JPH11256159A - Grouting material and grouting using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a grouting material excellent in permeability, capable of being grouted into fine gaps and readily controlling the gelation time and useful for reinforcing the ground or stopping water by using an alkali silicate (an aqueous solution) and a specific calcium silicate (a slurry) in combination. SOLUTION: This grouting material is obtained by using (A) an alkali silicate (an aqueous solution) [e.g. sodium silicate in the form of an aqueous solution, a colloid or an aqueous dispersion at respective concentrations of 10-70 wt.% SiO2 and 0.2-35 wt.% Na2 O] and (B) a calcium silicate having <=2 μm average particle diameter without any hydrating activity at normal temperatures under atmospheric pressure or a slurry containing the calcium silicate (e.g. wollastonite or a baked material of calcium silicate hydrate having <=1.0 molar ratio of Ca/Si) in combination. The grouting material is used by, as necessary, adding water to the components A and B, mixing the components A with B and grouting the resultant material into the ground.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection material having excellent permeability and easily controlling the gelation time, and an injection method using the same.

[0002]

2. Description of the Related Art In the construction of piers, tunnels, dams, buildings, and other structures, when the ground is soft, when there is groundwater seepage, or when there is mud during an earthquake, the ground is strengthened or water is stopped. However, a ground injection material is used for such a purpose.

Conventionally, a water glass-cement slurry system has been mainly used as an injecting material. The material of this system has sufficient strength of the ground after the injection, but has a fine particle due to large particles. There is a drawback that it cannot be injected into the ground with a gap. In this system, it was difficult to arbitrarily control the gel time.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an injection material which has excellent permeability and can be suitably used for injection into fine gaps, and which can easily control the gel time. I do.

[0005]

Under such circumstances, the present inventors have developed an average particle size of 2 which can be injected into the ground having fine gaps in order to develop a solidification system satisfying the above requirements.
We have searched for various materials that can be easily obtained with a thickness of less than μm and that can be hydrated at normal temperature and pressure. However, those having an appropriate hydration activity, such as synthetic calcium silicate hydrate, have an extremely large average particle size of several μm to several tens of μm, and may have excellent permeability. There was nothing.

[0006] Here, calcium silicate anhydrate represented by wollastonite has no hydration activity at normal temperature and normal pressure, and is therefore a material which cannot be used as an injection material. Have found that this is stimulated by the presence of an alkali metal ion, and its hydration activity is improved. Further, the present inventors have found that this calcium silicate anhydrate can be easily obtained in a fine particle size as compared with synthetic calcium silicate hydrate and the like. It has been found that the activity is improved, and even at normal temperature and normal pressure, the same hardening characteristics as those of the synthetic calcium silicate hydrate are exhibited, and the present invention has been completed.

That is, the present invention provides an alkali silicate or an aqueous solution thereof (agent A), a calcium silicate having an average particle diameter of 2 μm or less and having no hydration activity at normal temperature and pressure, or a slurry containing the same (agent B) And a method of injecting into the ground by adding water if necessary, mixing and injecting the injecting material consisting of

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Examples of the alkali silicate in Agent A used in the present invention include sodium silicate and potassium silicate, with sodium silicate being particularly preferred. In addition, as an aqueous solution of alkali silicate, SiO ₂
Concentration of 10 to 70 wt%, Na ₂ O concentration of those is preferably 0.2 to 35 wt%. The aqueous solution of alkali silicate referred to here may be obtained by dispersing a fine powder of silica, such as silica sol, colloidal silica, or the like, in addition to a completely solution state such as water glass, in an aqueous solution of sodium hydroxide. In this case, the concentration is a numerical value including the solid content in this case.

[0009] The silica powder obtained by dispersing the silica fine powder in an aqueous sodium hydroxide solution has an activity within a range of the above-mentioned Na ₂ O concentration due to elution of the surface of the silica fine powder with alkali. Because it is enhanced, it has the same properties as water glass. However, in order to further enhance the reactivity, a solution or a colloid is preferable, and the concentration is determined by the viscosity required for the injection material, the time required for gelation,
It can be appropriately adjusted according to the strength after gelation and the like.

The calcium silicate in the agent B used in the present invention may be any one having no hydration activity at normal temperature and normal pressure, such as synthetic or natural wollastonite, Ca / Si molar ratio is 1.
Examples include calcined products of calcium silicate hydrate of 0 or less. Calcium silicate with high Ca / Si such as C3S, C2S, cement, etc. having a high hydration activity of 1.0 is used because the reaction with the alkali silicate of the A agent progresses rapidly due to the dissolution of calcium. It is short and lacks ground permeability and workability, which is not preferable.

The average particle size of calcium silicate is 2 μm.
m, and preferably 0.2 to 2 μm. If the average particle size of calcium silicate exceeds 2 μm, the permeability to fine gaps is poor, which is not preferable. The concentration of the calcium silicate-containing slurry is preferably 5 to 50% by weight of calcium silicate (the remainder being water), and particularly preferably 5 to 35% by weight. If the calcium silicate concentration exceeds 50% by weight, the viscosity of the slurry increases, and the permeability decreases. On the other hand, if the calcium silicate concentration is less than 5% by weight, the dispersibility is reduced and good strength cannot be obtained.

[0012] The kneading time of the solid / liquid at the time of manufacturing the injection material of the present invention is desirably adjusted as appropriate according to the type and particle size of the calcium silicate raw material. In addition, at the time of kneading, in addition to the above-mentioned raw materials, if necessary, known admixtures generally used for preparing a ground injection material such as a dispersant and a gel time adjuster can be added.

The injection material of the present invention is used by mixing the agent A and the agent B with water, if necessary, mixing and injecting the mixture into the ground. That is, when the agent A and the agent B are in a powder or high concentration, water is added to obtain a solution, dispersion, or slurry having a desired concentration, and both are mixed and injected into the ground. Here, the total amount of water required, including the amount of water previously contained in the A agent and the B agent, is required to ensure good permeability and strength development. The amount is preferably 200 to 1000 parts by weight based on 100 parts by weight of the solid equivalent. This water may be used as an aqueous solution of the agent A or water of a slurry of the agent B, and may be prepared in advance as a liquid agent.
Agent and B agent as powder or high concentration,
Water may be added during use as described above. Also,
The mixing ratio of the alkali silicate aqueous solution of the agent A and the calcium silicate-containing slurry of the agent B is determined by the concentration of the silicic acid component in the alkali silicate solution, the pH of the alkali silicate solution, the viscosity required for the injection material, and the gel. It can be appropriately adjusted according to the time required for the gelation and the strength after gelation.

As a concrete method of injecting the injection material of the present invention into the ground, two methods are appropriately selected according to the gelation time of the injection material.
Any one of the shot, 1.5 shot, and 1 shot method can be selected and used. That is, when the gelation time of the injection material is short, the liquid A and the liquid B are mixed at the tip of the injection tube and injected (two shots). When the gelation time is slightly long, the liquid A and the liquid B are mixed. The liquids are mixed and injected (1.5 shots) in an injection tube. If the gelation time is sufficiently long, the liquids A and B are mixed and injected in a mixer or an injection pump (one shot). be able to.

[0015]

With the conventional suspension-type injection material, the average particle size of the particles is as large as several μm to several tens μm, and there is a limit to the permeability. However, this is because the hydration activity of the particles is high. It is considered that the particles are agglomerated. That is, in the present invention, by using calcium silicate having no hydration activity at normal temperature and normal pressure as the agent B, fine particles down to submicron can be obtained, and excellent permeability that can be injected into the ground having fine gaps Is obtained. In addition, by mixing with the aqueous solution of the alkali silicate of the agent A, the surface of the calcium silicate fine particles is stimulated by the alkali and silicate ions are eluted, so that the hydration activity of the calcium silicate increases, and at normal temperature and normal pressure, Can also be gelled. Therefore,
The amount of calcium silicate eluted varies depending on the particle size and concentration of calcium silicate in agent B, or the mixing ratio and concentration of alkali silicate in agent A to be mixed. Therefore, the gelation time can be controlled by adjusting these. is there.

[0016]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

In the following examples, the gelation time, compressive strength, and permeation amount of the injection material were measured as follows.

<Measurement of gelation time> A predetermined amount of solution A and B
The liquid was weighed into cups, and the contents were alternately transferred. The time when the self-fluidity of the mixture was lost by the "cup inversion method" was defined as the gelation time.

<Measurement of Uniaxial Compressive Strength> A predetermined amount of Solution A and Solution B are mixed, and within 50 minutes of gelation time, diameter 50 mm × height 100 mm
The cured product obtained by casting in a mold of No. 1 was cured in water at 20 ° C. for a predetermined number of days, and then subjected to a soil test method (JSF T 511-199).
0: soil uniaxial compressive strength test method).

<Evaluation of permeability> Toyoura standard sand was 50 mm in diameter.
A mold having a height of 500 mm was filled so as to have a porosity of 40%, and a Toura standard sand was previously saturated with water using a mold having a water permeability of 2.0 ± 0.1 × 10 ^-2 cm / sec. The injection material is injected here at a pressure of 1 kgf / cm ² , and until the gap in the Toyoura standard sand causes a clogging phenomenon (injection rate of 50 ml or less per minute)
The volume discharged from the other end different from the inlet was defined as the permeation amount.

Examples 1 to 5 and Comparative Examples 1 and 2 As solution A, silica sol (cataloid Si-30, manufactured by Catalyst Chemicals, Inc., SiO ₂ = 28% by weight, Na ₂ O = 0.4% by weight) or 3
No. ₂ water glass (SiO ₂ = 35% by weight, Na ₂ O = 10% by weight), and as a liquid B, natural wollastonite is wet-pulverized at a water / wollastonite weight ratio of 10 to obtain a predetermined average particle size. Using a wollastonite slurry having a diameter or a CSH slurry hydrothermally synthesized to Ca / Si = 1.0 (water / synthetic CSH weight ratio = 10), mixing was performed so that the A liquid / B liquid volume ratio = 1. Table 1 shows the results obtained by measuring the gel time, the permeability into the ground, and the homogel uniaxial compressive strength of the cured product in this case according to the above method.

[0022]

[Table 1]

Table 1 shows that it is important to keep the average particle size of the calcium silicate fine particles at 2 μm or less in order to maintain good permeability. Further, the gel time can be controlled within a range of ten minutes or more from the instantaneous setting.

Examples 6 to 10 and Comparative Examples 3 to 4 As solution A, silica sol (cataloid Si-30, manufactured by Catalyst Chemicals, Inc., SiO ₂ = 28% by weight, Na ₂ O = 0.4% by weight) or 3
No. ₂ water glass (SiO ₂ = 35% by weight, Na ₂ O = 10% by weight) was used, and as a B solution, CSH synthesized to Ca / Si = 0.8 was baked at 1000 ° C (fired CSH) with water / firing. A slurry containing calcined CSH having a predetermined average particle size by wet grinding with a CSH weight ratio of 10 and a CSH slurry (water / synthesis) hydrothermally synthesized to Ca / Si = 0.8
Using a CSH weight ratio = 10), mixing was performed so that the A liquid / B liquid volume ratio = 1. Table 2 shows the results obtained by measuring the gel time and the homogel uniaxial compressive strength of the cured product according to the above method.
Shown in

[0025]

[Table 2]

[0026]

According to the present invention, an injection material having an excellent permeability that can be injected into the ground having fine gaps and capable of easily controlling the gelation time, and an injection method using the same. Is provided.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09K 103: 00

Claims (4)

[Claims] An alkali silicate or an aqueous solution thereof (A)
An injection material comprising calcium silicate having an average particle size of 2 μm or less and having no hydration activity at normal temperature and normal pressure, or a slurry containing the same (agent B). 2. The agent A has an SiO ₂ concentration of 10 to 70% by weight, Na ₂ O
The injection material according to claim 1, which is an aqueous solution of an alkali silicate having a concentration of 0.2 to 35% by weight. 3. The agent B is one or more selected from calcined products of wollastonite and calcium silicate hydrate having a Ca / Si molar ratio of 1.0 or less, or a slurry containing the same. The injection material according to claim 1 or 2. 4. An injection method, wherein the A agent and the B agent of the injection material according to any one of claims 1 to 3 are added to water if necessary, mixed, and injected into the ground.