JP2007239443A - Suck-out preventive injection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To particularly quicken rising of strength, infiltrate into every part of an injection area, and improve suck-out resistance in a suck-out preventive injection method for use in reinforcement or cut-off of the soft ground, restoration of a building (righting the building) inclined by ground subsidence due to an earthquake, excavation work, or the like, backfilling of a tunnel or the like, filling of a cavity, consolidation under the water surface such as the sea bottom or underwater, or the like. <P>SOLUTION: Fluidized plastic gel is used as an injection material, and injection materials different in plasticity holding time are used in an initial stage of injection and a subsequent stage of injection. Further, a soil grain infiltrating type nonplastic injection material is injected in the ground in an injection area injected with plastic gel or every part of the injection area. Rising of strength is thereby quick, infiltration into every part of the injection area is attained, and suck-out resistance is improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention strengthens soft ground, stops water, restores buildings inclined due to ground subsidence due to earthquakes or excavations, etc., backfills tunnels, fills cavities, seabed, underwater, etc. This is a suction-injection injection method used for consolidation (collectively referred to as “backfilling”), and in particular, a backfilling injection material that quickly rises in strength, penetrates into the details of the injection region, and improves the suction resistance. It relates to the construction method using

  Cavity generated on the back of tunnels, and seawalls facing the sea and rivers, due to ground subsidence and cavities created by damage to the waterproof sheet, sucked backfill soil and reduced the strength of the seawall structure. . Therefore, conventionally, there are a method for injecting cement-suspended grout to solidify the ground, a method for injecting solution-type grout, and the like as a method for preventing suction of the backfill soil on the revetment.

  However, the cavities in the ground are often intricately detailed, and suspension grouting with low permeability, solution grouting with quick setting, suspension grouting with quick setting, or plastic injection Even if it is used, the formulation that loses its fluidity by instantaneously linking it cannot penetrate into details, the consolidation thickness becomes thin, fine cavities are formed, and the seawater becomes tide The consolidated layer may peel off while going in and out due to tidal periods, which may cause new sucking.

  Also, when solution type grout with high permeability is injected, the details of the cavity are filled, but it is diluted with the pore water at the location receiving the suction, the concentration changes and cannot be improved uniformly, and the strength is low It becomes an improvement and cannot be a long-term improvement.

JP 2003-105745 A JP 05-156252 A

Therefore, the present inventor completed the present invention by solving the following points as conventional problems.
(1) Fill the hollow details on the back of the back of the revetment.
(2) It shall not be diluted by pore water in the surrounding ground.
(3) Create a sufficiently thick consolidated layer that fills the void details, and increase the contact area of the consolidated injection material with the earth and sand to create a consolidated layer that is highly resistant to tides.
(4) To develop a method for preventing evacuation of backfill soil that shrinks after consolidation and does not create cracks or cavities.

  The plastic grout is gelled by adjusting the blending, then maintains fluidity for a long time and then solidifies. This fluid plastic gel exhibits the same fluidity and solidification as in the air without being diluted in the surrounding water even in water. Further, after the ground injection, the plastic gel that has been fed forward is dehydrated by consolidation with the subsequent plastic gel, and becomes a high-strength solidified body. In the present invention, paying attention to the characteristics of a plastic gel having fluidity as a ground injection material, the above-mentioned problems have been solved.

  The construction method using a plastic gel as a ground injecting material to prevent suction according to claim 1 of the present invention first forms a water-impermeable layer by injecting a fluid plastic gel into the suction part of the backfill soil of the revetment. Stop sucking. The plastic gel solidifies as time passes, but the pre-plastic plastic gel is pressed around while the pre-plastic plastic gel does not lose its fluidity. It is difficult to create cracks and cavities by entering new fine gaps and filling without gaps to prevent new suction. Further, since the plastic gel that has been fed forward is dehydrated due to the compaction of the subsequent plastic gel and becomes close to a blend having a high water-powder ratio, a high-strength consolidated body can be formed.

  Claim 2 of the present invention relates to a method of using an injection material having a different plastic holding time when the gap of the suction portion of the revetment due to the suction action is still small, in the initial injection stage and the subsequent injection stage, the initial injection stage The plastic gel is injected with a plastic material that has a longer plastic holding time than the plastic gel that is subsequently injected, and the plastic gel that has been previously injected with a longer plastic holding time is subsequently injected. Suitable for improving suction resistance by inserting a plastic gel with a short plastic holding time into a rough gap, and when the gap in the suction section is large, an injection material with a short plastic holding time in the initial stage With a large void, and then filled with an injection solution with a long plastic retention time, a small void is filled to form a thick consolidated layer with a large contact area with soil particles. Construction method I will provide a.

  Therefore, in the initial stage of injection, an injection material having a plastic holding time longer than that of the subsequent plastic gel is used, and the subsequent injection material is injected by pushing the previous injection material into the ground. Can be penetrated into the fine cavities, and since it is pumped by the subsequent injection material, it is dehydrated. As a result, the water-to-powder ratio is increased, resulting in a high strength improvement in the ground.

  In addition, by using a consolidation material having a different plastic retention time in the present invention, a sealing effect that fills the voids around the injection tube with a consolidation material having a long plastic retention time, cracks between soil particles and in the ground, and suction It is effective as a primary injection material to inject and strengthen the breakage or weak part of the revetment due to sewage, and the injection material with a short plastic holding time can be pressed into the ground and pushed into the ground to the details in the ground. The effect of permeating and dehydrating to increase the water powder ratio and increase the strength can be obtained. In addition, the surrounding ground can be improved with high strength by compaction, and suction of the improved ground can be prevented.

  Further, in the present invention, if it is pressurized, it will flow, and if the pressure is stopped, it will gel, and it will not be diluted with pore water such as groundwater. However, there is an advantage that the initial injection and the secondary injection can be performed continuously, and the surrounding water quality is not deteriorated.

  The fluid plastic gel that can be used as the injection material of the present invention is an injection material that is formed by mixing a suspension and a plasticizer, exhibits fluidity when pressurized, and exhibits non-fluidity when stationary. . "Flow indicating fluidity" and "slump value", "gelation time with plastic gel", "plasticity retention time", "solidification to become nonplasticized" as indicators of the flow characteristics of plastic gel in the ground Focused on “time”.

Of these, the gelation time is the time when the table flow is 20 cm after blending, and the plasticity retention time is the time when the gel does not flow even when external force is applied after gelation, that is, when the penetration resistance value exceeds 0.01 MN / m ^2. This was taken as the curing time.

  As a plastic injection material of this type, conventionally, a cement suspension or cement bentonite suspension as a curing agent, or a suspension obtained by adding slaked lime to a slag, water glass, aluminum salt, clay mineral, A material in which polymer materials or the like are merged can be used. Aggregates and additives (air generating agent, dispersant, retarder, strength promoter, thickener, etc.) are blended as necessary.

  In particular, when using plastic grout with fly ash as the main ingredient, large table flow or cylinder flow before injection into the ground or in the ground after injection, that is, fluidity such as 20 cm or more and less than 30 cm, slump 15 to 26 cm. Even if a certain composition is used, it is dehydrated by press-fitting into the ground, and even if the flow before injection is 30 cm or more, or even if the slump is 26 cm or more, it becomes a plastic gel in the ground, and the plastic holding time is sufficient. A plastic gel can be formed and grown into a sufficiently large lump gel.

  In order to consolidate in the ground, it is a ground injection material that forms a plastic gel that can flow by pressurization but does not penetrate between soil particles and does not split into veins. Is a ground injection material showing a range of 12 cm or more and less than 30 cm, preferably 15 cm to 28 cm, slump greater than 5 cm, preferably 10 to 28 cm, and cylinder flow greater than 8 cm and less than 28 cm, preferably 9 to 26 cm. It is preferable. In addition, in consideration of the formation of a plastic gel by pressure dehydration in the ground, it is a plastic gel before injection, or the water-to-powder ratio is reduced within 30% and the plastic gel 20 cm) is preferable.

The following conditions are preferable for the suction prevention method using a plastic gel.
Curing expression ratio C / F + C × 100 (%)
1 to 50% by weight, preferably 1 to 40% by weight, more preferably 1 to 20% by weight,
Water powder ratio W / F + C × 100 (%)
20 to 200% by weight, preferably 20 to 100% by weight, more preferably 20 to 50% by weight,
Aluminum ratio Aluminum / F + C × 100 (%)
0.01 to 0.52% in terms of Al ₂ O ₃ ,
Water glass 0-7.0% by weight with silica content,
Slump (cm)
Slump at the time of injection is 5 cm or more, preferably about 5 to 28 cm, more preferably 10 to 28 cm
Flow (cm),
The table flow during injection is 12 cm or more and less than 30 cm, preferably about 15 to 28 cm,
Cylinder flow at the time of injection is 8 cm to less than 28 cm, preferably about 9 to 26 cm,
breathing
10% or less, preferably 5% or less,
Use a plastic gel or a blend that reduces the water powder ratio by 30% or less, that is, a plastic gel or table flow within 20 cm.

  Further, an osmotic suspension grout can be used as an initial injection material or an injection material for injecting a plastic grout into a fine void after injection.

  In the present invention, any suspension grout can be used, but it is necessary to obtain a high strength with a long gelation time and to have excellent permeability.

As an example, a silica compound, an alkali metal aluminate salt solution, and a polyvalent metal compound are used. In particular, the alkali metal aluminate salt solution has a value of [Me ₂ O] / [Al ₂ O ₃ ] of 2 It is known that by mixing with a polyvalent metal compound such as an alkaline earth metal, an injection material having a long gelation time and excellent strength can be obtained. (See Patent Document 2: Japanese Patent Laid-Open No. 05-156252). Here, Me represents an alkali metal, [Me ₂ O] is the total molar concentration of Me ₂ O of aluminate alkali metal salt solution and the silica compound, [Al ₂ O _3] Al ₂ aluminate alkali metal salt solution Each represents the molar concentration of O ₃ .

Of course, the same applies when potassium aluminate is used instead of sodium aluminate. [Me ₂ O] when water glass, which is an alkali metal salt of silicic acid, is used as the silica compound corresponds to the molar concentration of Me ₂ O derived from both the alkali metal aluminate solution and the water glass. Examples of the silica compound include slag, silica fume, fly ash, white carbon, sinter, white clay and the like in addition to water glass. When Me ₂ O is not contained, it is natural that [Me] in the alkali metal aluminate solution itself. ₂ O] / [Al ₂ O ₃ ].

  Examples of polyvalent metal compounds include calcium compounds such as calcium carbonate, calcium chloride, calcium hydroxide, calcium sulfate, and calcium oxide, and magnesium compounds in place of calcium, other iron sulfate, iron chloride, iron alum, copper sulfate, and the like. It is done. Of the above, sparingly soluble alkaline earth metal compounds such as alkaline earth metal hydroxides, oxides and carbonates are particularly suitable for obtaining high strength in a long gel time.

[Factors and conditions as plastic grout]
(1) Hardening material ratio Cement content with respect to powder contained in grout, that is, fly ash and cement content:
Cement (hardening expression material) weight / {fly ash (silica-based non-curable powder) weight + cement (hardening expression material) weight} × 100 [%]
Cement is a material that develops hardening and can also be called fly ash plasticizer. When fly ash is mixed with cement, it causes a pozzolanic reaction to obtain consolidated strength. However, as the ratio of the cured material is increased, the characteristics as a plastic grout deteriorate. That is, precipitation increases the breathing, and the precipitated material is difficult to flow and hardly forms a plastic gel. Therefore, the ratio of the cured material is less than 50%, but the preferred range is a sulfate band (gelling accelerator). When not added, it is 1 to 20%, preferably 1 to 15%, more preferably 1 to 10%. Moreover, when adding a sulfuric acid band, it is 2 to 40%, Preferably it is 2 to 20%.

(2) Water powder ratio Water content with respect to the powder in the grout:
Water weight / {fly ash (silica-based non-curable powder) weight + cement (curing material) weight} × 100 [%]
When this value is small, it tends to be plastic. That is, the time for forming a plastic gel after blending is shortened, and the flow value is decreased. However, if the water powder ratio is too small, workability is impaired, so the range is 20 to 200%, preferably 20 to 100%, more preferably 20 to 50% (weight ratio). However, when water glass is used as an accelerator, the water powder ratio can be increased. In addition, since the properties of the grout differ depending on the mixing conditions, environment, and materials, the measurement of the breathing rate, flow value, and strength described later is important.

(3) Amount of sulfate band added Amount of sulfate band added to the powder in the grout:
Sulfuric acid band weight / {fly ash {silica-based non-curing powder} weight + cement (curing material) weight) × 100 [%]
The sulfuric acid band is a gelation accelerator, and when added to the fluid state of fly ash and cement, it promotes gelation and accelerates the time to become a plastic gel. However, since the sulfuric acid band also has the effect of reducing the consolidation strength, its addition amount is 2.0% or less, preferably 0.1 to 1.0%.

(4) Gel time Here, it does not mean chemical gelation that is solidified like that found in common water glass grouts, but it loses its fluidity due to its own weight after compounding, and plastic that flows when force is applied. The physical gelation time until it becomes a gel is expressed as gel time. Unlike a grout made from a common water glass, it cannot show a clear gelation time. Therefore, when the flow value was 20 cm or less using the flow value, it was regarded as gelation, and this was defined as gel time.

(5) Plasticity retention time Asphalt penetration test method Static penetration resistance was measured using a penetration cone with a total mass of 230 g, tip angle of 15 degrees, and 36 mm according to JIS K 2530-1961. When it exceeded MN / m ² , it became a non-plastic gel and was regarded as consolidated or cured, and the time from gelation to consolidation was defined as the plastic retention time.

(6) Breathing rate After blending, mix the grout thoroughly, then place the grout in a 200 ml graduated cylinder and seal it statically. Ask.
(Breathing water volume / measuring cylinder capacity) x 100 [%]
Here, the breathing rate after 1 hour has elapsed is shown. When the blending rate is 10% or more after 1 hour, the injected solution is easily separated and is easily injected in the form of veins or cracks. Thereafter, the breathing rate further increases as time elapses. Therefore, the blending rate after 1 hour is preferably 10% or less, preferably within 5%.

(7) Flow value Based on a flow test (JIS R 5201 table flow), the grout was subjected to 15 drop motions in 15 seconds, and the spread was measured. About 18-19 cm is said to be suitable as the plastic grout, but in the present invention, the fluidity due to its own weight disappeared when the flow value became 20 cm or less, and the gel time was used. The flowable injecting material in the present invention is used in such a composition that the water-to-powder ratio is lowered by pressure dehydration by pouring into the ground and the table flow reaches 20 cm or less.

The flow by the cylinder is to measure the spread of the grout when a cylinder having a height of 8 cm and a diameter of 8 cm is filled with the grout and the cylinder is removed. An appropriate range in that case is approximately 8 to 18 cm, and approximately 15 to 22 cm when a drop motion of 15 times similar to the table flow is given after removing the cylinder. Since it can be measured more easily than the above table flow, it is often used in the field. However, since it is simple, an artificial error may occur. FIG. 8 shows an approximate relationship between the table flow and the cylinder flow.
Even with such a high water powder ratio, the water powder ratio becomes 20% or less in the ground due to dehydration, and solidifies from a plastic gel through a non-plastic gel.

(8) Initial viscosity
Using the B-type viscosity form, the viscosity of the blended liquid immediately after blending was measured. Immediately after mixing, measurement was possible due to the fluidity, but when gelled, it becomes 100,000 cps or more, and measurement is impossible.

(9) Uniaxial compressive strength After blending, a well-mixed grout was packed in a mold having a diameter of 5 cm and a height of 10 cm, and cured for one day in a stationary state, and the uniaxial compressive strength was measured.

  As the injection material for injecting the plastic grout according to claim 3 of the present invention into the fine voids after the injection, a soil particle permeation type non-plastic grout can be used.

  The soil particle permeation type non-plastic grout in the present invention can be either a suspension type or a solution type, but it is necessary to obtain high strength with a long gelation time and to have excellent permeability.

  Suspended grout mixed with cement, cement bentonite, slag, etc., and / or water glass-based injection material using solution-type silica consolidated material may be used. An injection material mainly composed of a water-soluble silica compound obtained from glass by dealkalization treatment with an ion exchange resin or an ion exchange membrane or neutralization treatment with an acid is preferred. As an injection material mainly composed of such a water-soluble silica compound, a colloidal silica injection material (an injection material in which a curing agent such as an inorganic salt is added to colloidal silica to be gelled), an active silica injection material (active A pH adjusting material and an injection material in which an inorganic salt is added to gel if necessary, and a silica sol-based injection material (weak alkaline to neutral, acidic) are preferable. In the case of a colloidal silica-based injection material, the durability becomes better when the pH of the solidified body is lowered by adding a small amount of acids.

  On the other hand, in the case of acidic silica sol, or colloidal silica or activated silica, the gelation time may be greatly shortened due to the influence of the pH of the weak alkaline suspension injection material. It is desirable to use a material containing a metal sequestering agent. Examples of such compounds include phosphoric acid, phosphoric acid 1 soda, phosphoric acid 2 soda, phosphoric acid 3 soda, pyrophosphoric acid soda, acidic pyrophosphoric acid soda, tripolyphosphoric acid soda, tetrapolyphosphoric acid soda, hexametaphosphoric acid soda, and acidic metaphosphoric acid soda. .

  The flowable plastic grout used in the present invention will be described in detail in the following examples.

Materials used (1) Fly ash Coal ash discharged from thermal power plants: FA, silica-based non-curable powder,
A density of 1.9 to 2.3 g / cm ³ and a particle size distribution of 0.1 mm or less is 90% or more.
(2) Cement Ordinary Portland cement: PC, hardened material.

[Formulation Examples 1 to 3]
Mix fly ash, cement and water. The blending amount of fly ash and cement was similarly changed only in the blending amount of water. Table 1 below shows the adjustment conditions and physical property values of the ground injection materials of Formulation Examples 1 to 3 thus obtained.

  In Table 1, the gelation time refers to the time until the plastic gel is formed after blending, and the time when the table flow becomes approximately 20 cm is defined as the gelation time. The plastic holding time refers to the time during which a gel-like state is maintained if it is stationary but is in a state of flowing when a force is applied. As shown in Formulation Example 3, when the water powder ratio decreases, the blended liquid immediately becomes plastic. Therefore, immediately after blending as in blending examples 1 and 2, a fluid suspension is dehydrated in the process of being poured into the ground, and the plastic gel shown in blending example 3 is obtained.

  As shown in Table 1, Formulation 1 with the same cured material ratio of 8.05% and a water powder ratio of 35% and Formulation 2 with a water powder ratio of 30% are gelated until a plastic gel is formed after blending. Each time takes 480 or 300 minutes. When the water powder ratio is 25%, the gelation time is 2 minutes. This means that at the time of compounding, when the injection material that has not reached the plastic state before being injected into the ground is mixed in the ground, the water body ratio is 35% to 30% (dehydration rate is about 15%) and 25 % (Dehydration rate 30%), the gel time decreases to 2 minutes and becomes a plastic gel to form a lump. In addition, since the plastic state retention time is 7.5 hours at the time of gelation, the bulk gel expands, the breathing is small, the viscosity increases and it becomes difficult to diffuse, and the solidified product has high strength.

  Such characteristics have not been known so far. That is, the flowable injection material does not reach gelation until the water powder ratio is dehydrated from 35% to 25% after being pressed into the ground, and becomes 25% (dehydration rate of about 30%). After a minute, a plastic gel is formed, and the plastic retention time at that time is 7.5 hours. As the press-fitting continues, the gel remains large, and as the dehydration or curing phenomenon progresses, it does not flow. It becomes a gel and solidifies.

  Therefore, even if it does not exhibit plasticity at the time of injection, it can become plastic by dehydration in the ground. In injecting such a fluid injection solution, even if the compounding solution is injected as a single solution, the powder injection solution is A solution and gelation promoting material such as aluminum water glass is used as B solution. Alternatively, the liquid A can be applied to any plastic gel and the liquid B can be used as a gelation accelerator such as water glass regardless of the means.

  The performance evaluation of the present invention was carried out according to the Japan Highway Public Corporation "Guideline for the design and construction of the back cavity of the Yaita method tunnel". The blending at this time is blending 2 and 3 in Table 1 of Example 1.

1. Fillability test: Evaluation of limited injection property into the cavity was performed.

(A) Test equipment Fig. 1 shows the test equipment.
A mortar is placed and cured with a predetermined inclination on the bottom of a drainage groove having a height of 300 mm, a width of 300 mm, and a length of 4000 mm.
At the lower end of the hardened drainage ditch (container), four concrete blocks with a height of about 100 mm, four corners (wood) with a height of about 100 mm and two H-shaped steels are fixed at the upper end.
A transparent acrylic plate is fixed on the surface so that the filling state and the like can be confirmed. In order to prevent the acrylic plate from being lifted by the injection pressure, the steel plate is fixed at an appropriate interval.
In the container manufactured above, pressure gauges will be installed at two locations, 2m from the injection port.

(B) Test method An injection material is injected into the test apparatus.
The injection flow rate of the injection material (discharge amount from the injection hose) is 30 l / min.
Check the filling status from the acrylic board.
The pressure at the time of injection is measured with a pressure gauge.
The injection is terminated when the sample flows out from the discharge port at the tip.
After about 2 hours from the start of injection, disassemble the container and check the filling status. At this time, it is observed and recorded in detail whether or not the injected material is densely filled without gaps around the periphery of the square bar, H-shaped steel, etc. installed at the upper and lower ends in the container.
As an injecting material, as a comparison with the present invention, “Formulation 2” with a plastic holding time of 11 hours and “Formulation 3” with a plastic holding time of 7.5 hours were individually injected, and as an example of the present invention In the initial injection, “Formulation 2” was injected and then “Formulation 3” was injected.

(C) Results The result of injecting compound 2 with a long plastic holding time of the present invention first, and then injecting compound 3 with a short plastic holding time, and injecting compound 2 and compound 3 alone as a comparison of the present invention Table 2 shows the test results.

In Formula 2, since the plastic holding time was long and the fluidity was high, the details of the square and H steel could be filled without any gaps. In compound 3, large cavities were formed around H steel, and cavities were formed around square bars and concrete blocks.
When compound 3 was injected after compound 2 was injected, it could be filled without gaps in the vicinity of square bars, concrete blocks, and H steel.

2. Non-runaway test: The flow / outflow performance of cracks and lining cracks was evaluated.

(A) Test apparatus A test apparatus is shown in FIG.
A wooden frame, a wooden board, and a transparent acrylic board are processed, and a predetermined container is produced.
A transparent acrylic plate is installed on the front side of the container so that the condition of escape to the gap (injection depth of the injected material) can be confirmed.
A chute-shaped inlet having a length of about 400 mm is prepared on one side of the container.
In the lower part of the container, gaps of 1, 3, 5, 7, 10 mm are made with foamed polystyrene.

(B) Test method The pouring material is poured into the test apparatus. However, the injection material should not be poured directly, but should be poured in one cushion with a chute on one side of the container.
The discharge rate of the injection material is 30 l / min.
The injection ends when the height reaches 300 mm from the top of the foamed polystyrene.
Measure the depth of the injected material that has entered (entered) each gap at 10 min, 30 min, and 60 min.
“Ingredient 2” and “Ingredient 3” were used as injection materials, respectively, and performance evaluations were performed.

(C) Results Tables 3 and 4 show the results of the non-runaway test in Formulation 2 and Formulation 3, respectively.

3. Water separation resistance test: The separation resistance to water and the pH of surrounding water were measured.

(A) Test equipment Fig. 3 shows the test equipment.
26 l of water is put in a water tank of about 450 mm in length, about 300 mm in width, and about 300 mm in height. The water used is tap water with a pH of about 7-8.
Install a pH meter in the aquarium. At this time, the installation position of the pH meter is 10 cm from the water surface.
The turbidity is sampled with a dropper from a position 10 cm from the water surface, and the light transmittance at a wavelength of 800 mm is measured with a spectrophotometer.

(B) Test method The pouring material is poured into a flow cone having a diameter of 80 mm and a height of 80 mm (JHS standard).
Place the flow cone in the aquarium and quickly remove the flow cone. At this time, initial turbidity and the like are not generated as much as possible without giving an impact such as vibration.
Measure the pH and turbidity of the injected material before, immediately after, and after 10 min, 30 min and 60 min.
Observe the turbidity of each time course.

(C) Results FIG. 4 shows the change in pH per elapsed time, and FIG. 5 shows the change in turbidity.
From the figure, it was found that since the change in pH and turbidity was hardly seen, the influence on the pore water, seawater, etc. of the ground around the plastic gel was extremely small.

4). Non-shrinkage test: The shrinkage of the injected material was evaluated.

(A) Test apparatus A test apparatus is shown in FIG.
Prepare a container with a flat plate attached to the bottom of a rigid PVC pipe with a diameter of 300mm and a height of 1,000mm so that no leakage of the injected material occurs at the lower end.

(B) Test method An injection material is put into a container.
Capping is performed to prevent water from spreading from the injected material, and curing is performed in a room at 15 to 25 degrees.
Measure the amount of contraction after 28 days.
As the injection material, “Formulation 2” and “Formulation 3” were performed.

(C) Results The “composition 2” shrinkage amount was 5 mm, and the “composition 3” shrinkage amount was 4 mm.

  As an example of construction, backfill soil in the case where the evacuation of the back of the revetment from the deficient portion of the revetment occurs due to the tidal level of the existing revetment, and the subsidence and inclination of the revetment and the depression of the road surface occur. FIG. 7 shows the suction prevention method. An injection tube was installed along the sand-proof sheet on the ground behind the damaged portion of the suction prevention sheet. First, a grout having a long plastic holding time was injected and penetrated to repair the defective portion.

  In the construction, by injecting a plastic gel as the primary injection material into the defective part of the sheet and roughly closing the defective part of the sheet, it is possible to prevent dilution of the subsequent injection material by surrounding water such as seawater. It was possible to prevent the concentration of the injected drug solution from being lowered by the flowing water.

  At this time, the plastic gel is dehydrated under pressure in the ground using a quick-blending compound, and quickly solidifies, so that only the rough part and the surface of the stone are consolidated, so it easily breaks above and below the water flow and groundwater. Therefore, even if it is hardened with osmotic silica liquid by backfilling, its strength is weak, so that it is washed out to the free void side with groundwater and the sucking prevention effect cannot be obtained. However, by using a fluid plastic grout, the range of the bulk gel is gradually expanded during the plastic retention time, and dehydration is caused by pumping with the subsequent plastic gel. The body ratio can be reduced, and since the gelation time is shortened and the plasticity retention time is reduced, the body is solidified through non-plasticity, so that the voids can be filled firmly.

  After that, by injecting permeable suspension grout into the surrounding ground, it was able to penetrate between the soil particles and solidify the surrounding ground firmly.

  The above-mentioned present invention uses a flowable plastic gel as an injection material, and uses an injection material having different plastic holding times in the initial injection stage and the subsequent injection stage, and further, an injection region or injection into which the plastic gel is injected. By injecting the non-plastic injection material of the inter-soil particle penetration type into the details of the region, the strength rises quickly and penetrates into the details of the injection region to improve the suction resistance. Therefore, the present invention has high applicability in the field of injection prevention injection technology.

It is the figure which showed the testing apparatus of the filling property test in this invention. It is the figure which showed the test device of the non-escape test in this invention. It is the figure which showed the testing apparatus of the water-separation resistance test in this invention. It is the figure which showed the change of pH of the water-separation resistance test in this invention. It is the figure which showed the change of the turbidity of the water-separation resistance test in this invention. It is the figure which showed the testing apparatus of the non-shrinkage test in this invention. It is the figure which showed the construction method which inject | pours fluid plastic-like gel and secondary injection material to backfill soil in the suction prevention sheet | seat defect | deletion part of the revetment in this invention. It is a graph showing the relationship between a table flow and a cylinder flow.

Claims (4)

  An anti-suction injection method for preventing suction by injecting a ground injecting material, the method comprising injecting a fluid plastic gel as the injecting material to prevent suction.   A suction prevention injection method for injecting ground injection material to prevent sucking, and using a plastic gel as the ground injection material, injection materials having different plastic holding times in an initial injection stage and a subsequent injection stage are used. A sucking prevention injection method characterized by using.   3. The sucking prevention injection method according to claim 1, wherein a non-plastic injection material of an inter-soil particle penetration type is injected into the injection region into which the plastic gel is injected or the details of the injection region. The plastic gel injection material has a table flow at the time of press-fitting of 12 cm or more and / or a slump of more than 5 cm, and / or a cylinder flow of more than 8 cm, and the plastic gel is injected into the plastic gel before or during press-fitting into the ground. 4. The suction-preventing injecting method according to claim 1, 2, or 3, which is an injecting material.

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