GTS ₀ , one stage injection time or one batch injection time H. Specified injection by setting the composition of the mixture and the gelation time (GT ₀ ) or pH ₀ of the mixture as follows, while correcting according to the interval or consolidation diameter, or the injection method, or further based on the construction results The region can be osmotically consolidated (claim 18).
),
Air gel time GT ₀ = Instantaneous setting ~ 10000 min. However, normally GT ₀ is preferably 10 min ~ 10000 min. However, when using instantaneous setting as the primary injection, double pipe quick setting / slow setting combined injection method etc. Then, secondary injection is performed after a packer is formed by instantaneous injection by merging injection around the injection tube at the tip.
Underground gel time GT _S0 = 10 to 3000 minutes (GTs ₀ = 10 to 6000 minutes in Fig. 7, but _{10 to} 3000 minutes here) GTs ₀ is usually 10 to 3000 depending on the ground conditions A range of minutes is preferred,
When the ground Ca content is high, or when the ground is homogenized by injecting CB or the like as the primary injection in the heterogeneous ground, the soil gel time GT _S0 may be shortened to around 10 seconds.
Injection speed (discharge rate per minute) = 1-30L / min
1 stage length: 1-4m
Injection volume per stage = 132 to 25600L
Injection time per stage (H) = 10000 to 4.4 minutes Underground gel time (GTso) = 10 to 3000 minutes

Table 12 shows the relationship between the gel time in the soil (GT _S0 ), the injection rate, the injection amount per stage, and the injection time (H) per stage, based on the injection results.
In Table 12, a square is used for easy calculation of the holding area per piece. Actually, it is circular as shown in FIG. 81, but is substantially unchanged.
Table 12 (a) shows the injection time for point injection and columnar injection by determining the injection hole interval, injection method (Table 11, FIG. 82, FIG. 83), stage length, injection amount and injection speed of one stage. H) is calculated. (Injection rate 40%)
Table 12 shows the field test (Fig. 2, Fig. 84 (d) in the actual field test (Fig. 84) and the injection speed (Fig. 15) and the injection method within the limits of soil particle penetration in the field injection test. (FIGS. 82 and 83) and long-term injection effects including durability and liquefaction strength after construction (FIG. 85) are confirmed, and construction data that have achieved a predetermined injection purpose are shown.
1. Composition of injection solution (Fig. 3, Fig. 4 air pH: pHo, air gel time: GTo), soil gel time (GTs0) and soil pH (pHso) when the injection solution and soil collected in the field were mixed
2. Setting of injection speed within the limit of osmotic injection by in-situ injection test (Fig. 64)
3. Injection method and stage length, injection rate per minute (discharge rate per minute): Table 12 (a)
4. Injection time per stage: H
5). From Table 12 (b), calculate the range of H / GTs0 (or GTs0 / H) from the test results and actual data for the relationship between GTs0 and H.
Table 12 (b) shows the following.
* 1 H / GTs ₀ = 0.45 (GT s ₀ = 2.2H) (Fig. 84 (a))
Even if the soil gel time (GTs ₀ ) is longer than the injection time (GTs ₀ > H), the injection range after the pH is shifted to neutral during injection and the soil gel time (GTs ₀ ) is shortened to complete the injection. It is thought that it solidified to the predetermined area | region, without deviating outside.
* 2 H / (GTs ₀ ) = 1.44 (GTs ₀ = 0.69H) (Fig. 84 (c))
Even if the gel time in the soil (GTs ₀ ) is shorter than the injection time (GTs ₀ <H), the injection of the predetermined injection amount was completed by repeating the penetration while overcoming the previous gelled injection solution (magma action) Loss of fluidity at that point seems to have consolidated without departing from the predetermined injection range.
* 3 H / GTs ₀ = 1.13 (GTs0 = 0.88H) (Fig. 84 (b))
Same as * 2 * 4 H / GTso = 0.34 (GTso = 2.9H) (Fig. 17 (e))
Even if the gel time in the soil (GTs ₀ ) is about 3 times the injection time (GTs ₀ <H), the gel is gelled by shifting the pH in a neutral direction by infiltration at the injection speed in the soil particle infiltration range. Therefore, it seems that the fluidity stopped and solidified when the gel time was reached while the injection solution remained in the predetermined region even after the injection.
The range of H in Table 12 (b) is
0.34 GTs ₀ ≤ H ≤ 1.46 GTs ₀
That is,
The range of GTs ₀ is 0.69H ≦ GTs ₀ ≦ 2.9H.
FIG. 28 (b) shows
Examples of A = H / GTs ₀ = 2.16, 4.68, 2.2 are described, so
It becomes. If you include these,
0.21H ≦ GTs ₀ ≦ 2.9H ... Formula (1)
That is, 0.2H <GTs ₀ <3H ... Formula (2)
It can be seen that it is possible to construct a durable silica ground in which a predetermined injection effect can be obtained without deviating to a predetermined injection region and long-term durability can be obtained.
In the present invention, together with the results of the laboratory test that achieved these injection purposes, the results of the injection test using on-site collected soil,
Underground gel time GTso = 10 to 3,000 minutes (Figure 7)
Injection speed (discharge rate per minute) = 1 to 30 L / min
Injection amount per stage = 132 to 25,600L (Table 12 (a))
However, the injection rate is within the limit injection rate (Fig. 15).
Injection time per stage H = 10,000 to 4.4 minutes (Table 12 (a))
(In-air gelation time is a maximum of 10000 minutes from FIGS. 3 and 4. That is, since GT ₀ ≦ 10000 and H ≦ GT ₀ , H ≦ 10000.)
Therefore,

That is, 0.001H <GTs ₀ <1000H
More preferably,
0.2H <GTs ₀ <3H
It was found that the injection method, the injection hole interval, the stage length, and the blending prescription should be set so that the ground conditions, the injection method, the injection hole interval, and the relationship between GTs ₀ and H are satisfied.
Thus, from Table 12 (a) to Table 12 (b), the range of GTso and H is selected based on the data on GTso and H that achieved the purpose of injection, and the corresponding injection method, stage length, and injection By setting the time according to the ground conditions and construction conditions, it is possible to perform injection management that achieves the injection purpose while reducing deviation.
As described above, the infusion purpose (pHo, GTo) corresponding to the gel time in the soil (GTso) and the infusion time (H) can be managed to achieve the infusion purpose.
Table 12 (b) and FIG. 7 show the results of the gelation time in the soil that could achieve the injection purpose. From this range, the objective can be achieved from the injection results of H and GT _S0 , and the range of the appropriate ratio can be known.
Therefore, the injection time H and the gel in the soil are set such that the injection hole interval in the applied injection method is 1 to 4 m, the discharge rate per minute is 1 to 30 L / min, and the stage length per stage is 1 to 4 m. If the injection method, injection hole interval, discharge amount per minute, and stage length are set so that the relationship of the conversion time is within the range of [Equation 2] or Equations (1) and (2), the deviation from the predetermined injection region will occur. It can be seen that a predetermined improvement effect can be obtained while reducing.
For example, in the table, in the experimental results of Table 12 (b), when GTs ₀ = 150 minutes and 200 minutes, the injection hole interval, 1 stage length when H is selected in the range of 0.5H <GTs ₀ <2H, The injection method, injection time, and discharge amount per minute can be selected from Table 12 (a). That is, an injection method and an injection design that are in the range of H: 75 to 300 minutes when GTs ₀ is 150 minutes and H: 100 to 400 minutes when GTs ₀ is 200 minutes may be selected.
Thus, from Table 12 (a) to Table 12 (b), the range of GTs ₀ and H is selected based on the data related to GTs ₀ and H that achieved the purpose of injection, and the corresponding injection method and stage length By setting the injection time according to the ground conditions and construction conditions, it is possible to perform injection management that achieves the injection purpose while reducing deviation.
As described above, the injection purpose can be achieved by controlling the gel time (GTso) in the soil, the injection time (H), and the composition of the injection solution (pHo, GTo) corresponding to the injection design.
In the above, the discharge amount per minute is set within the limit speed of permeation between soil particles (FIG. 15).

In particular, in the ground conditions where the injected material deviates from the target range or is easily diluted, in addition to the above method, the compounding composition during the injection, that is, the silica concentration and the gelation time are changed. , Techniques such as lowering the pH (pH ₀ ), lowering the silica concentration later, and increasing the pH (
Fig. 28, Fig. 29 (a)) and the technique of measuring the homogenization of the ground using primary injection are useful (Figs. 16 (c) and 16 (d)).
Moreover, said (a)-(c) can also be used together according to a ground condition. (Claims 8 to 20)

From the research by the present applicant, it was found that the following method should be used.
(B) Under non-homogeneous ground conditions or under the influence of groundwater fluidity, the ground is preliminarily obtained by primary injection of suspension, powder (Table 6), lime, gypsum, calcium silicate, clay, etc. By setting the gelation time of the silica solution as described above, even if the silica grout injected at the time of injecting the predetermined amount has not yet reached the gelation time, the time is kept almost as it is. Gelates as time passes (Fig. 16 (c), (d), Table 6)

(B) In the ground that tends to deviate or in the ground with large voids, an alkaline suspension such as cement bentonite grout, a weak alkali material such as bentonite or magnesium hydroxide, or neutral silica powder such as white carbon is injected in advance. In addition, the gelation time of the silica solution described above can be set and injected. In this case as well, the above effect (a) is produced (FIGS. 16 (c) and (d)).

(C) Increasing the interval between the injection holes makes it easy for the solidified body to deviate to the ground surface and to reach the ground surface. In order to prevent this, deviation can be prevented by making the injection hole interval on the ground surface close (FIG. 29 (c)). Also, the injection stage can be prevented from escaping to the ground surface prior to the injection of the stage near the ground surface.

In this way, even when the injected solution deviates to the ground to be injected or is injected into a predetermined injection region after injection, the gelation time of the injected solution is too long and flows down and does not solidify into the predetermined region. In order to prevent this, it was found that the following should be done. (Claims 7, 8, 17, 18)
(1) Injection is performed within the limit speed of intersoil particle infiltration and within a pressure up to the upper load so that the injection rate does not become excessive (injection speed within the injection limit of intersoil particle infiltration showing the straight line in Fig. 15). range).
Here, “within the critical speed” means the permeation speed at least in the permeation injection region and the permeation / split injection region in FIG. 15 where no pressure drop occurs, but is preferably within the limit injection rate in the linear region.

(2) Mixing setting (GTo) of in-air gelation time (or gelation time before injection into the ground) of the injection solution is the gelation time in the soil (GTs) corresponding to the injection method to be applied and the ground conditions In particular, considering the initial soil gelation time (GT _S0 ), the injection rate (q) for injecting the injection amount per stage or batch, and the injection time (H) (or injection distance (L)) Using a formulation that takes into account the length setting, injection amount per stage and injection rate per minute, and injection time per stage, or after injecting a predetermined injection amount, it may deviate from the injection range. Alternatively, the gel time (GT ₀ ) that does not flow below the injection depth is set (Table 11, Table 12, FIGS. 82 to 84).

(3) Depending on the ground conditions such as rough soil layer, large void layer, heterogeneous ground, ground with groundwater flow, etc., the gel time per batch of injected liquid or the gel time of combined liquid should set the gel time to prevent deviation . Air pH (pH ₀ ), air gel time (GT ₀ ) and soil pH (pH _S ), especially initial soil pH (pH _S0 ), soil gel time (GT _S ), especially initial It is determined in consideration of the gel time in the soil (GT _S0 ), its change, etc., the injection amount and the injection time. Here, the initial soil pH _S0 and the initial soil gel time GT _S0 refer to the pH and gel time of the injected solution when the soil and the injected solution are mixed or infiltrated into the soil.
(4) The above (a), (b), (c) (1) to (3) are used in combination.

As described above, the gelation time in the soil, especially the gel time in the soil (GT _S0 ) is measured and the injection time H ≧ the soil gel time GT _S0 or H ≦ GT _S0 or H ≧ GTo depending on the ground conditions. , H ≦ GTo, or in combination.

In order for the non-alkaline silica grout to remain in the predetermined injection target area and solidify, the gelation time of the injection compound solution (GT ₀₎ corresponds to the setting of the injection stage, the setting of the stage length, the ground condition and the injection method. ), Soil gel time (GT _S , especially the initial soil gel time GT _S0 ), changes in soil gel time (GT _S ) during injection in the ground, and one stage injection amount and injection amount per minute (injection rate) To improve the durability of the ground, it is a silica grout with a compounding prescription (GT ₀ ) that reduces the deviation from the injection range when the injection time (H) and predetermined injection are completed. It turns out that the required injection material can be said. (Claims 6 and 8)

The soil gel time (GT _S), also said that the soil pH (pH _S), in but change is difficult to measure in the ground, the injection solution was mixed with the field soil a soil gel time (GT _S0) and soil Since pH (pH _S0 ) can be measured, it is preferable to consider it as a standard together with the pH (pH ₀ ) and gel time (GT ₀ ) of the mixed solution. 18 and 19 can be used to measure GT _Sf and pH _Sf , and these values can also be added to the standard for setting GT ₀ and pH ₀ .

  However, considering the heterogeneity of the ground condition, the reactivity of the silica solution with the soil, the change in the fluidity of the injected solution during the injection of various soil properties, the dilution of the injected solution, the injection method, the injection amount and the injection time, etc. Naturally, it is of course difficult to set the gelation time for surely penetrating and consolidating within a predetermined injection range.

For this reason, the present applicant has clarified the following factors related to each other, and has made it possible to ensure penetration and consolidation in a predetermined region.
Regarding the silica concentration, pH and gelation time of the blended solution, FIG. 6, FIG. 5, FIG. 8, FIG. 30, and FIG. 7, FIG. 9, FIG. 10, FIG. 23, FIG. 24, FIG. 26, FIG. 27, FIG. 25, FIG. 26, FIG. 39, FIG. c), (d), FIG. 58 and FIG. This is described in FIG.

From the examples shown in FIGS. 4, 6, and 7, the relationship between the gelation time in the soil (GTS ₀ ) and the air gelation time (GT ₀ ) varies depending on the ground conditions and the concentration of the injected material, but is almost It was found to be in range. (Claim 5)
4 and 7, from pH ₀ = 1 to 10 in the atmosphere GT ₀ = 10000 minutes (pH ₀ = 2), in the soil GT _S0 = 40 minutes (from pH ₀ = 2, pHso in the soil is about 4.7 In addition, GT _S0 = 10 minutes (pHso = 5.5) with respect to GT ₀ = 10 minutes (pH ₀ = 5.5). However, in ground with a lot of Ca, GT ₀ was almost 10 minutes compared to 10000 minutes for GT ₀ (Fig. 10).
So the ratio between GT ₀ and GT _S0 is

From FIG. 7, GT _S0 is usually in the range of 6000 minutes (the number 1 is in the range of 3000 (0080) to 10 minutes, but it is shortened when there is a lot of Ca or primary injection of cement etc., Gso = 6000 minutes to 10 Second range (0080)
In FIG. 7, the air pH is in the range of pH ₀ = 2 to 5.5, the air gel time is in the range of GT ₀ = 10000 minutes to 10 minutes, and the pH in the soil is pHso = 2 to 5.5 (FIGS. 26 and 27). The medium gel time is in the range of GTso = 6000 minutes to 10 minutes. In FIG. 6, the injection solution with pH ₀ = 2 and GT ₀ = 4000 minutes is mixed with the soil, the pH shifts to pHso = 4.5 and is shortened to GTso = 10 minutes to 20 minutes. In addition, if you inject by conjunctive injection, the gel time in the air will be
GT ₀ = 10000 minutes to 0.1 minutes.
From the above, it can be considered that the normal GT ₀ / Gso is in the range where the maximum value is 10000/10 = 1000 and the minimum value is 10/10 = 1. [Equation 3]

It is in the range.
However, GTs ₀ 6000 minutes to 10 seconds, GT ₀ = 10000 minutes to 0.1 minutes. (As 20 ℃)

The details will be described below. Examples of estimation calculation results of spherical infiltration and columnar infiltration when a predetermined amount of injection per stage is infiltrated between soil particles are shown in FIGS. When the injection is finished (injection time H), the pH of the injected solution will increase further under the condition that the injected solution is kept in place even if the injected solution is not gelled. To. The pH of the consolidated soil after the injection finally exhibits a nearly neutral region (FIG. 9 (b)).

However, if gelation does not occur after injection and the soil is rough, the injection solution will flow down to the lower layer with poor water permeability and gelation will occur. (Fig. 16 (b)
).
Therefore, in setting the gelation time (GTo) of the non-alkaline silica grout mixture, the pH of the injection solution (pHo), the pH of the injection ground and the soil properties such as the Ca content, ground conditions such as water permeability and groundwater conditions, soil Injection solution after completion of injection considering medium gelation time (GT _S0 ), injection amount per stage injected into a given injection region, injection speed within the limit injection speed that can penetrate between soil particles and injection time (H) It is important to set the air gelation time (GTo) that is difficult to flow.
In addition, when setting the pH (pH ₀ ) and gelation time (GTo) of the injection compounding liquid that reduces deviations outside the predetermined range, the pH of the compounding liquid is set to the acidic side of the soil pH, and the soil contains Ca. The gelation time in the soil containing the minute and the reactive agent makes the gelation time of the compounded liquid longer than the gelation time in the soil. Use a formulation that makes the soil gelation time (GT _S0 ) shorter than the injection time (H).

From Fig. 4 to Fig. 31 and Table 12, in such a case, by shortening the length of the stage, reducing the amount of one batch, or shortening the injection time by simultaneous injection of multiple injection stages, the air gel It is possible to repeatedly inject a magma action of extruding or getting over in a semi-gel state within a short time by shortening the gelation time (GT ₀ ) or the gelation time in the soil (GT _S0 ). Further, as shown in FIG. 28, the gelation time can be changed during the injection, and the pH and strength in the ground can be equalized over a wide range. (Claim 5)

From the above, it can be seen that the concept of gelation time in soil is important. According to the study of the present inventors, the pH in the soil fluctuates in a neutral direction as the injection distance becomes longer during the injection (FIG. 23). In addition, it was found that neutralization due to reaction with soil in the ground and dilution with groundwater caused a decrease in silica concentration and an increase in gelation time. Therefore, here, the gelation time due to the gel time when the injection solution is mixed with the in-situ sand is referred to as initial soil gel time (GT _S0 ). The gel time can be measured by mixing silica grout and soil in a container and adjusting the pH and gelation time of the supernatant liquid to the soil pH and soil gel time (GT _S0 ) of the injected liquid. The time at which the grout is filled and the needle is pierced and the hole remains open may be used as the gelation time. When the pH of the compounded liquid (pH ₀ ) is measured, the sand time in the container is taken and immersed in a silica liquid and the gel time is measured. The gel time in the initial soil (GTso) is usually GTo ≧ GTso .

The acidic silica grout is neutralized with the soil during the distance penetrated from the injection hole point of the silica grout injected into the ground (pHs) (Fig. 23), and the tip of the injected solution The gel time of the injection solution is shortened and gelation starts, but the subsequent injection solution penetrates after the neutralization reaction between the previous injection solution and the soil, so the pH of the injection solution remains long and the preceding gel Only after the membrane that has started to form (Fig. 17) breaks through and penetrates to the outside, a new neutralization effect occurs, the pH rises and the gelation time is shortened to produce a membrane that is about to gel. A predetermined region is consolidated while gelling repeatedly (FIG. 17). For this reason, it does not deviate in a predetermined injection | pouring area | region, but is hold | maintained and solidified as it is in a predetermined | prescribed area | region. Thus, it was found that when it permeates in a gelled state, it is difficult to be diluted with groundwater even if the injection length is long.

Also, H = αGT _S0 , H = βGT ₀ , 1 stage injection time or 1 batch injection time is H, α and β are based on ground conditions, injection hole interval or injection method, or based on construction results The composition and gelation time (GT ₀ ) or pH ₀ of the compounded liquid can be set while correcting, and can be permeated and consolidated in a predetermined injection region (claim 18). In this way, the gelation time that satisfies GT ₀ ≥ H ≥ GT _S0 is set when there is a large gap, a layer with large water permeability is present, groundwater is flowing, or there is insufficient packing around the injection pipe Also proved effective.

Furthermore, the present inventor has formulated a liquid pH (pH ₀ ) at which a predetermined osmotic solid is formed when a predetermined amount is injected.
Experiments were conducted to find out the relationship between the pH of soil and the soil pH that permeates and solidifies through a predetermined injection length. Even when a predetermined injection volume is injected, there is little reduction in the gelation time at the tip of the penetration of the injection solution, and if the time until the gelation is sufficiently long after injection of the predetermined volume, the injection solution will deviate. Or may flow downward or deviate from the periphery of the injection pipe to the ground surface (FIG. 16 (b)). Therefore, if the gelation time GTo of the injection solution is injected at a predetermined amount, or when it has penetrated for a predetermined distance (R) (pHsf, GTsf), or if it gels within a short time, the injection range There is no departure.

18 to 22 show examples of test methods. After filling in-situ sand into the injection pipe of length L or γL corresponding to the consolidation radius (or injection hole interval × 1/2) R by using FIG. 18, FIG. 19, and FIG. Then, after injecting silica grout and injecting the injection length R, discharging the interstitial water from the top end of the injection pipe, discharging the mixed water of the interstitial water and the injecting liquid, and continuing to inject thereafter, the injecting liquid itself is discharged. (Fig. 24). If the injection is stopped when the interstitial water is discharged and left as it is, gelation occurs and a solidified body is formed. FIG. 25 shows the intensity distribution obtained by cutting the consolidated column every 10 cm. It is considered that the strength decreases with the penetration distance due to dilution with water.
By in-situ extraction using a pipe with penetration length L, composition and gelation time (GT ₀ ) or pH (pH ₀ ) and gelation time in soil (GT _S0 ) or soil pH (pH _S0 ) and penetration length L
It is possible to know the relationship between the gel time in the soil (GT _Sf ) or the pH in the soil (pH _Sf ) after passing through. Based on this relationship, the gelation time GT _{S0 in the} soil, data can be accumulated for each site as follows.
A = GT _Sf / GT _S0 , B = pH _Sf / pH _S0 , C = pH ₀ / pH _S0
α = GT ₀ / GT _S0 , β = H / GT _S0
Here, H is the penetration time of L (Fig. 18) in the room penetration test, and is the one-stage injection time at the site, and the injection time of consolidation diameter = 1/2 of L or 1/2 of the injection hole interval It corresponds to. In the laboratory test, injecting soil L into a pipe of injection length L at in-situ density and injecting soil and silica injection solution filled with pore water, the gel time of the injection solution at the time when the injection solution overflows is set to GT _Sf , pH _Is pH _Sf, and its penetration time is H. Alternatively, the injection time in the work is H. In actual construction, the above A, B, C, α, β are different from the indoor injection test depending on the ground conditions, injection hole interval or consolidation diameter, injection time, construction method, but construction data in the construction work (Table 12) And confirmation of the effect after injection (Fig. 29
In consideration of FIG. 81), it is possible to select appropriate values by accumulating the data of the above A, B, C, α, and β. According to the inventor's research, depending on the ground conditions and construction conditions,
β = H / GT _S0 = 1000 to 0.001 (where H is the injection time in the construction work)
It was found that it can be in the range. (Table 12, Fig. 17), (0080)

Measure the pH (pHsf) of the overflowed injection (Figure 24) and measure its gelation time (GTsf). It is possible to set the gelation time (GTo) of the blended solution that gels. In this case, if the gel time of the overflowing injection solution (GTsf) in Fig. 18 is within the range of bGT _S0 ≤ GTsf ≤ aGTso and the gel time of the compounding liquid is set according to the ground conditions, the injection solution can be surely applied to the predetermined area. It can be gelled. If the injection material exhibiting GT _Sf in this range penetrates into the ground further, the pH will rise, and a and b to ensure gelation can be determined according to the ground condition, injection method and injection condition. It may be determined while making corrections based on data based on results.
For example, if 0 ≦ GT _Sf ≦ cGT _S0 , if c = 1, GT _Sf = GT _S0 , and even when the injection of the injection length L is finished, fluidity corresponding to GT _S0 is present, but the injection solidity is Considering that the joined bodies overlap each other (FIG. 80 (b), Table 12 (b) * 1, FIG. 82), it can be considered that there is no problem if the limit is GT _S0 . c should be corrected according to the ground conditions and injection conditions, and by adjusting the penetration and consolidation conditions after injection, taking into account experience values. Moreover, since the above injection test is a one-dimensional injection test and is actually performed in three dimensions, the actual injection time H is for three-dimensional injection (FIGS. 11 to 14, FIG. 17, FIG. 22, FIG. 28). , Fig. 29), much longer than the injection time H of the one-dimensional injection,
Therefore, since it reacts slowly with the soil for a long time and expands (it is considered to correspond to γL), the width of c cannot be determined in general. However, since a test value for γL can be obtained as a guide, H for GT ₀ , pH ₀ , GT _S0 , pH _S0 , GT _Sf , pH _Sf and γL is measured, and γ is L for one-dimensional injection. By associating with the data of the infiltration consolidation effect in the actual on-site injection as a coefficient in the three-dimensional injection, the numerical values corresponding to the ground conditions, construction conditions, and the conditions of the injection material are grasped and the infiltration solidification is surely made C, B and A can be obtained. Using these points as a guide, b, a, c, α, β, and γ may be set by adding not only calculated values but also experience values.

In addition, the correctness of the compounding setting that takes into account the silica grout injection method can be confirmed by a predetermined improvement effect by test injection at the site and measurement of the silica concentration by subsequent sampling (FIGS. 29 (b) and 58). . By appropriately blending and setting according to the ground conditions and injection method, and if a predetermined injection volume is injected at a predetermined injection speed at a predetermined injection stage, even if it does not gel at the completion of the injection volume, it remains as it is If left untreated, it will gel and solidify over time (Table 12, * ₁ , * ₄ , Fig. 84 (a)). This phenomenon occurs when the ground is relatively homogeneous and the water permeability is in the order of 10 ^-2 to 10 ^-4 cm / sec. This happens when

Moreover, it may be preferable to inject with a short gelation time of several seconds to 5 minutes depending on the ground having a large void, the inhomogeneous ground condition, or the case where the dilution of the injected liquid is expected to be large due to groundwater.

  If the injection time and the gelation time in the soil are almost the same for a given amount of injection, or if the gelation time does not reach the gelation time after the injection, but the injection solution does not move after injecting a given amount of the injection solution into the ground When gelation takes place at the time of formation, it penetrates in a spherical manner in a situation that conforms to the penetration theory of Maag (Figs. 11, 12, and 13). In that case, the possibility of deviating out of the injection range is reduced. In order to inject a wide range at one stage with a wide injection hole interval, the injection amount per stage must be increased. Inability to feed in 1 batch (usually 100L to 400L).

Generally, as long as a large amount of non-alkaline injection material, especially acidic injection material is injected, one batch injection time (H) is longer than one batch injection time (H). It is normal to become. Therefore, in this case, if the injection amount per stage is performed in a plurality of batches, the injection time of one batch of injection amount can be made shorter than the injection time of the gelation time in the soil, or in the soil It can be taken longer than the gel time. Either selection is possible depending on the ground condition and the injection hole interval.

In addition, even if the preceding injection solution starts to gel after the gelation time in the soil, the subsequent grout with long gelation time breaks the gelled film and spreads outward and solidifies as the gelation time in the soil elapses. (Figure 17). Thus, the injection amount per stage, the injection amount per batch, the injection time and the number of batches, the injection speed, the gelation time in the soil (GT _S0 and GT _S ), the gelation time in the air (GT ₀ ), the place Determine the composition and gelation time (GT ₀ ) at the time of blending according to the injection time (H) at the time of fixed-quantity injection and the pH (pH ₀ and pH _S ) of the injection solution, etc. be able to.
In this case, the injection time per stage or batch can be H ≦ GTso or H ≧ GTso (Table 12).

Such a gelation time (GT ₀ ) can be set in accordance with not only the normal ground but also the injection into the ground where the injected liquid tends to deviate or the ground where groundwater is flowing. In particular, if the ground conditions are poor and it is difficult to penetrate and consolidate with a specific strength into a specific injection area simply by adjusting the pH of the injection solution and the gelation time in the soil, these can be adjusted according to the injection conditions during the single-stage injection process. The gel time and silica concentration can be changed, and H ≧ GT _S0 , H ≦ GT _S0 and GT ₀ <H can be used together. (Claims 5, 6, 7, 15)

In the above, the injection time (H) is the time obtained by dividing the injection amount Q per stage (or the injection amount of one batch) by the injection speed (injection amount q per minute) in the range of intersoil particle infiltration (Q / q = H It is based on calculating.

In the case of the one-dimensional injection shown in FIG. 18, if the gelation time GTo is shorter than the penetration time (H), the injection solution gels in the middle before the penetration of the L length and the penetration stops before the L-length penetration finishes. Actually, the injection solution penetrates while expanding the penetration range (Fig. 22), and the three-dimensional spherical penetration penetrates and the range of the tip of the injection expands like the surface area of the sphere (Figs. 11 and 12). , Fig. 13, Fig. 14) and Fig. 17, even if the injection time is longer than the gelation time in the soil (GTs ₀ ), it will get over the tip surface that has gelled or the gelled injection solution It penetrates and solidifies while pushing in the direction. (Claim 8)

This phenomenon is the same as the magma ejected to the ground cools and loses its fluidity, and the subsequent magma gets over it and solidifies over a wide range while solidifying. Thus, by setting the gelation time (GTo) or the silica concentration according to the situation, it is difficult to deviate at large injection hole intervals, and it is difficult to dilute into groundwater, so that a wide range can be solidified reliably (FIG. 17 ( d) and FIG. 85 (b)). For this reason, it was found that there was little decrease in strength corresponding to the infiltration distance and there was little dilution with groundwater. Therefore, as the index, the injection speed, injection time, air gelation time, and soil gelation time (GT _S0 ) are appropriately set according to the ground conditions. FIG. 17 (e) shows the shape of consolidation in a homogeneous ground. In this case, H / GT _S0 = 0.34 as shown in Table 12 (a) * 4
In this example, the gel time in the soil (GT _S0 ) is not reached when the predetermined amount of injection is completed. In practice, however injectate at the tip of the injectate in proceeds toward neutrality than pH _S0 (Fig. 23), GT _Sf than GT _S0 is considered to be shorter than the GT _S0, completion of the injection At the same time, or after the completion of the injection, it is considered that the gel was rapidly gelled and consolidated into a spherical shape as shown in the figure.

Regarding the influence of dilution of the silica concentration, its tendency can be known from FIG. 4, FIG. 18, FIG. 19, and FIG. Using the apparatus in Fig. 18 (L = 1.5m), the pH and gel time of the injection solution with silica concentration of 5% is GT ₀ = 1000 minutes, and the injection solution with pH ₀ = 3.5 is injected with L = 1.5m. After the overflow, pHf and GTf of the overflowed infusion were measured (FIG. 24). When the pH of the overflow liquid is 6.6 and the gel time is 1 minute 30 seconds, it means that the point has shifted from FIG. 4 (a) to FIG. 4 (b), the silica concentration is almost 5%, and there is almost no dilution. I understand that.

Similarly, when the pH of the overflow liquid was 6 and the gel time was 7 minutes, it moved from the point of Fig. 4 (a) to the point of Fig. 4 (c), and diluted with groundwater, the silica concentration became 4% I understand. Fig. 4 (d) shows a case where it is necessary to maintain a 5% silica concentration under ground conditions where there is a lot of groundwater and is easily diluted.
After injecting the point composition (silica concentration 10%) and the pore water overflowing, if the composition of point (b) in FIG. 4 overflows, it can be seen that a silica concentration of 5% was secured. In addition, when the compound at point (a) in Fig. 4 was injected, the pH and gel time of the infused solution leaked to the ground surface were measured. You can see that In the above, instead of pH measurement, conductivity can also be measured (FIG. 74).

As described above, in order to ensure that the injection solution is held in the predetermined injection region and permeate and solidify,
(1) Appropriate injection rate and injection pressure (2) Air gelation time (GTo)
(3) Ground condition (ground pH, Ca content, particle size, hydraulic conductivity, groundwater condition, etc.)
(4) Gelation time in soil (GT _S0 )
(5) A grout blended in consideration of the stage length, injection speed, injection amount per stage, and injection time corresponding to each injection method must be injected. (Claim 23)

Setting pH ₀ and gel time of the liquid combination (GT ₀₎ and soil gelation time (GT _S0) and the injection time (H) by ground conditions and injection method to be reliably penetrate consolidated in a predetermined injection region than higher To do. In particular, either GT _S0 ≧ H or GT _S0 ≦ H or a combination thereof is required.

Depending on the ground conditions and injection conditions, the former method (H ≧ GT _S0 increases the silica concentration and lower pH ₀ ) at the beginning of the injection, and the latter method (H ≦ GT _S0 lowers the silica concentration and pH lower). _In some cases, the _value may be ₀ (higher). In addition, using a double tube, liquid A is silica solution (or silica solution + acid), liquid B is a reagent solution (or silica solution), or liquid A is a one-component silica / reactant mixture. May be injected into the B liquid using an accelerator, or after the injecting injection, it may be switched to the one-liquid A liquid injection (double pipe instantaneous setting / slow setting combined injection method). In this case, it is easy to inject a mixture liquid (GTo) having a gelation time shorter than the gelation time in soil (GTso).

From many construction results, it was confirmed that it penetrated and consolidated into a predetermined area under the following injection conditions. Table 11, Table 12, and Fig. 82-83, the silica concentration is 0.4-40%, the discharge rate per stage is 1-30 L / min, and the stage length per stage is 33 cm ~ 4m, injection point from single point injection to multi-point injection and columnar injection, gel time from instantaneous setting (within 10 seconds) to 10000 minutes (or 0.1 minute to 10000 minutes), injection hole interval 1 to 4m in the present invention Can be implemented. (Claim 8)

The photo in Fig. 84 (a) shows the consolidated shape by the columnar penetration method in Fig. 82 (c), Fig. 84 (c) shows the consolidated shape in Fig. 83 (b), and the photo in Fig. 84 (b) Fig. 83 shows the shape of consolidation by the injection method of Fig. 83 (a). Also, FIG. 85 shows the strength of day by core sampling of the consolidated soil in FIGS. 84 (a) and 84 (b) of the consolidated ground constructed 13 years ago. Through the above field experiment, the injection material penetrates and solidifies without deviating into the predetermined injection region, and the strength of the predetermined strength (100MN / m ² ) or more continues for 13 years or more and converges to the predetermined value or more. I found out. In addition, liquefaction strength tests using undisturbed samples of improved soil collected from the ground (Fig. 84 (a)) in which the field injection test was conducted in 1999, and after the Great East Japan Earthquake (March 2011) 2011) We conducted a liquefaction strength test of undisturbed samples of improved soil collected in September 2011 and compared them. The liquefaction strength of the core collected in the 12th year after the Great East Japan Earthquake showed a tendency to become stronger than the result conducted in the third year (2002) after the injection at any concentration. This shows a tendency to increase slightly after the third year, and it was found that the liquefaction strength did not deteriorate even after the big earthquake (Fig. 85 (b)).

(1) Air gel time (GT ₀ ) and soil gel time (GT _S0 )
From the inventors' experiments, the air gel time (GT ₀ ) and the soil gel time (GT _S0 ) in FIG.
7, FIG. 9 (a), including the example of FIG. 10, GT in the range of pH ₀ = 1~10 _0: GT _S0 in the range of 10000 minutes to 0.1 minutes in the range of usually 6000 to 10 minutes However, it was found that it was in the range of 600 to 10 seconds when there was a lot of Ca or when cement or the like was primarily injected. α = GT _{0 /} GT _S0 is in the following range from FIG. 6 to FIG.
In addition, when GT ₀ = 10 minutes, GTso is approximately 10 minutes or GTso is substantially the same as GT ₀ is shorter. Alternatively, GTso cannot be longer than GT ₀ , so the minimum value of GT _{0 /} GT _S0 is 1.

From Fig. 7, Fig. 9, and Fig. 10, the soil gel time is significantly shortened in the soil with a large amount of Ca. However, by lowering the pH ₀ enlarged injection region by the action of FIG. 17, it is consolidated at the time when a predetermined amount of injection.
Table 12 (a) (b), specific examples of injection conditions for osmotic consolidation in a predetermined region of the present invention, FIG. 4,
It is shown below including the examples of FIG. 7, FIG. 9, FIG. 10, and FIG.

(Example 1)
Injection hole interval or consolidation diameter L = 1.0 to 4.0m (Table 12 (a))
Injection rate q per minute q = 1-30L / min However, it should be within the limit injection rate.
Stage length: 0.33m to 4.0m (Table 12 (a))
Injection time per stage H 4.4 to 10000 minutes (Table 12 (a))
However, the injection time (H) may be selected in consideration of on-site workability and work schedule.
Air gelation time GT ₀ Instantaneous setting ~ 10000 minutes, preferably 3 minutes ~ 10000 minutes
pH (pH ₀ ) 1.5-10
Silica concentration 0.4-40% (wt%)
Underground gel time GT _S0 10 seconds to 3000 minutes, or 10 minutes to 6000 minutes (Figures 6 and 7)
Soil pH (pH _S0 ) = 3 to 10 (Figs. 9 and 10)
Ground a × 10 ⁰ 〜b × 10 ^-4 cm / sec (Table 2)
Ground pH 4-10 (Fig. 9, Fig. 10)
The pH above neutral up to the upper limit of 10 is the ground with a high Ca content and the ground with primary injection of CB.

(Table 12 (b), Figure 6, Figure 7, Figure 9 (a))

Preferably,
From β = 4.68 to 0.34 (0143)
From 0.2H <GTso <3H (0144)

(2) Number of stages, stage length, number of discharge ports in one stage, pH, gel time and silica concentration of the injection compounding solution are the injection speed per minute and the total injection volume (or 1 stage injection volume) corresponding to the injection method to be applied. Considering total injection time (or 1-stage injection time), soil gel time, initial soil gel time (GTs ₀ ) and soil gel time (GTsf) after infiltration into the specified soil, homogenization of ground, and groundwater effect reduction treatment And set from the range of (1) above. (Table 12 (a))

(3) Examples of the injection method are shown in FIGS. 60, 61, and 82 to 84.
(4) Table 11, Table 12, FIG. 28, and FIG. 80 show examples of the injection consolidation diameter, the injection amount, the injection speed, and the injection time.
Here, assuming that the injection hole interval is 4m at maximum, the interval rate is 40%, the gap filling rate is 100%, and the injection rate is 40%, the amount of injected solid soil per stage from one injection discharge port = 4/3 × π × r ³ = 33.5m ³ (r = 2.0m) (Figure 80)

Injection amount per stage from one injection discharge port = 33.5m ³ × 0.4 = 13,400L, but the injection injection length per stage is 4m, but the injection length per stage is 2m, so the injection length is simple. If 4m is divided into two parts, the amount of injection per stage will be about 13,400 ÷ 2 = 6700L (actually solidified in a cylindrical shape).

  If the discharge rate per minute of the limit injection speed between soil particles that permeate and consolidate into a given area (Fig. 15) is 1 L / min (point injection, Fig. 11, Fig. 12) to 25 L / min (column injection, Fig. 14), 1 The injection time per stage is 6700 / (1-25) = 6700-268 minutes = 111.7 hours-4.5 hours = 4.7 days-4.5 hours. If the injection length of one stage is 4 m and the column injection is 25 L / min, the injection time is 13400 L ÷ 25 = 536 minutes = 22 hours.

As a result, if the gelation time of the mixture is the injection time of the injection amount per stage, the maximum is 6700.
It should be ~ 536 minutes. However, the actual length of one stage differs depending on the injection method (Tables 11, 12, and 82 to 83). For example, the 32 point simultaneous injection method by point injection (FIGS. 60 and 83) is an injection from one injection point. A speed of 1 to 8 L / min is often used, and 10 to 30 L / min per stage is often used in the columnar infiltration method (Figs. 82 (c), (d), and Fig. 83 (b). ˜20 L / min is often used (FIG. 82 (a)).

  Furthermore, depending on the applied injection method, the stage length injection speed corresponds to the ground conditions, and the injection speed and injection time are set differently (Table 11). Is made. As described above, the durable silica grout is used to infiltrate and consolidate the silica concentration, compounding formulation, and predetermined injection area within the limit speed range of soil particle infiltration in accordance with the ground conditions and the injection method. It must be an injection material with gelling properties.

(5) Table 12 shows the injection hole interval, the length of one stage, the area of each piece (in this case, square for ease of calculation), the amount of soil that can be carried on one stage, and the amount of injection per stage. Examples of the injection time according to the injection speed of point injection and columnar injection will be shown.

(6) Fig. 28 shows an example of grounding that is easily affected by groundwater, in which the consolidation strength and the pH of the consolidated ground are equalized in consideration of the gel time and silica concentration during the injection process.

(Example 1) Table 12 will be described below as an example.
Point injection: Example of simultaneous injection construction (see Fig. 60 and Fig. 83 (a))
Table 12 injection hole spacing 1.5m in (a), one stage length 0.5 m, the case of consolidation per minute infusion rate 1L / min, 1 present per charge amount of soil 1.13 m ^3, the injection amount per stage 452L, injection time H takes 452 minutes. A total of 1350L can be injected in 452 minutes by injecting 3 injection points of 0.5m at a time of 1.5m.
That is, if the injection stage is 1.5 m and 1350 L is injected in 1350 minutes at 1 point injection at 1 L / min, the same injection can be injected in 452 minutes.
If the injection time per stage is shortened, the gelation time is shortened, the pH tends to be near neutral, and the strength increases.
As the injection solution, in FIG. 4, the silica concentration was 5%, pH ₀ = 3.0, GT ₀ = 3000 minutes, injection rate 1 L / min,
If the soil gelation time GT _S0 = 200 minutes, soil pH _S0 = 4.5, H = 452 minutes,

([Equation 1] [Equation 4] falls within the range of equation (2))

It becomes.
While this injection solution permeates the injection length (0.5m) of 1.5m / 3 over 452 minutes, the pH rises and the gelation time is shortened. It permeates and solidifies (consolidation example Fig. 84 (b), Table 12).

Example of columnar injection method (Fig. 82 (c), Fig. 83 (b) and Fig. 84 (c))
In Table 12, assuming that the injection hole interval is 4.0, the length of one stage is 2.0 m, the injection speed is 25 L per minute, the injection time is 512 minutes, and the injection solution is silica concentration 6%, pH ₀ = 3.0, GT ₀ = 1000 minutes in FIG.
Gelation time in soil GT _S0 = 150 minutes pH _{S0 in} soil was 3.7.

([Equation 1], [Equation 4] and fall within the range of equation (2))

This injection solution expands the injection range while infiltrating the injection length (2 m) of 4.0 m / 2 over 512 minutes, expanding the injection range while causing gelation while causing the phenomenon of FIG. This is an example of solidification that penetrates into and solidifies.

From FIG.

From Table 12 (b)

Together, the above

That is,
β = 0.68-0.34

Therefore,
2.94H> GTs ₀ > 0.21H
That is,
3H> GT s ₀ > 0.2H
It was found to be in the range.

(Example 2)
The following is an example when the ground is inhomogeneous or when the injected liquid tends to deviate under groundwater conditions, it may be easily diluted with groundwater. (Claim 5)
Therefore, the injection ground was divided into three regions as shown in FIG. 28 from the chemical solution discharge port, and the chemical solution was mixed and injected into each region. FIG. 28 (b) shows a cross section per stage of the injection ground shown in FIG. 28 (a). When the injection holes are embedded at intervals of 4 m, the penetration distance of the chemical discharged from the injection tube is 2 m (FIG. 29 (a) is actually arranged so as to be doubled as shown in FIG. 29 (b) or FIG. 81. ).
In this injection region, without escaping outside the injection range, each region is consolidated within about one day after the injection, and the uniaxial compressive strength of the consolidated body is almost uniformed to be about 0.1 MN / m ^2. Add chemicals.

A ground far from the discharge port of the injection tube and having an outer peripheral portion of 0.6 m is defined as a region (3). Conventionally, in this area, the chemical solution injected in the initial stage is neutralized by the reaction with the water in the ground and the ground, and the strength of the ground where the silica content is diluted and solidified by the water in the ground. However, there are problems such as reduction and unconsolidation. Therefore, injection is performed in consideration of the 2.0m test result of the penetration test using on-site sand.
In FIG. 28 (b), in the injection region (3), the silica concentration is increased to 6%, and the pH is decreased to ₀ .

In the area (2) of 0.6 m away from the discharge port, the alkaline content of the ground is neutralized by the chemical solution injected at the initial stage, and the dilution is small. Subsequent silica pH is reduced in rise and gelling time is reduced. Therefore, the silica concentration is 5%. In the region (1) near the discharge port, the pH of the homogel approaches from the neutral to almost the pH of the homogel in the ground by the previously injected chemical solution, and there is almost no dilution. Therefore, make pH ₀ close to neutral and make GT ₀ short.

Hereinafter, the specific injection | pouring method and the compounding method of a chemical | medical solution are described. (Figure 28 (b))
In actual injection, by managing the injection time of the chemical solution in each improved region, it is possible to inject by changing the composition of the chemical solution for each region.
The calculation of the chemical solution injection time was performed as follows.
[Calculation of injection time at each stage]
1. 4m embedding interval between injection pipes
2. Injection volume Solid body P = 2m × 2m × 2m × 4 / 3π = 33.49 (m ³ )

  The injection length per stage and the discharge amount per minute are determined by the injection method as shown in Example 1. Here, a spherical solid body with a diameter of 4 m is obtained, and the length per stage is 2 m. The speed is 8L / min.

The injection method is point injection of the double packer method shown in Table 11. 82 (c), (d) and FIG. 83 (b) may be used. When using other injection methods, as shown in Table 12, the optimum stage length may be determined according to the blending gel time, silica concentration, and injection method, and the injection speed, injection time, and soil gelation time may be set.
Depending on the injection method, the length of one stage can be set as follows, and the injection speed per each stage can be determined according to Example 1.

Point injection, multi-point injection 0.33m, 0.5m, 1.0m, 1.5m, 2.0m
Exppacker method 0.5m, 1.0m, 1.5m, 2.0m, 3.0m, 4.0m

3. Improved soil volume in area (1) (m ³ ) V (1) = 0.8m × 0.8m × 0.8m × 4 / 3π = 2.14
4. Improved soil volume in area (2) (m ³ ) V (2) = 1.4m x 1.4m x 1.4m x 4 / 3π) V (1) = 9.35
5. Improved soil volume in area (3) (m ³ ) V (3) = (2m x 2m x 2m x 4 / 3π)-(1.4m x 1.4
m × 1.4.m × 4 / 3π) = 22.00
6. Injection rate 0.35-0.40
7. Injection volume of chemical in area (1) (kl) Q (1) = V (1) × 0.35-0.40 = 0.75-0.86
8. Injection volume of chemical in area (2) (kl) Q (2) = V (2) × 0.35-0.40 = 3.27-3.74
9. Injection amount of chemical solution in region (3) (kl) Q (3) = V (3) × 0.35-0.40 = 7.70-8.80
10. Injection speed 8 (l / min)
11. Area (1) injection time (min) T (1) = Q (1) / injection rate = 93.75-107.5
12. Region (2) injection time (min) T (2) = Q (2) / injection rate = 408.75 to 467.5
13. Area (3) injection time (min) T (3) = Q (3) / injection rate = 962.5-1100

  Table 12 shows formulation examples of chemical solutions to be injected in three stages based on the calculated injection time. Further, one day after the injection, the solidified body in each region was sampled, and the uniaxial compressive strength and pH were measured.

In the above, the composition to be injected into the region (1) is set at a relatively low silica concentration of 4% and a pH of 4 to 4.5 because there are a large amount of silica molecules in the ground due to the preceding injection solution. And set higher. This formulation usually has a gel time of about 200 to 300 minutes as shown in Table 4 in the state of a homogel, but in the ground it is thought that a gel time of about 500 minutes is required because the pH is lowered by the chemical solution in the previous stage. It is done.

[Durable ground improvement method and injection management]
As described above, in order to infiltrate and consolidate without deviating to a predetermined region, the relationship between pH and silica concentration as described above, the composition and concentration of the liquid mixture corresponding to the injection purpose and the injection method, and the gel time of the injection liquid The gel time in the soil, the injection speed, and the injection time will be set, but the gel time will be set temporarily considering the diversity of the ground and soil properties, the flow characteristics of the injected solution, and the chemical reaction of the injected solution with the soil. Since it is difficult to homogenize the ground by primary injection, and to homogenize the ground by coarse filling injection by primary injection to make the injected ground into a ground with a hydraulic conductivity that does not easily flow down into the predetermined area after the acidic silica grout is injected. Sampling after injection together with the above-mentioned pre-injection test, infusion solution design, and management of infusion fluid flow during infusion (Figs. 60-78), such as using techniques to reduce excessive water permeability (Fig. 16) by By analyzing the silica concentration (Fig. _{58), GT 0, GT S0} , pH 0, pH S0, H and confirmation of check and osmotic consolidation and strength the relationship between injection amount and the like, FIG. 29 (a), ( b), and compared with the pre-injection test above, it is desirable to apply the gel time pH ₀ and GT _S0 for the site to the site by setting the injection volume, injection rate, and injection time H at the injection stage. I understand that. (Claims 15 to 23)

The present invention is used for ground improvement of large-capacity soil, such as ground improvement for liquefaction prevention construction and rapid construction in large-scale construction, and in particular, the injection liquid is in a wide range of penetration consolidation with an injection hole interval of 1.5 to 4 m. It is required to be osmotically consolidated without deviating within a predetermined range and at an optimum amount and injection rate at each adjacent injection stage without deviating outside the injection range. For this reason, using the above-mentioned durable silica grout, the gelation time GT ₀ and pH ₀ of the compounded solution should be improved when injecting the silica solution taking into account the gelation time in the soil (GT _S0 ) and the injection time (H). A plurality of injection pipes are installed on the ground, and when the above injection liquid is simultaneously or selectively injected from the plurality of injection pipes, the injection from the plurality of injection pipes is simultaneously managed to control each injection stage. An injection management method that grasps in real time that the injection is infiltrated into each injection region must be applied. (Figs. 60-84)

Moreover, it is necessary to visualize by the three-dimensional construction management so that it can be confirmed that the injection solution which has been gelled due to the gelation time in the soil is appropriately injected into each injection stage. As a result, the plurality of stages can be continuously improved both in plan and in cross section as shown in FIG. 29 (b) without the injection solution deviating (FIGS. 60 to 73).

60 and 61 include a centralized management device 26 that improves the ground by injecting silica injection solution into the ground, and an injection monitoring panel (FIG. 62) connected to this device . When the flow rate pressure detectors f and P are respectively injected into a plurality of injection stages in the ground through a plurality of injection solution feeding pipes, the flow rate, pressure and / or integration of the injection solution detected by the flow rate pressure detectors f and P. The injection amount data signal is input to the central control device 26, and further, the data signal input to the central control device is displayed on the injection monitor panel (FIG. 62) (FIGS. 63 to 73). Based on the information of the data, it is configured to collectively monitor the injection status at each injection stage from the injection liquid feeding pipe on the screen and manage the injection.

  Furthermore, according to the injection management method of the present invention, when injecting into a plurality of injection stages in the ground through a plurality of injection liquid feeding systems, a representative injection region is set in a predetermined injection region of the ground. An appropriate pressure and / or flow rate at each injection stage where the injection region is located is measured, and an appropriate range of the obtained value is set in a centralized control device equipped with an injection monitoring panel. Injection at each injection stage in the injection region can be performed.

Furthermore, according to the present invention, when injecting the ground infusion liquid into the plurality of injection stages in the ground through the plurality of infusion liquid feeding pipes, it was detected from the flow rate pressure detector provided in the plurality of infusion liquid feeding pipes. The infusion pressure and / or flow rate data is sent to a centralized control device equipped with an infusion monitoring board, and these data are displayed on the infusion monitoring board for batch monitoring of the infusion status. While injecting while maintaining each injection pressure and / or flow rate within a predetermined range, the injection can be completed, stopped, continued or reinjected based on the information of the data. (Claim 25)

Thus, the following durable ground improvement is attained by this invention.
(1) An economical formulation can be determined by quantitatively evaluating the durability according to the purpose of injection.
(2) In the active composite silica, silica sol, or active silica colloid, it is possible to determine an economical composition by quantitatively evaluating the durability according to the purpose of injection. (Claims 11-14, 16-19)
(3) The durability level is quantified for the strength reduction rate of the consolidated soil, the volume change of the homogel, and the leaching of silica from the consolidated body (homogel or sand gel). It can be used as an evaluation standard for ground injection.
(4) Quantification values can be corrected based on actual results and research.
(5) Durability can be quantitatively evaluated according to the period related to durability.
(6) In the active composite silica, the volume shrinkage can be adjusted by the content of the silica colloid, and the strength reduction rate can be improved.
(7) The improvement strength can be adjusted by the concentration of water glass (silica sol).
(8) In the active composite silica grout, the amount of colloid used can be determined according to the durability level, and the amount of water glass used in the injection material can be adjusted according to the target strength.

It is the graph which showed the range with the possibility of liquefaction regarding the particle size etc. of sand. It is the graph which showed the particle size accumulation curve of on-site sand. It is a graph which shows the relationship between the pH of the silica solution of durable silica grout, and gelation time. It is a graph which shows the example of the gel time of non-alkaline silica solution, pH, and a silica concentration. It is a graph which shows the gelatinization time of non-alkaline silica sol. It is a graph which shows the gel time of the homogel and sand gel of a silica sol grout. It is a graph which shows the relationship of pH, air gel time, and soil gel time of a non-alkaline active composite silica grout. It is a graph which shows the relationship between the silica density | concentration of active composite silica, and the air gel time. (a) is a graph showing the relationship between the pH of the soil and the gel time in the soil of the active composite silica, and (b) is a graph showing the relationship between the pH of the active composite silica and the pH of the consolidated soil. It is a graph which shows the influence which Ca content has on the gel time in soil. It is explanatory drawing of the penetration | invasion theory of Maag. It is a graph of a spherical penetrating radius estimation calculation (Maag's equilibrium formula). It is a graph which shows the relationship between the injection | pouring time and penetration radius in Maag's formula. It is a graph which shows the estimation calculation (Theim's equilibrium formula) of a columnar penetration radius. It is explanatory drawing of the limit injection | pouring speed | velocity | rate between soil particles. It is explanatory drawing of the deviation prevention by a compounding composition. It is explanatory drawing regarding the permeation consolidation method of a silica grout. It is explanatory drawing of the test apparatus regarding osmosis | consolidation consolidation. It is explanatory drawing of the test apparatus regarding osmosis | consolidation consolidation. It is explanatory drawing of the relationship between air pH and air gel time, soil pH and soil gel time, osmosis distance, injection time, etc. It is explanatory drawing of the change of pH of an injection solution, and gel time. It is explanatory drawing of the change of pH of an injection solution, and gel time. It is a graph which shows the relationship between the osmosis | permeation distance of an osmosis solidified body, and pH. It is a graph which shows the relationship between the outflow amount of injection liquid, and pH. It is a graph which shows the uniaxial compressive strength of an osmosis solidified body, and a permeation distance. It is a graph which shows the relationship between the gel time and pH of a homogel, the gel time in the soil of sand gel (in-situ sand), and the pH in soil. It is a graph which shows the example of the relationship between the gel time of a homogel, pH, and a silica density | concentration, and the change of gel time and pH when diluted with groundwater. It is explanatory drawing regarding the method on the ground conditions which an injection material deviates to a target range, or is easy to be diluted. (a) is a plan view with respect to (cross-sectional view) of FIG. 28 (a), (b) is a plan view of an example showing a sampling position after injection, and (c) is an example of an injection cross-sectional view. It is a graph which shows the relationship between reaction material addition amount, pH, and gel time. It is a graph which shows the example of the relationship between the kind of acid in non-alkaline silica grout, and gelation time. It is a graph regarding the amount of dissolution of silica. It is a graph of the time-dependent change (9,000 day measurement result) of the leaching rate of the silica from the homogel in long-term curing. (a) is a graph of the volume change (9,000-day curing) of the homogel of the silica sol injection material, and (b) is a graph of the volume change (9,000-day curing) of the active silica colloid (CSN injection material). It is a graph regarding the long-term strength of a sand gel. It is a graph regarding the laboratory test result of various silica grouts, strength expression, and the mechanism of strength reduction. It is explanatory drawing regarding the example of a time-dependent change of the intensity | strength of the consolidated soil by the silica grout from which durability evaluation differs according to a durable period, and time improvement. (a) is a bar graph of the results of long-term permeability test for a number of days when water permeability was maintained for a long period of time when water permeated to consolidated Toyoura sand at a hydrodynamic gradient of 50, and (b) is various silica grouts under hydrodynamic gradient of 50 It is a water permeability test result of solidified standard sand. It is a graph regarding the uniaxial compressive strength of consolidated Toyoura sand (sand gel) by active composite silica. It is a graph which shows the relationship (AS) of pH and gel time according to concentration. It is a graph regarding the time-dependent change of a homogel volume change rate. Type of base material is a graph of the effects on the volume change of Homogeru (SiO ₂ = 12%). It is a graph showing the final volume variation of the relationship SiO ₂ concentration and Homogeru. It is a graph which shows a time-dependent change of the uniaxial compressive strength of a homogel. It is a graph which shows the relationship between the uniaxial compressive strength of a homogel, and the deformation coefficient of a homogel. Is a graph showing the relationship between the uniaxial compression strength of SiO ₂ concentration and Homogeru. It is a graph which shows the relationship between homogel strength and the fracture strain of a homogel. It is a graph of a particle size accumulation curve. It is a graph which shows a time-dependent change of the uniaxial compressive strength of a sand gel. It is a graph which shows the relationship between the uniaxial compressive strength of a sand gel, and a deformation coefficient. It is a graph regarding the uniaxial compressive strength of a homogel and a sand gel. It is a graph regarding the uniaxial compressive strength of silica concentration and sand gel. (a) It is a graph regarding the final volume change rate of a silica concentration and a homogel, (b) It is a graph regarding the strength ratio of a silica concentration and a sand gel. It is explanatory drawing regarding the relationship of the deformation | transformation coefficient of a homogel, a volume change rate, and the strength reduction of a sand gel. It is a graph of the estimation of the time-dependent change of the intensity | strength of consolidated Toyoura sand by the acceleration test by a heat curing. It is a graph of the estimation of the time-dependent change of the intensity | strength of consolidated Toyoura sand by a heating accelerated test. It is a graph of an acceleration test (silica sol). It is explanatory drawing regarding confirmation of the improvement effect by the amount analysis of silica. It is explanatory drawing and graph regarding the analysis result of a masking silica produced | generated on the concrete surface, and X-ray diffraction. It is explanatory drawing regarding the injection | pouring management in an injection | pouring field. It is explanatory drawing regarding the injection | pouring management in an injection | pouring field. It is explanatory drawing which shows the example of a ground improvement management system. It is an operation flowchart of a centralized management apparatus. It is a graph which shows the relationship between a flow volume and injection | pouring pressure, the soil particle | grain penetration limit injection | pouring speed | rate, and limit pressure. It is explanatory drawing of the injection | pouring block division of an injection | pouring area | region. It is the figure which displayed the injection pressure P with respect to time t, the flow volume Q, and the integrated flow volume for every stage. It is explanatory drawing which shows the injection pressure of each stage for every injection hole. It is explanatory drawing in the case of injecting by calculating the ratio of the actual integrated flow rate to the design integrated flow rate of each stage for each injection hole. (Cross section) It is explanatory drawing in the case of injecting by calculating the ratio of the actual integrated flow rate to the design integrated flow rate of each stage for each injection hole. (Plan view) It is explanatory drawing of each stage injection pressure and an actual integration flow rate for every injection hole. (Cross section) It is explanatory drawing in the case of injecting by calculating the ratio of the actual integrated flow rate of each stage for each injection hole. (Plan view) It is explanatory drawing which shows the injection | pouring order of the injection | pouring stage of the uppermost improved ground. (Cross section) It is explanatory drawing which shows the injection | pouring order of 3 steps | paragraphs of injection | pouring stages. (Cross section) It is a graph regarding the relationship change with the silica density | concentration of the electrical conductivity of the injection liquid using a silica solution. It is explanatory drawing at the time of carrying out injection | pouring management so that a ground sensor may be provided in the structure of the injection | pouring area | region vicinity, and the displacement of a structure may be settled in an allowable range. It is a flowchart of a ground displacement management system. It is explanatory drawing of the electrical conductivity meter or pH management system of an injection solution. It is explanatory drawing which shows the example of the density | concentration measuring apparatus of a ground injection liquid. It is the conceptual diagram which put together the requirements in the durable ground improvement construction method as an integrated technology, elemental technology, and the relation between each other. It is a conceptual diagram regarding a consolidation diameter, injection amount, and injection time. It is a conceptual diagram regarding injection | pouring management and subsequent quality control. It is explanatory drawing of various rapid osmosis injection construction methods. (a) is a diagram showing an osmotic consolidation model of a multi-point simultaneous injection method, and (b) is a system outline diagram of a columnar osmotic injection method. It is explanatory drawing of the consolidation state in construction results. (a) is a graph for demonstrating aged solidification of consolidated ground with active composite silica, and (b) is a graph for the effect on the liquefaction strength of the Great East Japan Earthquake.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. (Claim 25)

  When injecting ground infusion solution from an infusion pump through multiple infusion fluid delivery systems to multiple infusion points in the ground, one or more representative infusion points are set in a predetermined infusion area of the ground. An appropriate pressure and / or flow rate at each injection stage where the injection point is located is measured, and an appropriate range of the obtained value is set in a centralized control device equipped with an injection monitoring panel, and a predetermined range is determined based on the set range. Injection at each injection stage in the injection region can be performed.

  Furthermore, according to the injection management apparatus of the present invention, the central management apparatus and the injection monitoring panel connected to the apparatus are provided, and the plurality of injection liquid supply systems having the flow rate pressure detector from the ground injection liquid to the injection pump. When injecting into a plurality of injection points in the ground through the injection pressure and / or flow rate data signals detected by the flow rate pressure detector, the central control device is further input, and the injection monitoring panel The data signals input to the central control device can be displayed on the screen, and the status of injection from a plurality of injection liquid feeding systems can be collectively monitored to manage the injection.

  Furthermore, in the ground injection method that injects the ground infusion solution into multiple injection stages in the ground through multiple infusion fluid delivery systems, each of the multiple infusion fluid delivery systems is provided with a flow pressure detector and detected from these detectors. The injection pressure and / or flow rate data of the injected liquid is sent to a central control device equipped with an injection monitoring panel, and these data are displayed on the screen of the injection monitoring panel to monitor the injection status in a batch and send the liquid. While injecting while maintaining the respective injection pressures and / or flow rates in the system within a predetermined range, the injection can be completed, stopped, continued or reinjected based on the information of the data. FIG. 60 shows a part of the ground improvement system in the present invention by the ICT of FIG. 62 (b).

  60 and 61, when injecting the ground infusion liquid from a plurality of infusion pumps to a plurality of different infusion points 5a, 5a,. The flow rate and / or pressure data of the infusate detected from the flow rate pressure detectors f and P is transmitted to the central control device 26 and displayed on the screen of the infusion monitoring panel to display the construction status. By such data display on the screen, the injection status is collectively monitored to manage the injection of the injection solution, and, for example, as shown in FIG. 60, the first improvement block and the second improvement block are formed.

  A printer is connected to the daily report creation device and the daily report creation device to the central management device 26, and a daily report is created and printed out by the printer.

  62 and 63 show an operation flow chart of the centralized management device 26. FIG. First, the pressure specification value (appropriate pressure range) and the specified injection amount (appropriate integrated injection amount range) of the injection specification file for No. 1 to No. 10 of the liquid supply pipeline, that is, the desired injection pressure and flow rate (units) (Flow per hour and / or integrated flow) is set in the central control unit 26 in advance (system specification setting registration), and then the No. 1 to No. 10 start switch 14 of the central control unit 26 is turned ON to record data To start.

  At this time, the construction display panel X5 is also turned ON by the lamp 15. In the injection monitoring board, the injection data from the injection liquid feeding pipe is displayed on the screen, and when these data reach the set value, the central control device 26 outputs a completion signal and displays it on the injection monitoring board. At the same time, the completion status is displayed on the construction display panel X5 by the lamp 15, and a signal for closing the stop valve 28 of the liquid supply line is output.

After the injection of all the liquid supply pipes is completed, the recording of data by the central control device is completed by turning off the start switch of the central control device. Based on these recorded data, a daily report is created by a daily report creation device and printed out by a printer.

  In this way, the relationship between the pressure and the flow rate at each injection stage of the plurality of liquid supply conduits can be grasped in real time, and the injection can be managed so as to be within a predetermined setting range. Furthermore, the centralized management device can also create reports such as injection specification files, injection result lists, injection charts, daily schedules, weekly schedules, monthly schedules, and analysis data.

  Thus, for each injection stage in each injection hole, the block No., injection hole No. and stage No. At the same time, pressure, flow rate, and chart can be displayed (FIGS. 60 and 61) (FIGS. 60 and 65).

  Furthermore, from these data, the injection pressure P, the flow rate Q, and the integrated flow rate (l) with respect to time t can be displayed for each injection hole and for each stage (FIG. 66).

  In addition, for each injection hole, the ratio of the actual integrated flow rate to the design integrated flow rate of each stage is calculated, and as shown in FIGS. 65 to 69, the horizontal surface for each stage (FIG. 69) for each injection region section. And a vertical plane (FIG. 68) are shown in a plane, so that a zone with insufficient injection can be identified and the region to be reinjected can be known. 68 is a cross-sectional view taken along line AA of FIG.

  FIG. 70 is an example of a screen in which the injection pressure distribution and the integrated flow rate at a plurality of injection points (each injection stage) in the vertical direction in the ground are represented on the injection monitoring board. In FIG. 70, the integrated flow rate at each injection stage is also displayed. Therefore, by this screen display, the injection pressure and the integrated flow rate at each injection stage are displayed on one screen, and the injection is managed by collective monitoring.

  FIG. 71 is an example in which the integrated injection amount of the horizontal section at a specific injection stage in the ground is planarly displayed on one screen. By this screen display, the integrated flow rate at each injection point in a specific injection stage is displayed on one screen, and injection is managed by collective monitoring.

  FIG. 67 is an example of a screen in which the injection pressure distributions at a plurality of injection stages in the ground are three-dimensionally displayed on the injection monitoring board X2. By this screen display, the injection pressure at each injection stage is displayed three-dimensionally, and injection is managed by three-dimensional batch monitoring. Similarly, the integrated flow rate can also be displayed three-dimensionally to manage the injection status.

In this way, the region where the injection pressure has increased excessively and the injection amount was insufficient can be grasped in three dimensions. In this case, the injection pressure is decreased and reinjection is performed until a predetermined amount is injected. Furthermore, it is possible to grasp that the injection pressure is too low even though a predetermined amount of injection has been performed. In this case, it can be found that the injection has deviated or the set value is too low. The injection effect can be ensured by taking measures such as injecting the optimal integrated flow rate by changing In addition, in order to determine the effect after injection, the resistance pressure of the injection ground in each injection region is measured within the limit pressure and limit flow rate of curve 2 in FIG. 67, 68, and 69, the injection effect of the entire injection region can be grasped and reinjected into an insufficient portion to obtain a predetermined injection effect.

  60 shows an example in which injection is performed at the injection points of the first injection block and the second injection block in FIG. In general, alluvium is stagnant horizontally, so the hydraulic conductivity in the horizontal direction is larger than that in the vertical direction. Therefore, in FIG. 60, the soil layer of the first stage has almost the same hydraulic conductivity near any outlet, for example, sand, and the soil layer of the nth stage also has almost the same hydraulic permeability near any outlet. For example, fine sand (FIGS. 72 and 73).

  Appropriate pressure, flow rate, and integrated flow rate in each of the above-described injection stages are measured by measuring the pressure and flow rate with a centralized control device. In this case, the appropriate pressure, flow rate, and integrated flow rate can be determined by adding the measurement value obtained by the actual injection to the measurement value obtained by the injection test and correcting the value.

  In the test injection hole, at each stage or at a representative stage, prior to injection, a water injection test or an injection test with an injection solution having a long gelation time was conducted, and a Pq curve (curve 1) shown in FIG. And 2), ie a P (injection pressure P) -q (flow rate 1 / min) curve.

In FIG. 64, up to curve 1 and O1 point, the injection speed and the injection pressure are in a proportional relationship, and ground destruction does not occur, and complete osmotic injection is performed. Up to this point is the limit pressure or limit flow rate. However, the injection speed (flow rate) and the injection pressure are not proportional to the points O1 to O2, and partial splitting occurs, but there is no decrease in injection pressure at which the ground breaks down and the injection solution escapes. The injection pressure at the O2 point may be referred to as a limit injection pressure Pro and a limit water injection speed (or limit injection speed) (flow rate) qr0, but the former is preferred. In this way, the limit injection pressure Pr0 and the limit injection flow rate qr0 (injection speed) at which the ground breaks can be known. However, it is preferable to inject within the flow rate and injection pressure in the linear region up to O ₁ . In order to know whether the injection effect is sufficient or incomplete, or when reinjecting when it is determined that the injection effect is incomplete, a resistance pressure is usually applied, so the relationship of curve 2 is obtained.

  As described above, it is possible to know the limit injection pressure and the limit injection speed (flow rate) that can be injected without destroying the ground in each stage, thereby knowing the appropriate injection pressure range or the appropriate injection speed range of each stage. it can. This numerical value is stored in the centralized management device 26, and injection management is performed by performing injection at that stage so as to maintain this appropriate range.

  As shown in the operation flow chart of the central control apparatus in FIG. 63, when the integrated flow rate reaches this appropriate range, the injection at the injection stage is completed at that time. Also, if the appropriate injection pressure is exceeded before the set integrated flow rate is reached, the injection at that stage is also terminated. The set value of the appropriate injection pressure or injection rate can be corrected while the injection process is in progress. The reason for this is that during the injection process, during the injection of the same stage, due to the influence from another injection stage, and further due to the partial penetration of the injection liquid from other injection holes, an interference effect is caused.

  Also, by selecting the injection order of the injection points, or by selecting the injection order of the injection blocks, the ground is strengthened by the preceding injection, so that the subsequent injection increases the injection pressure by the restraining effect. Can be injected without destruction. The same applies to reinjection when the injection amount is insufficient.

In the above-described case, in FIG. 64, the penetration crack injection region has a linear relationship up to the point O1, but is not a straight line between the point O1 and the point O2, but is partially split. However, Prf at the O1 point is the limit pressure and qrf is the limit injection flow rate. In this way, the final limit injection pressure and the limit injection flow rate (injection rate) are set as Prf and qrf, respectively, and the design injection amount (integrated flow rate) is injected within the limits. These values are stored in the central control device X1, and when the design flow rate is injected, the injection is terminated. If the limit injection pressure is reached before the design flow rate is reached, the injection is terminated at that point. To do. In this way, it is possible to obtain a reliable injection effect by setting an optimum range for the injection process.

If the injection pressure does not increase at all during the injection, or if the injection pressure is increased too quickly during the injection and the injection is stopped, the injection is expected to be insufficient. It is also possible to cut the target or planarly (FIGS. 67 to 71) and reinject into that region. 68 and 69, even if the injection is completed by injecting a predetermined amount, if it is determined that the injection is insufficient from the state of the injection pressure, the setting value can be changed and the injection can be continued. The injection can be continued by switching. In addition, even if the injection pressure exceeds the set value during injection and an injection interruption signal is given, if it is determined that the injection is insufficient from the injection volume, the injection pressure is changed or the injection pressure is changed to manual injection. It is also possible to continue the injection, and the injection can be continued by instantaneously reducing the set value of the injection amount. 68 and 69 calculate the ratio of the actual integrated flow rate to the designed integrated flow rate for each stage, and display the horizontal plane (Fig. 69) and vertical plane (Fig. 68) for each stage for each injection area section. As a result, the region to be reinjected can be known. In the above, since the injection seems to be incomplete in the already injected region, a resistance pressure is generated when the reinjection is partially consolidated. In this case, the injection solution is injected before injection by the same principle as curve 2 in Fig. 64 to create a pressure distribution for the specified injection speed at the injection stage (Fig. 64, curve 1), and adjustment of the consolidated ground after injection In FIG. 64, a resistance distribution is created by injecting at a predetermined injection speed with an injection liquid (FIG. 64, curve 2), and the injection effect in the injection region can be confirmed. In the above, a water injection test can be performed instead of the injection liquid, but the ground can be prevented from being destroyed by the water injection test in the injection liquid injection test.

  In this way, a slab that is planarly achieved for each stage is formed by permeation consolidation by simultaneous injection or selective injection from the discharge port. This consolidated layer is continuously formed from the first stage to the nth stage. Furthermore, the permeation consolidation by simultaneous injection from the discharge port can be formed in the vertical direction, and further, can proceed simultaneously in both the horizontal direction and the vertical direction. It is also possible to selectively inject from the discharge port or from the discharge port opened in a portion having a large water permeability (FIGS. 72 and 73).

  The principle of the injection method is to replace the water in the soil particle gap with the injection solution. For this reason, in the simultaneous injection method, even if simultaneous injection is performed from a large number of outlets to a large volume of soil, if the soil water loses its escape space due to the injected liquid, water pockets are created in the ground, or the injected liquid is water. Once diluted, the intended injection cannot be achieved. In order to prevent this, as shown in FIGS. 72 and 73, assumed improvement blocks (1), (2), (3), (4), (5) having substantially the same soil conditions on the ground to be consolidated. ), And from a plurality of discharge ports (not shown), the ground improvement water (1) and (2), which are determined at intervals, are simultaneously injected to remove the groundwater from the block, and then the assumed improvement block ( 3), (4), and (5) can be simultaneously injected in the same manner as described above to remove the groundwater from the block, and the whole can be consolidated sequentially to consolidate almost the same soil layer while releasing the groundwater. .

  In addition, as shown in FIG. 73, when the injection region is divided into several blocks and the injection sequence is set so that the groundwater can easily escape, and when a predetermined injection pressure or a predetermined integrated injection amount is reached, Fully automatic injection is possible by injecting so as to shift to the injection of the block. Depending on the purpose of injection and the ground conditions, the ground can be effectively strengthened by selecting the injection order so that the preceding injection section constrains the injection section to be injected later.

  The silica injection solution used in the present invention can set the gelation time from several seconds to several tens of hours, so there is no concern about gelation even if a large amount of injection solution is prepared and a large amount of injection solution is used. There is an advantage that the liquid can be fed over a long period of time, and after being injected into the ground, it is surely gelled, further having a low viscosity and less stickiness.

FIGS. 60 to 78 show specific examples of the on-site sampling soil blending design method and the confirmation management of seepage consolidation in a predetermined area. In the present invention, it is possible to continue the injection while checking the state of the ground uplift. For example, in the apparatus of FIG. 75, a ground elevation sensor is installed on the ground surface (FIGS. 60 and 61). In this case, when the ground uplift range is set to 5 to 20 mm in advance in the specification settings, the electrical signal from the ground uplift sensor is transmitted to the central control device, and if the uplift exceeds 20 mm, the infusate liquid supply line The injection from is stopped. However, if the ridge is within the range of 5 to 20 mm, this is an acceptable range, and the ridge within the range indicates that the reaction for ground strengthening is surely performed. In addition, by providing this ground sensor in the structure near the injection region, the injection can be managed so that the displacement of the structure falls within the allowable range (FIG. 75).

  60, 61, 75, and 76 show a durable ground improvement method in which a silica injection solution is injected into each injection step from an injection material supply unit equipped with a control device. A level sensor is arranged at an injection site or an arbitrary place around the injection site and the displacement amount of the level sensor is measured, and the measured value of the displacement amount is transmitted to the control device of the injection solution supply unit. The control unit in the material supply unit automatically selects and injects each data of the composition of the injection solution, gel time, injection amount, and discharge amount of the injection material supply pump according to a program set in advance based on the measured value. The injection material is supplied from the material supply unit, and the composition, gel time, and injection amount of the injection material are adjusted so as to minimize the deformation of the ground surface and surrounding structures and the escape of the injection liquid to the injection target area. can do. FIG. 76 shows a flowchart for managing ground displacement.

  Furthermore, in the present invention, injection of any one of the plurality of injection liquid supply systems S, S... S is completed and connected to the next injection pipe 5 or the injection pressure is higher than the limit value. In the case of re-injection after interruption of injection, the liquid supply system S is washed with water in order to prevent the injection liquid from gelling in the liquid supply system S. In this case, it is necessary to set a characteristic for determining whether the amount of liquid to be injected or the amount of water to be washed.

  The characteristics indicating the difference between water and the injected liquid are, for example, pH, electrical conductivity, density, and the like. Therefore, a sensor related to these, that is, a pH meter, an electrical conductivity meter, a density meter, and the like may be provided in the infusate feeding line. FIG. 74 is an example that makes it possible to distinguish between water and injected liquid based on electrical conductivity.

In addition, by measuring the electrical conductivity of the underground liquid that has escaped to the ground surface, whether the groundwater has overflowed to the ground surface, the injection liquid has overflowed, or even in the case of the injection liquid, the concentration of the silica solution depends on the conductivity. It can be seen that the silica content present in the ground is calculated. FIGS. 77 (a) and (b) show the pipe X for injecting the chemical into the ground, and the pH value or electrical conductivity of the chemical arranged at any location of the pipe X. A pH detector or an electrical conductivity detector is shown. By this, the injection amount can be measured by judging the pH value of the chemical solution (or the gelation time, the injection solution and the amount of liquid to be washed with water). It is possible to control the concentration of the silica solution from the pH detector and the electric conductivity detector as shown in FIG. 75, and it can be injected into the ground under sufficient control.

FIG. 74 is a graph showing the state of change in conductivity when the silica solution obtained by neutralizing an alkali in water glass with an acid was diluted with water. Distilled water is 0.01μ, tap water is 119.5μ
Conductivity. Therefore, in FIG. 60 and FIG. 61, even when the infusion solution feeding pipe line where the infusion is completed is washed with water or when the gel is clogged in the infusion solution feeding pipe line, the detection value is 1 ms / If it is equal to or less than cm, it is regarded as washing water, the injection solution is identified, and the injection amount is grasped. Note that this conductivity differs depending on the injection liquid or the washing water, and therefore, a range to be measured and identified in advance may be recognized and registered in the system specification setting of FIG.

  Of these, the density meter is illustrated. FIG. 78 includes a radiation source for irradiating the ground injection liquid with radiation, a radiation detector for detecting the transmission intensity or reflection intensity of the radiation, and an arithmetic unit for calculating the concentration of the ground injection liquid from this detection value. An apparatus for measuring the concentration of ground injection solution is shown.

A radiation source for irradiating the injection liquid passing through the liquid supply conduit with radiation is disposed on the outer wall of the injection liquid supply conduit. Further, a radiation detector for detecting the transmission intensity or reflection intensity of the radiation is disposed on the outer wall of the liquid supply line facing the radiation source. Furthermore, an arithmetic unit for calculating the concentration of the injected liquid from the detected value is provided to provide a concentration measuring device.

  The radiation source is a gamma ray source, and in this case, the radiation detector is a gamma ray detector. The computing unit is configured to calculate the concentration of the injected liquid from the ratio of the incident intensity and the transmitted intensity of the gamma rays or the ratio of the reflected intensity.

  Furthermore, the radiation source can also be a neutron source, in which case the radiation detector is a neutron detector. The computing unit is configured to calculate the concentration of the injected liquid from the ratio between the incident intensity and the transmitted intensity of the neutron beam or the ratio of the reflected intensity.

  The calculated concentration of the infusion solution or data indicating this concentration is continuously transmitted to the central control device and converted into the density or concentration of the infusion solution by the arithmetic control unit (cpu) in the central control device. Recorded in the central control device at regular intervals. Then, the density of the injected solution can be controlled by setting the density of the injected solution within a range of 1.6 to 2.2, for example.

  As described above, the injection solution can be managed by detecting the pH, conductivity, concentration, and the like of the injection solution. Therefore, the injection liquid data such as the type, concentration, and composition of the injection liquid can be transmitted to the central management device, and the injection management can be performed as the injection liquid data. In the above, even if the detector is not directly installed in the pipeline, as shown in FIG. 19, the injection solution can be extracted periodically from the pipeline via the valve provided in the pipeline or at an arbitrary time and measured. Can do.

  An observation well is provided in the ground, and by measuring the pH value, conductivity, etc. in this observation well, it is found that the injected solution is flowing into the water by concentrating the data. It transmits to a management apparatus, these are displayed on screen as influence data, and injection | pouring can be interrupted based on this and the influence on water can be prevented. Also, as described above, as shown in FIG. 75, not only the above-described ground displacement but also the displacement of the structure can be transmitted to the centralized management device, and when the limit value is reached, the injection can be interrupted to prevent the influence. Therefore, these can be injected and managed as influence data. (Claim 23)

[Data information management and injection automation]
Furthermore, the present invention enables a ground improvement management system in which a predetermined injection is performed in a predetermined injection region using a ground improvement system based on ICT and a predetermined effect can be obtained. (Fig. 60, Fig. 62 (b)
) The data includes ground data, chemical data, injection data, environmental data, etc., and there is a specific example Fig. 62 (b) A group.
These (1) Injection liquid data (2) Injection method and drilling data Block division of injection region or injection hole, injection hole interval, injection pressure, flow rate (injection speed) and integrated flow rate data at each injection stage, etc. Injection data (3) In addition to the above (1) and (2), environmental data, etc. is sent to the data information management center server or cloud in real time from the injection site during construction, and collectively managed for ordering and construction companies , Enabling the field office to grasp the injection status in real time and to hold, share, or disclose or provide data information at any point in time.

  In addition, these site data are analyzed by the data information management center or cloud server, or automatically determined by the data information management center based on a large amount of data collected from many sites already accumulated (Fig. 79) Alternatively, it is possible to give necessary instructions to the site through the Internet and store or disclose it, and confirm that the predetermined injection has been performed in the predetermined injection region, and reinject the insufficient injection region enough An effective injection effect can be obtained.

In this way, the effect shown in the example of group B in FIG. 62 (b) can be obtained. As described above, the infusion liquid data includes, for example, the ground conditions, the composition and composition of the infusion liquid, the silica concentration, the gelation time GT (GT ₀ and GT _S0 ), pH (pH ₀ and pH _S0 ), the injection hole interval, Confirmation of injection effect and injection design data at the injection stage and injection range, distinction of injection liquid and flush water, or determination of the content of overflow water to the ground surface There are judgments. Moreover, it is described in the endurance data of the injection liquid and the injection liquid consolidated soil. The injection construction data (2) above is described above and in FIGS. In this way, injection management capable of ground injection having a predetermined effect in a predetermined region is possible. In addition, in this way, the progress of construction, visualization of the three-dimensional consolidation status and completed shape, quality status, consolidation status in the ground, visualization of the completed shape, visualization of construction contents and process, data during construction Analysis can be performed in real time, and feedback can be instructed to the injection site or the central control device so that the injection speed and the injection amount are appropriately performed for each stage according to the ground condition and the injection situation.

Environmental data includes groundwater pH, ground displacement, structure position and displacement. In this way, from the long distance, the management system shown in FIGS. 60, 61 and 62 (b) manages the data processing of group A information shown in FIG. 62 (b) using signals from the sensors of the measuring instruments at each injection site on the Internet. Centralized management by the center server and analysis based on Group B basic data, evaluation of the construction status, or automatic judgment results and improvement points can be fed back to each construction site. The road to automatic injection by the instruction to the central control device by control becomes possible. In addition, in terms of the displacement amount associated with the injection related to the ground condition and the gel time of the injection material, it is possible to respond to the addition of a sensor or the change of the control program through the actual penetration distance, injection pressure, injection speed, and injection amount.

In addition, information from the data information management center server and the cloud is so large as to be called big data, and selection of information is important for data analysis. For this purpose, quantification of information is important. In the present invention, in (0065) to (0150), the osmotic solidification property in a predetermined region is quantified, and the durability of the injected ground is quantified as shown in Table 4 to facilitate data collection and analysis. . Correspondingly, quantification of silica grout is also described in (0267) to (0294) (Figs. 33 to 57) and (0315 to 0320), (0152) to (0202) are construction management, (0204) ~ (0216) shows the method of confirming the effect (0199) ~ (0202) and Figs. 79 and 81 show the integration of these elemental technologies. Analysis and feedback to the construction site to meet the purpose of injection at this site and share information to make it possible to improve the durable ground. This ground improvement system can be applied not only to the injection of a silica solution, but also to the injection of a chemical solution containing a suspension type grout that contains silica containing cement or slag as a main component and gelation.

[Quality control of injected ground]
As described above, in the present invention, when a ground infusion solution is simultaneously or selectively injected into a plurality of different injection stages from a plurality of infusion solution supply lines, a flow rate pressure detector is provided in each of the plurality of infusion solution supply lines. Since the flow rate signal or pressure signal of the infusion solution detected from these detectors is sent to the central control device, and the infusion status is monitored by recording data and displaying the screen, the infusion is managed. In order to improve the ground by injecting the injection solution into the target soil layer from a plurality of injection pipes installed therein, the injection solution can be simultaneously or automatically at the optimum set flow rate or set pressure, or Selective injection allows reliable injection while reducing deviations at each injection stage, and can improve a wide area of ground quickly and reliably.

As mentioned above, durable silica grout has a wide interval between injections and is required to improve the target ground under various ground conditions. It is necessary to conduct a survey to confirm that the infiltration and consolidation are suitable for the purpose of injection without deviating from (Figure 29).

  FIG. 58 shows an injection plan before injection and quality control after injection. Of these, it is confirmed by quality control afterwards whether or not a predetermined infusion solution has permeated and solidified in the infusion ground (FIG. 81). In order to know the presence or absence of an injection material after injection for a temporary purpose, a sample sample is often judged by a phenol reaction. However, it is necessary to know whether or not the intended strength is obtained in the permanent injection such as the liquefaction countermeasure method. In this case, the strength of the specimen is usually measured by sounding or core boring, but it is often difficult to collect an undisturbed sample when the ground contains a lot of reki or there are many fine particles. . For this purpose, a method for evaluating the improvement effect by silica amount analysis is used (FIGS. 29, 58, and 59).

This test method seeking SiO ₂ concentration of the chemical solution from the measured value of the SiO ₂ concentration of the implanted ground, a method of estimating the strength of the implant ground. A specimen with the same density as the spot was prepared in advance using the soil collected in the field, and a solid specimen was prepared by infiltrating an injection solution having various silica concentrations into the specimen, and a strength test was performed (FIG. 58 (a )). Analyze the silica concentration of the specimen and find the relationship between silica concentration and strength (
Fig. 58 (b)), the strength of the injected ground is estimated from the analysis result of the silica concentration of the collected soil (Fig. 19 (b)) (Fig. 58 (a)).
ICP-AES (inductively coupled plasma emission spectroscopy) or atomic absorption is used for analysis of soluble silica.

1) Preliminary test In the construction, an indoor blending test is conducted to determine the blending (silica concentration) that satisfies the design strength, and the relationship between the silica concentration SiO ₂ and the uniaxial compressive strength is determined (28-day strength). The indoor compounding strength is twice the design strength in consideration of the safety factor such as strength reduction due to dilution of the injected drug solution at the injection hole interval.

The test results are shown in FIG. The design strength at this site is 60 kN / m ² , and the indoor compounding strength is 120 kN / m ² with the safety factor added. The above-mentioned laboratory test was conducted, and the on-site blended silica concentration was 6%.

The specimen used in the uniaxial compression test was measured for the amount of soluble silica described above, and the relationship between the silica concentration of the injection material and the amount of soluble silica SiO ₂ S from the injected soil was determined (FIG. 58 (b) ).

2) Post-evaluation Since undisturbed samples could not be obtained due to the effect of leeks after construction, the strength after on-site improvement was predicted using the relationship between silica content and uniaxial compressive strength performed in advance. The prediction method was 100 kN / m ² when the silica content of the disturbance sample collected after the improvement was measured, the silica concentration was determined, and the improvement strength was predicted from that concentration (FIG. 58 (a)).
From this result, it was found that the design strength satisfied 60 kN / m ² .

By injecting active composite silica having a silica concentration of 6% (FIG. 7) in this way, it was found that the injection ground could obtain 100 kN / m ^{2 at a} strength of 28 days. In the laboratory test, a silica solution of 120 kN / m ² is injected and 100 kN / m ^{2 on} site. As a result, it was found that it penetrated and consolidated into a predetermined area.

As described above, the present invention enables a ground improvement method having excellent durability characterized by using a silica solution that satisfies the durability conditions, and using a silica solution that satisfies the durability conditions by blending and formulating the following method. To do.
(1) Investigation of the ground to be injected: The density is measured. The density measurement may be an N value.
(2) Prepare specimens adjusted to the on-site density using the soil collected from the target ground.
(3) A constraining pressure corresponding to the on-site loading pressure is applied to the specimen, and silica grouts having various silica concentrations are injected to prepare a consolidated specimen.
(4) Curing the consolidated specimen for a predetermined period.
(5) Conduct a strength test of the consolidated specimen.
(6) Analyzing the silica concentration of the consolidated specimen to grasp the relationship between silica concentration and strength.
(7) Analyze the silica concentration using soil collected from the injected ground.
(8) The ground consolidation strength is grasped from the measured silica concentration.

The soil of the test specimen is dried, and a fixed pressure corresponding to the actual ground stress condition is applied to the test specimen using the 2.00 mm sieve permeate to infiltrate and inject the silica grout according to claims 1 to 13 for solidification. A bonded specimen is prepared, and a ground improvement method with excellent durability using a silica solution that satisfies the durability condition is made possible by using any of the following methods.

(1) The silica content of the target ground is measured in advance, and the silica content of the consolidated specimen is measured. Since the Ca content in the soil affects the gel time and strength, it is desirable to measure the Ca content.
(2) By subtracting the silica content of the local board from the silica content of the consolidated body, the relationship between the silica content of the injected solution and the strength of the specimen is grasped.
(3) Measure the silica content of on-site consolidated soil, subtract the silica content before injection from the measured value, and measure the silica content (injected consolidated soil silica content) resulting from the injected solution The field strength is grasped from the silica concentration.
(4) Grasp the injection rate of the injected ground from the solidified silica content of the injected ground. (5) From the relationship between the strength of the specimen and the silica concentration, confirm the formulation at the time of injection that satisfies the design numerical value or target strength.

In addition, for the preparation of the specimen, the relationship between the amount of silica and the strength corresponding to the density of the soil before pouring can be measured by a mixing method. In the above, the mixing method is a method of forming a specimen so as to have a soil density corresponding to the density of the ground in the field by mixing silica grout and soil, or filling the silica grout into a mold and introducing the soil. Say.
The amount of silica can be analyzed by JIS K 0101-1979, molybdic acid yellow method, molybdenum blue colorimetric method, ICP high spectroscopic analysis method or atomic absorption spectroscopic method.
As the silica content of the test specimen, the silica content calculated from the injection quantity of the injection solution in the test specimen or the silica content obtained from the consolidated specimen by the silica analysis method is used.

[Durability period and durability]
The present invention clarifies the meaning of the durability of silica grout applied to the durable ground improvement method, reveals the durability period for which durability is required, reveals the durability characteristics of the corresponding silica grout, and shows the strength over time It enables a blended formulation with characteristics (claims 24-31). Furthermore, we focused on the fact that durability is not simply determined by the durability of the injection material itself, but is greatly affected by the condition of the injected ground, and developed a method that does not reduce durability even in such a case ( Claims 2-11, 32-38). In addition, the application of durable grout has a long-term environmental impact on the surrounding ground, and there is a need for durable ground improvement that does not cause any problems. For this reason, the properties of "composite silica with colloidal silica, water glass and acid as active ingredients", "colloidal silica" and "silica sol" having the above different characteristics are integrated into an economical combination corresponding to the above application conditions. The silica solution that can adjust the formulation and its application method have been developed.

  As described above, the purpose of chemical injection considering durability is permanent water stoppage, prevention of liquefaction, reinforcement, etc., but the durability period and required durability are different in each, and the durability between them is Sustainability over time and a predetermined improvement effect during the service period are required.

  Conventionally, how to select injection materials and blends to meet the effects and economics for the purpose of injection, the service life and the sustainability of the required improvement effect under the conditions described above The method was unclear.

  Silica grout that seems to be durable has long-term durability, changes in strength, characteristics of gelled products and solidified bodies, and characteristics that vary depending on the ground conditions into which they are injected, and construction conditions. And because they are related to each other in environmental conditions, the criteria for judgment were unclear even if it was a durable ground improvement. The reason was that the long-term change over time corresponding to the durability purpose of the consolidated ground was unclear. The inventor has studied the long-term strength change of silica grout, including decades of long-term durability research against earthquakes, etc. that do not know when it will occur for decades, as well as numerous field trials and first experience such as the Great East Japan Earthquake. By clarifying the long-term durability of each silica grout through the development of measured values and accelerated tests, the concept of setting durability in consideration of the durability period has become possible.

FIG. 37 is an example summarizing the trend of changes in strength over time in a durable silica solution.
If the silica leaching is negligibly small than this, it can be said that the grout has excellent durability, but if it is considered that the durability means obtaining a predetermined strength suitable for the purpose of injection in consideration of the durability period, it is injected during the service period. It can be seen that the concentration and composition of silica that can maintain the strength required for the purpose is required as a durable grout.

  The durability grout ground improvement method is also used to confirm the environmental preservation during the endurance period of the infusion solution, the characteristics of the infusion solution that is permeated and consolidated without departing from the injection target area, the conditions of the injection ground, and the improvement effect of the injection ground after injection. As required.

FIG. 3 and FIG. 37 relate to the range of silica sol grout in which the above-mentioned silica grout can be integrated and the durability satisfying the above conditions can be selected. FIG. 38 shows an example of the range of the strength of silica grout and the time-lapse intensity line of the number of days elapsed. Within this range, it is possible to obtain an optimum blending formula that satisfies the purpose of durability taking into consideration the effects and economy.

FIG. 37 shows lines of 7-day, 28-day strength and 100-day strength as initial strength or blend strength (indoor blend strength). In-service periods of 10 years, 20 years, 50 years, and 100 years are shown. You can also show examples of 400-day and 1,000-day lines as intermediate comparison strengths. (Claim 9)

Also, these lines show examples of initial strength: strength within 1 year or strength at the time of blending, permanent durability strength, peak strength, convergence strength, time strength, service life strength, and the like. In the case of durability, there is a period in which a predetermined improvement effect is expected depending on the purpose of injection, and this was used as a service period. (Fig. 37) (Claim 14)

Here, the durability is defined as one or more of the following depending on the purpose of injection. The durability period refers to a period in which durability is required for the purpose of injection, and durability refers to the property of maintaining a predetermined improvement effect required during the durability period. Such a silica grout is referred to as a durable silica grout. The consolidated strength test strength is the indoor target strength multiplied by the safety factor against the design reference strength. (Claim 10)
(A) Permanent durability: Durability that seems to last the prescribed durability permanently (b) Timed durability: Durability that seems to maintain the prescribed durability for a certain period of time (c) Service durability: Specified (D) Convergence durability: Durability that will eventually converge to the required durability

  In order to maintain a predetermined improvement effect during the endurance period in order to obtain a silica solution with a durability level corresponding to the injection purpose, as shown in FIG. 37, the strength that can maintain the predetermined strength during the endurance period You have to get a silica grout that gives you a blended line setup.

  For that purpose, the silica solution is infiltrated into (or mixed with) the specimen corresponding to the density at the site using on-site collected soil or standard sand, and the strength at the time of blending is added to the strength at the time of blending, Alternatively, use a silica grout with a blending ratio at the time of design so that the design strength can be obtained by applying a safety factor in consideration of dilution to the infiltration distance and groundwater.

Therefore, from the range of FIG. 37, the silica grout of claims 1 to 4 is selected, and the amount or ratio of silica due to the total silica concentration, the colloid of the total silica concentration, or the concentration of water glass is determined. (Or acid agent) type, concentration and gelation time. In the case of active composite silica, since it is a silica grout in the acidic region containing colloid and water glass as active ingredients, the amount of shrinkage can range from the active silica colloid line to the silica sol line in FIG. Further, the strength can take a range from the upper limit line to the lower limit line of the silica sol and the active silica colloid in FIG. 36 (b). The shaded area in FIG. 37 shows the strength change over time of a grout integrated with an acidic-neutral silica solution containing colloid and water glass as active ingredients. The formulation of the pH and additive to obtain the gelation time including the blending of the main agent capable of sustaining the gelation and the gelation time in the soil that can permeate and solidify in a predetermined region shall be set.

In addition, in the above-described durable ground improvement injection, a silica grout capable of obtaining a predetermined strength during the durability period can be selected in consideration of conditions that affect the durability.
In this way, it is possible to select a durable grout using the minimum economical composition according to the purpose of injection and the ground conditions.

Alkaline water glass grout, whether the reaction agent is an inorganic compound or an organic compound, has unreacted alkali remaining in the gel, so the gel is depolymerized by alkali, and silica leaching of the homogel is large. It was found that long-term durability could not be obtained (Table 4, Table 13, FIG. 33, A ₂₀ , A ₁₅ , A ₀₆ ).

In FIG. 32 (a), the solubility of silica is small when the pH is 10 or less, and increases when the pH is 10 or more.
FIG. 32 (b) shows that the larger the silica particle size, the smaller the specific surface area, the smaller the amount of dissolution, and the smaller the particle size, the larger the amount of dissolution.

Table 5 shows the particle size of amorphous silica. Tables 5 and 6 show the particle sizes of each silica solution and fine particles. From this, it can be seen that the durability of the non-alkaline region is superior as the silica has a larger particle size.

  In addition, even if the silica concentration is low (Table 1), the low concentration silica injection solution with the addition of fine particles and microbubbles shown in Table 6 or the low concentration silica solution after the primary injection of the suspension or fine particles It can be seen that a ground with excellent durability can be formed by pouring (claims 2, 32, 36 to 38).

[Durability of homogel and durability of sand gel]
When the volume change of the homogel was examined (FIGS. 34 (a), (b), FIG. 36 (c), and FIGS. 41 to 43), the volume change of the silica sol gel contracted over a long period of time, and finally it was very large. understood. (FIG. 34 (a), FIG. 36 (c), FIG. 41 (1)) Further, it was found that the silica colloidal gel has negligible shrinkage over a long period of time. (Fig. 34 (b), Fig. 36 (c), Fig. 41 (3)) Although the shrinkage of the homogel increases the strength of the consolidated sand together with the strength of the gel itself, excessive shrinkage causes the strength of the sand gel to decrease (Fig. 35, FIG. 36 (b), FIG. 37, FIG. 49 (a), FIG. 54, FIG. 57).

  When the homogel was cured in a graduated cylinder, the silica sol had a large volume change and was peeled off from the glass container, and the silica colloid was integrated with the glass container. In this case, since the container is glass, the state of the gel between the soil particles can be predicted. Note that the volume changes in FIGS. 34 and 36 are the measurement results using the glass container. Further, from FIG. 38, it can be predicted that the shrinkage of the homogel not only has resistance to water pressure, but also influences the durability on the size of the soil particle size or the size of the gap. That is, excessive shrinkage of the gel against large particle size, loose soil, groundwater flow and water pressure adversely affects durability, reduces the adhesion between the soil particles, and the gel between the soil particles. It is possible to estimate a decrease in strength due to peeling.

  The results of examining the durability of the homogel and the long-term strength of the consolidated Toyoura sand are shown in FIG. 35 to FIG. 44, FIG. 49, and FIG. In addition, it was found from FIG. 36 that the relationship between silica leaching, silica gel shrinkage, and strength change of consolidated Toyoura sand is greatly influenced by silica gel shrinkage.

Non-alkaline silica sol from which alkali of water glass is removed with acid has very little silica leaching (Fig. 32, Fig. 33), and strength development is early (Fig. 46, Fig. 49) for low concentration, and excellent long-term solidification. However, the gel contracted excessively over a long period of time (Fig. 33 (a), Fig. 36 (c), Fig. 41 (1), Fig. 54
) As a result, after nearly 200 days after curing, the strength of the consolidated sand reaches its peak, and then the strength decreases over a long period (Fig. 35 (a), Fig. 36 (b), Fig. 54 (b)). I understood.

Colloidal silica is so small that leaching of silica from homogel and sand gel is negligible (Fig. 33, Fig. 36 (a)), and there is almost no shrinkage of homogel (Fig. 34 (b), Fig. 36 (c)). Since the strength does not deteriorate and the strength continues to increase for a long time (FIG. 35 (b), FIG. 36 (b)), the improvement effect is permanent. However, since the surface activity of the colloid is small, the strength development is slow (FIG. 35 (b)), and the gel strength is low at a low silica concentration (FIG. 44 (c)).

  FIG. 38 shows the number of days for which the water stoppage was maintained when water was continuously permeated to the consolidated Toyoura sand with a dynamic water gradient of 50. It can be seen that the silica colloid with less shrinkage shows long-term water pressure resistance even under water pressure, and the silica sol with large shrinkage has low long-term water pressure resistance.

The applicant's long-term durability study revealed the following.
Due to the relationship between silica leaching, homogel shrinkage and uniaxial compression of sand gel in each silica grout, both silica sol and silica colloid have almost no silica leaching, but silica colloid has no homogel shrinkage and continues to increase in strength over time. . Although the initial strength of the silica gel sand gel is high, the homogel shrinks excessively (20 to 30%), and the strength decreases after about 100 to 200 days and the strength reaches a peak. (Fig. 35 (a), Fig. 36 (b))

Further, it can be seen from FIGS. 33 and 36 that the decrease in strength of the organic water glass is due to dissolution of the gel by the unreacted water glass or alkali in the gel. Further, FIG. 33, FIG. 36 and FIG. 38 show that the disappearance of the water-stopping persistence of silica sol under water pressure occurs almost 200 days after the gel shrinkage reaches 20% or more.
On the other hand, it can be seen that the active silica colloid has excellent water-stopping durability due to the above-mentioned properties.

FIG. 37 shows an example of the change over time of the strength of each silica grout based on the data shown in FIGS. Here, an example of the endurance period is shown, and a specific example of the endurance period is shown. Table 4 shows examples of quantitative evaluation of durability levels.

A grout with silica leaching, such as an alkaline water glass grout, has a significantly reduced strength and cannot be durable. Even when there is no leaching of silica as in acidic / neutral silica grout, the change in strength over time depends on the shrinkage of the gel. If there is no or less gel shrinkage, the gel shrinkage will increase the strength of the consolidated sand. However, when the gel shrinkage becomes excessive, the strength of the consolidated sand starts to decrease from the peak.

The reason for this seems to be that the gel shrinkage is due to the effect of tightening the sand of the consolidated sand in addition to the adhesive effect, but if the shrinkage is excessive, the gel peels off from the soil particles, reducing the adhesive effect and the tightening effect. It seems to be because. In addition, when the soil particle size is large or the ground has a large void, the gel shrinkage causes voids between the soil particles, so that the water stoppage and water permeability are also lowered. For this reason, in the ground with a large gap, even if the silica concentration is low, the silica powder is added to the silica solution, or before the silica solution is injected (secondary injection) as a primary injection, the silica powder, cement bentonite suspension is added. A turbid liquid can be injected to prevent adverse effects due to gel shrinkage. Table 1 shows the caking properties of homogel and sand gel of low concentration silica. (Claims 6, 7, 12, 18)

The present inventor has found that it is effective to mix silica particles that are less reactive with an acidic silica solution in addition to increasing the content of silica colloid in order to prevent a decrease in the strength of the sand gel accompanying excessive shrinkage of the silica gel. When the gel shrinkage of the silica solution is 25% or more, the strength of the sand gel is remarkably lowered, so attention was paid to adding silica powder corresponding to the shrinkage amount of 25% or more. For example, if shrinkage of 28% occurs, silica powder corresponding to 3% volume may be added.
If the shrinkage amount is 10%, 10% powder may be added. In the ground with a large particle diameter or a ground with a large gap, the shrinkage of the homogel has a great influence, and therefore silica powder for the shrinkage amount of 20% or more can be added. In this case, when the silica powder has little reactivity with the silica solution, the influence of shortening the gelation time and the like can be reduced. Regarding the permeability, it is known that the particle size of the soil and the particle size of the powder that can penetrate into the voids of the particle size can already be calculated as the permeation limit of the suspension. The powder should be selected. In this way, a gel having almost no shrinkage of the gel can be filled between the soil particles to form a durable ground (Claim 10, Tables 5 and 6).

Suspension injectable limit (groutability):
85% diameter (D ₈₅ ), 95% diameter (D ₉₅ ) of the particle size distribution of suspended particles
If the 10% diameter (D ₁₀ ) and 15% diameter (D ₁₅ ) of the particle size distribution of the ground,
N ₁ = D ₁₅ / D ₈₅ ≧ 15
N ₂ = D ₁₀ / D ₉₅ ≧ 8
If it is not satisfied, it cannot penetrate smoothly.
(J.C.king, Proc. ASCE, 1961) Construction 1972.1-1974.7
Chemical injection method series No. 1-27 for field engineers; by Shunsuke Shimada and Yo Kanematsu

  In this case, the silica solution can be used by mixing these silica powders, microbubbles, clay, and microbubbles at a thin concentration of about 0.4 to 3%. Microbubbles seem to be effective in desaturating the ground without the silica gel in the diluted silica solution sticking to the surface and escaping over a long period of microbubbles. (table 1)

It was found that when microbubbles were included in a silica solution with a high silica concentration, the resistance to earthquakes was determined by the strength of the consolidated soil because the microbubbles were included in the strong silica solution. On the other hand, when the silica concentration is very low, the silica gel around the microbubbles is very weak and can follow the displacement, and the pore water pressure due to earthquake motion acts directly on the microbubbles, causing the microbubbles to deform and increase the pore water pressure. This prevents the liquid from becoming liquefied. The same phenomenon occurs when microbubbles and clay are mixed. Further, by adding a thickener to a thin silica solution, it is possible to make a silica solution that is difficult to be diluted with groundwater even if the silica concentration is low. It is effective to add a thickener to either or both of microbubbles and clay. For this reason, the silica concentration is 3% or less, preferably about 2 to 0.4%. At this concentration, gelation time can be obtained for a long time in almost neutral region, which is preferable from the viewpoint of environment (Claim 3).

In FIGS. 36 (b) and 36 (c), the strength continues to increase until the gel shrinkage of the silica sol reaches around 20% (glass graduated cylinder method), and then the strength of the consolidated sand turns from a peak to a decrease. Since the time is about 200 days after gelation, silica leaching, volume change and strength change over time do not exist independently, but are related to each other and solidified soil. It can be seen that this has an effect on the durability over time.

  Active silica colloids have less homogel shrinkage and sand gels continue to increase in strength. However, strength development is slow when the silica concentration is high. On the other hand, active composite silica can have a range from silica sol to active silica colloid in terms of gelation time, homogel shrinkage and sand gel strength, depending on the concentration and mixing ratio of silica colloid and water glass. It was found that the glass ratio becomes closer to the characteristics of silica sol as the colloid content decreases, and the characteristics of the silica colloid become closer as the colloid ratio increases.

FIG. 36 (b) and FIG. 37 show the long-term strength of the active composite silica. That is, it can be seen that a formulation can be obtained that exhibits rapid strength and does not decrease strength even at low silica concentrations. (Fig. 39 (a)-(d), Fig. 39, Fig. 49 (b))

Even if the active composite silica has a small colloid ratio, in the composite silica gel, it is considered that small silica is adsorbed with a large colloid as a nucleus and the colloid grows. For this reason, even if there is much small silica content resulting from water glass, the durability effect of a large silica colloid becomes remarkable. In this way, by adjusting the silica concentration and the mixing ratio of colloid and water glass, the composite silica has a gel shrinkage within the range from the silica sol to the active silica colloid in FIGS. 36 (b) and (c). 3 can be adjusted within the shaded area in FIG. 3, and therefore the range of the maximum intensity can be arbitrarily adjusted from the upper limit of the silica sol to the upper limit of the active silica colloid (FIG. 36 (b),
Fig. 37), and the minimum strength can be arbitrarily adjusted to the minimum concentration of low concentration shown in Table 1 (Fig. 37).

  Further, by adding a colloid to the silica sol, it is possible to obtain a blending region in which the strength increases or the final strength converges even in a region where the strength of the silica sol decreases (FIGS. 42, 43, 53, and 54). Moreover, although the silica concentration of the active silica colloid is high, the disadvantage that the strength is low and the strength is slow can be solved. In this way, it can be seen that the strength range with time of the silica injection solution (concentration and composition thereof) can be set so as to last for a durable period corresponding to the injection purpose.

  It has been found that the strength of the consolidated soil by the active composite silica grout is due to the effect of restraining the soil particles by the volume shrinkage accompanying the progress of the siloxane bond of the small silica in addition to the application of the adhesive force by the silica gel as the main material. Furthermore, since the active silica colloid contained in the active composite silica forms a skeletal structure in the gel and plays a role of adjusting the volume shrinkage, the active composite silica causes a certain amount of shrinkage although it causes some shrinkage. It has been found that a composition that does not occur and increases the strength can be obtained (FIG. 36 (c), after 400 days, the volume change converges to about 8%). Therefore, the active composite silica has a lower silica than the active silica colloid. Strength develops rapidly with concentration, and the improvement effect (strength) tends to stabilize over time. (Fig. 36 (b), Fig. 39 (a)-(d), Fig. 49 (b), Fig. 53, Fig. 54)

The active silica colloid has a large particle size (Table 5), and the gel resistance to water pressure is large (
(Fig. 38) No gel shrinkage (Fig. 34 (b), Fig. 36 (c)) and silica leaching is negligibly small (Fig. 34 (b)). Permanent still water at 10-30% silica concentration. It is also suitable for bedrock still water. In addition, a barrier wall can be used to store a reservoir, waste disposal, a barrier wall for harmful substances, or fuel such as liquefied gas in the ground.

As the durable silica grout, it is possible to use a grout made of a composition capable of obtaining a durable strength corresponding to one or a plurality of durable periods described above with respect to a durable period corresponding to the injection purpose.

FIG. 33 shows the silica leaching rate up to 9,000 days in the gel of the injection material in FIG. FIG. 34 shows volume change rates of acidic silica sol and active silica colloid up to 9,000 days.

FIGS. 35 (a), (b) and FIGS. 36, 37, and 39 show changes in strength of consolidated Toyoura sand up to 9,000 days due to acidic silica sol injection material, active silica colloid, and active composite silica, respectively.

[Improved durability]
In the ground where the silica solution is coarse-grained soil, large voids, or groundwater is flowing, the gel shrinkage is reduced and the gel strength is increased by any of the following methods (a) to (d). Or, it is a ground improvement method characterized by increasing the resistance to water pressure or reducing the fluidity of the injected liquid with respect to the groundwater to reduce the strength reduction of the consolidated sand. 49 (a) and FIG. 53, it was found that when the silica concentration is increased, even if the shrinkage is large, the rigidity is increased and the strength reduction is suppressed.

(A) Increase the silica concentration (FIGS. 38, 43, 49 (a) and 53).
(B) The molar ratio is increased and the colloid concentration is increased (FIGS. 36, 41, 42, 43, 53, and 54).
(C) Add silica fine particles (Table 6).
(D) Perform primary injection to reduce ground homogenization, water permeability reduction and groundwater fluidization (Fig. 16 (c), (d)).
(E) Dilution with groundwater can be reduced by adding a thickener to the silica solution. High molecular weight polymer as thickener. For example, there are polyacrylamide, carboxymethylcellulose, methylcellulose, polyvinyl alcohol, clay and the like.

In the above-mentioned silica solution, in a non-alkaline silica grout comprising a silica component resulting from silica colloid and water glass, a colloidal silica component (precipitated silica or salted-out silica) added as a salt to water glass as the colloid ( By adding Table 6), it is possible to increase the colloid content and improve the durability.

In order to increase the colloid concentration in the above silica solution, the addition of white carbon, refined silica gel, precipitated silica (salting out silica), and clay as silica fine particles increases the silica colloid content and reduces gel shrinkage. In addition, it can increase the water pressure resistance and improve the durability (Table 6).
Here, the precipitated silica refers to silica fine particles which are precipitated by adding seawater or a polyvalent metal salt to water glass and salting out. Clay colloid size 5μ or less (Clay Handbook Japan Society of Clay Sciences, P.114, January 15, 1967, clay particle size 5μ or less (Japan Society of Civil Engineers)

The durability by silica grout means the durability of the injected ground. However, as for the durability of the injection material, not only the physical properties change over time depending on the compounding prescription, but even if the durability of the injection material itself is excellent, there are many factors that affect the durability of the injection ground as described above. It was difficult to judge the durability of the ground.
Thus, the biggest reason why it is difficult to improve the durable ground using durable silica grout is that the long-term durability varies depending on the condition of the injected ground.

As a result of studying the long-term durability of the injection ground by silica grout for many years, the present applicant has found that the durability of silica homogel and silica sandgel differ as shown in the experimental examples. (Claims 9 to 13)
That is, the time-dependent durability of the silica homogel is as follows: (1) In the non-alkali region, there is almost no silica leaching.
(2) Although the shrinkage and strength of the homogel change with time, the values are determined by the formulation.
(3) Homogel increases in strength over time, but does not show a decrease in strength, and shows almost a predetermined value over time depending on the composition and concentration. The final durability (strength and shrinkage) of the homogel was found to be almost constant depending on the composition and formulation (FIGS. 41 to 47).

  On the other hand, it was found that the sand gel into which it was injected had different durability depending on the condition of the soil to be consolidated, such as the type and density of the injected soil, even though the homogel was blended with time to achieve a predetermined value of shrinkage and strength. (FIG. 7, FIG. 35 to FIG. 39).

  Therefore, paying attention to homogel that shows a certain durability regardless of the state of the consolidated soil, by grasping the durability of the different sand gel corresponding to the state of the soil, the period during which the strength during the durability period does not decrease In addition, it has become possible to estimate the consolidated soil strength and period that can maintain a predetermined strength during the service period. In order to estimate the consolidated soil strength in a short period of time, an accelerated test by sand gel heating curing is effective. However, homogel can be easily promoted compared to sand gel, so it is easier to estimate the strength of consolidated soil. (Table 3 (a), (b), Fig. 45)

[Experimental example]
Experimental examples are shown below.
1． Types and composition of silica grout used (Table 7)
Here, the molar ratio is calculated from this equation: n = weight ratio (SiO ₂ / Na ₂ O) × 1.032

2． Gel time
The pH is non-alkaline (weak alkali to acidic: pH = 1 to 10) as shown in Fig. 3. The silica concentration is 0.4 to 30 wt%, and the gel time is 6700 minutes from instantaneous setting as shown in Fig. 3. FIG. 40 shows gel times according to silica concentration of a mixture of water glass and acid (silica sol: symbol AS) used in the experiment. The instantaneous setting usually means a gelation time within about 10 seconds.

3． Characteristics of volume change of homogels are shown in FIGS. In this experiment, a homogel column specimen was used.
Accordingly, in each case, the lower the silica concentration, the larger the shrinkage, and the higher the silica concentration, the smaller the shrinkage.
The active composite silica system (HS) has a smaller shrinkage as the molar ratio is higher, and the active colloid system has very few. (The expansion rate is about 0 to + 1% for glass volumetric flasks, but 5% for cylinder specimens. Gel shrinkage is more cylindrical with a plastic cylinder than for glass volumetric flasks. The sample was found to be larger, and the shrinkage of the gel itself seems to be more compatible with the plastic container, but since the soil particles are silica, the shrinkage of the gel in the ground is closer to the glass volumetric flask. It seems to be.)
On the other hand, in the case of acidic silica sol, it can be seen from FIGS. 42 and 43 that when the SiO ₂ concentration is the same, the final volume change is the same regardless of the molar ratio of water glass.
In addition, as shown in FIG. 41 (1), the 400-day shrinkage is 25 to 28% at a silica concentration of 12% to 6%.

On the other hand, in the active composite silica system, the final volume change is smaller as the amount of colloid is smaller and the amount of colloid is larger than the acidic silica sol, that is, the higher the molar ratio is, the smaller the final volume change is (FIGS. 41, 42, 43).
The active composite silica at the same molar ratio or the same colloid / water glass ratio (hereinafter referred to as colloid content) tends to have a smaller volume shrinkage as the concentration of the chemical solution increases.
Further, when the total amount of silica in the injection material is the same, the higher the colloid content, the smaller the volume shrinkage tends to be.

Also, in FIG. 41, the volume change of the active composite silica is 400% shrinkage 18% to 21% at a SiO ₂ concentration of 15% to 9%. The shrinkage of composite silica approaches CS as the molar ratio increases (Fig. 41 (3)).
FIG. 43 shows the relationship between the silica concentration and the final volume change rate (ε _νχmax ).

... Formula (3)

here,
ε _νχ : Volume change rate of material age χ (%)
a: Constant χ: Material age (days)
ε _νχmax : Final change rate

Four. Examples of uniaxial compression test of homogels are shown in FIGS.
From FIG. 44, it can be seen that the uniaxial strength of the homogel does not decrease with time regardless of the silica concentration, the molar ratio of the main material, and the colloidal content, and finally tends to be a constant value.
In silica sol (AS), if the silica concentration is the same, there is no difference in the final uniaxial strength due to the difference in molar ratio. In active composite silica (HS), the strength decreases as the colloid content increases.
FIG. 45 shows the relationship between the uniaxial compressive strength of the homogel and the coefficient of change.
E _50pq = 0.006 × qu _pg ^1.41 ... Formula (4)
Are in a relationship.
E _50pg : Deformation coefficient of homogel (MN / m ² )
q _upg : Uniaxial compressive strength of homogel (kN / m ² )

FIG. 46 shows the relationship between the SiO ₂ concentration and the uniaxial compressive strength of the homogel at the age of 400 days.
In either case, the uniaxial compressive strength increases as the silica concentration increases, but silica sol depends on the silica concentration regardless of the molar ratio of water glass. In the composite silica, when the colloidal content is increased and the molar ratio is increased, the strength development ratio is decreased, and when the water glass concentration is increased and the molar ratio is decreased, the strength development ratio is increased.

FIG. 47 shows the relationship between the fracture strain εf (%) of the homogel and the uniaxial compressive strength.
From this, it can be seen that there is a relationship of formula (5) regardless of the molar ratio, colloidal content, and silica concentration.

q _upg = 467 × ^{εf -1.83} (5)
q _upg : Uniaxial compression strength (kN / m ² )
εf: Homogel fracture strain (%)

Four. Properties of sand gel
4-1 Test Method Samples (Table 8) were prepared by filling the gap with the silica solution using the silica grout of Table 7 and Table 2 and the Toyoura sand of FIG.

4-2 Change with time of uniaxial compressive strength _qupg of sand gel (Figs. 49-54)
Although acidic silica sol grout does not reduce the uniaxial strength of homogels (Figure 44 (a))
A decrease in strength of the sand gel is observed. The decrease in strength was greater as the silica concentration was lower, and occurred at an early stage (FIG. 49 (a)).

On the other hand, in the case of active composite silica or active silica colloidal system, it is possible to obtain a sand gel that is stable without decreasing the improvement effect regardless of the silica concentration (FIGS. 49 (b) and (c)). These strength characteristics can be controlled by a composite ratio depending on the content of silica colloid.

FIG. 50 shows the uniaxial compressive strength and deformation coefficient of sand gel. The relationship between the uniaxial compressive strength of the sand gel and the deformation coefficient is represented by the following formula regardless of the SiO ₂ concentration, molar ratio, and colloidal content.
E _50sg = 0.02q _usg ^1.56 (6)
E _50sg : Sand gel deformation coefficient (MN / m ² )
q _usg : Uniaxial compressive strength of sand gel (kN / m ² )

FIG. 51 shows the uniaxial compressive strength of homogel and sand gel.
From this, the increase rate of the strength of the sand gel with respect to the homogel strength can be seen.
FIG. 53 (b) shows the relationship between the silica concentration and the uniaxial compressive strength q _usg when the average value of the uniaxial compressive strength of the sand gel is maximized.
From FIG. 53 (a), it can be seen that the volume change of the composite silica is 25% or less and that the intensity change is hardly seen from FIG. 53 (b). From FIG. 52, in the case of acidic silica sol grout, the strength is almost the same regardless of the molar ratio. In the active composite silica, the strength decreases as the colloid content increases, but the strength increases as the water glass concentration increases. Therefore, it can be seen that the colloidal content should be increased in order to prevent the shrinkage and the strength from being reduced.

Since the strength of the homogel / sand gel is mainly determined by the water glass (silica sol) concentration, regardless of the colloid content, a concentration that satisfies the target strength by the water glass concentration is used (FIG. 52). FIG. 53 shows the silica concentration, shrinkage rate, and strength ratio.
Regardless of the silica concentration of the injection material, the higher the colloid concentration, the smaller the volume shrinkage. It can also be seen that if the silica concentration is increased, the strength is not easily lowered even if the volume shrinkage is large. This seems to be because the adhesive strength between soil particles by silica gel increases.

FIG. 53 (a) shows the relationship between the silica concentration and the final volume change rate of the homogel (FIGS. 41 to 43). FIG. 53 (b) shows the relationship between the silica concentration and the strength ratio of the sand gel.
The strength ratio is a value obtained by dividing the value qu400day of the material age 400 days (average value) by the value q _umax at which the uniaxial compressive strength (average value) of the sand gel during the curing period is maximized.
It can be seen from these that a sand gel can be obtained in which the active composite silica and the active silica colloid do not show a decrease in strength. On the other hand, it was found that the acidic silica sol showed a decrease in strength and became larger as the silica concentration was lowered. However, it has been found that when the silica concentration is higher than 10 wt%, preferably when the silica concentration is 12% or more, the strength decrease is extremely small.
From FIG. 53, the SiO ₂ concentration is 5 to 15%, the volume change rate of the homogel is 30% or less, and the strength ratio of the sand gel to the maximum strength up to 400 days is 100% to 80%. It can be a durable silica grout that converges to strength.

Five. Prediction of durability relationship between homogel and sand gel and durability strength of consolidated soil FIG. 54 is a test example in which the relationship between the durability of sand gel was found from the shrinkage rate of homogel and the deformation coefficient of homogel. FIG. 54 (a) shows the volume change rate ε _v (%) with time of the silica sol homogel (FIG. 41).
) In the uniaxial compression test (Figs. 44 and 45) corresponding to the homogels (Fig. 45)
) Are plotted on the vertical and horizontal axes, respectively. And even though the homogel increases in strength with time (with time), the strength of the sand gel decreases when the homogel contraction exceeds a certain level. This is indicated by an X on the curve. The boundary line is indicated by a solid line. There is a branch point on the solid line where the strength of the sand gel decreases. In the case of silica sol (AS), it can be seen that when the silica concentration is low, the strength is reduced at a low shrinkage, and when the silica concentration is high, the shrinkage at the branch point is increased.
The point in the figure indicates a state where the strength of the sand gel is increased or maintains a constant value, and X indicates a state where the strength of the sand gel is reduced.
In FIG. 54 (a), the white triangle plots the acid silica sol with a molar ratio of 3.75 silica concentration of 12% (FIG. 49 (a) AS 12%).

With the curing, the volume change rate of the homogel increases (Fig. 41 (1)), and the homogel strength (Fig. 44) and deformation factor also increase (Fig. 45). 50) It was found that the uniaxial compressive strength of the sand gel decreases when the volume shrinkage of the homogel becomes excessively large (FIG. 49 (a)).
FIGS. 54 (b), (c), and (d) show the case of silica concentration 6% in FIG. 49 (a).

Fig. 54 (b) shows the relationship between sand gel strength and the number of days of curing, Fig. 54 (c) shows the relationship between the volume change rate of homogel and the number of days of curing, the relationship between the deformation coefficient of uniaxial strength of homogel and the number of days of curing, and Fig. 54 (d) The relationship between the volume change rate of a homogel and the deformation coefficient of a homogel is shown.

The branching point of strength 450kN / m ² (b) is 18% in volume change rate (b) and occurs around 10 days of curing.
It can be seen that the deformation coefficient at that time is 0.3 MN / m ² (c) (d).

Even if the deformation coefficient of the homogel is near 1.0MN / m ² (g), the volume change rate is 30% (f) (
H), it can be seen that the strength of the sand gel (e) is reduced to 300 kN / m ² .
Such a figure can be drawn with each formulation, but is omitted here.
FIG. 54 (e) is a semilogarithmic graph of FIG. 54 (a).

From this figure, it can be seen that the relationship between the deformation coefficient and the volume change rate and the branch line of the decrease in strength of the sand gel can be shown by a substantially straight line. From this, it can be seen that if the gradient of the deformation coefficient of the initial strength change at each silica concentration, for example, the one week strength and the 28th strength, is known, the deformation coefficient until the volume change rate at the branch point is obtained.

FIG. 54 (f) shows an example of active composite silica and active silica colloid. It can be seen from this that the active composite silica can obtain a consolidated body located in a region where the gel shrinkage is small and the sand gel does not cause a decrease in strength. Further, it can be seen that the active silica colloid does not reach the limit line because the strength does not decrease at all. It can also be seen that the active composite silica can be adjusted to the active silica colloid region by increasing the amount of colloid and increasing the molar ratio.

  On the other hand, it can be seen that the deformation coefficient of the homogel and the uniaxial compressive strength of the homogel are almost on the straight line in FIG. The present inventor already has a characteristic that a homogel can take a certain value depending on the blending, unlike a sand gel, as has already been clarified in the above-mentioned experiment.

54 (e) and (c), it is possible to obtain a deformation coefficient value within the range of the homogel shrinkage rate that does not decrease due to the silica concentration in the silica sol, the composite ratio with the colloid in the active composite silica colloid, and the silica concentration. (FIG. 54 (f)), and as a result, the uniaxial compressive strength of the homogel can be obtained from FIG. 45 and formula (4).

Furthermore, as shown in Figs. 54 (e) and (f), the deformation coefficient (→ uniaxial compressive strength) of the homogel corresponding to the curing days until reaching the branch point where the strength does not decrease in the curing days is known, so that it can be used for injection purposes. It is possible to know the deformation coefficient (→ uniaxial compressive strength) of the homogel in the period, the endurance endurance period or the permanent endurance period. (Fig. 45)
Next, from the relationship between the strength of the homogel and the consolidated sand, it is possible to know the strength that converges during the durability period or finally (Claim 7) and (FIG. 51).
Further, it can be seen from FIGS. 54 (e) and 54 (f) that the sand gel whose strength does not decrease is not uniquely determined only by the volume change rate of the homogel but is related to the deformation coefficient of the homogel. That is, it can be seen that even when the volume change rate of the homogel is 20% or more, if the deformation coefficient is large, that is, if the rigidity is large, a sand gel with no decrease in strength can be obtained.
This is considered to be because if the homogel has high rigidity, the soil particles are firmly bonded to each other to form a skeleton structure, and even if the gel in the gap contracts, the influence of the strength reduction is reduced.
The direct range in which the strength does not decrease can be said as follows from FIGS. 54 (e) and 54 (f). In the semilogarithmic graph, if the vertical axis is a scale of the homogel deformation coefficient E ₅₀ (MN / m ² ) and the horizontal axis is a scale of the volume change rate εv (%) of the homogel, E ₅₀ (0.1 MN / m ² ), εv E ₅₀ from (20%) point (100 MN / m ^2), the left area of the straight line passing through the points of .epsilon.v (30%) E50, be a silica grout without the strength of Sandogeru decrease consisting Homogeru there is .epsilon.v Also, if it is in the right region, it can be seen that it is a silica grout in which the strength of the sand gel is lowered.
As described above, the strength of the sand gel can be obtained by obtaining the deformation coefficient within the range of the shrinkage rate of the homogel that does not decrease the strength by the method described in (0290). Fig. 39 (d)
These show the uniaxial test result of the sand gel when changing the silica concentration under different ground conditions in the construction. The formulation of each silica grout is known, and the silica concentration, volume change, and deformation coefficient of the homogel can also be shown as in FIG.
Therefore, the difference in the strength of the large number of curves corresponding to various silica concentrations is the difference in soil conditions at each site. Therefore, if the composition of the silica concentration to be applied is set, the strength of the sand gel obtained at the actual site corresponding to similar soil conditions can be estimated.

As described above, the strength of the homogel is different from the strength of the sand gel and can obtain a constant value over time. Therefore, if the time-dependent value is taken, the strength during a predetermined durability period can be estimated. Moreover, if the convergence strength is obtained, the final ground strength can be obtained, and the time-dependent change in the homogel strength may be an actual measurement value until it becomes a substantially constant value, or may be an actual measurement value by an accelerated test (FIG. 57). . Of course, an actual measured value of sand gel or a verified value by an acceleration test may be used. Further, the strength in a predetermined durability period can be predicted from the initial strength of the sand gel, for example, the strength of 1 week strength, the strength of 28 days, and the like, and the tendency of the type and concentration of the injected material.

  In any case, it can be seen that the strength change and shrinkage rate of the homogel can be easily measured because the change over time can be measured only by the type and concentration, and it can be easily measured by the accelerated test by heating curing (FIG. 57).

  In the blending setting of the silica grout in which the above-described strength change occurs, if it is confirmed that a predetermined strength can be obtained in a predetermined period, a test over a long period of time at room temperature will not be in time for the injection design. For this purpose, the strength of the accelerated curing is increased by changing the strength of the standard curing (20 ° C) of the consolidated sand and increasing the curing water temperature based on Arrhenius chemical reaction kinetics that the chemical reaction is accelerated at higher temperatures. It was found that the acceleration magnification was obtained by moving the change to the time axis, and the secular change of the uniaxial compressive strength could be known.

The rate of chemical reaction is influenced by temperature. Arrhenius's chemical reaction kinetics can be applied to the ground injection from the point where the reaction rate becomes faster at higher temperatures. Since the chemical reaction is promoted by warm curing, the value of change over time and the final value can be known by knowing the acceleration magnification due to temperature, so here both are as accelerated tests by warm curing It is shown below.
It is possible to predict the standard curing intensity from the accelerated curing by superimposing the vertical axis with the intensity on the vertical axis and the time on the horizontal axis and moving on the time axis.

Hereinafter, an active silica colloid system will be described as an example (FIGS. 55 and 56).
The strength of the active silica colloid-based consolidated Toyoura sand continues to increase significantly over a long period of 1000 days or longer under standard curing. (Plot of Fig. 55) A chemical experiment and physical change were promoted by raising the curing temperature, and a promotion experiment was conducted on the assumption that long-term strength could be predicted by grasping the temporal change of strength in a short time. (Plot and solid line in Fig. 56)
The solid line in FIG. 55 is obtained by inserting the solid line of the acceleration test result in FIG. 56 into the standard curing at the magnification shown in the figure. This magnification is considered to be the acceleration magnification at a curing temperature of 50 ° C.

In this way, the silica sol grout and the active silica colloid were subjected to a normal temperature test and an acceleration test, and the results are shown in FIG. 35 and Table 3. In this way, long-term strength can be predicted by heating the sand gel. Therefore, in FIG. 35 and FIG. 36, Table 3 shows the acceleration magnification when the curing temperature is 20 ° C., 40 ° C., 55 ° C., and 65 ° C. By this method, even an intensity of 10,000 days or more can be known by an accelerated test. In FIG. 35, the value converted into the curing at 20 ° C. in the acceleration test is graphed. Since the strength reduction rate (including the strength increase rate) and the volume change rate are phenomena caused by the progress of chemical change, the numerical value corresponding to the endurance period can be grasped by heating curing as in the case of strength. The present inventor has further found that the accelerated test is possible not only in the sand gel but also in the strength and shrinkage of the homogel and the influence on the concrete in the acidic gel. FIG. 57 is an example of a silica sol gel acceleration test.

Table 3 (b) shows the accelerated test results of normal temperature curing (20 ° C) and warming curing (55 ° C) of silica sol and composite silica for the homogel uniaxial compressive strength test with a silica concentration of 6%.
As a result, in this example, the strength of the silica sol homogel reached 10 times the normal temperature and the strength of the composite silica homogel reached 14 times the same strength, indicating that the accelerated test was effective. It was found that the gel shrinkage with time was almost the same (FIG. 57 (b)). In the accelerated gel test, the strength reduction was also confirmed from FIGS. 57 (c) and (d). Compared to sand gel, homogels are easy to accelerate, and the strength can be obtained by mixing, so the strength and shrinkage of the homogel can easily be used to predict the strength of the sand gel and the presence or absence of strength changes. It was found that the strength of consolidated soil can be predicted using constants related to soil conditions.

  Therefore, it is possible to quantitatively evaluate the durability by using a promotion method by heating curing with respect to the service life in the quantitative evaluation.

For the same reason, the accelerated method by heating curing enables quantitative evaluation of durability corresponding to the durability period for the following. (Claims 13 and 21)
(1) Strength change of consolidated product (sand gel, homogel) (2) Silica leaching from consolidated product (3) Shrinkage of homogel (4) Effect of consolidated product of chemical substance (environmental condition, ground condition)
Can be applied to

[Quantitative evaluation of durability]
Factors affecting the durability of consolidated soil with silica solution are as shown in the section of the problem to be solved by the invention, but for strength and penetration consolidation into a predetermined region, pH, silica concentration, Influenced by gelation time, gelation time in soil, leaching of silica from gel or consolidated sand over time, silica gel shrinkage, silica gel strength, consolidated sand strength, silica gel structural stability, water pressure resistance, etc. The injection method using a long gelation time and the injection speed are affected, and for the environment, pH, safety to fish and shellfish, safety to water quality, acid type and concentration, safety to concrete And so on.

The present inventor has developed a silica grout and an application method thereof that can achieve a predetermined object economically corresponding to these application conditions.
As described above, although silica solutions have different characteristics from the viewpoint of durability, the improvement of the durability ground using chemical solution injection is economical under various conditions shown in the section of the problem to be solved by the invention. In order to apply silica grout that satisfies the durability requirements (ie, the formulation with the least amount of material used), the criteria for durability conditions according to the purpose of injection are quantitatively set, and the corresponding silica Grout prescription and application become important.

  Moreover, economical evaluation can be used by quantitatively evaluating the durability. Thus, in order to improve the durable ground, the present invention clarifies the factors affecting the durability (see the section of the problem to be solved by the invention) and how to clarify the level of durability itself. Depending on whether the silica solution is formulated, it is necessary to embody the application method of the durable grout.

For this reason, the present inventor made it possible to set an economic composition by quantitatively evaluating the improvement level according to the purpose of injection (Table 4). Moreover, it is preferable to set the optimal economical silica grout which can anticipate the intensity | strength required during a service period in consideration of the intensity | strength change of the target ground after injection | pouring. Durability corresponding to the service life with one or more of the initial strength, final strength, maximum strength, service life strength, and convergence strength as the standard strength as a prescription for silica solution that is the standard for evaluating durability over time The ground improvement construction method characterized by using the composition which can obtain strength was developed. By applying the silica grout in combination with the durability characteristics, durability level, and service life, economical application according to the durability conditions has become possible. (Claims 14-17)

As described above, the durability of the injection material itself is as follows: (1) The larger the total amount of silica, the smaller the shrinkage of the silica gel.
(2) In the acidic silica solution, the strength increases as the silica concentration resulting from water glass increases.
(3) As the colloid concentration is increased, shrinkage is reduced and durability is improved. Various durability characteristics can be obtained by adjusting the content ratio of the colloid.
(4) The strength of the active composite silica mainly depends on the silica concentration caused by the water glass. The effect of reducing or keeping the strength decrease by reducing the shrinkage of the silica is due to increasing the colloid in the total amount of silica.

The present inventor has found the following technique in selecting the composition of the durable silica grout corresponding to the ground conditions. (Claims 4, 10-13, 20-22)
(1) In the composite silica grout, the strength of the sand gel is mainly determined by the content of water glass. On the other hand, colloids have the effect of reducing the amount of gel shrinkage, but hardly contribute to the increase in strength. If a certain amount is contained in the silica solution, the amount of shrinkage can be reduced regardless of the concentration of water glass. Therefore, it was found that in the acid composite silica, the durability depends on the colloid and the strength should depend on the water glass. Moreover, it was found that when the content of water glass increases, the amount of shrinkage decreases as compared with the case where the content of water glass is low. It is not necessary to keep the ratio of colloid to water glass in the total silica amount constant because the amount of water glass is increased, and the colloid content is kept constant to increase the durability and consolidation strength of the sand gel. It was found that a sand gel having high durability and high consolidation strength can be obtained by increasing the content of water glass. In the above, the amount of colloid is selected in the range of 0.5 to 15 g per 100 cc of silica solution according to the particle size of the soil, water permeability coefficient and void conditions (Table 2), and the amount of water glass used is determined according to the required strength. Just do it. If the particle size is small, the hydraulic conductivity is small and the gap is small,
Even if the amount of colloid is small, the effect of gel shrinkage is small.
In this case, it was found that even if the amount of water glass is increased, the bond with the sand is increased, so that the skeleton is strengthened even if there is contraction, so that durability is obtained. In this case, the value of the constant colloid amount is in the range of 0.5 to 15 g in 100 cc of the silica solution, and the amount is selected according to the ground conditions, particle size, and soil density (claim 16).

(2) Corresponding to ground conditions, particle size and density, the powder is added to the acidic silica solution as described above to reduce shrinkage. The selection of powder and the amount added are as described above.

(3) The strength and durability of the sand gel vary depending on the ground condition, but the strength and shrinkage of the homogel will be constant over time depending on the composition and blending, so that the homogel itself will be solidified from the condition of the injected ground due to the durability of the homogel itself. Can be estimated. (Claims 11-16, 19)

Based on these studies, the evaluation of durability is expressed numerically on the basis of composition and concentration of silica, silica concentration in the total silica amount, colloid concentration, water glass concentration, gel volume change and strength, and for injection purposes. It is possible to carry out a compounding design that provides the corresponding durability (Table 4).
Durability evaluation items are set, Table 4 shows the evaluation level of the durability improvement effect according to the injection purpose, and auxiliary means for improving durability are added to Table 4 based on the volume change of silica gel. Example of quantitative evaluation Show. (Claims 14-17)

  As described above, an economical composition can be determined by quantitatively evaluating the durability of the active composite silica or silica sol. In the active composite silica, the volume shrinkage due to the content of the active silica colloid is adjusted to improve the strength reduction rate.

FIG. 42 shows the shrinkage of the gel of acidic silica sol using water glass with a molar ratio of 3.75 and 4.35 and the shrinkage of the gel of acidic composite silica composed of water glass and silica colloid with a molar ratio of 3.75. Accordingly, the active composite silica at the same molar ratio or the same colloid / water glass ratio (hereinafter referred to as colloid content) tends to have a smaller volume shrinkage as the concentration of the chemical solution increases. Further, when the total amount of silica in the injection material is the same, the volume shrinkage tends to decrease as the colloid content increases.
From FIG. 41 to FIG. 43 and FIG. 53, it can be seen that the volumetric shrinkage decreases as the colloid concentration increases regardless of the silica concentration of the injection material.

In the active composite silica grout, the amount of colloid used is determined according to the durability level from FIG. 42, FIG. 43, FIG. 44, FIG. 46, FIG. 52, FIG. 52 and 54, it is understood that the amount of water glass used (silica sol concentration) may be adjusted according to the required strength. Furthermore, with reference to FIG. 54, it is possible to grasp the fact that it is within the limit of the strength reduction of the sand gel, confirm the durability by the quantitative evaluation of the durability level in Table 4, and perform the blending design required for the durability period.

Table 4 shows an example of quantitative evaluation of the durability level. Durability level is quantified for strength reduction rate of consolidation, volume change of homogel, and silica leaching from consolidated body (homogel or sand gel), and evaluation criteria according to injection purpose and durability period (service period, timed durability) It is possible to select numerical values and refine the design based on experience and results.
The initial value of the durability strength is a value within a period of one year. Usually, the strength is 7 days or 28 days, but it can be selected according to the purpose.

The numerical values for quantitative evaluation of durability shown in Table 4 are examples. Since the durability is based on the durability period corresponding to the purpose, the evaluation numbers are set at a level corresponding to the durability period. The durability level and the items that affect the level and durability are strength change rate, shrinkage rate, silica leaching rate, and the period requiring durability is permanent durability, timed durability, service durability, convergence durability If the strength does not drop below 50%, it is positioned as a durable grout, and if it is below 50%, it is not a durable grout. Level I is defined as convergence durability that increases in durability over time or continues at a constant value. (Claims 12-14, 16, 17)

In Level II, the durability will remain at a constant value during the service period, or even if it tends to decrease, it will eventually become a constant value. Further, even when the strength reaches a peak and then decreases, what is maintained at a predetermined strength during a predetermined period, that is, a service period, can be said to be timed durability. The level that satisfies the durability condition during the service period. Level III is so small that leaching of silica is almost negligible, and sufficient persistence of consolidation is obtained, but deterioration of durability is inevitable, and it is unclear whether durability can be maintained for a specified period, or environmental conservation It is unclear from the point of view of the property, but the caking property is used for long-term temporary construction because it can be predicted for its durability during the service life. Level IV, silica is leached and durability is not predicted.

  In addition, the durability affects the volume change of the homogel and the strength of the consolidated sand depending on the density and particle size of the soil, and also affects the strength reduction rate. Moreover, if the ratio of the colloid in the total amount of silica is increased, the volume change and the strength decrease are improved or almost zero.

From Table 4, the colloidal content in the injection material at level 1 and level 2 is 0.5 to 15 g per 100 cc of silica solution, the volume change of the homogel is 0 to 20% (measuring flask measurement method), and the colloid amount is the gel shrinkage. The durability is improved by reducing the amount. The amount of colloid may be selected considering the fact that the gel shrinkage has a large effect on a ground with a large space or a rough ground and has a small effect on a fine ground. On the other hand, the content of water glass is determined by the required strength. Since it was found that the shrinkage does not increase by increasing the amount of water glass, the above setting became possible. In the injection material at level 3, the silica content is derived from water glass, and the shrinkage of the gel is increased.
The following can be understood by summarizing Table 4.
Non-alkaline (pH is 10 or less), leaching from homogel is within 5%, leaching from sand gel is within 10%, volume change of homogel is 0-20% in volumetric flask measurement method, and / or by plastic mold If it is within the range of 0 to 25% in the cylinder measurement method and there is no decrease in the strength of the sand gel or homogel, or it can be considered that the strength will eventually converge to the predetermined strength, it is considered as a permanent endurance and is also temporarily set in the permanent injection It can also be applied to injection. Moreover, the volume change of the homogel is 20 to 35% in the measuring flask measuring method and / or 25 to 35% in the cylindrical measuring method with a plastic mold, and there is a decrease in the strength of the sand gel, but the limited period or service period Then, since the caking property persists, it can be applied for timed durability, limited durability, and long-term temporary use.
However, alkaline and homogel silica leaching 5-100%, leaching from sand gel 5
When the volume change of the homogel is ˜100% and the homogel volume is 5˜100%, the durability is assumed to be short-term temporary.
Also, non-alkaline composite silica colloids composed of large silica and small silica are excellent in terms of durability against ground voids and diverse groundwater pressure. Further, by adding fine particle silica according to the voids and inhomogeneity of the ground, or by increasing the silica concentration, the primary injection is performed to reduce the influence of silica gel shrinkage and improve the durability.
In particular, in the above case, a composite silica colloid composed of large silica and small silica, and when the strength of the sand gel is stable for 200 days or more, it can be regarded as long-term durability. (Claims 7, 12, 16)

As described above, according to the inventor's research, silica grout has different strength development in the long term due to the type of silica used as the main agent, the blending ratio, and the volume shrinkage after gelation by the additive, It has been clarified that the particle size and gap, ie density, of sand in the soil affects the volume shrinkage and strength development, and the groundwater dynamic gradient in the ground influences the durability as well as the soil quality.
In addition, the type and amount of the acid neutralizing agent greatly affect the environmental conservation mentioned above, that is, groundwater quality, aquatic organisms, concrete structures, etc., and these are related to the strength, gel time, etc., that is, the construction method. The inventor found that there is. That is, the durable silica grout, the environmental conservation and the construction method are related to each other, and therefore, a durable silica grout prescription and ground improvement method integrated with these are required. The present inventor has made it possible to apply an appropriate silica grout in accordance with these improvement objectives, durability conditions and environmental conservation (claims 26-31, FIG. 79).

  On the other hand, durable ground improvement is used directly under existing structures and in the vicinity of infrastructure, etc., and when it is used with acid injection material, environmental conservation for existing structures such as concrete, aquatic organisms and human bodies is important. become. In particular, concrete must take into account the effects of acids such as sulfuric acid (claims 2, 4, and 14).

[Durable grout and environmental conservation]
The present inventor further made the following invention which is suitable for environmental conditions. (Claim 7)
1. Safety for concrete underground structures A ground improvement method using a silica solution according to any of the following methods when safety for the environment is required.
(1) The use of phosphoric acid as an acid or a mixed acid of phosphoric acid and sulfuric acid to reduce the amount of sulfuric acid used to neutralize the alkali content of silica to ensure safety for concrete structures. (2) A sequestering agent is added.
(3) The amount of acid used is reduced by increasing the proportion of colloid used and reducing the amount of water glass used.

2. Safety against water quality: A method of adjusting the type, amount and ratio of acid as a neutralizing agent for fish shellfish and algae, or adjusting the ratio of colloid to water glass.

When the mortar specimen is embedded in an acidic silica solution having the same volume of phosphoric acid and sulfuric acid as neutralizing agents and cured, a colored coating on the surface of the mortar specimen is formed within approximately one year. This coating was found to be effective in preventing alkali (Ca) elution from inside the mortar and preventing the penetration of sulfate ions into the specimen. Table 10 shows the analytical value of the white coating on the surface of the specimen.

The X-ray diffraction of the white coating is shown in FIG. For comparison, an acidic silica solution was made with a neutralizing agent containing only sulfuric acid and the same test was conducted. The mortar specimen was partially damaged in one year. Phosphoric acid (75% solution) and sulfuric acid (75% solution) as neutralizing agents, the ratio of phosphoric acid and sulfuric acid is converted to 75% concentration, and 15% by volume or more, preferably 50% of phosphoric acid in the total acid volume It was found that when used above, mortar has a protective effect against sulfuric acid. According to the experiment, in the case of 50% or more, no problem occurred even if it was cured in gel for 16 years or more. (Claim 7)

  Due to the same effect, the peripheral part of the concrete structure may be adjusted with an acidic silica solution using a sulfuric acid-based neutralizer. The sequestering agent used in the present invention includes condensed polyphosphoric acid such as tetrapolyphosphate, hexametaphosphate (especially sodium salt is good), tripolyphosphate, pyrophosphate, acidic hexametaphosphate, acidic pyrophosphate, etc. Examples thereof include salts, ethylenediaminetetraacetic acid, nitrilotriacetic acid, gluconic acid, tartaric acid, citric acid, and salts thereof, and practically condensed phosphates are preferable.

  Examples of phosphoric acid compounds include phosphoric acid, various acidic phosphates, neutral phosphates, and basic phosphates. In this way, a durable ground in the vicinity of the concrete structure can be formed by selecting a composition according to the environmental conditions.

  Also, as a safety against water quality, the amount of acid used is reduced by adjusting the type, amount and ratio of acid as neutralizing agent for fish shellfish and algae, or by adjusting the ratio of colloid and water glass ( It is possible to obtain an injection material having a small amount of reaction product and a small change in water quality.

[Elemental technologies related to durable grout injection and their integration]
[Integrated technology]
As described above, in the ground improvement method with excellent durability, the factors affecting the durability described in the section of the problem (0020) to be solved by the invention and the injection conditions for improving the durable ground are clarified ((1) (5)), and the elemental technologies (1) to (6) described in the heading (0012) were developed and integrated, and they were found to be related to each other rather than being independent of each other. And improved durability ground. (Fig. 79) (Claims 23-33)

[Relevance of durability factors]
In general, ground conditions, site conditions, and required improvement effects are given in the design, and the implementation side can select the composition and concentration of the `` injection material '' and the composition design, the selection of the `` injection method '' and the injection design The composition of the injection material satisfying the “environmental conservation”, and the empirical data thereof. In actual construction, under the ground conditions, construction conditions, and environmental conditions that differ from site to site, `` In order to improve the ground to clear the predetermined quality to satisfy the durability, the chemical ground improvement effect by gelation of silica is The invention is easily affected by the conditions described in the section of the problem to be solved. For this reason, the three requirements in FIG. 79 and the elemental technologies constituting them are related to each other, and one is good and the other is bad. Because it is easy to occur, it is possible to establish a durable ground improvement method that integrates them for the first time by performing quality control in combination design and construction that combines elemental technologies so that the purpose of improvement can be obtained using on-site soil. (Fig. 79)

First, the injection material must be injected at a small discharge speed within the limit pressure that allows the soil particles to infiltrate using silica grout with excellent durability and injecting from the injection target range while preventing diastole ( Figure 15). If the discharge speed is excessive, the durability of the injection solution is excellent, but the durability of the injection ground cannot be obtained if the injection solution deviates in a pulse shape (FIG. 16 (a)). Therefore, an injection method that allows such an injection design must be used.
On the other hand, since economical construction is required as a large-scale ground improvement method, the number of drilling holes can be greatly reduced if the drilling interval can be increased (1.5-4 m intervals). In this case, since the injection volume and injection time of the injection stage are extremely large, it has an ultra-long gelation time that allows continuous injection for a long time, and an osmotic solidification characteristic that enables a wide range of osmotic solidification properties and durability. It is necessary to be an injection material that develops sex. (Fig. 4, Fig. 32-57, Table 11) In order to obtain durability by gelation for a long time, it must be a silica solution in an acidic region from which alkali that causes deterioration of silica grout is removed (Fig. 3) (claim) Item 1-4).

In order to be able to improve the durability ground by silica grout, the following durability requirements related to each other must be combined to meet the durability purpose and durability durability corresponding to the durability period.
(B) Durability factors of silica grout ・ Silica grout composition, silica concentration, air gelation time, soil gelation time and permeation solidification in specified region ・ Silica leaching from gel ・ Gel shrinkage ・ Gel Strength ・ Relationship between gel durability and sand gel durability ・ Sand gel durability (silica leaching, solidified soil strength and changes over time)
・ Soil gelation time and permeation solidification within a specified range

(B) Characteristics and construction method of injection ground ・ Gran grain size and particle size distribution ・ Soil density ・ Soil properties ・ Ground condition ・ Construction method (Injection hole interval, gelation time, injection amount, discharge amount per minute, injection Stage, primary injection and secondary injection)

(C)
-Formulation design method using on-site collected soil, quality control of silica grout and injected consolidated ground.
・ Mixing control, control of injection volume and injection speed ・ Silica grout composition, silica concentration and gelation time (gelation time and pH during compounding, pH of soil, gelation time in soil, penetration distance and gelation time Management / Management of construction methods / Quality control by the silica amount of the consolidated ground after construction from the silica amount of the injected solution and the silica amount of the consolidated soil, and / or confirmation survey by core sampling, environmental management, water quality and soil structure Environmental conservation for goods

  Durable silica grout is related to the type and concentration of silica, the type and amount of acidic reactant, the alkali content of the main material, and the silica concentration. In the present invention, in the ground improvement that satisfies the above-mentioned durability conditions, the three requirements of the compounding prescription of the injection material, the injection construction method, and the environmental conservation are not independent of each other, but are related to each other. In practice, the problem of the above-mentioned durable ground improvement method is by selecting the injection material as an integrated technology corresponding to the injection purpose and construction conditions and using the ground improvement method using it. Can be solved. (Claims 26-30)

  For this reason, the present inventor has developed the following elemental technologies and systematized them to make it possible to improve the durable ground for the first time. These are related to each other and enable a durable ground improvement method using durable grout (Fig. 79).

  The inventor has clarified the composition and concentration range of the non-alkaline silica grout, and the gelation time and the infusion solution in the infused ground to ensure solidification into a predetermined region in the ground when the non-alkaline silica grout is injected. The relationship between the pH behavior and the injection time was clarified from the permeation and consolidation characteristics, focusing on the gelation time in the soil and its behavior. The soil strength of the injected ground is determined by the condition of the ground to be injected and the strength of the gel over time of the injected grout. Moreover, the shrinkage of the gel over time increases the strength of the consolidated soil over time, while if it becomes excessive, the strength of the consolidated soil decreases. That is, the present inventor focused on the change in volume and strength of the homogel over time, and studied how it would affect the durability of the injected ground.

As a result, it was found that the relationship between the strength over time of the consolidated soil and the change in strength, that is, the durability period, can be known through the strength over time and the shrinkage of the homogel. This makes it possible for the present inventor to grasp the durability of the consolidated soil based on the composition of silica and the chemical change, physical property change, and strength change of the gel over time. The reason why the infusion design for ground improvement of durable grout is unclear is because it depends not only on the durability of the injection material itself but also on the state of the soil into which it is injected. In addition, when the durability is counted from several tens of years to 100 years, the final change is not well understood. Therefore, the present inventor has paid attention to the composition of the non-alkaline silica grout gel from which the alkali has been removed, the permeation consolidation characteristics, and the change in the characteristics of the gel. That is, it has been found that the leaching of silica from the gelled product, the shrinkage of the gel, and the strength of the gel over time are determined over time depending on the composition and concentration of the silica grout. That is, it can be grasped quantitatively.

  The inventor has found that the gel shrinks more or less over time, with increasing strength. However, unlike sand gel, the increase in gel strength takes a constant value over time, and the final strength of the gel should be non-alkaline, as it does not change or decrease in strength depending on the soil condition as in sand gel. For example, it is determined by the composition, shrinkage rate and curing period. On the other hand, the durability of the strength of the consolidated sand is determined by the condition of the ground to be injected, the amount of gel shrinkage, the silica concentration, and the permeation consolidation in a predetermined region. Accordingly, it is possible to estimate the durability of the sand gel that varies depending on the ground conditions using the durability of the gel that can be quantitatively grasped as a mediation. Moreover, it was found that the physical property change of the gel can be obtained in a much shorter time than the sand gel by the heating acceleration test, which further facilitates the grasp of the durability of the consolidated soil. In this way, the present inventor has developed the durable ground improvement technology by developing the following durable element technologies that constitute the durability requirements related to each other in FIG. An improved construction method is possible.

  The present invention systematically enables the improvement of the ground of a durable grout that has been unclear in the past and its durability injection design. According to the present invention, the structure of durable silica and the physical properties of long-term durability are clarified, and the durable silica and durability are obtained to improve the filling purpose by injecting into the injection ground and surely infiltrating and consolidating into a predetermined region. The ground improvement method using silica was made possible. For this reason, it is possible to grasp the durability period according to the purpose of injection, select a silica grout based on a quantitative evaluation example of the durability level, and determine the silica concentration and composition in consideration of environmental conditions. In addition, the durability was improved, the composition was designed using on-site collected soil, the silica content was measured, the strength of the injected ground was grasped from the silica content of the injected ground, and the specimen with the injected solution Acceleration test of the product allows the confirmation of the compounding prescription and injection effect required for the durable ground by measuring the strength during the durability period and performing the compounding design that can obtain the injection design strength, and the Internet system Systematization of the durable ground improvement method is made by the management method used, and the practical ground improvement method that satisfies the injection purpose is made possible.

Claims (33)

A silica grout having a pH of 1 to 10 used in a durable ground improvement method for improving the ground by injecting a silica injection solution into the ground, the silica injection solution being either one of silica colloid or water glass Or, when one or more of an acid or a salt as an active ingredient is used as an active ingredient and the silica injection solution is composed of a colloid, water glass and an acid, the silica concentration and water glass resulting from the silica colloid Silica concentration ratio is 100: 0 ~ 0: 100, silica concentration is 0.4 ~ 40wt%, silica molar ratio is 2.0 ~ 100, and gelation time is selected from a combination of 10000 minutes from instantaneous setting. A durable silica grout, wherein a prescription that provides durability according to the purpose of injection is selected within the above range. 2. The silica grout according to claim 1, wherein the silica injection liquid is a silica grout having the following composition (1) to (3), and a prescription for obtaining a predetermined durability according to the purpose of injection and the ground condition is as follows: Durable silica grout characterized by being selected within the range of
(1) The silica concentration of the silica injection solution is selected from the following range.
0.4% ≦ SiO ₂ · T ≦ 40%
0 ≦ SiO ₂ · S ≦ 30%
0 ≤ SiO ₂ · C ≤ 40%
However,
The silica concentration resulting from the silica colloid is SiO ₂ · C (%),
The silica concentration resulting from the water glass or silica sol is SiO ₂ · S (%)
The total silica concentration in the silica injection solution is SiO ₂ · T (%) (= SiO ₂ · C (%) + SiO ₂ · S (%
)).
(2) The gel time of the silica is adjusted using the silica concentration and the reactants, and is selected within a range of 10,000 minutes or less from instantaneous setting. The silica colloid is selected from the ion exchange method, the ion exchange membrane method, and the metal silica method. Or silica colloid obtained by the precipitated silica method or one or more kinds of silica fine particles as silica colloid, water glass is a silicate having a molar ratio of 2.0 to 5.0, or an acidic silica solution containing water glass and acid as active ingredients It is selected from one or more types, the reaction material is selected from sulfuric acid and / or phosphoric acid as the acid, and the salt is selected from monovalent or polyvalent metal salts or sequestering agents.
(3) A gelling time for osmotic consolidation in a predetermined region and a prescription that is injected while managing a predetermined amount of osmotic injection at each stage to reduce deviation from the predetermined injection region. The silica grout according to claim 1 or 2, wherein the silica grout is blended in a curve of pH and gel time of a silica solution, wherein the S line is a silica sol line composed of water glass and acid, and the C line is a silica colloid line. When the D line is a composite silica line of silica colloid, water glass, and acid, the silica sol line showing the minimum gel time at the same pH is 10000
The application range E is the range with the upper limit of minutes, and the S-line of the time-lapse line corresponding to the time axis of the sand gel's durability is the silica sol line, the C-line is the silica colloid line, and the D-line is the composite silica line. Assuming that the range surrounded by the line and the minimum line is the application range F, within the range of the application range F, within the endurance period according to the injection purpose, the silica concentration and gelation time at which the strength satisfying the predetermined durability can be obtained. Durable silica grout, characterized in that the distribution to satisfy is selected from range E. The silica solution according to claim 1, 2 or 3, the gelation time for permeating and consolidating into a predetermined region using any one or more of the following methods, and a predetermined amount of permeation injection at each stage, and managing the predetermined injection region A durable silica grout characterized in that a predetermined durability is obtained by reducing deviation to the outside.
(1) The gel time is adjusted by adjusting the silica concentration, pH, acid and salt addition amount, and adjusting the ratio of colloid to water glass in the total silica amount.
(2) The strength and gelation time are adjusted by using either sulfuric acid or phosphoric acid as an acid reactant or in combination, as an acid reactant, in addition to the silica concentration, composition, and amount of reactant added.
(3) A durable silica grout, characterized in that the effect on gel time adjustment, gel shrinkage, strength and environmental integrity is adjusted by the composition and concentration of the silica solution and the reactive agent in the silica grout. + Colloid + Acid glass grout with acid as active ingredient Water glass without colloid + Silica solution with acid as active ingredient presents an acidic region, the silica concentration or the amount of colloid and acid in the silica concentration, or acid By adjusting the amount of sulfuric acid or phosphoric acid or the ratio of phosphoric acid and sulfuric acid, the amount of shrinkage of the gel is reduced, the strength is converged to a predetermined value or more, and the effect on the environment is reduced. Durable silica grout characterized by improved properties.
(4) In the silica grout, the silica amount resulting from the colloid is a durable silica grout of 10 to 100% of the total silica amount, and sulfuric acid or phosphoric acid is used as the acid of the silica grout, and both are used in combination. In this case, the ratio of phosphoric acid in the acid is 75% sulfuric acid, converted to 75% phosphoric acid, and the phosphoric acid is 15-50% by volume of the total acid amount. Durable silica grout that reduces the effects of
(5) In the silica grout, the composition of the silica solution is adjusted by adjusting the silica concentration, the ratio of colloid to water glass, the ratio of sulfuric acid and phosphoric acid, and the gelation time in the vicinity of weakly acidic to neutral. (GTs), soil pH (pH _S ), permeation distance and injection time related to injection hole interval, and on-site conditions, adjustment and composition of air gelation time (Gt ₀ ) and air pH (pH ₀ ) Select the ratio of colloid in the total silica from 10 to 100% and the ratio of phosphoric acid to the total acid (sulfuric acid + phosphoric acid) from 15 to 100%. Durable silica grout that can be injected within the limits of interparticle penetration to reduce deviations from a given injection area and to consolidate in a wide range. (6) In the silica grout, the prescription for the silica grout is to select the prescription to be injected while managing the gelation time in the soil and the predetermined amount of osmotic injection at each stage to reduce the deviation outside the predetermined injection region. By using a prescription in which the relationship between air gel time (GT ₀ ), soil gel time (GTs ₀ ), and injection time (H) is in the following range, injection outside the prescribed injection region is reduced. Durable silica grout characterized by obtaining ground durability according to the purpose.


Preferably β = 0.68-0.34, ie 0.2H <GTs ₀ <3H

However, the silica concentration is 0.4 to 40%, the discharge amount per minute is 1 to 30 L / min, the stage length per stage is 33 cm to 4 m, and the injection point is one point injection or multi-point injection or A durable silica grout characterized by columnar injection, gel time of 10,000 minutes from instantaneous setting, injection hole interval of 1 to 4 m, and discharge rate per minute within the limit penetration range. The silica grout according to any one of claims 1 to 4, wherein the silica grout sets a compounding prescription in which the injection ground satisfies a predetermined durability based on the following factors related to each other: Silica grout.
1. 1. Physical properties of homogel and sand gel; leaching of silica in homogel, change in volume, change over time in strength or rigidity, leaching of silica in sand gel, change in strength of sand gel over time 2. Physical properties of silica solution; pH, silica concentration, colloid concentration, water glass concentration, molar ratio, composition ratio and additive, gelation time Soil condition; soil particle size, density, soil properties (soil pH, Ca content, etc.), groundwater condition Osmotic solidification; gelation time (in-air gelation time, soil gelation time), penetration limit speed Construction method: Injection method, injection hole interval, injection stage, injection amount, injection speed, injection time The silica grout according to any one of claims 1 to 5, wherein the silica grout is a non-alkaline composite silica solution containing a colloid and water glass, and the silica colloid and water glass have a predetermined durability according to the following formulation. A durable silica grout that is characterized in that it has improved properties or improved durability.
(1) In the silica grout, the consolidation strength mainly depends on the total silica concentration or water glass concentration, and the reduction of homogel shrinkage is a silica grout mainly depending on the amount of colloid, and the colloid content of the silica injection solution Durable silica grout characterized in that the amount is determined in consideration of the durability depending on the ground conditions in the range of 10% or more of the total silica amount, and the water glass content is determined according to the required strength.
(2) A silica grout in which the volume shrinkage is adjusted mainly by the content of silica colloid to improve the rate of decrease in strength, or the strength of improvement is increased mainly by the concentration of water glass.
(3) In the silica grout, increase the molar ratio of water glass or add a colloid to reduce the strength of the consolidated soil accompanying the shrinkage of the gel of the acidic silica sol, or increase the molar ratio by adding colloid, or fine silica as a silica colloid A durable silica grout that suppresses strength reduction by adding a colloid or making the water glass concentration 10% or more.
(4) In the silica grout, the silica concentration of the solidified soil by the silica colloid is low in strength, but the property of slow strength development is mixed with the silica colloid solution and water glass or acidic silica sol to make acidic composite silica. According to the above, a durable silica grout characterized in that the strength is increased while the silica concentration is low and the strength expression is accelerated, and in the acidic composite silica, the silica colloid is 10% or more of the total silica amount, A durable silica grout that reduces strength reduction even when shrinkage occurs by increasing the total silica content by increasing the water glass concentration in the silica solution when the silica colloid is less than 10% of the total silica content. .
(5) In the silica grout, the colloidal content is 10% or more of the total silica amount per 100 cc of silica solution or 0.5 to 15 g, and the water glass content is a durable silica grout determined by the required strength of sand gel.
(6) A durable silica grout characterized in that durability is improved by reducing homogel shrinkage or sand gel strength reduction by using silica fine particles as an active ingredient in the silica grout.
(7) In the silica grout, as a silica colloid of fine particles, white carbon,
By adding one or more kinds selected from refined silica gel, precipitated silica (salt salted silica), and clay, silica colloid content was increased, and silica gel shrinkage was reduced to improve durability. Features durable silica grout. The silica grout according to any one of claims 1 to 6, wherein the durable silica grout has the following characteristics.
(1) In the silica grout, the pH is non-alkaline, the silica leaching is within 5% of the homogel, the sand gel is within 10%, the strength of the homogel does not decrease, and the volume change rate of the homogel is 0 to Durable silica grout that is within a range of -20%, or 0 to -25% as measured by a cylindrical measurement method, and the strength reduction of the sand gel is 0 or the final strength converges within a predetermined range. In the present invention, non-alkaline means a pH range from acidic to 10.
(2) In the silica grout, the pH is non-alkaline, silica leaching is within 5% of homogel, sand gel is within 10%, and the volume change rate of homogel is -20 to -35% according to the volumetric flask measurement method.
In addition, a durable silica grout that is within a range of -25 to -40% by a cylindrical measurement method, and that maintains its caking property for a limited period or service period even if the strength decreases.
(3) In the silica grout, when the vertical axis is a scale of the homogel deformation coefficient E ₅₀ (MN / m ² ) and the horizontal axis is a scale of the volume change rate εv (%) of the homogel in the semilogarithmic graph, E ₅₀ ( 0.1 MN / m ² ), εv (20%) point to E ₅₀ (100 MN / m ² ), εv (30%) point to the left of the straight line that passes through the straight line, if it is a homogel with E ₅₀ and εv A durable silica grout with a silica grout that does not decrease the strength of the silica, and a silica grout that reduces the strength of the sand gel if in the right region.
(4) Durable silica grout obtained by predicting the strength of silica grout sand gel during the durability period from the properties of homogel strength and volume change rate.
(5) In the silica grout, the SiO2 concentration is 5 to 15%, the volume change rate of the homogel is 30% or less, and the strength ratio of the sand gel with the maximum strength up to 400 days is 100% or more to 50 Durable silica grout that converges to the desired strength in%.
(6) A durable silica grout to which a fine particle silica colloid is added in response to the excessive amount of homogel shrinkage that causes a decrease in strength.
(7) In the silica grout, the volume change rate of the homogel is reduced by one or more of the following methods according to the ground condition and the purpose of injection, and the durability against groundwater pressure is improved, or the environmental conservation is improved. Improved durable silica grout.
(A) 1. Add silica fine particles as colloid or colloid to adjust volume shrinkage to improve strength reduction.
2. Increase the silica concentration or increase the deformation coefficient.
3. Increase the molar ratio.
(B) Primary injection of instantaneous grouting and suspension grouting to reduce large voids in the ground, groundwater drainage and ground inhomogeneity, and reduce the effects of shrinkage of homogels injected into the ground.
(C) Reduce the impact on soil structures and water quality.
(8) A weakly acidic to neutral silica grout having a silica concentration of 0.4 to 3%, which is a durable silica grout containing silica powder, microbubbles or clay.
(9) The silica solution is a silica colloid solution and has a pH of weakly acidic to weakly alkaline and a silica concentration of 10 to 40%, and has a water pressure resistance such as water-stopping purpose, storage, containment of industrial waste, etc. Durable silica grout used for the purpose of constructing a water stop zone.
(10) A durable silica grout wherein the silica solution reduces the environmental impact by any of the following methods.
1. Durable silica grout is injected into the vicinity of concrete underground structure by the following method.
(a) Phosphoric acid is used as the acid or a mixed acid of phosphoric acid and sulfuric acid, and the ratio of phosphoric acid and sulfuric acid is adjusted, and the ratio of phosphoric acid is 15% or more of the total acid and silica. Reduces the amount of sulfuric acid used to neutralize the alkali content of the concrete to ensure the safety of the concrete structure. However, the phosphoric acid and sulfuric acid concentrations are converted to 75 wt%.
(b) Add a sequestering agent.
(c) The amount of colloid used is increased to reduce the amount of water glass used, thereby reducing the amount of acid used.
2. Adjust the amount and ratio of pH, colloid and water glass for safety against water quality.
3. Phosphoric acid (75% solution) and sulfuric acid (75% solution) as neutralizing agents, the ratio of phosphoric acid and sulfuric acid is converted to 75% concentration, and more than 15% by volume of phosphoric acid in the total acid volume, preferably If it is used at 50% or more, the protective effect of mortar against sulfuric acid is obtained. The durable silica grout according to any one of claims 1 to 7, wherein the silica injection liquid is a grout injected into the ground within the following range (A), and any one or more of the following (B) Based on the ground condition, injection hole interval or injection condition, the composition and gelation time are set so as to satisfy the relationship between soil gelation time (GT _S0 ) and injection time (H), and the silica grout injection region A durable silica grout characterized by obtaining a durability note according to the purpose of injection by penetrating and consolidating into a predetermined injection region while reducing outward deviation.
(A) Silica concentration is 0.4 to 40%, discharge amount per minute per stage is 1 to 30 L / min, stage length per stage is 33 cm to 4 m, injection point is single point injection or multipoint injection Alternatively, it is a columnar injection, a silica grout in which the gel time is set to 10,000 minutes from the instantaneous setting, the injection hole interval is set to 1 to 4 m, and the discharge amount per minute is injected at an injection speed within the limit penetration range.
(B)
(1) In the silica grout, the pH of the silica solution (pH ₀ ) is adjusted to be more acidic than the pH of the ground, and the injection speed is injected within the limit speed of soil particle infiltration to the ground. The decrease in strength due to the dilution of the silica concentration and the deviation from the injection area due to the increase in the penetration distance of the silica can be reduced by increasing the pH of the silica injection liquid in the ground or by promoting the gelation by the reactive components in the ground. A silica grout in which a composition and a gel time of an injection solution that permeates and consolidates into a predetermined injection region and obtains durability according to the injection purpose are set.
(2) In the silica grout, the air pH ₀ is 6 ≧ pH ₀ ≧ 1.5, and the pH of the ground is 6-10.
However, pH10 is the ground with a lot of Ca or the ground where CB was primarily injected.
Instantaneous setting ≤ GT ₀ ≤ 10000 min, GT ₀ ≥ H ≥ GTs ₀
^{k = 10 0 ~10 -5 cm /} sec, the injection hole spacing 1.0~4m
A silica grout entering with an air gelation time (GT ₀ ) that is shorter than the injection time (H) in the soil gelation time (GT s ₀ ).
(3) In the silica grout, a. Ground condition, b. Injection speed and pressure within the limit of osmotic injection, c. Gelation time in soil (GTs ₀ ), d. Stage length corresponding to each injection method A silica grout that reduces the deviation outside the predetermined range by setting the composition based on the injection amount per injection stage and the injection time (H) and achieves permeation and consolidation into a predetermined injection region.
However, the injection time H is a time obtained by dividing the injection amount of one stage or the injection amount of one batch by the injection amount per minute within the limit speed of osmotic injection.
(4) In the silica grout a. Composition of injection solution and air gel time (GT ₀ )
b. ・ Injection hole interval ・ Stage length ・ Injection amount per stage ・ Injection amount per minute ・
Injection time per stage (H)
c. If the ratio of the gelation time (GTs ₀ ) and (H) in the soil between the soil collected at the site and the injected solution is β = H / GTs ₀ , A silica grout in which a and b are set so as to be within the range of the β data that has achieved the purpose of injection obtained by a set confirmation test.
(5) In the silica grout, the silica injection solution includes the in-air gel time (GT ₀ ) or in-air pH (pH ₀ ) and in-soil gel time (GTs ₀ ) or in-soil pH (pH _S0 ) and the infusion time. A silica grout obtained by setting a composition and a concentration and composition in which air permeation consolidation within a predetermined range is obtained from (H), the injection hole interval, or the permeation distance (L), and air gel time or air pH ₀ .
(6) A silica grout wherein the silica grout has a gel time (GT ₀ ) and a soil gel time (GTs ₀ ) set in the following ranges. However, the gelation time in the soil (GTs ₀ ) refers to the gelation time when the soil in the field and the injection solution are mixed, or the gelation time of the silica injection solution in a state where the injection solution penetrates the soil and is stationary.

However, pH ₀ = 1.0 to 10, GT ₀ = 10000 to 0.1 minutes, GT _S0 = 6000 minutes to 10 seconds.
(7) In the silica grout, the gelation time in the air is GT ₀ , the gelation time in the soil is GT _{S0, and} the injection time of one stage is H,

Preferably,
β = 0.68-0.34
That is,
0.2H <GTs ₀ <3H
The composition and gelation time (GT ₀ ) or pH _{0 of the} liquid mixture with correction according to the ground conditions, injection hole interval or consolidation diameter, injection method, stage length, or further based on the construction results A silica grout that sets and penetrates into a predetermined injection area.
However, air pH (pH ₀ ) = 1.0 to 10.0, air gel time (GT ₀ ) = 0.1 to 10000 minutes, soil gel time GT _S0 = 10 seconds to 3000 minutes, soil pH (pH _S0 ) = 3 to 10, ground pH = 4.0 to 10.0, injection speed = 1 to 30 L / min, injection hole interval or consolidation diameter = 1.0 to 4.0 m, 1 stage = 0.33 to 4.0 m, injection time per stage H = 10000 to 4.4 Minutes and the injection rate should be within the critical rate of osmotic injection. Further, the range of (H) can be shortened according to practical workability and construction period.
(8) In the silica grout, when the injection ground is pH 4.5 to 8.5, and the injectable range is infiltration range between soil particles, instantaneous setting ≦ GT ₀ ≦ 10000 minutes, GT ₀ ≧ H ≧ GT _S0 , By injecting in the soil gelation time (GT _S0 ) shorter than the injection time (H) and expanding the injection region while the gelation proceeds in the soil, the silica concentration of the injection solution is reduced and the predetermined injection region Silica grout to reduce deviation.
(9) A durable silica grout characterized in that, in the silica grout, the injection amount of one stage is divided into a plurality of times, and the gel time and / or the silica concentration is changed and injected and solidified into a predetermined region.
(10) In the silica grout, in the first stage injection, the pH is low or the silica concentration is high in the initial injection, and in the subsequent injections, the pH is high or the silica concentration is low and the deviation is outside the injection region. Durable silica grout characterized by homogenizing the strength of the entire injection area and reducing acidification of the injection ground while reducing
(11) In the silica grout, ground conditions injection hole spacing, or in response to injection situation H ≧ GT _S0, H ≦ GT silica concentration in combination any or any one of _S0 and aerial gel time (GT A durable silica grout characterized in that a deviation from a region other than the injection target region of silica grout or a decrease in silica concentration is reduced by setting ₀ ).
(12) In the silica grout, one stage of injection is one stage of injection time or one stage of injection with multiple batches of injection, one stage of injection time or one batch of injection time A durable silica grout, wherein H is H, H ≧ GTs ₀ , H ≦ GTs ₀ , or a combination of these and an air gel time (GT ₀ ).
(13) In the silica grout, predetermined penetration distance passage gel time of the infusate in the ground at the time (GTsf) or pH (PHsf) and soil gelation time (GTs ₀₎ or, soil pH (pH _S0 ) As the following A, B, α, β, and based on the injection test in which the soil of the column penetration length L or γ · L is filled with soil in the field, ground conditions, injection hole interval or consolidation diameter, injection method A durable silica grout characterized in that the composition and gelation time (GT ₀ ) or pH (pH ₀ ) of the blended liquid are set according to the conditions and permeated and consolidated in a predetermined injection region.
However, here, when the predetermined penetration distance is passed, the penetration length corresponding to the injection consolidation radius or penetration length is L or γ · L, and the L or γ · L pipe is filled with the soil at the site density. After filling the gap with water, the silica injection solution is injected and the injection solution overflows. GTsf and pHsf are the gel time and pH of the injection solution at that time. H is the injection time corresponding to the injection time at the passage of the penetration length (L or γ · L) or the injection time of one stage, and γ is the coefficient for three-dimensional injection relative to L for one-dimensional injection. .
(14) In the silica grout, since the silica injection solution stays in the predetermined injection target region and solidifies, the gelation time (GT ₀ ) of the injection compounding solution corresponding to the setting of the injection stage, the ground condition, and the injection method ) And soil gel time (GT _S ), especially the initial soil gel time (GT _S0 ), the change in soil gel time (GT _S ) during injection in the ground and the amount of injection in one stage Durable silica consisting of a compounded formulation (GT ₀ ) that reduces the deviation of the injection solution at the tip of the injection region outside the injection range when the injection rate (injection rate), injection time (H), and predetermined injection is completed. grout.
(15) In the silica grout, in the injection in one stage or in the injection in one batch, the main component of the injection solution is the liquid A, the reactant is the liquid B, and the liquid A and the liquid B are mixed or joined together. Durable silica grout characterized in that H ≧ GT _S0 or H ≦ GT _S0 or these are used together to set the silica concentration and gelation time (GT _O ) of the compounded liquid according to the ground conditions. In the silica grout test method according to any one of claims 1 to 8, the gel time of an infusion solution to be infused while reducing deviation from a predetermined infusion region by using any one or more of the following methods: And test method or apparatus for setting the composition.
(1) Preliminarily measure the relationship between the silica concentration of the injection solution and the gel time, fill the pipe with the infiltration length L of a predetermined length with the soil density at the site density, fill the gap with water, and then the injection solution Injecting at a flow rate and injection pressure that does not cause boiling, the gel time in soil (GT _S ) and the pH in the soil before overflowing from the tip of the pipe (pH _S ) or / and the change in gel time in the soil and / or the penetration rate Measure the relationship between pH, gelation time, set the injection time for one stage or batch, and mix the silica injection solution and gelation time (GT ₀ ) according to the ground conditions, injection term interval or injection method
Alternatively, the test method is characterized by setting pH ₀ , or adjusting and setting the composition of the infusion solution during the infusion according to the infusion conditions.
(2) A method for testing the silica grout, wherein the gel time (GT ₀ ) and pH (pH ₀ ) of the injected solution
) And the soil gelation time (GTs ₀ ) and soil pH (pHs ₀ ) measured with the soil collected at the site, and if the injection hole interval is L, the injection soil with an injection distance of γL is filled with the site soil. After filling with water, the injection solution is injected, the pH (pH _S f) and the gel time (GTsf) of the overflowing injection solution are measured, and GT ₀ or pH _{0 is set} to GT ₀ = β ₁ GTsf or pH ₀ = Predetermined injection area by setting β ₂ pHsf and setting α, β ₁ , β _{2 according} to the ground conditions, injection hole interval L or γ · L or injection method, or further correcting based on construction results A test method characterized by setting a gel time and a composition of an infusion solution to be infused while reducing deviation from the above.
(3) A test apparatus for the silica grout, which is provided with a measurement port for an injection liquid at a predetermined position in the permeation path to measure the composition, pH and gel time of the injection liquid during injection. . In the durable silica grout according to any one of claims 1 to 8, setting a prescription that provides a predetermined durability in a durability period according to the purpose of injection by any one or more of the following methods: Features durable silica grout.
(1) A durable silica grout characterized in that, in the silica grout, durability associated with any one or a plurality of durability periods of the group B is obtained from any one of the group A or a plurality of durability characteristics.
Group A
1. Gel shrinkage and strength
2. Silica elution
3. Strength of consolidated soil
4. Environmental conservation
5. Endurance period
Group B (a) Permanent Durability: Durability that seems to last the prescribed durability permanently (b) Timed Durability: Durability that seems to maintain the prescribed durability for a certain period of time (c) Durability for the service period Durability: Durability that is expected to maintain the specified durability during the specified service period (d) Convergence durability: Durability that will eventually converge to the specified durability (e) Special purpose durability: Permanent durability However, high-strength permanent water, high-strength permanent reinforcement, bedrock still water, or industrial waste, polluted water, sealed water for energy storage, high density durability, low strength desaturation Permanent durability to enable)
(F) Non-durability; non-durable, temporary solidification that is not durable or unclear (2) In the silica grout, the long-term change characteristics of the sand gel maintain a predetermined strength during the durability period Silica grout, which is composed of silica sol line composed of water glass and acid, C line as silica colloid line, and D line as silica colloid in the curve of pH and gelation time of silica solution. When the composite silica line of water glass and acid is used, the range with the upper limit of 10,000 minutes from the silica sol line showing the minimum gel time at the same pH is the application range E, and the time line S corresponding to the durable time axis of the sand gel The line is a silica sol line, the C line is a silica colloid line, the D line is a composite silica line, and is surrounded by the maximum and minimum lines of strength over time. Is applied within the range F, and within the endurance period according to the injection purpose, the distribution that satisfies the silica concentration and gelation time that provides the strength that satisfies the specified durability is selected from range E. Durable silica grout, characterized by
(3) In the silica grout, one or more of initial strength, permanent strength, peak strength, time strength, maximum strength, service life strength, and convergence strength is used as a reference strength, and a predetermined strength according to the durability period. A durable silica grout characterized by setting a blend consisting of a silica concentration and a composition that yields a slag.
(4) The silica grout has the property that the strength of the solidified silica by the silica colloid in the acidic silica solution is high but the strength is low and the strength development is slow. By using composite silica, silica grout with high strength and quick strength development for low silica concentration.
(5) In the silica grout, by combining silica sol grout that produces a sand gel strength peak with a colloid, the strength can be kept constant or improved, or the strength can be lowered within a predetermined range, and a predetermined improvement effect within the durability period can be obtained. Sustained silica grout.
(6) In the silica grout, the initial strength of the silica gel is compounded with the silica colloid that maintains the strength of the strength over time and the silica sol where the strength of the strength of the sand gel maintains the strength over time and the silica sol that produces the peak strength. A durable silica grout that maintains a predetermined improvement effect within a durability period while keeping the improvement and strength constant, or improving, or reducing the strength within a predetermined range. (7) A durable silica grout in which the final strength of the sand gel is equal to or greater than the initial strength or converges within a predetermined strength range within 50% of the maximum strength within the durability period even if the strength is lowered.
(8) The design standard strength of the silica grout sand gel is determined depending on the purpose of injection, the durability period, and the strength within the durability period over time, the initial strength or the strength within one year, or the strength for 400 days, or the strength for 1000 days. Or durable silica grout set by normal temperature curing or warming curing at the time of blending.
(9) The indoor test target strength shall be the indoor test target strength obtained by multiplying the design standard strength by a safety factor, and the indoor test target strength shall be a strength that satisfies the injection purpose during a predetermined endurance period.
(10) A silica grout that selects a blend that satisfies one or both of the following:
(A) The initial strength of the consolidated soil using on-site collected soil of the ground to be injected is set by multiplying the consolidated strength required during the endurance period by a safety factor that takes into account changes in strength over time and / or construction. To do.
(B) The composition obtained by adding durability improvement means to the composition that provides the consolidated strength required during the durability period is the initial strength of the consolidated soil using the site-collected soil of the ground to be injected.
(C) It is set according to the purpose of injection, ground conditions, environmental conditions, and durability conditions depending on the type and amount of the acid.
(11) A durable silica grout containing a silica colloid having a particle size of 5 μm or less. The durable silica grout according to any one of claims 1 to 10, wherein the silica grout is blended with the silica grout in a curve of pH and gel time of a silica solution with S line as water glass. If the silica sol line consisting of acid, the C line is a silica colloid line, and the D line is a composite silica line of silica colloid, water glass and acid, the upper limit is 10,000 minutes from the silica sol line showing the minimum gel time at the same pH. The application range is E, and the S line of the time line corresponding to the time axis of the sand gel's durability is the silica sol line, the C line is the silica colloid line, and the D line is the composite silica line. If the range is the application range F, the specified durability is satisfied within the range of the application range F and within the endurance period according to the purpose of injection. Durable silica grout, characterized by comprising selected allocation from a range E of degrees satisfies the silica concentration and the gelation time obtained. The durable silica grout according to any one of claims 1 to 11, which is formulated and formulated according to any one or more of the following.
(1) Durable silica grout in which silica leaching is within 5% for homogels and within 10% for sandgels, the homogels do not decrease in strength over time, and the volume over time of the homogel does not decrease the strength of the sandgel .
(2) Silica leaching is within 5% for homogels and within 10% for sand gels. The homogels do not decrease in strength over time, and there is a volume change over time in the homogels. Durable silica grout that converges to a predetermined strength.
(3) A durable silica grout in which silica leaching is within 5% for homogels and within 10% for sand gels, and a predetermined sand gel strength is maintained within a durable period according to the purpose of injection.
(4) A durable silica grout in which the leaching of silica is within 5% for homogel and within 10% for sand gel, and the strength over time of sand gel is set from the strength over time of homogel.
(5) Silica leaching is within 5% for homogels and within 10% for sand gels. Homogels do not decrease in strength over time, and sand gels decrease in strength but maintain a predetermined strength within the durability period. A durable silica grout that is formulated from the concentration and composition.
(6) The silica leaching is within 5% for the homogel and within 10% for the sand gel, the strength of the homogel does not decrease over time, and the volume change rate (shrinkage rate) of the homogel is 20 to Durable silica grout with 35%, or 25-40% by cylindrical measurement method, and the strength of sand gel lasts for the service period.
(7) Silica leaching is within 5% for homogels and within 10% for sand gels, and the volume change rate (shrinkage rate) is within 20% in the volumetric flask measurement method without the homogels decreasing in strength over time. In addition, a durable silica grout that is within 25% as measured by a cylinder measurement method, and that there is no decrease in strength of the sand gel or the final strength converges within a predetermined range even if the strength is decreased.
(8) In the silica grout of (6) and (7) above, durability characterized by improving the sand gel durability by reducing the volume change rate by the following method or increasing the deformation coefficient of the homogel Silica grout.
1. Colloid or fine silica colloid is included.
2. Increase the silica concentration. Alternatively, the water glass concentration is increased.
3. Increase the molar ratio.
4. Colloid content per 100cc of silica solution is 0.5-15g.
(9) In the silica grout, the sand gel strength at the time of blending the silica grout is an actually measured value shown in the strength within 28 days or within one year or a predicted strength based on an accelerated test, and the blend is in the durability period. Alternatively, a durable silica grout having a silica concentration and composition that provides a predetermined strength according to the purpose of injection during a plurality of durability periods.
(10) In the silica grout, know the time-dependent strength of the sand gel from the initial strength and time-dependent strength change in the homogel at normal temperature or in the accelerated heating test, or the time-dependent change in volume change rate, and satisfy the purpose of injection during the endurance period. Durable silica grout that provides strength.
(11) A durable silica grout that uses a formulation that predicts the durability of the sand gel of the silica grout during the durability period from the properties of the homogel strength and volume change rate and obtains durability according to the purpose of injection.
(12) A durable silica grout characterized by adding a colloid or a fine particle silica colloid corresponding to the volume change rate of the homogel of the silica grout and the ground condition and the limit of soil injection.
The fine particle colloid has a long permeability and reduces the shrinkage of the gel when a fine particle cement containing a silica solution and a small amount of a reactive agent other than cement particles is used. In the durable silica grout according to any one of claims 1 to 12, the durability of grasping the strength in the durability period of the sand gel from the normal temperature of the homogel or the time-dependent strength of the heating acceleration test by any of the following methods: Silica grout.
(1) Durable silica grout obtained by grasping the durability period strength or convergence strength of sand gel from the durability of homogel strength over time.
(2) Durable silica grout obtained by grasping the durability or convergence strength of sand gel from the initial strength of homogel and sand gel.
(3) Durable silica grout obtained by grasping the strength of the consolidated soil in consideration of the conditions of the soil to be injected from the strength of the homogel during the durability period.
(4) A durable silica grout that grasps the strength or convergence strength of a sand gel during the durability period from changes over time in the strength and volume change rate of the homogel.
(5) A durable silica grout that estimates the strength of the sand gel during the durability period from the initial strength of the homogel.
(6) A durable silica grout comprising a formulation that predicts the durability of a silica grout sand gel during the durability period from the durability characteristics of the homogel and obtains durability according to the purpose of injection.
(7) Durable silica grout in which the strength change of consolidated soil using on-site collected soil is within the limit range of strength during the durability period.
(8) Durable silica grout obtained by grasping the durability of sand gel by the homogel warming acceleration test.
(9) Durable silica grout that is based on the final strength of the homogel, taking into account the ground conditions and estimating the durable strength of the sand gel.
(10) In the compounding formulation in which the composition of the silica grout and the silica concentration are set, the endurance period corresponding to the purpose of injection is set, and the combination of the strength within 28 days or the strength within 1 year satisfies the purpose for the lifetime A durable silica grout comprising a silica concentration and composition that provides the strength of The durable silica grout according to any one of claims 1 to 13, wherein durability is evaluated by any one or more of the following methods.
(1) In the silica grout, the silica grout used for the ground improvement method for improving the ground by injecting a silica injection solution into the ground is suitable for the durability period according to the purpose of the silica grout injection. A durable silica grout, wherein the composition and silica concentration of the silica grout are set by setting one or more of the following as items for evaluating durability.
1. Gel shrinkage
2.Elution of silica
3. Strength of consolidated soil
4.Environmental conservation
5. Durability period (2) Durable silica grout, which is a quantitative evaluation of durability according to the period related to durability.
(3) A durable silica grout that is quantitatively evaluated as an evaluation of durability according to the purpose of injection.
(4) Durable silica grout that is evaluated by setting a durability level for durability evaluation.
(5) A durable silica grout characterized by mainly determining the amount of colloid used according to the durability level and further adjusting the amount of water glass used according to the target strength.
(6) Durable silica grout with consideration of soil structure and water quality from the viewpoint of environmental conservation.
(7) A durable silica grout characterized in that the durability of the injected ground is evaluated for durability against a decrease in consolidation of consolidated soil under pressurized water permeability or leaching of silica.
(8) A durable silica grout characterized by using an accelerated method by heating curing for the durability of the lifetime in quantitative evaluation.
(9) A durable silica grout characterized in that quantitative evaluation is made by one or more of the following strengths during the durable period in the silica grout.
1. Initial strength, strength within 1 year, strength at the time of blending, strength at normal temperature or warm curing at 400-day strength or 1000-day strength
2.Permanent strength
3. Peak intensity
4.Timed strength
5. Convergence intensity
6.Service period strength The durable silica grout according to any one of claims 1 to 14, wherein one or more of the following group A is set as a durability evaluation reference item, and the durability during the service period corresponding to the injection purpose of group B: A durable silica grout characterized by
Group A (1) Silica grout pH or soil gel time and soil pH
(2) Strength change of consolidated soil (3) Volume change of homogel (4) Leaching of silica from homogel or consolidated soil (5) Strength change of consolidated soil under pressurized water permeability or silica leaching (6) Change in strength of consolidated soil or homogel or leaching of silica, or change in gel volume in accelerated test by heat curing
Group B (1) Permanent still water, liquefaction prevention, permanent ground reinforcement (2) liquefaction prevention, reinforcement (3) durable ground improvement, long-term temporary (4) short-term temporary In the durable silica grout according to any one of claims 1 to 15, for any one or more of silica leaching from the homogel, gel shrinkage, and strength change of the consolidated sand for the durability period. A durable silica grout that satisfies any one or more of the following conditions, characterized by quantitatively evaluating durability and setting a prescription that satisfies the purpose of injection.
(1) The silica grout is non-alkaline (pH is 10 or less), silica leaching from homogel is within 5%, silica leaching from sand gel is within 10%, and homogel strength change is initial value during durability period Durable silica grout that is within 50% of.
(2) In the silica grout, it is non-alkaline (pH is 10 or less), silica leaching from homogel is within 5%, leaching from sand gel is within 10%, whether the strength of sand gel is reduced,・ The volume shrinkage (shrinkage) of the homogel is within 20% in the glass volumetric flask measurement method and / or the volume change rate of the homogel in the plastic cylinder measurement method is within 25%. In particular, a silica grout that can be regarded as having a sand gel strength that converges within a predetermined range, and is a durable grout that is applied to permanent ground improvement, liquefaction prevention, reinforcement, and temporary ground improvement.
(3) Silica leaching from homogel is within 5%. ・ Silica leaching from sand gel is 10%.
Within%, Homogel volume change (shrinkage ratio) is 20-35% in volumetric flask measurement method, plastic cylinder measurement method is 25-40%, and solidification during limited period or service period even if strength of sand gel is reduced A durable grout that is durable, timed, in service, or applied to temporary infusions.
(4) In the above (1), (2), (3), the volume change rate (shrinkage rate) is reduced, the deformation coefficient is increased, or groundwater is used according to the ground conditions and the purpose of injection. Silica grout with improved resistance to pressure and improved durability.
1. Colloid or fine silica colloid is included.
2. Increase the silica concentration.
3. Increase the molar ratio.
(5) A durable silica grout characterized by applying silica grout having the following characteristics as the silica grout to permanent ground improvement, liquefaction prevention, reinforcement, and temporary injection.
1. Silica grout, which is a non-alkaline composite silica colloid composed of large silica and small silica, has no decrease in homogel strength, and is stable even after 200 days or more.
2. A silica grout imparted with durability by applying a composite silica colloid composed of non-alkaline large silica and small silica to the voids and soil diversity in the silica grout.
3. A silica grout to which a fine particle silica colloid corresponding to the shrinkage amount of an excessive homogel that causes a decrease in strength is added.
4). 4. Silica grout in which the strength of the homogel does not decrease and the strength of the sand gel is constant within a predetermined strength after 200 days. In the silica grout, a durable silica grout that converges to a constant value in the long term by reducing the decrease in strength of the sand gel even if the homogel shrinks by the following method.
a. Silica sol; silica concentration is 10% or more.
b. composite silica colloid;
・ Set the colloid ratio in the total silica to 10% or more.
・ When the colloid ratio in the total silica is 10% or less, the silica concentration in the total silica is increased, and the concentration is determined according to the ground condition and required strength.
・ The amount of colloid per 100cc of silica solution is 0.5-15g, and the amount of water glass used is determined according to the ground conditions and required strength.
6). A silica grout in which the homogel strength does not decrease, the silica leaching of the sand gel is within 10%, the sand gel strength decrease is within 50% of the initial strength, and the caking property persists during the durability period. In the durable silica grout according to any one of claims 1 to 16, correction is made according to ground conditions, injection hole interval or consolidation diameter, injection method, or stage length, or further based on construction results. A ground improvement method characterized in that the composition and gelation time (GT ₀ ) or pH ₀ of the compounded liquid is set and allowed to infiltrate and solidify into a predetermined injection region. Durable ground injection method characterized by satisfying the following conditions.
(A) The injection rate is within the limit osmotic injection rate.
Injection hole interval or consolidation diameter L = 1.0-4.0m
Injection rate q per minute q = 1-30L / min However, it should be within the limit injection rate.
1 stage length: 0.33m-4.0m
Injection time per stage H 4.4 to 25600 minutes However, the injection time (H) can be shortened in consideration of the workability on site and the shortening of the latter period.
Air gelation time GT ₀ 0.1 min to 10000 min, or 3 min to 10000 min Air pH (pH ₀ ) 1 to 10
Silica concentration 0.4-40% (wt%)
Underground gel time GT _S0 10 seconds to 6000 minutes, or 10 minutes to 6000 minutes Underground pH (pH _S0 ) = 3 to 10
Ground pH 4-10
(B) If the gelation time in air is GT ₀ , the gelation time in soil is GT _{S0, and} the injection time for one stage is H,


Preferably,
β = 0.68-0.34
That is,
0.2H <GTso <3H In the durable ground pouring method using the durable silica grout according to any one of claims 1 to 17, in the ground where coarse-grained soil, large voids, or groundwater is flowing, the following (1) Whether to reduce the shrinkage of the gel, increase the strength of the gel, increase the resistance to water pressure, or reduce the influence of the shrinkage of the gel on the ground gap by any one or a plurality of methods of (8) A durability ground improvement method characterized by reducing the deviation and dilution of the injected liquid due to groundwater, reducing the strength reduction of the consolidated sand, or improving the durability of the injected ground.
(1) Increase the silica concentration.
(2) Increase the colloid concentration.
(3) Add fine particle silica colloid.
(4) Add precipitated silica.
(5) A silica solution containing a silica colloid having a particle size of 5 μm or less is injected.
(6) Perform primary injection to reduce ground homogenization, water permeability reduction and groundwater fluidization.
(7) In non-homogeneous ground, the suspension grout is first injected to reduce the voids of the coarse soil layer, and the durable silica grout is secondarily injected.
(8) As the suspension grout, finely divided silica is primarily injected with a suspension containing weakly alkaline fine particle silica such as clay or magnesium hydroxide or neutral silica powder such as white carbon. (9) A durable silica grout having improved durability by obtaining one or more of the effects (B) by any one or more of the following (A).
(Method A)
1. Increased molar ratio
2. Increase in total silica concentration
3. Application of composite silica containing colloid and water glass as active ingredients
4.Improvement of sand gel durability by increasing silica concentration due to colloid in total silica concentration and increase of sand gel strength by increasing water glass concentration
5. Reduction of gel shrinkage by applying powdered silica
6. Colloidalization by application of salting out silica
7. Reduction of dilution with groundwater by adding thickener (effect B)
8. Suppression of strength reduction
9. Constant intensity change
10. Increasing consolidation strength
11. Reduction of gel shrinkage
12. Reduction of silica leaching
13. Improvement of environmental conservation In the durable ground improvement method using the durable silica grout according to any one of claims 1 to 16, the durability level is set as a durability evaluation standard, the strength change rate of the consolidated soil, the volume change of the homogel, the homogel Or, for silica leaching from consolidated soil, the evaluation criteria should be set according to the purpose of injection and the durability period, or the durability of the silica grout sand gel during the durability period from the properties of homogel strength and shrinkage durability. A durable ground improvement method using a formulation that predicts and obtains durability according to the purpose of injection. Alternatively, a durable ground improvement method characterized by correcting the quantified numerical values based on actual results and research. In the durable ground improvement method using the durable silica grout according to any one of claims 1 to 16, the strength in the durability period required for a predetermined injection region is the strength of the sand gel specimen of the ground to be improved. It is calculated from the relationship between the silica concentration and the laboratory test target strength in the compounding recipe at the time of injection to satisfy the design value, which is obtained by multiplying the design value by the safety factor. A durable ground improvement method characterized by determining in any one or a plurality of kinds of variations in consolidated strength due to the length between them and a change in strength during the durability period. 21. The durable ground improvement construction method according to any one of claims 17 to 20, wherein the acceleration method by heating curing targets any one or more of the following.
(1) Strength change of consolidated product (sand gel, homogel) (2) Silica leaching from the consolidated product (3) Shrinkage of homogel (4) Change in water permeability of consolidated product (sand gel) (5) Chemical substance Effect on solidified matter Use of the durable silica grout according to any one of claims 1 to 16, and a durable ground capable of obtaining a predetermined improvement effect while reducing deviation from a predetermined injection region by satisfying any of the following: Improved construction method.
(1) The silica grout has an air gelation time (GT ₀ ) that permeates and solidifies into a predetermined injection region in consideration of the injection time (H) and the soil gelation time (GT _S ) at a predetermined injection stage. The silica grout formed by selecting the composition having is used. Here, the gelation time in the soil refers to the gelation time when the in-situ collected soil and the injection solution are mixed or the gelation time of the silica grout in which the injection solution penetrates the soil in the site.
(2) The silica grout is sent from a plurality of injection pumps to an injection liquid supply system that is supplied to a predetermined injection stage, and each liquid supply system is provided with a flow rate / pressure detector. By sending and displaying the flow rate and / or pressure data detected by the flow rate / pressure device to the central control device, the injection status in a plurality of injection stages can be collectively managed, and a predetermined injection can be performed in a predetermined injection region. Permeate and consolidate as done.
(3) The silica grout is checked for penetration and consolidation in a predetermined injection region using the following method.
a. Using soil collected on site, adjusting the soil density to the density of the target ground, preparing solid specimens with silica solutions of various silica concentrations, conducting strength tests, and checking the silica concentration of the consolidated bodies To understand the relationship between the silica content of the silica solution and the strength of the consolidated specimen.
b. Measure the silica content of the soil collected from the in-situ ground before and after injection, and confirm the infiltration consolidation and the ground improvement strength from the relationship between the silica content and the strength of the injected liquid.
c. Analyze the amount of silica in the collected soil from a predetermined injection range from the injection hole or from the adjacent injection range to confirm that it is infiltrated and consolidated into the predetermined region.
d. A durable silica grout that uses the following method (I) or (II) in the silica grout to obtain a permeation-solidified silica injection solution that satisfies the injection purpose in a predetermined injection region.
(Method I)
1.Predetermined durability is obtained, using a compound composition consisting of a predetermined silica concentration and gelation time, creating a field-collected soil consolidation specimen with silica injection, Adjust the soil density to the density of the target ground, conduct a strength test of the consolidated specimen, analyze the amount of silica with the consolidated specimen, and understand the relationship between the silica content and the strength of the consolidated specimen To do.
2. Measure the silica content of the soil sampled from the in-situ ground after injection before and after the injection, and estimate the strength of the ground from the relationship between the silica content and the strength in the laboratory test to obtain the design strength. It is determined whether or not.
3. Analyze the amount of silica sampled from the injection range from the injection hole or from the adjacent injection range to confirm that it is infiltrated into the predetermined region.
(Method II)
A durable ground improvement method characterized by setting a silica concentration at which a predetermined strength can be obtained by the following method, and determining whether or not a permeation consolidation in the injection region and a predetermined strength are obtained.
1. Measure density of ground to be injected.
2. Set the design strength of the injection ground and the target strength of the laboratory test by multiplying the design strength by the safety factor.
3. Prepare specimens adjusted to the on-site density using the soil collected from the target ground. Alternatively, the silica content of the collected soil is further measured.
4. Applying constraining pressure corresponding to the on-site loading pressure to the above specimen and injecting silica grout with various silica concentrations to produce consolidated specimens. Alternatively, in-situ soil and silica grout having various silica concentrations are mixed to prepare a consolidated specimen so that the density of the soil in the test sample corresponds to the in-situ density.
5. Curing the consolidated specimen under the above conditions for a specified period.
6. Conduct a strength test on the consolidated specimen.
7. Analyze the silica concentration of the consolidated specimen to determine the relationship between silica concentration and strength. Alternatively, the increase in the amount of silica due to the injection solution is analyzed to grasp the relationship between the increase in the amount of silica and the strength.
8. Inject the above silica grout into the ground to be injected.
9. Analyze the silica concentration using soil collected from the injected ground. Alternatively, the increase in the amount of silica due to the injection solution is grasped.
10. From the measured silica concentration, the ground consolidation strength is estimated from the relationship between the silica concentration and the strength, and it is determined whether or not the strength satisfying the predetermined design strength is obtained. Alternatively, the ground consolidation strength is estimated from the relationship between the increase in the amount of silica and the strength, and it is determined whether or not the strength satisfying the predetermined design strength is obtained. Alternatively, the injection amount in the injection target ground is further estimated.
11. Silica content is analyzed by JIS K 0101-1979 Molybdate Yellow Method, Molybdenum Blue Colorimetric Method, CP Emission Spectroscopy, Atomic Absorption Spectroscopy. In the ground injection method using the durable silica grout according to any one of claims 1 to 16, the silica concentration is 0.4 to 40%, the discharge amount per stage is 1 to 30 L / min, 1 The stage length per stage is 33 cm to 2 m, the injection point is one point injection, multi-point injection, or columnar injection, the gel time is 10,000 minutes from instantaneous setting, and injection is performed in the range of 1 to 4 m between injection holes. A ground improvement method characterized in that the injection solution is surely held in a predetermined injection region and allowed to permeate and solidify.
(1) Injection speed and injection pressure are within the limits of osmotic injection (2) Air gelation time (GT ₀ )
(3) Ground condition (ground pH, Ca content, particle size, hydraulic conductivity, groundwater condition, etc.)
(4) Gelation time in soil (GT _S0 )
(5) Inject a grout blended in consideration of the stage length, injection speed, injection amount per stage, and injection time corresponding to each injection method to be applied. Using the durable silica grout according to any one of claims 1 to 16, it is infiltrated and consolidated in a predetermined injection region by preventing deviation to the ground surface by any one or more of the following methods. The injection management method in the durable ground improvement construction method characterized by this.
(1) Prior to the injection of the silica grout, an alkali agent, a suspension, or an instantaneous injection material is primarily injected into the injection region, and after filling a portion where the ground is likely to deviate, the silica grout is injected secondarily. .
(2) The deviation of the injection liquid to the ground surface is reduced by narrowing the pitch of the injection holes in the ground surface side region of the ground or by consolidating the vicinity of the ground surface in advance.
(3) Injecting from a plurality of discharge ports simultaneously or selectively, or injecting a region that tends to deviate in advance, restrains the injection region and reduces the deviation of the injection solution outside the injection range. .
(4) Repeat interruption and low speed injection when leaking to the ground surface.
(5) Constraining the injection region by bringing the outer periphery of the solidified body of the injection stage into contact, thereby reducing deviation from the injection range.
(6) Precede injection at the injection stage close to the ground surface. 25. The ground improvement construction method according to any one of claims 17 to 24, wherein the predetermined injection region is used while preventing any deviation or ground displacement from the ground surface, water, or a predetermined injection region, using any one or more of the following. Durable ground improvement construction method characterized by injecting and managing so that it can permeate and consolidate.
(1) When injecting the ground infusion solution from the infusion pump to multiple infusion points in the ground through multiple infusion fluid delivery systems, one or more representative infusion points are set in the predetermined infusion area of the ground. Measure the appropriate pressure and / or flow rate with the infusate or water at each infusion stage where the representative infusion point is located, and set the appropriate range of values obtained in the centralized control device with the infusion monitoring panel. An injection management method characterized by performing injection at each injection stage in a predetermined injection region based on a set range, or an appropriate pressure and / or flow rate range at each injection stage was obtained by an injection test An injection management method that is set by correcting the set range by taking the actual measurement value into account. (2) When injecting the silica injection liquid from a plurality of injection pumps to a plurality of injection stages in the ground through a plurality of injection liquid supply pipes, a flow rate pressure detector is provided in each of the injection liquid supply pipes to detect these. The flow rate and / or pressure data of the infusate detected from the vessel is sent to the central control unit, and the infusion status at each stage from the infusate liquid delivery tube is displayed in a lump, and for each infusion stage under specified conditions An injection management method characterized by centrally managing that injection is performed.
(3) An injection management method characterized in that injection management is performed by displaying on the injection monitoring panel time data, location data, and injection data related to injection pressure and / or flow rate on a screen.
(4) An injection pressure and / or flow rate in a desired range is set in advance in the central management device, and injection at each injection stage from the injection liquid feeding pipe is performed on the screen of the injection monitoring panel in the central management device The injection management method is characterized in that the injection management is performed by reducing the deviation from a predetermined injection region so that the injection state is maintained in the set range.
(5) Data on injection pressure, injection speed, injection volume, and infiltration status are visualized three-dimensionally on a screen display, and the injection status in a predetermined injection area is grasped in real time or the injection result is obtained. Alternatively, an injection management method for finding a portion that does not satisfy at least one set range of flow rate and reinjecting the portion.
(6) In the ground injection method of injecting ground injection liquid from multiple injection liquid pumps to multiple injection points in the ground through multiple injection liquid supply systems, a flow pressure detector is provided for each of the multiple injection liquid supply systems. The infusion pressure and / or flow rate data of the infusate detected from these detectors is sent to a central control device equipped with an infusion monitoring board, and these data are displayed on the infusion monitoring board to display the infusion status at once. The monitoring is performed to inject while maintaining each injection pressure and / or flow rate in the liquid supply system within a predetermined range, and the injection is completed, stopped, continued, or reinjected based on the information of the above data. After injection, inject the injection solution into the injection solidified ground, grasp the injection effect from the distribution of resistance pressure, and reinject if it is insufficient to obtain the predetermined injection area and the predetermined injection effect An injection management method characterized by the above.
(7) The ground or structure in the injection area is provided with a displacement sensor, and information from this displacement sensor is transmitted to the central control device to grasp the displacement status of the ground or the structure and the infiltration consolidation state of the injected liquid. Injection management method.
(8) Before injection, measure the silica concentration or pH and electrical conductivity of the non-alkaline silica grout in advance, and measure the silica concentration of soil in the field, or the soil pH, soil conductivity and Ca content. The soil collected in the field is infiltrated or mixed with the silica grout at the density of the ground and consolidated to determine the relationship between the silica concentration of the injected solution and the silica concentration and strength of the consolidated soil, or the gelation time of the compounded solution (GT ₀ ), pH (pH ₀ ), soil gelation time (GT _S , GT _S0 ), soil pH (pH _S0 , pH _S ), and the electrical conductivity of consolidated soil After the injection, measure the silica concentration of the sampling sample of the soil in the injection target area, or further measure the solid soil pH and electrical conductivity, or confirm the improvement effect of the predetermined injection region by sounding or core boring Infusion management method.
Here, GT _S and pH _S refer to the gel time and pH in the ground during the process of infusion of the injection solution into the ground, and values that can vary. GT _S0 and pH _S0 are the gel time and pH of the injection solution in a state where the injection solution and the ground soil are mixed, and correspond to the initial values injected from the injection hole.
(9) An identification sensor for identifying whether it is an infusion liquid or a non-infusion liquid is provided in a plurality of infusion liquid feeding systems, and information from the identification sensor is transmitted to a central control device, and the infusion injected into the ground An injection management method that distinguishes the liquid flow rate from non-injection liquid.
(10) A method of managing the environmental impact by any of the following methods or a plurality of methods.
1. Measure the pH, conductivity, and silica concentration of the injected solution, and understand the relationship between these values during injection or those values, and measure the groundwater in the observation well provided on the surrounding ground or to the ground surface. An infusion management method that measures outflow from the infusion area by measuring the amount of escaping liquid and interrupts the infusion or prevents it from affecting the water.
2. An injection management method in which the displacement of the ground or structure is transmitted to the central control device to manage the displacement of the ground uplift or subsidence, or when the displacement reaches the limit value, the injection is interrupted to prevent the influence.
(11) Use one of conductivity measuring device, pH measuring device and concentration measuring device to manage the injected solution, or install one or more of these devices in the feeding system, and these during feeding The measured value data is transmitted to the central control unit, and the type and composition of the injected solution during injection, the identification of the washing water and the injected solution, or the underground solution overflowing the ground surface is injected as groundwater. An injection management method for identifying the ratio of the injection liquid contained in the liquid or the underground liquid and grasping the actual injection volume or performing quality control. The injection management method used in any one of the silica-based grouts of claims 1 to 16 and the ground injection method of claims 17 to 25, wherein the ground data at the injection site, silica-based grout data, drilling data, injection data, environment One or more injection data shown in the following group A or group B related to any of data, quality data, work type data, process data, and construction management data is sent to the information management center server or cloud in the Internet in real time. An injection management method characterized in that one or more of an enterpriser, a construction company, and a site contractor can grasp the injection status and hold information in real time or at any later point in time.
However, in the above, the silica-based grout means injection of a silica injection solution or a suspension type injection solution containing silica.
Group A consists of (1) ground data and drilling data (2) injection device data (3) measurement device and measurement data (4) injection solution data (5) injection method data (6) injection plan data (7) injection test data (8) Injection data of each injection stage and limit value or tolerance data (9) Injection effect confirmation data and injection effect analysis data (10) Additional injection data (11) Environment such as ground displacement, underground objects and water quality Data (12) Field sampling soil mix design (13) Improvement target value and improvement value
Group B is: ・ Visualization of data ・ Instruction to injection site or centralized control equipment by data collection and analysis ・ Understanding of process ・ Data retention and analysis ・ Confirmation that a predetermined amount is injected into a predetermined area ・ Improvement effect And durability data ・ Indication of insufficient improvement ・ Past data accumulation ・ Improvement target ・ Data in Fig. 79
・ Analysis of accumulated data ・ Comparison and handling of field data and laboratory tests ・ Automatic injection by remote control In the injection management method used in any one of the silica-based grouts of claims 1 to 16 and the ground injection method of claims 17 to 26, the data is accumulated in the information management center server as follows: The data from the construction site from the Internet is analyzed together with the existing data, and the result is fed back to the construction site via the Internet, or if it is determined as a result of the analysis that the intended injection has not been performed, Instruct corrections to the construction site to ensure reliable construction, or send the information to a central control device at the site, or automate injection, and manage the information process in the data information center or cloud. An injection management method that can be disclosed in real time or at any time required.
(1) Injection ground data and drilling data (2) Injection device data (3) Measuring device and measurement data (4) Injection liquid data (5) Injection method data (6) Injection plan data (7) Before and after injection Test data (8) Injection data (9) Additional injection data (10) Environmental data (11) Injection effect confirmation data However, in the above, chemical injection means injection of silica injection liquid or suspension type injection liquid containing silica Say. The durable ground improvement method using the durable silica grout according to any one of claims 1 to 16, wherein the durable ground improvement method integrates the following related durability requirements and provides a predetermined improvement effect during the durability period. Durable ground improvement method characterized by maintaining the durability.
(A) Silica grout and durability characteristics and environmental conservation (b) Construction method and durability of consolidated ground and injection design method (c) Demonstration of durability by construction results (d) On-site soil mixing design method and quality control In the durable ground improvement construction method using the durable silica grout according to any one of claims 1 to 16, a durable ground having durability that satisfies the injection purpose by integrating the following durable element technologies: Durable ground improvement method characterized by obtaining.
(A) Durability and environmental conservation of durable silica grout (1) Clarification of durability and ground strengthening mechanism (2) Durability of homogel and sand gel (3) Durability corresponding to ground conditions (4) Solid ground Long-term durability (5) Formulation setting that can achieve seepage and consolidation in a given area (6) Environmental conservation (b) Durability of ground and construction method and durability of ground The following ground conditions and construction method and injection Durability is affected by the material composition design.
(1) Ground conditions: Ground grain size and particle size distribution, soil density, soil properties, hydraulic pressure (2) Wide-area penetration injection method (3) Permeation solidification and gel time in soil (4) Magma action method ( 5) Masking silica method (c) Demonstration of durability based on construction results (1) Wide-area penetration injection method (2) Demonstration of durability of durable silica-injected ground by large-scale field injection test using wide-area penetration injection method (3) Demonstration of seismic resistance of injection ground in the Great East Japan Earthquake (d) On-site soil composition design method and quality control (1) On-site soil composition design method (2) Ground silicidation evaluation method (3) Construction management (4) Material management and injection management (5) ) Prediction of improvement effects in advance and management of subsequent improvement effects (6) Environmental management The durable ground improvement construction method using the durable silica grout according to any one of claims 1 to 16, wherein the durability requirements are each composed of one or more of the following elements.
(1) Durability of solidified silica grout (a) Temporal change in silica leaching from homogel and / or sand gel (b) Temporal change in shrinkage of homogel (c) Strength of homogel and / or sand gel Change over time (2) Compounding design of injection solution (a) Compounding design for penetrating and consolidating in a predetermined region (b) Compounding design for obtaining a predetermined durability effect satisfying the injection purpose during the durability period (c) Strength prediction of the durability period (D) Mixing design using on-site collected soil (3) Ground conditions and construction method Ground conditions (a) Ground grain size and particle size distribution (b) Soil density (c) Soil properties (d) Water pressure (hydrodynamic gradient)
Construction method (a) Injection hole pitch (b) Discharge amount per minute and gelation time (c) Primary injection and secondary injection (d) Injection stage (4) Quality control (a) Composition, formulation and gelation of silica grout Quality control related to time (b) Quality control related to safe construction (c) Quality control related to environment (d) Quality control of injection ground by silica amount measurement and / or core sampling (e) Confirmation of injection effect by in-situ test Quality control In the durable ground improvement construction method using the silica grout according to any one of claims 1 to 16, the following durability requirements are combined to satisfy the durability purpose and the durability effect corresponding to the durability period. Durable ground improvement construction method characterized.
(1) Durability factors of silica grout ・ Silica grout composition, silica concentration, air gelation time, soil gelation time, and osmotic solidification in specified area ・ Silica leaching from gel ・ Gel shrinkage ・ Gel Strength ・ Relationship between gel durability and sand gel durability ・ Sand gel durability (silica leaching, solidified soil strength and change over time)
・ Gelation time in soil and seepage solidification within specified range (2) Characteristics and construction method of injection ground ・ Gran grain size and particle size distribution ・ Soil density ・ Soil properties ・ Ground condition ・ Construction method (injection hole interval) Gelation time, injection volume, discharge volume per minute, injection stage, primary injection and secondary injection)
(3) Management ・ Combination design method using on-site collected soil, quality control of silica grout and injected consolidated ground.
・ Combination management, injection amount and injection rate management ・ Silica grout composition, silica concentration and gelation time (gelation time and pH during mixing, soil pH and soil gelation time, penetration distance and gelation time Management ・ Management of construction method ・ Quality control by silica amount of solidified ground after construction based on silica amount of injected solution and silica amount of consolidated soil and / or confirmation survey by core sampling (4) Environmental conservation Claim 1 Durable silica grout using a durable silica grout of ~ 64, characterized by reducing environmental impact by any of the following methods: (A1) In the vicinity of concrete underground structures Durable silica grout is injected by the following method.
(A) A phosphoric acid system is used as the acid or a mixed acid of phosphoric acid and sulfuric acid, and the ratio of phosphoric acid and sulfuric acid is adjusted. Reduces the amount of sulfuric acid used to neutralize the alkali content of the concrete to ensure the safety of the concrete structure. However, the phosphoric acid and sulfuric acid concentrations are converted to 75 wt%.
(B) A sequestering agent is added.
(C) The amount of acid used is reduced by increasing the amount of colloid used and reducing the amount of water glass used.
(2) Adjusting the amount and ratio of pH, colloid, and water glass for safety against water quality. The durable ground improvement construction method using the durable silica grout according to any one of claims 1 to 16, wherein the following grounding management and quality control before and after the filling are performed.
(1) Soil quality and permeability (2) Characteristics of injection solution and solidified body (3) Silica content, Ca content, pH and gel time of soil collected on site (4) Injection method, injection hole interval and one stage length (5) Injection rate and injection volume (6) Injection speed, injection pressure, injection volume, injection time, determine the appropriate injection speed by the limit injection speed test, set the upper limit pressure during construction (7) Composition and composition Correspondence to pH (pHo), gel time (GT ₀ ), soil gel time (GTs ₀ ), injection time (H), penetration and consolidation range, and environmental conditions (effect on water quality and soil structure).
(8) Control of pH (pHo) and gel time (GT ₀ ) of injection solution corresponding to gel time (GTs ₀ ) and injection time (H) in soil (9) Injection method, injection hole interval, one stage length and limit injection Selection of injection rate per minute within the speed and injection time (H) for one stage, laboratory experiment, and soil gel time (GTs ₀ ) and injection time (H) based on past construction results corresponding to site conditions and ground conditions From the control of the pH (pH ₀ ) and gel time (GT ₀ ) of the injection solution so that a predetermined quality can be obtained by reducing the deviation from the predetermined injection range and penetrating and solidifying into the predetermined injection range.
(10) Quality control before and after injection Quality control before and after injection by one or more of the following: Boring position 1/2 or 2 to 4 intersections of improved radius etc. Strength check Uniaxial compression test, triaxial compression test, liquid Strength test Core boring or sounding ・ Others (before and after injection)
Silica content test before and after injection Horizontal loading test in the hole Ca content test of injected ground Ground displacement by injection A ground injection method according to any one of claims 17 to 32, wherein the durable ground improvement method uses any of the following.
(1) Double pipe instantaneous setting and slow setting injection method
(2) Double packer method
(3) Multi-point simultaneous injection method
(4) Columnar injection method
(5) Bag packer injection method
(6) Point injection method