Site injection method

Abstract

To provide a suspension-type ground-solidification material and a grouting method which are excellent in terms of environmental conservation, and which can have effects on solidifying ground and achieve integrated ground improvement and water cut-off property even in ground where suspended particles cannot penetrate.SOLUTION: There is provided a suspension-type ground-solidification material whose active ingredients are suspension particles made from slag or fly ash and water glass, wherein a bleeding liquid gelates and a sand gel, which has been soaked in the bleeding liquid, stands on its own.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a high-strength suspension-type ground consolidation material that contains slag or fly ash as an active ingredient and has permeable consolidation properties and environmental conservation properties, and to a ground grouting method.

[0002] Ground improvement methods using slag-based suspension grout have the problem that, because it is primarily composed of suspended particles, it cannot penetrate between fine soil particles. Therefore, in ground containing fine-grained soil, which suspended particles cannot penetrate, the consolidation effect cannot be achieved, making it difficult to achieve integrated ground improvement and watertightness. To solve this problem, the present invention provides a ground grouting method that utilizes the gelation of the suspension's bleeding liquid, making it possible to improve ground where suspension penetration is not expected. The present invention also relates to a ground consolidation material and a ground grouting method that can be used in high-pressure injection methods by imparting a stable consolidation effect.Furthermore, the present invention relates to a ground improvement technology using a low-carbon grout injection method that uses a fine particle injection material whose main component is fine particle slag in the ground.

[0003] The CO2 emissions during production of blast furnace slag, the main ingredient of the ground consolidation material of this invention, are about one-tenth of those of cement, and are expected to be more effective in reducing CO2 emissions than cement-based suspension-type injection materials.In addition, this invention is a ground injection method that can be implemented economically by using industrial by-products as materials, and reduces the environmental impact, and is a technology that also contributes to carbon neutrality, which has become a national issue in recent years for preventing global warming. [Background technology]

[0004] Conventionally, high-strength ground improvement methods have been used to form high-strength consolidated bodies in the ground by high-pressure injection and mixing of cement-based grout. This method is excellent in that it forms large-diameter solidified bodies in the ground, but its principle is to mix and mix the soil in the ground with cement using high-pressure injection, replacing the soil particles with cement solidified bodies, which results in a large amount of soil being discharged. Disposal of this soil poses challenges in terms of high costs and CO2 reduction, which are environmentally problematic from the perspective of carbon neutrality.

[0005] Soil improvement methods have been proposed in which finely divided cement or slag grout is injected into the ground to increase its strength. However, these suspension-type grouts have the following problems when used in sandy ground. (1) It is prone to clogging. Therefore, in ground that contains a mixture of fine-grained soil or ground that consists of soil layers of different particle sizes, the penetration of suspended particles is insufficient, resulting in insufficient solidification and water-stopping properties. (2) The finer the particles, the more they are electrically re-agglomerated, which effectively increases the particle size. As a result, the permeability is limited to the area around the injection tube, or the injection is pulsed. (3) Bleeding causes the suspended particles and the mixed water to separate in the ground, making it difficult to form a consolidated mass. (4) Because bleeding occurs, the solidification rate of the solidified body relative to the injection amount is small. (5) When using high-pressure injection, the injection force may cause the injection material to disperse, resulting in insufficient solidification.

[0006] Furthermore, even if a dispersant is added to the fine particle suspension, the suspended particles separate from the mixing water during the process of high-pressure injection and mixing into the ground, making it difficult to form large, uniform aggregates.

[0007] Furthermore, suspension grouts made by mixing cement and water glass have been known for some time. However, such suspension grouts have a gelling time of about 1 to 10 minutes, and it is difficult to extend the gelling time any longer. They also lack durability, and the suspended matter tends to separate and clog in the ground, or to be injected in the form of veins, limiting the infiltration and solidification area to the area around the injection pipe, or causing clogging, making it difficult to form a large, homogeneous solidified mass.

[0008] The following describes prior art related to suspension grout. Conventionally, suspension grout, a mixture of water glass and cement, is known as LW, but it has a gel time of about one minute, high viscosity, and low strength. Grouts containing acidic silica sol, obtained by mixing water glass with acid, as well as cement and hydrated lime, are also known. This grout has a short gel time and is prone to forming floc-like precipitates, resulting in poor permeability.

[0009] Furthermore, grouts containing the above-mentioned acidic silica sol and slag are also known. In this case, the slag acts as a neutralizer for the acidic silica sol, accelerating the gelation time, but does not contribute much to the strength.

[0010] For this reason, grouts made by mixing low-molar ratio water glass with slag cement have been developed, but although they are strong, they have problems with a gel time of about 10 minutes, high viscosity, and poor permeability when injected into soil. This is because low-molar ratio water glass significantly increases viscosity when mixed with cement, shortening the gel time, and the calcium content of the cement reacts with the water glass and is consumed, preventing it from reacting sufficiently with the slag.

[0011] Suspension grouts can achieve higher strength than solution grouts, but because they are particulate, they have poor permeability to fine-grained soil. If this issue could be improved and they could be widely applied to a wide variety of ground types, such as sandy ground, clayey ground, sandy soil containing fine particles, and ground mixed with gravel, their usefulness would be immeasurable.

[0012] In response to this, the present applicant has already developed grouts made of water glass and slag (Patent Documents 1 to 3). These grouts have excellent strength, but because they are suspensions, they have the problem of insufficient permeability in fine-grained ground. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Japanese Patent Application Publication No. 8-67875 [Patent Document 2] Patent No. 3413398 [Patent Document 3] Patent No. 6961270 Summary of the Invention [Problem to be solved by the invention]

[0014] The object of the present invention is to provide a suspension-type ground consolidation material and a ground injection method that have excellent penetration and consolidation properties and environmental conservation properties, and that can achieve a consolidation effect even in ground that cannot be penetrated by suspended particles, and that enables integrated ground improvement and watertightness to be achieved. [Means for solving the problem]

[0015] The invention described in Patent Document 1 is a ground grouting solution consisting of water glass, fine particle slag, and an alkali metal salt of hydrogen carbonate or carbonate in a molar ratio of 2.8 or more. This invention has the effect of achieving low viscosity and a long gelling time by using water glass, slag, and carbonate in addition to the water glass and slag. However, the carbonate has low alkalinity, resulting in low strength. Furthermore, because the carbonate is easily soluble in groundwater, the carbonate dissolves in groundwater, which reduces the increase in strength.

[0016] Furthermore, the invention described in Patent Document 2 is a high-pressure injection method using grout made of water glass, slag, and hydrated lime. However, in the case of high-pressure injection, the injection action causes the injection liquid to separate, resulting in poor solidification over a wide area and problems with the stability of gelation.

[0017] In order to solve the problems of permeability and gelling stability in grouts containing slag as an active ingredient, the present inventors focused on Patent Document 3 by the applicant and further developed it to complete the present invention.

[0018] The inventors focused on the gelation of the bleeding liquid to solve the problem of the permeability of suspension grout. In conventional grouting methods, the particle size range of soil into which suspensions can be injected and the permeability range of solution-type grouts have been discussed, but no attention has been paid to the bleeding of suspension grout, its gelation, gel strength, or the consolidation and strength of sand permeated with the bleeding liquid. Furthermore, no research has focused on the consolidation stability when using slag-based grout in high-pressure injection methods. A characteristic of conventional suspension grouts is their frequent bleeding, which has been considered a drawback. The present invention focuses on the bleeding liquid to solve the problem of the permeability and consolidation of suspension grout.

[0019] As mentioned above, the present applicant has already proposed the techniques described in Patent Documents 1 to 3. These inventions have shown that slag-based grouts can achieve high strength and a long gel time. However, because they are suspensions, they are thought to be unable to achieve a solidifying effect in ground that cannot be penetrated by suspended particles. Furthermore, when used in high-pressure injection mixing methods, the grout components are dispersed by the injection action, making it difficult to achieve stable solidification.

[0020] Through the above research, the applicant has found the following: Although slag-based grouts can be summarized in Table 1, it has been difficult to select materials and formulate them to ensure reliable penetration and solidification, because gel time, strength, permeation characteristics, permeability into the ground and injection effect, which depend on factors such as the molar ratio and amount of water glass, slag particle size and Blaine value, Ca / SiO2 additives, slaked lime, carbonate, alkali bicarbonate, alkali aluminate, other salts, caustic alkali, cement, etc., as well as sand particle size and permeation distance.

[0021] [Table 1]

[0022] In a previous application by the present applicant (Patent Document 3), the present inventors discovered that the portion of the injection liquid at the penetration front where the amount of slag is small gelled. Based on this phenomenon, the present inventors studied the gelling of the bleeding liquid, the self-sustaining ability of the homogel of the bleeding liquid, and the self-sustaining ability and strength of the sand gel produced by the bleeding liquid in order to improve the penetration and solidification of the suspension grout. By using these conditions, they improved the penetration and solidification of the suspension grout in fine-grained ground or sandy ground containing fine-grained soil, which was previously thought to be inapplicable, and completed the present invention.

[0023] First, the present applicant focused on the penetration test described in the specification of Patent Document 3 (paragraphs

[0127] to

[0134] ,

[0149] , [Table 15], [Figure 8], [Figure 9], and [Figure 11] of Patent Document 3). The penetration test of slag-based grout described in Patent Document 3 showed that the grout containing slag penetrated up to 180 cm. It also showed that gelation occurred even at the end of the 180 cm, even in areas with a low slag filling rate, and that solidified bodies could be integrated. Furthermore, it also described that a solidified zone where silica is solidified is formed around the periphery of a large-strength solidified body, even if its strength is low, resulting in an integrated, connected solidified body with excellent water-stopping properties, and that the supernatant liquid from the bleeding gels. Furthermore, it also described that cement-based grouts that do not gelatinize tend to bleed in the ground and do not solidify without the penetration of cement.

[0024] The present applicant further completed the present invention based on the following findings. (1) Range of permeability of fine-grained soil using solution-type grout (Figure 8). (2) Self-supporting homogel at low silica concentrations in solution-type grout, solidification of sand gel, and self-supporting ability of consolidated sand (Table 13). (3) Grain size distribution of sand used in the infiltration test (Figure 9).

[0025] As described above, the inventors of the present invention focused on the fact that, in Patent Document 3, a solidified silica-rich suspension formed around the outer periphery of the injected suspension, connecting adjacent solidified bodies. While the high level of bleeding in suspensions has traditionally been considered a drawback, the present inventors focused on the fact that the bleeding liquid can penetrate between soil particles where suspended particles cannot penetrate, and conducted research into the gelation of the bleeding liquid. As a result, they found that the gelation and strength of the bleeding liquid itself, the permeability of the bleeding liquid into the sand, and the strength of the sand gel significantly affect the improvement of the penetration and consolidation properties of suspension grout. Based on these findings, the inventors identified the conditions for the penetration and gelation of the bleeding liquid into areas where suspended particles could not penetrate, the homogelation of the bleeding liquid, and the strength of the sand gel, thereby solving the above-mentioned penetration and consolidation problems of suspension grout.

[0026] Furthermore, the present invention provides a ground consolidation method that uses a non-cement based ground consolidation material containing slag as its main component, thereby making it possible to obtain a solidified body with excellent durability and that is expected to have a CO2 reduction effect.

[0027] The present inventors conducted the following specific research. We investigated the gelation of the bleeding solution of a suspension containing water glass and slag as active ingredients, or the gelation of the bleeding solution of a suspension containing water glass, calcium hydroxide, or gypsum as active ingredients. We also investigated the penetration of suspended particles in a one-dimensional column penetration test and the consolidation caused by the bleeding solution when water glass was included. These results demonstrated that the bleeding solution can gel and consolidate even in areas where slag particles do not penetrate (Figures 7, 5, and 6). We also conducted a penetration consolidation test on a suspension containing slag but not water glass, and confirmed that gelation caused by the bleeding solution did not occur. Furthermore, we found that when the suspension contains salts, hydroxides, or chlorides of Ca, Mg, Al, etc. in addition to water glass, the bleeding solution contains water-soluble Ca and Mg, which improves the gelation and self-supporting properties of the bleeding solution and the self-supporting properties and strength of the sand gel produced by the bleeding solution.

[0028] The inventors have further researched suspensions containing slag and water glass as active ingredients, and grouts containing slag, water glass, and slaked lime as active ingredients, and as a result have discovered that by using a formulation in which the bleeding liquid gels and the homogel made from the bleeding liquid has the strength to stand on its own, and / or by which the sand gel permeated with the bleeding liquid solidifies and has the strength to stand on its own, it is possible to consolidate ground that is impermeable to suspended particles, and to form an integrated consolidated body even under conditions in which it was previously difficult for suspended particles to penetrate.

[0029] As a result, even if the target injection area is ground with complex particle sizes, in sandy ground that can be penetrated by solution-type silica grout, a solidified body can be formed that is integrated with the infiltrated area with a high-strength suspension, resulting in the invention of a ground consolidation method using a low-carbon injection method that is high-strength, water-stopping, and environmentally friendly.

[0030] The present invention also provides a consolidating agent and an injection method that can be applied to high-pressure injection methods. High-pressure injection is a method of replacing underground soil and sand with a cement suspension by injecting it into the ground. However, this method emits a large amount of CO2 due to the cement solidification material itself and the disposal of the ejected soil and sand. In contrast, the injection of slag-based grout into the ground uses low-carbon grout, making it a low-carbon injection method. However, when high-pressure injection is used with slag and water glass as active ingredients, the water glass may escape during the injection process, causing the alkalinity of the water glass to become ineffective, making it difficult for the slag to solidify. In contrast, when slag suspensions contain active ingredients such as hydrated lime, gypsum, and salts, oxides, and hydroxides of calcium, magnesium, and aluminum, the slag itself reacts with these ingredients to solidify sufficiently without cement or water glass. Adding water glass to the mixture provides sufficient self-sustaining strength, allowing for stable solidification even with high-pressure injection.

[0031] The present invention is a ground injection method in which a ground consolidation material consisting of a suspension containing suspended particles of slag or fly ash and water glass as active ingredients is injected into the ground through a plurality of injection holes provided in the ground, The bleeding liquid of the ground consolidation material gels, and the homogel has a strength to stand on its own, and the sand gel solidified by the penetration of the bleeding liquid has a strength to stand on its own, The bleeding liquid penetrates into parts of the ground that the suspended particles could not penetrate, and integrates with the parts of the ground that the suspended particles penetrated to form a solidified body, thereby connecting the solidified bodies made of suspended particles from adjacent injection holes, making the excavated ground surface self-sustaining and capable of stopping groundwater. Here, in the above, the bleeding liquid gelling and the resulting homogel being self-supporting means that the silica concentration of the bleeding liquid is 0.5 w / v% or more, and the homogel is self-supporting without collapsing even when tilted diagonally within the mold. The sand gel being self-supporting means that the silica concentration of the bleeding liquid is 0.5 w / v% or more, the sand gel is prepared by a mixing method using No. 6 silica sand and the bleeding liquid so that the relative density is 60%, and the size is 5 cm in diameter and 10 cm in height, and the sand gel is self-supporting, and the minimum strength in a uniaxial compression test measured using the sand gel is 2.0 kN / m 2 This means that it is more than or equal to this. Furthermore, the Blaine value of the slag is 4000 to 15000 cm 2 The molar ratio of the water glass is 1.0 to 5.0, and the blending amount is 10 to 150 liters / 400 liters.

[0032] Even when the surface of the excavated ground is scraped, the consolidation effect of the bleeding liquid stops the flow of groundwater, and the consolidation surface of the bleeding liquid remains unbroken and can stand on its own.

[0033] In the present invention, it is preferable that the ground consolidation material further contains a polyvalent metal compound, which is preferably one or more of hydroxides, oxides, or salts of Ca, Mg, or Al, and / or gypsum.

[0036] In the present invention, it is preferable that the ground consolidation material further contains an alkaline agent other than the polyvalent metal compound, and that the alkaline agent satisfies the following conditions. (1) Blaine value: 4000~13000cm 2 / g. (2) Compounding amount: 1~50kg / 400L.

[0038] In the present invention, the unconfined compressive strength of the solidified body infiltrated with the bleeding liquid is 2.0 kN / m after 7 days using a specimen size used in an unconfined compressive strength test. 2 As described above, it is preferable that the bleeding liquid penetrates into the areas where the suspended particles have not penetrated, gels, and solidifies the ground.

[0040] In the ground grouting method of the present invention, the ground consolidation material can be used in a high-pressure injection mixing method.

[0041] In the ground grouting method of the present invention, the improvement effect due to the solidification of the suspended particles can be confirmed by a non-destructive test, which is preferably performed by elastic wave velocity logging, acoustic tomography, or surface wave exploration. [Effects of the Invention]

[0042] According to the present invention, it is possible to provide a suspension-type ground consolidation material and a ground injection method that have excellent penetration and consolidation properties and environmental conservation properties, which can achieve a consolidation effect even in ground that cannot be penetrated by suspended particles, and enable integrated ground improvement and watertightness to be achieved. [Brief explanation of the drawings]

[0043] [Figure 1] FIG. 10 is a photograph showing the bleeding state in Example 2. [Figure 2] FIG. 1 is a photograph showing the bleeding state in Comparative Example 1. [Figure 3] FIG. 1 is a photograph showing the state of Example 2 several days after penetration. [Figure 4]FIG. 1 is a photograph showing the state of Comparative Example 1 several days after penetration. [Figure 5] 1 is a graph showing unconfined compressive strength as a function of permeation distance. [Figure 6] 6 is a graph showing an enlarged portion of the permeation distance of 90 cm to 120 cm in FIG. 5. [Figure 7] This is a photograph showing the state in which the bleeding liquid has gelled and the gel does not collapse (stands on its own) even when tilted. [Figure 8] These are particle size accumulation curves for various on-site sands that have been treated with liquefaction countermeasures using solution-type grout. [Figure 9] 1 is a graph showing the particle size distribution of sand used in a permeation test. [Figure 10] FIG. 10 is a photograph showing the strength measurement status on day 7 of Example 14. [Figure 11] FIG. 11 is a photograph showing the state of the test piece after strength measurement in Example 14. [Figure 12] 1 is a graph showing the relationship between the unconfined compressive strength (28-day strength) and the S-wave velocity measured by the bender element method in Toyoura sand specimens consolidated with the grout of the present invention. [Figure 13] 1 is a graph showing an example of the relationship between the number of curing days and shear wave velocity. [Figure 14] This is an explanatory diagram showing how to measure S-wave velocity Vs and P-wave velocity Vp by installing receiving and transmitting holes in the consolidated zone or the zone expected to be consolidated. [Figure 15] This is a graph showing the relationship between unconfined compressive strength and S-wave velocity Vs in laboratory tests of solidified specimens using field soil. [Figure 16] FIG. 1 is a photograph showing the equipment used in an indoor penetration test of a suspended ground consolidation material. DETAILED DESCRIPTION OF THE INVENTION

[0044] Hereinafter, embodiments of the present invention will be described in detail. The ground consolidation agent of the present invention is a suspension type ground consolidation agent containing suspended particles of slag or fly ash and water glass as active ingredients.

[0045] The suspension grout used in the present invention is a suspension-type grout whose main components are slag or fly ash. Examples of hardeners include silica solution, gypsum, slaked lime, alkaline salts or hydroxides, salts or oxides of Ca, Mg, or Al, and caustic alkali. Cement or the like may also be added to adjust the consolidation time and strength. Furthermore, the ground consolidation material of the present invention preferably contains a polyvalent metal compound, and the polyvalent metal compound is preferably one or more of hydroxides, oxides, or salts of Ca, Mg, or Al, and / or gypsum.

[0046] In addition, polymeric thickeners such as polyacrylates, acrylic acid polymers, and CMC (carboxymethyl cellulose) can be added to these to increase viscosity and make them less likely to disperse even when sprayed at high pressure, or microbubbles or nanobubbles can be added to increase fluidity and form large solidified bodies.

[0047] As mentioned above, non-cementitious hardening materials containing slag and water glass as active ingredients exhibit high strength over a long gel time due to the alkalinity of the water glass acting on ground granulated blast furnace slag, stimulating the slag's latent hydraulic properties and the silica in the water glass causing gelation. Furthermore, the bleeding liquid can gel to form a self-supporting homogel, or penetrate into sand to form a self-supporting sand gel. In this case, using a low molar ratio of water glass further develops the slag's latent hydraulic properties and achieves high strength. When using No. 3 water glass or a high molar ratio, or to control the gel time, it is preferable to add chlorides or hydroxides of Ca, Mg, or Al.

[0048] It is also possible to use a material whose active ingredients are slag and an alkaline agent (for example, slaked lime, dolomite, or an alkaline salt such as carbonate).The above suspension-type grout can be called low-carbon grout (trademark registered by the present applicant, No. 6683218).

[0049] In the above, the suspended particles may be slag and / or fly ash.

[0050] Furthermore, in place of or in addition to the slag or fly ash, materials that react with sodium carbonate, Ca (calcium carbonate, calcium chloride, etc.) or Mg (magnesium chloride, magnesium carbonate, magnesium sulfate, etc.) and solidify through pozzolanic action, such as calcined sludge, 2-layer clay, 3-layer clay, volcanic ash, tuff, diatomaceous earth, calcined clay, etc., can also be used. Furthermore, part of the slag or fly ash can be replaced with cement. Furthermore, water glass or a mixture of water glass and silica colloid can be used as the silica solution.

[0051] Furthermore, in recent years, from the perspective of preventing global warming, the realization of a low-carbon ground improvement method using non-alkaline cement or a reduced amount of cement has become an issue, and the above-mentioned solidification material can be said to be an environmentally friendly ground improvement method that solves this issue by using industrial by-products.

[0052] Furthermore, the present invention further provides a method for adding cement and / or lime, particularly those having a specific surface area of ​​4000 cm², to the above-mentioned water glass-slag system. 2 / g or more, preferably 8000 cm 2 / g or more and an average particle size of 10 μm or less, and by adding and mixing fine particle cement or lime, and further by adding and mixing a calcium elution amount adjuster, it is possible to adjust the gelation time, permeability or solidification strength.

[0053] Examples of calcium elution regulators mentioned above include sodium bicarbonate, sodium carbonate, disodium hydrogen phosphate, and sodium hexametaphosphate, as well as potassium salts of these, as well as condensed phosphates as sequestering agents such as pyrophosphate, acid pyrophosphate, tripolyphosphate, tetrapolyphosphate, and acid metaphosphate, as well as sequestering agents such as ethylenediaminetetraacetate, nitrotriacetate, citrate, and tartrate, and ordinary phosphates such as sodium phosphate and sodium hydrogen phosphate. Of these, soluble alkali agents such as bicarbonates, carbonates, and phosphates including condensed phosphates are particularly suitable.

[0054] In the present invention, any reactant capable of adjusting the gelation time may be used in combination. Examples of such reactants are as follows:

[0055] Esters: fatty acid esters of monohydric alcohols such as ethyl acetate, methyl acetate, butyl acetate, and amyl acetates. Fatty acid esters of polyhydric alcohols such as ethylene glycol diacetate, glycerin triacetate, and succinic acid diester. Total esters. Intramolecular esters such as δ-butyrolactone and ε-caprolactone. Cyclic esters: lactones. Partial esters of polyhydric alcohols such as ethylene glycol monoformate, ethylene glycol monoacetate, ethylene glycol monopropionate, glycerin monoformate, glycerin monoacetate, glycerin monopropionate, glycerin diformate, glycerin diacetate, sorbitol monoformate, sorbitol monoacetate, glycolic acid monoacetate, and low-polymerization partially saponified vinyl acetate. Unsaturated fatty acid esters such as diacetooxyethylene. Carbonates such as cyclic carbonates such as ethylene carbonate, propylene carbonate, and glycerin carbonate.

[0056] Aldehydes: dialdehydes such as glyoxal, succinic dialdehyde, malondialdehyde, succinaldehyde, glutaric dialdehyde, and furfural dialdehyde.

[0057] Amides: formamide, dimethylformamide, acetamide, dimethylacetamide, propionamide, butylamide, acrylamide, malondiamide, pyrrolidone, caprolactam, and the like.

[0058] Alcohols: ethyl alcohol, methyl alcohol, amyl alcohol, glycerin, polyvinyl alcohol, etc., monohydric or polyhydric alcohols, or synthetic polymer alcohols.

[0059] Acids: Inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid, etc. Organic acids such as formic acid, acetic acid, malonic acid, succinic acid, maleic acid, tartaric acid, etc.

[0060] Inorganic salts: chlorides such as calcium chloride, sodium chloride, magnesium chloride, potassium chloride, and aluminum chloride; sulfates such as calcium sulfate, sodium sulfate, and aluminum sulfate; aluminates such as sodium aluminate and potassium aluminate; hydrochlorides such as ammonium chloride, zinc chloride, and aluminum chloride; chlorates such as sodium chlorate, potassium chlorate, and sodium perchlorate and potassium perchlorate; carbonates such as sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, and ammonium bicarbonate; bisulfates such as sodium bisulfate, potassium bisulfite, and ammonium bisulfite; bisulfites such as ammonium silicates, silicic acids such as sodium silicic acid and potassium silicic acid, silicates such as alkaline earth metal salts of silica and aluminum salts, borates such as sodium borate, potassium borate, and ammonium borate, hydrogen phosphates such as sodium hydrogen phosphate, potassium hydrogen phosphate, and ammonium hydrogen phosphate, pyrosulfates such as sodium pyrosulfate, potassium pyrosulfate, and ammonium pyrosulfate, pyrophosphates such as sodium pyrophosphate, potassium pyrophosphate, and ammonium pyrophosphate, dichromates such as sodium dichromate, potassium dichromate, and ammonium dichromate, and permanganates such as potassium permanganate and sodium permanganate.

[0061] Organic salts: sodium acetate, sodium succinate, potassium formate, sodium formate, sodium citrate, etc.

[0062] Quicklime, alumina, iron oxide, magnesium oxide and other metal oxides, Ca, Al, Mg salts.

[0063] Furthermore, in the present invention, silica colloid, acidic silicic acid aqueous solution, and other optional gelling agents can be used in combination. Furthermore, pozzolans such as fly ash, siliceous silica, diatomaceous earth, and clays can also be used in combination to formulate a ground injection solution that takes advantage of the properties of each. Furthermore, to prevent settling, a small amount of dispersant can be used in combination to form a homogeneous solidified body.

[0064] When injecting the above-mentioned ground consolidation material of the present invention, for example, a one-component chemical solution with a long gelling time can be prepared and injected directly into the ground, or a cement-based or slag-based injection material can be injected into the ground in advance, and then the above-mentioned chemical solution can be injected into the injection site.

[0065] Alternatively, the water glass compounded solution according to the present invention may be designated as solution A, and the compounded solution containing the fine particle slag according to the present invention may be designated as solution B, and these two solutions A and B may be combined and injected. Alternatively, the compounded solution containing the above-mentioned water glass and slag, or further a calcium elution regulator, may be designated as solution A, and the gelation accelerator compounded solution or any other gelling agent compounded solution may be designated as solution B, and these solutions A and B may be combined and injected after adjusting the gelation time of the chemical solution as desired.

[0066] Furthermore, a double injection pipe can be prepared, and the chemical solution of the present invention with an adjusted long gelling time can be designated as liquid A, and the gelling accelerator mixed liquid can be designated as liquid B. First, both liquids A and B are pumped into the ground through separate pipes in the double injection pipe, and the two liquids are combined at the tip to form grout with a short gelling time. This can then be injected into the voids around the injection pipe to form a packer, and then only liquid A can be injected.

[0067] Furthermore, the water glass mixture of the present invention, or a mixture of water glass and slag, or a mixture of these and a calcium elution amount adjuster, may be designated as Liquid A, the slow-setting reactant mixture as Liquid B, and the quick-setting reactant mixture as Liquid C. First, the grout with a short gelling time obtained by combining Liquids A and C may be injected into the ground, and then the injection may be switched to the combined liquid AB, and the above steps may be repeated while increasing the injection stage.

[0068] Furthermore, water glass and slag (which may contain a calcium elution amount adjuster if necessary) can be used as Liquid A, a liquid containing a quick-setting reactant mixture can be used as Liquid C, and a quick-setting grout made from the AC combined liquid can be injected into the ground from the upper outlet of the double pipe, and a slow-setting grout made from Liquid A can be injected into the ground from the lower outlet.

[0069] Furthermore, a chemical solution having a long gelling time of several hours can be prepared by adding slag to water glass and, if necessary, a calcium elution regulator, to form a chemical solution A, and a compound liquid containing slag and / or other reactants can be formed as a chemical solution B. During construction, a chemical solution of the present invention having a predetermined gelling time and strength can be prepared by adding a chemical solution B to a chemical solution A, and then injecting this into the ground.

[0070] Furthermore, a compound grout can be performed by injecting a quick-setting grout made from the AC combined liquid into the ground, using a No. 3 water glass mixed liquid with a molar ratio higher than 2.8 as liquid A, a water glass mixed liquid with a molar ratio in the range of 1.0 to 5.0 as liquid B, a quick-setting reactant mixed liquid as liquid C, and the fine particle slag mixed liquid of the present invention as liquid D. From the viewpoint of consolidation strength and viscosity, the concentration of water glass in the total liquid is suitably about 1.5 to 20% as SiO2 component.

[0071] The slag, gypsum and lime used in the present invention are useful for adjusting the gelling, viscosity and solidification strength of the water glass, respectively. However, the size of these particles is important. The average particle size is 10 μm or less, and the specific surface area is 5000 cm. 2 / g or more, preferably 8000 cm 2 At slag density of 1 / g or higher, the large silica content of the slag, the small silica content of the water glass, and calcium combine with an appropriate amount of alkalinity in the water glass as a stimulant to form a dense, strong composite silica-calcium gel.

[0072] In other words, the net spaces of large silica particles originating from the slag are filled with small silica particles originating from the water glass, which are then linked and solidified by calcium to form a dense hardened material.

[0073] Furthermore, when a calcium elution regulator is added to the system of the present invention, for example, when a carbonate, bicarbonate, or phosphate is added, inactive calcium carbonate or calcium phosphate is produced, thereby delaying gelation.

[0074] In the above, if the molar ratio of water glass is lower than 1.0, the alkali content will be excessive, and gelation will not occur, or the gelation time will be extended to an extent that it is not practical as a pouring material, resulting in insufficient solidification, or the viscosity will increase and remain increased, making it difficult to achieve clear gelation. Therefore, the molar ratio of water glass is preferably 1.0 or more.

[0075] If the molar ratio of water glass is greater than No. 3 water glass, i.e., greater than about 2.8, the amount of alkali in the water glass is insufficient to stimulate the latent hydraulic properties of the slag and harden it, and therefore the slag does not develop its inherent strength. As a result, the water glass and slag do not react easily, significantly delaying gelation and causing the slag and water glass to separate, making it difficult to obtain a homogeneous solidified mass. However, the slag will harden if slaked lime, gypsum, or alkali is added.

[0076] Furthermore, if the particle size of the slag is coarser than the above range, the reaction between the alkali and calcium content of the water glass and the slag is significantly reduced, so that gelation does not occur within the range suitable for injection, and furthermore, the alkali-induced solidification of the water glass is insufficient.

[0077] That is, according to the present invention, the average particle size is 10 μm or less and the specific surface area is 5000 cm 2 By using a formulation in which the bleeding liquid gels using fine particle slag with an active reactivity of 1 / g or more and water glass, and the sand gel permeated with the bleeding liquid becomes self-sustaining, it is possible to obtain a wide range of gelation times and excellent permeability to fine soil for the first time.

[0078] Moreover, it has been found that the gelation time can be effectively shortened by using gypsum and / or lime, dolomite, or salts or oxides of Ca, Mg, or Al in combination with such a water glass and slag system, and furthermore, by using a calcium elution amount adjuster in combination, it is possible to increase the strength of the sand gel into which the bleeding liquid has penetrated and to effectively delay the gelation time, thereby making it possible to easily control the gelation time.

[0079] When the molar ratio of water glass is lower than 1.0, the addition of lime or cement requires a very large amount to shorten the gelling time, and the viscosity increases significantly, resulting in a thixotropic behavior, which significantly reduces the permeability. Moreover, it is impossible to significantly shorten the gelling time.

[0080] In contrast, within the range of water glass according to the present invention, even small amounts of gypsum, lime, or salts of Ca, Mg, or Al, or their oxides or hydroxides, effectively shorten the gelation time. Therefore, viscosity does not increase significantly, and therefore permeability is not impaired. Furthermore, within the range of water glass according to the present invention, slag can maintain a low viscosity without exhibiting thixotropic properties, unlike cement or lime, in the presence of water glass. This is thought to be because the CaO in the slag is low in CaO, which is easily liberated like that in cement or lime, and only liberates when a certain amount of alkali is present in the water glass.

[0081] To solve the above problems, the present invention provides a ground grouting method for consolidating ground using a ground consolidation agent containing slag and, preferably, water glass in a molar ratio of 1.0 or greater as active ingredients. The bleeding solution in the grouting solution gels, creating a self-supporting sand gel. Even if the suspended particles disperse or form veins, the solution consolidates the suspended particles, thereby increasing the grouting solution's consolidation rate. Furthermore, since a mixture of slag and gypsum and / or hydrated lime forms a high-strength consolidation mass, adding water glass to the suspension can further enhance the stability and reliability of the consolidation. Furthermore, the addition of a polymeric thickener can form a consolidation mass that is difficult to disperse, and the addition of microbubbles (or nanobubbles) can improve permeability through their rolling action.

[0082] Furthermore, the inventors have found that in order to use slag-based grout for high-pressure injection, the injection material must be difficult to disperse under the injection force and must be firmly solidified. To achieve this, the bleeding liquid of the suspension must gel, and the sand gel permeated with the bleeding liquid must have sufficient strength to stand on its own. Furthermore, the strength of the sand gel was found to be 2.0 kN / m after 1 to 7 days in a uniaxial compression test. 2 It was found that it was necessary to use the above-mentioned formulation.

[0083] The present invention is a method for determining the Blaine value in a range of 4000 to 15000 cm 2 The preferred ground consolidation material is a suspension type ground consolidation material containing, as active ingredients, fine particle slag of 1 / g and water glass in a molar ratio range of 1.0 to 5.0, or a suspension type ground consolidation material further containing, as active ingredients, one or more of an alkali additive, gypsum, calcium hydroxide, salts of Ca, Mg, and Al, or their oxides or hydroxides. By satisfying the following conditions A and B, the bleeding liquid penetrates into the areas where the suspended particles of the ground consolidation material have not been able to penetrate, gelling and solidifying the ground.

[0084] A. Composition range of ground consolidation materials 1. Fine particle slag (1) Blaine value: 4000~15000 cm 2 / g (2) Mixing amount: 50-150 kg / 400 liters (3-16 w / v%) 2. Water glass (1) Molar ratio: 1.0 to 5.0 (2) Mixing amount: 10 to 150 liters / 400 liters 3. When using the following alkaline agents in combination: (1) Blaine value of alkaline agents, especially calcium hydroxide or gypsum: 4000 to 13000 cm 2 / g. (2) Compounding amount: 1~50kg / 400L.

[0085] B. The bleeding liquid gels, and the sand gel that has been permeated with the bleeding liquid solidifies and becomes self-supporting. Here, the sand gel is preferably self-supporting at a specimen size used in an unconfined compressive strength test, and preferably has an unconfined compressive strength of 2.0 kN / m 2 In the present invention, the unconfined compressive strength of the solidified body infiltrated with the bleeding liquid is 2.0 kN / m after 7 days using a specimen size used in unconfined compressive strength tests. 2 As described above, it is preferable that the bleeding liquid penetrates into the areas where the suspended particles have not penetrated, gelling and solidifying the ground.

[0086] In the ground consolidation agent of the present invention, the bleeding liquid preferably gels at an SiO2 concentration of 0.5 w / v % or more.

[0087] Table 2 shows the component values ​​of common water glass, and the molar ratios were calculated from the values ​​of silicon dioxide and sodium oxide. Furthermore, in the present invention, water glass with a molar ratio of 1.0 or more may be used by adding sodium to the water glass to lower the molar ratio. Furthermore, colloidal silica can be added to water glass with a molar ratio of 1.0 or more to increase the molar ratio of the silica solution containing water glass as an active ingredient. In this case, the molar ratio of the water glass to which silica colloid has been added is 5.0 or more, and the molar ratio can be increased to about 100. Even without using a combination of silica colloid, the molar ratio of the silica colloid is 103. The molar ratio of water glass can also be increased to 100 or more.

[0088] Table 3 shows the specific surface area, average particle size and particle size of slag, and Table 4 shows those of slaked lime. These are representative examples.

[0089] Here, the high molar ratio water glass refers to water glass having a molar ratio higher than 2.8, whereas the low molar ratio water glass has a molar ratio of 2.8 or less.

[0090] [Table 2]

[0091] [Table 3]

[0092] [Table 4]

[0093] The ground grouting method of the present invention is characterized by using the ground consolidation material of the present invention. In particular, the ground grouting method of the present invention is preferably used in a high-pressure injection mixing method.

[0094] In the ground grouting method of the present invention, the improvement effect of solidifying the suspended particles can be confirmed by non-destructive tests such as seismic velocity logging, acoustic tomography, and surface wave exploration.

[0095] The present invention forms a consolidated area of ​​a suspended ground consolidation material over a wide area in the ground, thereby consolidating the ground over a wide area. The inventors have found that the consolidated ground is effective for confirming the improvement effect by the above-mentioned elastic wave velocity logging and acoustic tomography.

[0096] The suspension-type ground consolidation material of the present invention has the following properties related to strength and permeability, and it has been found that elastic wave velocity logging is extremely effective in understanding the ground improvement effect of this suspension.

[0097] (Relationship between uniaxial compressive strength and elastic wave velocity using bender elements) This will be explained in detail below. Figure 12 shows the relationship between the unconfined compressive strength (strength at 28 days) and the S-wave velocity measured by the bender element method for Toyoura sand specimens consolidated with the ground consolidation material of the present invention. FIG. 13 shows an example of the relationship between the number of curing days and the shear wave velocity.

[0098] FIG. 14 is an explanatory diagram showing how to measure S-wave velocity Vs and P-wave velocity Vp by installing receiving holes and transmitting holes in the consolidated zone or the zone to be consolidated. The injection hole may be used as a receiving hole and a transmitting hole to measure the S-wave velocity Vs and the P-wave velocity Vp. In laboratory tests, the S-wave velocity Vs and P-wave velocity Vp are measured using the bender element method, with transmitter and receiver units installed at both ends of a solidified specimen, but in the field, the S-wave velocity Vs and P-wave velocity Vp are measured using surface wave exploration and velocity logging.

[0099] Since the strength of the ground consolidation material of the present invention is determined almost exclusively by the amount of suspended particles in the suspension, the improvement effect can be estimated by knowing the amount of suspended particles and the S-wave velocity Vs and P-wave velocity Vp.

[0100] The relationship between the unconfined compressive strength and S-wave velocity Vs in laboratory tests on consolidated specimens using field soil, and the relationship between the amount of suspended particles in the suspension and the unconfined compressive strength, are shown in Figure 15, where the measured values ​​of S-wave velocity at points A and B in the injected ground are plotted. From this, we can estimate the unconfined compressive strength at points A and B. We can also estimate the amount of suspended particles in the suspension at those points.

[0101] In this way, the extent and strength of consolidation at the injection site can be grasped. In the example of Figure 15, it can be seen that the target S-wave velocity Vs is met at points A and B, and therefore the design Vs is met.

[0102] Furthermore, if the relationship between the filling rate and content of suspended particles and the S-wave and P-wave velocities is determined in laboratory tests, the unconfined compressive strength can be determined by measuring the S-wave and P-wave velocities in the field, thereby determining the amount of filling and the composition of the ground. Figure 16 shows the equipment used in the laboratory permeation test of the suspended ground consolidation material of this invention, and Figures 3 and 4 show the state after a one-dimensional injection test with a mold length of 1.5 m. Figure 5 shows the unconfined compressive strength as a function of permeation distance. From the results of this uniaxial test, the shear wave velocity of the consolidated material at each permeation distance can be determined using Figure 12. Furthermore, the amount of suspended particles filled in the ground can be determined.

[0103] In addition, by comparing the penetration test values ​​of the injected ground before and after injection and the strength test values ​​of the specimen obtained by core sampling with the estimated shear wave velocity and strength at that point, the results can be useful in analyzing the non-destructive test results (Figure 15).

[0104] Furthermore, if the receiver and transmitter are installed before injection (Fig. 14), the seepage situation in the ground can be monitored in real time during injection, making it possible to make real-time adjustments to the injection amount and the amount of suspended particles mixed.By non-destructively measuring the S-wave and P-wave velocities that change with curing, it is possible to determine whether the desired improvement effect has been achieved.

[0105] As described above, the flow characteristics, injection design, and injection effects of the ground consolidation material of the present invention can be understood and incorporated into the design.

[0106] The test results are shown below.

[0107] (Test Method) 1. Consolidated material test materials The materials of the binders used are listed below. No. 3 water glass: specific gravity 1.41, silica concentration 29 w / w%, molar ratio 2.9. No. 1 water glass: specific gravity 1.35, silica concentration 21 w / w%, molar ratio 2.0. Slaked lime: specific gravity 2.5. Slag: specific gravity 2.9, Blaine value 8000 cm 2 / g. Sodium aluminate: Specific gravity 1.6. Gypsum: specific gravity 2.16. Fly ash: specific gravity 2.15. Cement: Specific gravity 3.0. Colloidal silica: specific gravity 1.2.

[0108] 2.Composition The formulations used in the tests are shown in Tables 5 to 12. The results are the same when using one shot formulation.

[0109] [Table 5]

[0110] [Table 6]

[0111] [Table 7]

[0112] [Table 8]

[0113] [Table 9]

[0114] [Table 10]

[0115] [Table 11]

[0116] [Table 12]

[0117] (fluidity test) The gelation time was measured using the cup inversion method, and the gelation time was determined as the time when the solution no longer flowed when the cup was tilted or when the viscosity reached 100 mPa·s on the viscometer.

[0118] Tables 5 to 12 show the gel time for each formulation.

[0119] (Breeding test) A predetermined amount was placed in a φ5 × 50 cm polyethylene bag (grout bag), and measurements were performed in accordance with JSCE-F-522-2013 to measure the bleeding rate. The results are shown in Table 13. In addition, the presence or absence of gelation of the bleeding liquid when measuring the bleeding rate was confirmed.

[0120] Here, the bleeding rate = 100 × (L1 / L), and is calculated as L = L1 + L2. L1: Length of gelled bleeding liquid L2: Length of the suspended particle section L: length of the solidified suspension

[0121] In the bleeding test, the color turned blue-black over time, indicating the progress of the hydration reaction. It was also confirmed that the bleeding portion at the top had become opaque and solidified due to gelation (see Figure 1). On the other hand, in the comparative example shown in Figure 2, the bleeding portion was transparent and did not gel.

[0122] (Strength test) (Preparation of sand gel specimen) Using No. 6 silica sand and bleeding liquid, specimens measuring 5 cm in diameter and 10 cm in height were prepared using a mixing method to achieve a relative density of 60%, and the unconfined compressive strength was measured after 28 days. Table 13 shows the bleeding rate and strength of the sand gels prepared using bleeding liquid.

[0123] The bleeding rate was higher when the amount of water glass was higher and when the amount of slag was lower. In the sand gel using bleeding liquid, the strength was higher when the amount of water glass and slag was higher. In addition, Example 7 was Example 2 plus gypsum, and the addition of gypsum reduced the bleeding rate and increased the strength.

[0124] The gelation and self-supporting properties of the bleeding solution, as well as the strength and self-supporting properties of the sand solidified by the bleeding solution (sand gel), depend on the amount of slag and water glass in the suspension, the ratio of silica concentration (SiO2) in the water glass to CaO content in the slag (CaO / SiO2), gel time, and the particle size and density of the sand solidified by the bleeding solution. Therefore, to determine the self-supporting properties of the sand gel, which involves these multiple factors, and to integrate the fine-grained soil areas where the penetration of suspended particles was difficult or where penetration was not sufficient, we conducted tests to determine the minimum strength of the sand gel impregnated with the bleeding solution, assuming that it would be self-supporting. Table 13 shows the bleeding rate (%) and the strength measurements of the sand solidified by the bleeding solution.

[0125] [Table 13]

[0126] From these results, it was found that gelation occurred whether the bleeding rate was over 50% or under 50%, and that a composition was obtained in which the bleeding liquid penetrated and the sand gel was self-supporting. The minimum strength at which the sand gel could stand was 2.0 kN / m 2 The strength of the self-supporting sand gel containing only slag and water glass (Example 14) was 15 kN / m on the 28th day. 2 Furthermore, if the bleeding solution contains salts such as Ca, Mg, and Al, the strength of the sand gel can be expected to increase further.

[0127] For Example 14, the strength was also measured on the 1st and 7th days. The 1st day strength was 2.0 kN / m 2 On the 7th day, the strength was 10 kN / m 2 A similar trend was also observed with Toyoura sand. In this invention, the test specimen is adjusted to the size of the specimen for the uniaxial compression test of soil, with the diameter D0 (mm) usually being 35mm or 50mm, and the height H0 (mm) being 1.8 to 2.5 times the diameter D0 (mm). As long as it is a self-standing sand gel, judgment can be made at any age. Figure 10 shows the test conditions. From this, it can be seen that even with in-situ sand, a 2.0kN / m 2 It was found that if the strength of the improved ground is obtained, the soil will be self-sustaining. 3 The injection volume per injection is 0.4m 3 This becomes: Figure 11 shows the condition of the test specimen after the test was completed.

[0128] In Examples 1 to 7, the gel time was shortened as the amount of added slaked lime increased, and the strength increased as the amount of slag increased. In Example 8, the entire composition gelled, and the bleeding portion also solidified. In Comparative Example 1, the solidified portion solidified, but the bleeding portion did not gel. In Example 9, the bleeding portion also gelled, but the gel time was longer than in Example 8. Example 10 was a combination of a low molar ratio and hydrated lime, and gelation of the bleeding liquid was confirmed. In Example 11, fly ash was used instead of slag. The bleeding liquid gelled in the same way as in the case of slag. In Examples 12 and 14, although there was no clear gelling time, the bleeding liquid eventually gelled and gelled. The bleeding liquid of Example 13 gelled. In Comparative Example 2, there was no clear gel time, and the bleeding liquid did not gel. The bleeding liquid of Example 15 gelled. It was found that the bleeding liquid also gelled when colloidal silica and water glass were used in combination. If the sand gel made using bleeding liquid does not stand on its own, the slag will not be able to penetrate completely, and the ground will not become integrated and will harden.

[0129] The sands used in the one-dimensional infiltration tests were No. 5 silica sand, No. 6 silica sand, No. 7 silica sand, and Toyoura sand. Their particle size distributions are shown in Figure 9. These sands were filled into long molds of 2 m or 1 m in length with varying relative densities, and infiltration tests were conducted.

[0130] (Relationship between silica concentration and strength) The neutral to alkaline solutions used in Table 13 were placed in an acrylic mold with a removable bottom and allowed to solidify. The homogels were checked for gelation and the self-supporting ability of the gels at different silica concentrations. The same procedure was also performed on sand gels to check for solidification and the self-supporting ability of the consolidated sand. The results are shown in Table 14.

[0131] At silica concentrations below 0.5%, the homogel and sand gel did not become self-supporting. Further testing revealed that gelation occurred even at a silica concentration of 0.25%.

[0132] [Table 14]

[0133] Figure 7 shows the state in which the bleeding liquid has gelled and remains self-supporting even when tilted. Even if the entire amount of bleeding liquid has not gelled, the sand gel was able to remain self-supporting even when tilted, as the gel remained in the bleeding liquid and did not collapse when tilted.

[0134] (Permeability test) (Test equipment and test method) A one-dimensional infiltration test was carried out on No. 6 silica sand using a one-dimensional infiltration apparatus (length 2m), and the infiltration length and strength distribution were investigated. Test conditions: acrylic mold h=2m, mixed liquid 3L After the sample was saturated with water, the suspension was poured into the bottom until no more liquid was discharged.

[0135] The test was carried out using the formulations of Example 2 and Comparative Example 1 (FIGS. 3 and 4).

[0136] Figure 3 shows the results for the formulation of Example 2. Strength measurements were possible even at a penetration distance of 120 cm. Although there was no discoloration of the sand gel after 90 cm, the strength measurements were possible because the bleeding liquid solidified after 90 cm (Figures 5 and 6). From Table 14, it appears that the portion after 90 cm contains 0.5% or more silica.

[0137] Figure 4 shows the results obtained using the formulation of Comparative Example 1. The strength could be measured up to 90 cm, but there was no discoloration after 90 cm, making it impossible to measure the strength, and it was found that the bleeding liquid had not gelled.

[0138] In the penetration test, the areas where there was no discoloration of the slag were thought to be areas where the slag had not penetrated, and it was found that the Ca content was not enough to cause the bleeding fluid to gel.In contrast, in Figure 3, it is presumed that the Ca and silica content was enough to cause the bleeding fluid to gel, become self-sustaining, and develop strength by the sand gel being self-sustaining.

[0139] From the above, under conditions where the soil particle size density and particle size distribution of suspended particles prevent penetration between the soil particles, only the bleeding liquid will penetrate. Furthermore, if the particle size of the ground that the bleeding liquid can penetrate is within the range of the particle size accumulation curve of the in-situ sand in Figure 8, it can be seen that penetration and solidification will occur.

[0140] From Figure 6, even if the penetration distance of the suspended particles in the suspension is just under 90 cm, the bleeding liquid will penetrate up to 120 cm, and if the bleeding liquid is strong enough to stand on its own or the sand gel is strong enough to stand on its own, it can be predicted that the silica concentration will be 0.5 to 2% or higher. Therefore, with an injection hole spacing of 30 x 2 = 60 cm, the homogel of the bleeding liquid will connect the solidified bodies penetrated by the suspended particles, which will have high strength to stand on their own.

[0141] In this way, an integrated solidified body can be formed even under ground conditions where suspended particles cannot penetrate, and even if the injection hole spacing is wide, the solidified bodies between them can be connected by the gelled product of the bleeding liquid, which can stand on its own, thereby forming an integrated solidified ground.

Claims

1. A ground injection method for injecting a ground consolidation material, which is a suspension containing suspended particles of slag, water glass, and slaked lime as an alkaline agent as active ingredients, into the ground through a plurality of injection holes provided in the ground, The water glass is No. 3 water glass, the Blaine value of the slaked lime is 4000 to 13000 cm 2 / g, and the blending amount is 1 to 50 kg / 400 L, The silica concentration of the bleeding liquid of the ground consolidation material is 0.5 w / v% or more, the bleeding liquid gels, and the homogel has a strength to stand on its own, and the sand gel solidified by the penetration of the bleeding liquid has a strength to stand on its own, A ground injection method characterized in that the bleeding liquid penetrates into parts of the ground that the suspended particles could not penetrate, and integrates with the parts of the ground that the suspended particles have penetrated to form a solidified body, thereby connecting the solidified bodies of suspended particles from adjacent injection holes to each other, making the excavated ground surface self-sustaining and capable of stopping groundwater. Here, in the above, the bleeding liquid gelling and the resulting homogel being self-supporting means that the silica concentration of the bleeding liquid is 0.5 w / v% or more, and the homogel is self-supporting without collapsing even when tilted diagonally within the mold. The sand gel being self-supporting means that the silica concentration of the bleeding liquid is 0.5 w / v% or more, the sand gel is prepared by a mixing method using No. 6 silica sand and the bleeding liquid so as to have a relative density of 60% and has a diameter of 5 cm and a height of 10 cm, is self-supporting, and the minimum strength in a uniaxial compression test measured using the sand gel is 2.0 kN / m2 or more in one-day strength. ２ This means that it is more than or equal to this. Furthermore, the Blaine value of the slag is 4000 to 15000 cm ２ The amount of water glass blended is 10 to 150 liters / 400 liters.

2. 2. The ground grouting method according to claim 1, wherein the ground consolidation material further contains a polyvalent metal compound.

3. 3. The ground grouting method according to claim 2, wherein the polyvalent metal compound is one or more of hydroxides, oxides, or salts of Ca, Mg, or Al, and / or gypsum.

4. 2. The ground grouting method according to claim 1, wherein the ground consolidation material is used in a high-pressure injection mixing method.

5. 2. The ground grouting method according to claim 1, wherein the improvement effect due to the solidification of the suspended particles is confirmed by a non-destructive test.

6. 6. The ground grouting method according to claim 5, wherein the non-destructive testing is performed by elastic wave velocity logging, acoustic tomography, or surface wave exploration.

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