JPS59140285A - Solidification of ground with grout - Google Patents

Abstract

PURPOSE:To slow down gelation of water glass for easier on-site operation and produce high-strength gel for strong solidification of ground, by using a non- alkaline aqueous solution of silicic acid as reactant for water glass. CONSTITUTION:In the solidification of ground by pouring into the ground a grout consisting of a mixture of water glass and a reactant and conditioned to have alkalinity, a neutral to acidic aqueous solution of silicic acid obtained by mixing water glass with acid is used as reactant. The use of the reactant retards gelation of water glass making on-site operation easy and produces a gel with high strength leading to strongly solidified ground.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ground injection method using water glass, and more particularly, to a ground injection method using a non-alkaline silicic acid aqueous solution obtained by mixing water glass and an acid as a reactant for the water glass. 0 Regarding construction methods Conventionally, in the ground injection method in which a reactive agent is added to water glass and the water glass is gelled to solidify the ground, acids, salts, esters, glyoxal, etc. are used as the reactive agent for the water glass. I came. Among these, organic reactive agents such as esters and glyoxal allow for easy adjustment of gelation time, long gelation time, and the preparation of high-strength completely opaque water glass grout; however, they pose the problem of ground contamination. wake up

On the other hand, inorganic reactants such as acids and salts do not cause ground contamination problems (COD and BOD problems), but slight differences in the amount added may result in no solidification, etc. However, the problem arises that it is difficult and the strength is low.

An object of the present invention is to provide a ground injection method in which water glass is slowly gelled and the gelled product exhibits high strength by using a non-alkaline silicic acid aqueous solution as a reactant for water glass. 0 In order to achieve the above-mentioned object, the present invention (C) uses a ground injection method in which an injection material mixed with water glass and a reactive agent and adjusted to a pH value in the alkaline region is injected into the ground and solidified. The method is characterized in that a neutral or acidic aqueous acid solution obtained by mixing water glass and an acid is used as the reactant.

Hereinafter, the present invention will be specifically explained in detail using experimental examples.

(Experiment-1) Using sulfuric acid as a reactant in a No. 3 water glass aqueous solution, the relationship between water glass concentration - sulfuric acid concentration - gelation time was obtained by experiment. The experimental results are shown in Figure 1.

However, when sulfuric acid is used as a reactant, a slight difference in the amount of sulfuric acid causes instant gelation or no gelation at all, and there is little control over gelation time. It turns out that it is impossible. For this reason, it can be seen that, due to variations in the injection operation, the injected grout may not solidify, or it may set instantaneously, resulting in the infiltration of the acid at the site.

(Experiment-2) Water glass having a molar ratio of 3.6 was added to dilute sulfuric acid to prepare an acidic silicic acid aqueous solution.

In this case, the amount of water glass used to make 100 CC of acidic silicic acid aqueous solution is 4Q, and the amount of CC197% sulfuric acid is 3.5C.
The pH value of the acidic silicic acid aqueous solution obtained in Example C was 3.0.

In order to gel the No. 3 water glass aqueous solution, the above acidic silicic acid aqueous solution was added, and the relationship between water glass concentration - SiO2 concentration - gelation time was obtained by experiment. The experimental results are shown in Figure 2.

However, the SiO2 concentration here refers to the concentration of 5i02 caused by the acidic silicic acid aqueous solution.

This shows that when an acidic silicic acid aqueous solution is used as a reactant, the gelation time can be controlled over a wide range.

Therefore, it can be seen that it is possible to easily obtain a grout with a predetermined gelling time even if there are slight variations in injection operations and mixing operations at the site0 (Experiment 3) According to the method described in Experiment 2. 3. Adding water glass at a molar ratio of 3.6 to a dilute sulfuric acid aqueous solution to create neutral to acidic silicic acid aqueous solutions with various pH values 3. Using this silicic acid aqueous solution as a reactant, the No. Test 1-1 shows the relationship between the concentration of 5IO2 caused by this silicic acid aqueous solution and the gelation time, and the results are shown in FIG. In this case, the No. 3 water glass concentration was 0.53 mol/A. From these results, it can be seen that the lower the pH value of the silicic acid aqueous solution, the steeper the gelation time curve, and the higher the pH value, the gentler the gelation time curve.

It can also be seen that even if the pH value is low, it is extremely easy to control the gelation time compared to FIG.

In the following two experiments-1, 2, and 3, gelation was caused by P.
This should be done in an alkaline region with an H value of 10.5 or higher.

As described above, according to the present invention, gelation of water glass in an alkaline region can be freely controlled using an inorganic reactant. Conventionally, this was only possible using organic reactants, and not possible with inorganic reactants.

Next, an example of a strength test is shown.

(Experiment-4) As shown by the X point in Figures 1, 2, and 3, using a formulation with a gelation time of approximately 10 minutes, the solidified standard sand was uniaxially cured for one day. A compression test was conducted.

The results are shown in Table-1.

Table 1 shows that compared to the case where sulfuric acid is used as a reactant in water glass, an acidic-neutral silicic acid aqueous solution obtained by mixing water glass and sulfuric acid and removing the alkali in water glass is prepared, and this silicic acid aqueous solution is It can be seen that the strength is significantly greater when water glass is used as a reactant to gel.

This is thought to be because silicic acid as a reactant itself imparts strength when water glass gels, and also adds to the structure of the gel when water glass gels, giving structural strength to the gel. .

In addition, in the above, a monovalent or polyvalent metal electrolyte substance,
For example, the combined use of alkali metal salts, polyvalent metal salts, or their oxides or hydroxides helps to adjust the gelation time.
In particular, these metal ions react with silicic acid in a relatively short time in an aqueous water glass solution in an alkaline region, but in an acidic to neutral region, they do not react with silicic acid immediately, but react relatively slowly. Therefore, when these metal ions are mixed in the acidic to neutral silicic acid aqueous solution and reacted with water glass, they not only act effectively as a gelling promoter, but also promote the gelling of silicic acid. However, the formation of insoluble silicic acid has the effect of increasing strength. Of course,
A small amount of these metal ions may be mixed into the water glass aqueous solution.

(Experiment 5) As a reactant, an acidic silicic acid aqueous solution containing various substances (additives) that generate metal ions shown in Table 2 was used, and each of these was added to water glass to obtain an injection material. A strength test was conducted.

The blending was carried out by adding various additives to the blend (6) in FIG. 2 in an amount of 1% by weight based on the total blended solution.

Table 2 shows that polyvalent metal salts are particularly effective in increasing strength.

Table 2 In the above explanation, an example was shown in which sulfuric acid was used as the acid to create a neutral to acidic silicic acid aqueous solution, but other inorganic acids such as hydrochloric acid, nitric acid, and phosphoric acid, acidic sulfates, and acidic phosphoric acid Acidic salts such as salts, organic acids, aldehydes, esters, etc. that react with alkali to form acids can be used. Furthermore, as is already known, the relationship between the pH value and the gelation time when water glass is gelled becomes the shortest when the pH value is around 8.5.

Therefore, the acidic to neutral silicic acid aqueous solution used in the present invention preferably has a pH value of 85 or less, particularly a pH value of 7 or less.

In addition, when using these silicic acid aqueous solutions as a reaction agent for water glass and kelizing it with alkali', the pH value is 8.5 or higher, preferably 10.5 or higher, which allows the gelation time to be arbitrarily controlled. is desirable.

As explained above, the present invention uses neutral to acidic silicic acid as a reactant to gel water glass.
This completely breaks the conventional wisdom regarding water glass grout in the alkaline area.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between sulfuric acid concentration and gelation time when sulfuric acid is used as a reaction agent for water glass, and Figure 2 is a graph showing the relationship between sulfuric acid concentration and gelation time when sulfuric acid is used as a reaction agent for water glass. FIG. 3 is a graph showing the relationship between iOz concentration and gelation time, and FIG. 3 is a graph showing the relationship between 5i02 concentration and gelation time in non-alkaline silicic acid aqueous solutions of various pH values. Patent Applicant Reinforced Earth Engineering Co., Ltd. Agent Patent Attorney Someya Hitoshi Do not change the contents of the Western-style building in the drawings - 1 Yu A & Kenoura υ 1 (Rōnri T) Answer 2 s, to 2 J Izumi 00 approx. ψ Notebook 3 Mei Fuho wo 02 t/i Kaya) Procedural amendment March 1948/Bay Japan Patent Office Commissioner Saita Wainu-dono ■, Indication of the case ■ Japanese I and year Patent Application No. 7417RI No. 3 2,! 'ILO$''Nase, 1γsi main input Niji Dai 3, relationship with the amended person's case Patent applicant 3-15-1 Hongo, Bunkyo-ku, Tokyo, Japan Procedural amendment book Showa evening? Year 4 Product 3 Days Commissioner of the Patent Office Mr. Hakusugi Wainu 1, Indication of the case Showa I Year Patent Application No. 1yZtJ No. 3, Person making the amendment Relationship with the case Patent Applicant Separate Instrument kLy)l-Yuu. The scope of the patent claims of the present application is amended as follows.
In the ground injection method in which the injection material adjusted to the specified value is injected into the ground to solidify the ground, it is recommended to use a neutral or acidic silicic acid aqueous solution obtained by mixing hydraulic lath and acid as the reactant. Characteristic ground injection method. 2. The ground injection method according to claim 1, characterized in that at least one of the water glass and the silicic acid aqueous solution as the reactant contains a monovalent or polyvalent electrolyte substance. Ground injection method. ”

Claims (1)

[Scope of Claims] 1. In a ground injection method in which an injection material mixed with water glass and a reactive agent and adjusted to a pH value in the alkaline region is injected into the ground to solidify the ground, water glass is used as the reactive agent. A ground injection method characterized by using a neutral or acidic silicic acid aqueous solution obtained by mixing silica and acid. 2. The ground injection method according to claim 1, characterized in that at least one of the water glass and the silicic acid aqueous solution as the reactant contains a monovalent or divalent electrolyte substance. Ground injection method.