JPH0216351B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a water glass-based ground injection method that is used as a solidifying chemical solution for consolidating soft or leaky ground or for water stopping. It is a construction method. In the present invention, grout is a ground consolidation or water stop consolidation method that uses water glass as a main ingredient, and is injected into soft ground such as construction foundation excavation work sites, subway excavation work sites, etc. to make the ground water resistant. It is used to create a solid foundation or to stop water. The method of consolidating water glass using an inorganic curing agent in the alkaline region, which has been applied in the conventional construction method, has a large amount of syneresis water in the consolidated water glass gel, resulting in low consolidation rate and consolidation strength. It was stable and had the drawback of continuing to leach alkali even after solidification. Although the present invention uses water glass acid as a hardening agent to harden water glass in an alkaline region, it is sufficient to compensate for the above-mentioned drawbacks as much as possible. Add a glass aqueous solution to prepare an acidic water glass solution,
Add water glass solution to this and adjust the pH to 8.5~
It is characterized by instantaneous solidification of water glass in the alkaline region of 10.5. The hardening of water glass according to the present invention has the following excellent properties. (1) Compared to conventional caking in the alkaline region using an inorganic curing agent, there is less syneresis water and the caking rate is good. Therefore, there is little alkali leaching and the solidification strength is also excellent. (2) Compared to the method of solidifying a strongly acidic water glass solution with water glass or an alkaline agent in a neutral or weakly acidic region, the instant solid state can be maintained over a wider range and preparation is easier. The following will be specifically described in detail with reference to examples. The consolidation rate indicates the percentage of the consolidated volume to the total volume.

[Table] Table 1 shows a wide range of acidic water glass solutions (A
PH when water glass aqueous solution (B liquid) is added to liquid)
The gelation time, consolidation rate, and homogel unconfined compressive strength are shown. Here, the acidic water glass solution of liquid A was prepared by adding No. 3 water glass to the sulfuric acid aqueous solution to have the final composition shown in the table. From Table-1, when the pH of the combined liquids of A and B in Examples 4 to 10, 13, and 14 is in the range of about 8.5 to 10.5, instantaneous setting is easily obtained and there is little syneresis water. The solidification rate was good, the homogel strength was high, and an extremely stable solidified body was obtained. As the pH of the combined liquids A and B becomes more acidic (Execution Nos. 3 to 1 and 12), the gelation time becomes longer, and a solid in a constant flash solid state cannot be obtained. When the AB confluence of Examples 11, 15, and 21 becomes strongly alkaline (PH > 10.6), it is not only impossible to obtain an instant setting state, but also the setting rate and homogel uniaxial compressive strength are extremely reduced. Table 2 shows an example in which a sulfuric acid solution and a water glass aqueous solution are directly blended without preparing an acidic water glass solution.

[Table] When directly blending from Table 2, compared to when preparing the acidic water glass solution from Table 1, even if the final blending ratio is the same, syneresis water is higher, consolidation rate, and uniaxial compression. Both strength is extremely low. The solids of representative experiment No. were selected from Table-1 and Table-2, and cured in water of 10 times the amount (volume) of the solids.
Table 3 shows the results of replacing the water every day and measuring the pH immediately before the water replacement over time.

[Table] Experiment Nos. 18 to 23 were all prepared by preparing an acidic water glass solution and neutralizing it with a water glass solution.
18 and 19 in the acidic to neutral range, the PH of the curing water quickly shifts to neutral. Moreover, even in the alkaline region of Experiment Nos. 20 to 22 according to the present invention, the PH of the curing water shifted to neutral fairly quickly. When the pH of the solidified material in Experiment No. 23 reached 11.2, the transition to neutrality was slow. The solids obtained by directly reacting the water glass with the acidic reactant without adjusting the acidic water glass solution in Experiment No. 24 had a pH of 9.8, but were similar to those in Experiment No. 22. Contrary to the pH of 10.5, the transition of curing water to neutrality is extremely slow. Thus, it can be seen that although the solidification itself according to the present invention exhibits alkalinity, it quickly shifts to a neutral region in water. Although the water glass used in this example has a molar ratio of 3.5, the same direction can be seen in water glasses with general molar ratios of 1 to 4. Furthermore, other mineral acids such as phosphoric acid may be used instead of sulfuric acid as the acidic reactant. As described above, according to the present invention, although the water glass is consolidated in the same alkaline region as the conventional method, the drawbacks of the conventional method can be significantly improved. Furthermore, it has been found that the present invention has the advantage of always producing stable solids in an instant solid state compared to solids obtained in neutral to weakly acidic conditions by neutralizing an acidic water glass solution with an alkaline reactant. .

Claims (1)

[Claims] 1 An acidic water glass aqueous solution obtained by mixing an acidic reactant with a water glass aqueous solution and adjusting the mixed solution to have a PH value of 2 or less and a water glass content of 20 volume % or more, and a water glass content of 20 volume %. A ground injection method characterized by combining the above water glass aqueous solution, adjusting the pH value of the combined liquid to a range of 8.5 to 10.5, and injecting it.