JP2007051492A - Checking method for soil improvement effect, and grouting method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To check a soil improvement effect by grasping an injection rate after the injection of solution-type silica grout into the ground and the status of the consolidation of the improved ground, and checking the distribution of the range and status of the consolidation of the improved ground. <P>SOLUTION: In this method for checking the effect of improving the ground by injecting a chemical solution of the solution-type silica grout, the injection rate λ(%) of the improved ground is determined by an expression: B/A×100. In the expression, (A) represents a measurement value of a silica content per unit volume of a test specimen which is prepared by setting the injection rate at 100% by the use of sand extracted from the ground before chemical grouting, and (B) represents a measurement value of a silica content per unit volume of consolidated soil extracted from the improved ground subjected to the chemical grouting. Otherwise, the injection rate λ(%) of the improved ground is determined by an expression: (B-D)/C×100. In the expression, (C) represents a silica content which is computed from a chemical solution required for the preparation of a test specimen, (B) represents a measurement value of a silica content of consolidated soil extracted from the improved ground subjected to the chemical grouting, and (D) represents a measurement value of a silica content per unit volume of the sand extracted from the ground before the chemical grouting. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for confirming the ground improvement effect of chemical injection using solution-type silica grout, particularly non-alkaline silica grout. Specifically, the injection rate after injection and the consolidation status of the improved ground are grasped and further improved. This is a ground improvement effect confirmation method for confirming the ground improvement effect by confirming the distribution of the consolidation range and consolidation status of the ground, and a ground injection method using this method.

  In recent years, liquefaction prevention and foundation reinforcement work has been carried out by a ground injection method using a silica solution having a long-term durability, and a method for confirming the effect of the injection ground has become extremely important. This is because, as long as chemical injection is used in the main construction, the injection material itself is excellent in long-term durability, and it is possible to penetrate between the soil particles of the applied injection method and widen the injection hole interval. It is necessary to be able to perform economical construction by wide-range penetration consolidation.

  As a conventional method for confirming the effect, in-situ tests such as a standard penetration test and a water permeability test have been used. However, in the construction work such as liquefaction prevention, it is common to grasp the uniaxial compressive strength corresponding to the liquefaction strength after injection by core sampling of the injected ground.

  On the other hand, when undisturbed samples are collected, there are many cases where it is not possible to collect cores due to uniaxial compressive strength if gravel or the like is present on the local board.

  In addition, in the conventional temporary ground injection, the interval between the injection holes was about 1 m. However, in recent years, economical construction is necessary for the main construction, so the interval between the injection holes is set to 1.5 to 4 m. The present applicant has invented an injection method capable of a long penetration distance by the multi-point simultaneous injection method.

  On the other hand, it has been found that in a wide range of injections, the permeation and consolidation strength decreases as the distance from the injection hole increases. As a method for confirming the injection effect for such injection purposes, there have been problems such as difficulty in collecting cores by core sampling, a limited number of samplings, and difficulty in shaping.

So by measuring the content of caking soil chemical, S _i O ₂ and Na 2 _{method O} was eluted from the consolidated soil is quantified as the main component of the chemical by chemical analysis that does not require undisturbed sample is there.

However, in the method of obtaining the content from the measurement of S _i O _{2 in} the consolidated soil, the amorphous silica content contained in the soil particles is also measured. The amorphous silica content in the local board is not necessarily the same as the silica content in the silica grout, and it is possible to detect both types of silica separately, but this is a complicated process. However, even if the silica content in the silica grout is analyzed, the measured silica content is the absolute value of the silica content injected into the consolidated ground. It does not always indicate.

Further, in the method for determining the content from the measurement of Na ₂ O in consolidated soil, the gel Na ₂ O hardened in the ground exists as a soluble component, and is easily moved by water in the ground, in ground with the influence of sea water has a problem such as inability to use can not be distinguished from the Na 2 _O of Na 2 _O and seawater due to water glass silica grout.
None

  In the present invention, as a method for confirming the injection effect after the ground improvement in the chemical solution injection, the silica content in the consolidated soil of the improved ground is obtained to grasp the injection rate of the chemical solution into the injection target ground. Here, the injection rate is the percentage of the amount of grout injected per unit volume of the amount of soil to be injected, expressed as a percentage, which significantly affects the injection effect and strength development.

  However, the measured value of the silica content by measuring only the solid soil of the improved ground obtained by the above chemical analysis method is a value including various uncertain factors, and the absolute value of the silica content injected into the improved ground It does not indicate a value.

  Therefore, by adjusting the relative density of the ground using sand collected from the ground before chemical injection, a test specimen was prepared with an injection rate of 100% when all the existing voids were filled with the injected liquid. A method that calculates the injection rate from the ratio of the silica content per unit volume of the consolidated soil after ground improvement to the reference value, assuming the silica content per unit volume as 100% injection rate, or before chemical solution injection Silica calculated from the chemical solution required to prepare the specimen so that the injection rate is 100% when all the voids existing by adjusting the relative density of the ground using sand collected from the ground are filled with the injection solution Subtracting the amorphous silica content of the ground from the silica content per unit volume of the consolidated soil after ground improvement and calculating the injection rate from the ratio to the reference value 2 ways to do To solve the above problems by calculating the injection rate regardless of the uncertain factors, and to establish a simple and accurate method for confirming the ground improvement effect, and to perform highly reliable ground improvement And

  In the first invention, the silica content per unit volume of consolidated soil collected from the improved ground after chemical solution injection is measured and adjusted to the relative density of the ground using sand collected from the ground before chemical solution injection. A method for obtaining the injection rate from the ratio to the silica content per unit volume of a specimen prepared with an injection rate of 100% when all the existing voids were filled with the injection solution was used as a means for solving the above problems.

  In the second invention, the silica content per unit volume of the consolidated soil collected from the improved ground after the chemical solution injection is measured, and the amorphous silica content of the ground before the chemical solution injection is subtracted from this, the chemical solution injection It was calculated from the chemical solution required to prepare the specimen so that the injection rate was 100% when all the voids existing by adjusting the relative density of the ground using sand collected from the previous ground were filled with the injection solution The method for obtaining the injection rate from the ratio with respect to the silica content was used as a means for solving the above problems.

  In the third invention, a ground improvement effect confirmation method for confirming the distribution of consolidation status after injection and consolidation status in the ground improvement range from the injection rate obtained using the methods of the first and second inventions. Means for solving the above-described problems were provided.

  In the fourth invention, the ground injection construction method including the step of confirming the ground improvement range and the consolidation status after the injection from the injection rate obtained by using the methods of the first and second inventions is defined as a solution to the above problem. .

  According to the method for determining the injection rate of the present invention, the silica content per unit volume of the consolidated soil collected from the improved ground after the chemical solution injection according to claim 1 is measured, and the sand collected from the ground before the chemical solution injection. The filling rate is determined from the ratio of the test specimens prepared with the filling rate of 100% when all the existing voids are adjusted to the relative density of the ground using, and the filling rate is 100%.

  Further, the silica content per unit volume of the consolidated soil collected from the improved ground after the chemical solution injection according to claim 2 is measured, and the amorphous silica content of the ground is subtracted therefrom, and the sand collected from the ground. Injecting from the ratio to the silica content calculated from the chemical solution required to prepare the specimen so that the injection rate is 100% when all the existing voids are adjusted to the relative density of the ground using Find the rate.

  Furthermore, it is characterized in that the relative density of the specimen collected from the ground before the chemical solution injection and the sand sampled from the ground before the chemical solution injection is made the same as the relative density of the ground. Therefore, a method for confirming the injection effect after ground improvement in simple and accurate chemical injection can be established, and highly reliable construction management can be performed.

  The solution-type silica grout used in the present invention is a grout having excellent permeability, long gel time, excellent durability, and capable of economical construction by osmotic consolidation in a wide injection range. A water glass grout made of water glass and a reactant.

  Preferable specific examples include (1) acidic silica solution obtained by dealkalizing water glass and acid, (2) silica solution obtained by dealkalizing water glass by ion exchange resin treatment or ion exchange membrane treatment, 3) Water glass is dealkalized to an acidic silica solution, and an alkali material is added thereto to make it neutral to alkaline. (4) Silica solution or water glass obtained by dealkalizing water glass Acidic silica solution obtained by dealkalizing again the silica solution made neutral to alkaline by adding an alkali material to the acid silica solution obtained by dealkalizing, and (5) dealkalizing the water glass Stabilized colloidal silica solution obtained by concentrating and increasing the size of acidic silica solution, (6) No self-hardening obtained by mixing water glass and colloidal silica Acidic silica solution obtained by dealkalizing a standardized silica solution, (7) No self-hardening obtained by mixing water glass, colloidal silica, and silica solution obtained by dealkalizing water glass Examples thereof include acidic silica solutions obtained by dealkalizing a stabilized silica solution.

  A gelling modifier can be further added to the silica solution. Examples of the gelation modifier include sulfuric acid, phosphoric acid, aluminum sulfate chloride, polyaluminum chloride, sulfate bands, organic acids (citric acid, succinic acid, acetic acid), etc. Examples include inorganic salts such as alkali metal salts and alkaline earth metal salts. Among these, sequestering agents and phosphate compounds such as citric acid and condensed phosphates form an insoluble coating film on the concrete structure in the ground and trace metals in the soil, and the alkali action by masking action. Since the leaching is blocked, the concrete is protected.

  Specific examples of the sequestering material include aliphatic oxycarboxylic acids such as citric acid and gluconic acid, condensed phosphates such as pyrophosphoric acid, triphosphoric acid and trimetaphosphoric acid, sodium polyphosphate, acidic sodium polyphosphate and tripolyphosphoric acid. Examples thereof include polyphosphates such as sodium, sodium tetrapolyphosphate, sodium hexametaphosphate, acidic sodium hexametaphosphate or potassium salts thereof, ethylenediaminetetraacetic acid, nitrilotriacetic acid, and salts thereof.

As a method for obtaining the injection rate of the chemical solution injection ground, one is the relative density b%, mass M _b [g], volume V _b [cm ³ ], density ρ _b collected from the ground after the chemical injection for which the injection rate is desired to be obtained. = M _b / V _b [g / cm ³ ] consolidated soil and sand collected from the ground before chemical injection, adjusted to the relative density of the ground and filled with all the existing voids Two types of specimens with a relative density of b%, mass M _a [g], volume V _a [cm ³ ], density ρ _a = M _a / V _a [g / cm ³ ], produced at an injection rate of 100% The silica content [mg] per 1 [g] of the specimens prepared by measuring the silica content [mg] per 1 [g] and measuring the silica content [mg] per 100 [g] ], of each of the silica content of the caking soil collected from the ground after chemical injection B '[mg / g] density [rho _a, the [rho _b Flip silica content A per unit volume [mg / cm ^3] to obtain the B [mg / cm ^3], the silica content per unit volume of the specimen prepared as an infusion rate of 100% as a reference, against which The injection rate λ is obtained from the ratio of the silica content per unit volume of consolidated soil collected from the improved ground. When the above content is simply expressed by an equation, λ = (B ′ · ρ _b ) / (A ′ · ρ _a ) × 100 = B / A × 100 [%] (Equation 1.1).

As a second method, the relative density b%, mass M _b [g], volume V _b [cm ³ ], density ρ _b = M _b / V _b collected from the ground after the chemical injection for which the injection rate is desired to be obtained. Silica was analyzed for 2 types of samples of solid soil of [g / cm ³ ] and sand collected from the ground before chemical injection, and the silica content per 1 [g] of each sample was measured, and after chemical injection determine the silica content B per unit volume [mg / cm ^3] is multiplied by the silica content B '[mg / g] to the density [rho _b of caking soil collected from the ground, the silica eluted from this sand Subtract the silica content D [mg / cm ³ ] per unit volume obtained by multiplying the content D '[mg / g] by the soil dry density ρ _d when the relative density is b%, and then the ground before chemical injection The case where all the voids that exist by adjusting the relative density of the ground using sand collected from M with a silica concentration C ′ [%] of a chemical solution (mass M _cG ) required for a specimen having a relative density of b%, mass M _c [g], and volume V _c [cm ³ ] produced so that the injection rate is 100%. based on the _{cG /} V _c obtained by multiplying by silica content per unit volume calculated C [mg / cm ^3] to determine the injection rate as a percentage of this. The above contents can be simply expressed by an equation: λ = (B ′ · ρ _b −D ′ · ρ _d ) / {(C ′ / 100) × (M _cG / V _c ) × 1000} × 100 = (B -D) / C × 100 [%] (Formula 1.2).

  Previously, the soil improvement effect after injection was judged only from the measured value B ′ [mg / g] of the silica content of the consolidated soil collected from the ground after the chemical injection. A high injection rate is required, and confirmation of the ground improvement effect after injection is more certain. Therefore, by comparing the injection rate obtained from the measurement of the silica content by the above method and the design injection rate, further adjusting the relative density of the ground using sand collected from the ground before chemical injection, The strength of the ground after the chemical solution injection can be estimated from the strength of the specimen prepared with an injection rate of 100% when all the existing voids are filled with the injection rate, and the ground improvement effect is sufficient by comparing with the design strength Can be evaluated.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
Method for Measuring Silica Content (1) Method for Preparing Sample Solution for Measuring Silica Content Place the sample in a high temperature chamber at 105 ° C for 2 hours and dry. Collect 5 g from the dried sample, add 20 ml of 10% sodium hydroxide (NaOH) solution and 50 ml of pure water, stir for 1 hour, filter with filter paper, and wash the sample on the filter paper with pure water While making a filtrate, water was added to the obtained filtrate to prepare a test solution for measuring the silica content to 250 ml. At that time, the loss on drying [%] when the sample was dried was determined by Formula 2.1.

Where G: Loss on drying [%]
E: Weight of sample before drying [g]
F: Weight of sample after drying [g]

(2) Measurement method
Si was measured by ICP-AES (inductively coupled plasma emission spectroscopy). SiO ₂ was converted from Si _{2 according} to Formula 2.2.

    Here, ICP-AES analyzes elements by plasma emission and spectroscopy of components in a substance, and it is a main component element such as metal, glass, ceramic, paper, fiber, cleaning processed water, industrial wastewater, etc. -Trace element elements can be qualitatively and quantitatively analyzed with high sensitivity and high accuracy. It is particularly effective for analysis of trace elements.

Here, J: SiO ₂ amount per liter of sample solution [mg]
H: Amount of Si per liter of sample solution [mg]

(4) was determined SiO ₂ per sample 1g than Determination of formula 2.3 SiO ₂ per sample 1g.

Here, K: SiO ₂ [mg / g] per 1 g of sample
J: SiO ₂ [mg / L] per 1 [L] of the sample liquid
l: Sample liquid volume (250 [ml])
m: Weight of dry sample used for measurement (5 [g])
G: Loss on drying [%]

  In order to understand the influence of relative density when determining the injection rate, Touraura standard sand and solution type non-alkaline silica sol grout with silica concentration of 4, 5 and 6% are used, and injection rate is 100% at relative density of 40% and 80%. Samples were prepared and the relationship between relative density and strength, and relative density and silica content were determined.

(1) Chemical solution The solution type non-alkaline silica grout shown in Table 1 was used.
This solution-type non-alkaline silica grout is based on activated silica (SiO ₂ concentration 4 Wt%) obtained by dealkalizing water glass by ion exchange, and it has a predetermined silica concentration and pH by water glass and acid (phosphoric acid). It is the acidic silica solution adjusted to.

  Here, instead of active silica, colloidal silica may be used as a base, or an acidic silica solution composed of an acidic silica sol obtained by adding water glass and an acid to remove the alkali of the water glass may be used. .

(2) Sample sand Toyoura standard sand
(3) Preparation of specimen A specimen was prepared using a mold having an inner diameter of 50 mm and a height of 100 mm.

(4) Measurement of strength and silica content The uniaxial compressive strength of the specimen was measured, and the silica content of the consolidated sand after the measurement of the strength was analyzed by the method for measuring silica content, and the mass of the specimen. Expressed as a ratio of silica content to Further, since the silica of the chemical solution and the silica of the sample sand are eluted from the specimen, the silica content of only the sample sand is also measured to obtain a blank.

(5) Results Table 2 shows the measurement results of uniaxial compressive strength. In addition, as a representative, the relationship of the strength with respect to the silica concentration of a chemical solution having a relative density of 40% and 80% for 4 weeks strength is shown in FIG.

  The higher the silica concentration in the chemical solution, the higher the uniaxial compressive strength, and even if the silica concentration in the chemical solution is the same, the higher the relative density of the specimen, the higher the uniaxial compressive strength. It was found that the strength was greatly affected.

  Next, the silica content of the specimen subjected to strength measurement was measured by the measurement method described above, and the ratio of the silica content to the mass of the specimen is shown in Table 3 and FIG.

The silica content of the sample sand alone is 0.07 wt%, and it is thought that the soluble silica of the sample sand was eluted. In FIG. 2, this value is plotted as a silica concentration of the chemical solution of 0%, and an approximate line is drawn.
As the silica concentration of the chemical solution increased, the ratio of the silica content to the mass of the specimen also increased in proportion thereto.

  The relative density of 40% is higher than 80%, and the ratio of the silica content to the mass of the specimen is higher. This is because the equation for obtaining the relative density is shown in Equation 3.1 because the gap becomes smaller when the relative density of the specimen is high.

  The gap is expressed by the gap ratio and the porosity, and it is a factor that has a great influence on the soil mechanical properties along with the soil density. It will be different. However, when compared at the same relative density, the mechanical properties of the soil are often determined regardless of the type of sand and are widely used. Relative density is an indicator of how the current tightness of the sand is between the densest state and the loosest state of the sand. Therefore, when determining the silica content, the influence of the relative density of the specimen sample must be fully considered.

Where e: sample gap ratio
ρ _d : Dry density of sample [g / cm ³ ]
e _max : The gap ratio of the sample by the minimum density test
e _min : sample gap ratio by maximum density test
ρ _dmax : Dry density of sample by maximum density test [g / cm ³ ]
ρ _dmin : Dry density of sample by minimum density test [g / cm ³ ]

Experiment 1
In order to understand the relationship between the penetration distance and the injection rate and strength in the improved ground by chemical injection, we conducted a one-dimensional penetration test of a solution-type non-alkaline silica grout with a silica concentration of 6% using on-site collected sand. Measure the uniaxial compressive strength of the knot to determine the relationship between the penetration distance and strength, and calculate the injection rate of solid soil collected from the specimen after strength measurement using the above-mentioned method for measuring the silica content, and calculate from equation 1.1. The relationship between the penetration distance and the injection rate was determined.

(1) Chemical solution The same solution type non-alkaline silica grout as shown in Table 4 as in Example-1 was used.

(2) Sample sand On-site sampling sand (3) One-dimensional infiltration device Figure 3 shows a one-dimensional infiltration device.

(4) One-dimensional penetration test method Sample sand was filled in a transparent acrylic mold having an inner diameter of 50 mm and a length of 1.5 m so that the relative density was 60%. After injecting water in advance to saturate, the chemical solution was injected. The chemical solution was injected at a constant pressure of 0.03 MPa from the bottom of the mold. At the beginning of chemical injection, water is pushed out from the upper part of the mold and collected in the graduated cylinder. The pH of the liquid is neutral, but when the chemical reaches the upper part of the mold, the pH of the liquid collected in the graduated cylinder becomes acidic. Thus, it was confirmed that the water in the mold was replaced with the chemical solution, and the injection was terminated. After curing for 4 weeks and removing the end of the mold by 50 mm, the mold was cut every 100 mm to obtain specimens of 50 mm × 100 mm.

(5) Specimen with an injection rate of 100% Using a mold with an inner diameter of 50 mm and a height of 100 mm, adjusting the relative density to 60% using sample sand, filling all existing voids with the injection solution, and injecting A specimen having a rate of 100% was produced.

(6) Measurement of strength and silica content (4) One-dimensional penetration test and (5) uniaxial compressive strength of the specimen obtained from the preparation of the specimen with 100% injection rate was measured. The silica content of the set sand was analyzed by the above-described method for measuring the silica content.

(7) Results Results of measurement of the mass [g] and volume [cm ³ ] of the specimen prepared at an injection rate of 100% and the specimen obtained from the one-dimensional penetration test, and calculating the density [g / cm ³ ] Is shown in Table 5.

  Table 6 shows the silica content of the specimen prepared at an injection rate of 100% and the silica content of the specimen by the one-dimensional penetration test.

Table 7 shows the results obtained by calculating the uniaxial compressive strength and the injection rate of the specimen by the one-dimensional penetration test using Equation 1.1, and FIG. 4 shows the relationship between the penetration distance, the injection rate, and the strength. Furthermore, the relationship between the injection rate and the strength is shown in FIG. FIG. 5 includes the strength 0.35 [MN / m ² ] of the specimen prepared with an injection rate of 100%.

  In FIG. 4, the injection rate and the strength decrease as the penetration distance increases. This is because the injection was finished immediately after confirming that the chemical reached the upper part of the mold, and since the chemical injected first into the saturated soil was diluted, the amount of the chemical filled between the soil particles was reduced. This is because it has decreased.

  Therefore, the injection rate and the intensity distribution with respect to the penetration distance are very similar. Therefore, the relationship between the injection rate and the intensity is plotted in FIG. 5, and the correlation coefficient between the injection rate and the intensity was as high as 0.97. For this reason, the measurement of the injection rate by chemical analysis is considered to be effective as an auxiliary means for estimating the strength of the improved ground as well as confirming the improved range by chemical injection and the consolidation status of the improved ground.

Experiment 2
The experiment was performed in the same manner as in Experiment 1 using the method for obtaining the injection rate according to Equation 1.2, and the relationship between the penetration distance and the injection rate was obtained.

(1) Chemical solution and experimental method Same as Experiment 1

(2) Measurement of silica content The solidified sand whose strength was measured and the silica content of the sample sand used for the production thereof were analyzed by the method for measuring silica content.

(3) Results Results of measurement of the mass [g] and volume [cm ³ ] of the specimen prepared with an injection rate of 100% and the specimen obtained from the one-dimensional penetration test, and calculating the density [g / cm ³ ] Is shown in Table 8. Moreover, Table 9 shows the mass [g] of the sample sand and the mass [g] of the chemical solution when the specimen was prepared with an injection rate of 100%.

Table 10 shows the measurement results of the silica content of the specimen prepared with an injection rate of 100%, the silica content of the specimen by the one-dimensional penetration test, and the silica content of the sample sand. Here, the dry density of the sample sand at a relative density of 60% was 1.433 [g / cm ³ ].

Table 11 shows the results obtained by calculating the uniaxial compressive strength and the injection rate of the specimen by the one-dimensional penetration test using Equation 1.1, and FIG. 6 shows the relationship between the penetration distance, the injection rate, and the strength. Furthermore, the relationship between the injection rate and the strength is shown in FIG. FIG. 7 includes the strength 0.32 [MNm ² ] of the specimen prepared with an injection rate of 100%.

  Similar to Experiment 1, the injection rate and strength distribution with respect to the penetration distance were very similar, and the correlation coefficient between the injection rate and the strength was as high as 0.99.

  The present invention grasps the injection rate after injecting the solution type silica grout into the ground and the consolidation status of the improved ground, and further confirms the distribution of the consolidation range and consolidation status of the improved ground, and improves the ground improvement effect. Since it is to be confirmed, the applicability of the ground improvement material in the injection technology field is high.

It is the graph which showed the relationship of the uniaxial compressive-strength measurement value of the curing period of 4 weeks of the test body produced with the silica density | concentration and relative density of a chemical | medical solution being 40% and 80%. It is the graph which showed the relationship between the silica concentration of a chemical | medical solution, and the ratio of the silica content with respect to the mass of a test body. It is a schematic diagram of a one-dimensional osmosis | permeation apparatus. FIG. 6 is a distribution diagram of a measured uniaxial compressive strength of an infiltration specimen with respect to an infiltration distance by a one-dimensional infiltration test and an injection rate according to Formula 1.1. It is a graph showing the relationship between an injection rate and a uniaxial compressive strength measured value. FIG. 5 is a distribution diagram of a measured uniaxial compressive strength of an infiltration specimen with respect to an infiltration distance by a one-dimensional infiltration test and an injection rate according to Formula 1.2. It is a graph showing the relationship between an injection rate and a uniaxial compressive strength measured value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Pressure gauge 3 Injection liquid 4 Injection liquid valve 5 Valve 6 Valve 7 Acrylic mold 8 Sample sand 9 Outlet 10 Measuring cylinder

Claims (7)

  This is a method for confirming the ground improvement effect by chemical solution injection of solution-type silica grout, and the measured value of the silica content per unit volume of a specimen prepared using sand collected from the ground before chemical solution injection with an injection rate of 100% Is (A), and the measured value of the silica content per unit volume of consolidated soil collected from the improved ground where the chemical solution was injected is (B), and the injection rate λ [percentage of the improved ground from B / A × 100 ] The confirmation method of the ground improvement effect characterized by calculating | requiring.   It is a method for confirming the ground improvement effect by chemical solution injection of solution type silica grout, and was calculated from the chemical solution required to prepare the specimen so that the injection rate was 100% using sand collected from the ground before chemical solution injection Silica content per unit volume of sand sampled from the ground before chemical solution injection, with the silica content as (C) and the measured value of the silica content of the consolidated soil collected from the improved soil injected with the chemical solution as (B) A method for confirming the ground improvement effect, wherein the measured value of the content is (D) and the injection rate λ [percent] of the improved ground is obtained from (BD) / C × 100.   3. The method for confirming the ground improvement effect according to claim 1 or 2, wherein the relative density of the specimen to be prepared with the injection rate of 100% using the sand collected from the ground before the chemical injection is the relative density of the ground before the chemical injection. A method for confirming the ground improvement effect, characterized in that it corresponds.   The method for confirming the ground improvement effect according to claim 1 or 2, wherein the ground improvement effect is obtained particularly when non-alkaline silica grout is used as a chemical to be injected.   It is a confirmation method of the ground improvement effect of Claim 1 or 2, Comprising: The confirmation method of the ground improvement effect which confirms the consolidation condition of the ground improvement range from the calculated | required injection rate.   A ground improvement effect confirmation method for evaluating the ground by confirming the ground improvement effect of claim 1 or 2 over time. A ground injection method comprising the step of confirming the ground effect of either or both of claims 1 and 2.