JPS62172088A - Ground grouting process - Google Patents

Abstract

PURPOSE:To attain broad impregnation and consolidation effect and to obtain a homogeneous consolidated material having excellent durability, by injecting a liquid compounded with a non-cement reactive agent into ground and further injecting an alkaline non-cement water-glass grout to the injected ground. CONSTITUTION:A liquid compounded with a non-cement reactive agent is injected into ground and a non-cement water-glass grout exhibiting alkaline nature (>= 9 pH) is injected into the treated region of the ground.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides tI! using non-cement water glass grout.
! qJ The present invention relates to the main artificial method, and particularly relates to a ground injection method in which a shortage of reactant is replenished in the ground to reduce leaching of silica content, thereby obtaining a solidified body with improved durability.

[Known technology and its problems]

Non-cement water glass grout, which is alkaline, has good permeability and penetrates into the spaces between fine soil particles.
Widely used as a solidifying agent for ground injection.

However, in order to maintain good permeability in this type of grout, the amount of reactant added must be small, and therefore a large amount of unreacted water glass remains, making it difficult to obtain a high-strength aggregate. Not only is it not possible, but the silica content is leached out over a long period of time, making it impossible to obtain durability.

It is also known to inject a reactive agent into the ground in advance and then inject a neutral water glass grout into the injection area. However, in this method, because the gelation time of the neutral water glass grout is short, it is difficult for the grout to penetrate between the soil particles, and therefore, the reaction between the grout and the reactant is difficult to occur in the fine-grained soil parts of the ground. If the improvement of the granular soil is insufficient, a strainer injection pipe is driven in when water glass is injected, and calcium chloride is injected through this injection pipe while the injection pipe is pulled up to cause the water glass and calcium chloride to react in the ground. Methods of doing so are also known. However, with this method, highly viscous water glass is pushed outward when calcium chloride is injected, resulting in non-uniform solidification of water glass and calcium chloride in a certain area around the injection tube.

[Purpose of the invention]

The object of the present invention is to reduce the leaching of silica by replenishing the shortage of the solidification reactant in the ground when solidifying non-cement water glass grout, thereby improving the durability of the solidified water glass grout. The object of the present invention is to provide a ground injection method that improves the drawbacks of the above-mentioned known techniques.

[Key points of the invention]

In order to achieve the above-mentioned object, according to the present invention, a non-cement reaction agent mixture is injected into the ground in advance,
Next, the trick is to superimpose and inject non-cement water glass grout exhibiting alkalinity with a pH value of 9 or more into the injection area of this mixed solution.

Specifics and Explanation of the Invention] The circumstances leading to the completion of the present invention are as follows.

(1) If sand gel solidified with non-cement water glass grout in the alkaline range is immersed in curing water, the silica content of the water glass will leach out over time and its strength will drop significantly. In particular, if the amount of reactant is reduced in order to prolong the gelation time, the product will collapse within several tens of days. However, even with this type of sand gel, no decrease in strength was observed in curing water containing a non-cement-based reactant mixture.
Rather, the strength is increased orally (.

(2) Even if the above-mentioned sand gel is cured in cement cement or cement-water glass gel, no improvement in strength can be obtained.

(3) Infiltrate a water tank filled with sand with a non-cement reaction agent mixture in advance, and then add a non-cement neutral water glass grout and an alkaline non-cement water glass grout with a pH of 9 or higher (both of these are When the same Gelquim (at the same water glass concentration and the same Gelquim) was injected at the same injection pressure, the latter had a significantly larger penetration range.

(4) Pre-infiltrate a water tank filled with sand with a non-cement reaction agent mixture, then add a water glass solution and P) 49 or higher alkaline non-cement water glass grout under the same conditions as in (3) above. When injected, the latter was more homogeneous and had a sufficiently large solidification strength.

(5) Water glass solution and PH in a water tank filled with sand
When 9 or more non-cement water glass grouts were infiltrated and then the reactant aqueous solution was injected before they gelled, a homogeneous solid was not obtained depending on the injection area, and sufficient strength was not obtained. I couldn't.

(6) When a non-cement based reactant mixture solution was infiltrated in advance into a water tank filled with sand, and then a non-cement based water glass grout exhibiting an alkalinity of P09 or higher was injected under the same conditions as above, the result was a homogeneous water tank. Moreover, a solid body with significantly improved strength over time was obtained.

(7) Cement grout or cement-water glass grout was injected in advance into a water tank filled with sand, and then non-cement water glass grout exhibiting alkalinity with pH 9 or higher was injected under the same conditions as above. No improvement in oral strength of the solids was achieved 9 .

(8) When a non-cement based reactant aqueous solution was infiltrated in advance into a water tank filled with sand, and then cement based grout or cement-water glass grout was injected under the same conditions as above, vein-like solids were formed. However, only sand gel was obtained.

Based on the circumstances described in (1) to (8) above, the above-mentioned objects of the present invention are as follows: (a) Inject a non-cement reactant mixture into the ground in advance as a subsequent injection; (b) Then, inject this mixture into the ground. Achieved by a ground injection method consisting of steps (a) and (b), in which a non-cement water glass grout that is alkaline with a pH of 9 or higher and containing a reactive agent is injected into the liquid injection area as a secondary injection. be done.

In the present invention described above, when the secondary injection material and the secondary injection material are directly mixed, an instantaneous setting occurs and penetration between soil particles cannot be expected, but the secondary injection material is mixed with the secondary injection material. The injection pressure pushes it toward the outer periphery and replaces it with the secondary injection material, resulting in a state where it is covered with the secondary injection material. This is similar to the state in which the solidified material of the secondary injection material is immersed in the reactant mixture at the time when the secondary injection material is gelled. Then, over time, the reactant penetrates into the solidified body of the secondary injection material, and the reactant reacts with the unreacted water glass in the solidified body. As a result, all the water glass in the solidified body is completely absorbed. The polymerization of the silica component progresses orally, increasing the strength of the solid body.

Therefore, the primary injection material in the present invention is a non-cement reaction agent mixture, and the secondary injection material is P.
A non-cement water glass grout with an alkalinity of H9 or higher is necessary in order to cause a reaction between soil particles, and this allows the reaction of the primary and secondary injection materials in the fine-grained soil layer to occur. It becomes possible.

The present invention will be explained in detail below using experimental examples.

The gelation time of the mixture of Dai-Keichijo No. 3 water glass and the reactant was measured, and the results are shown in Table 1.

The diameter of the specimen obtained by solidifying standard sand using Table 1 (Tetopuku) Ten- (-1 Mixtures 6, 1o, 13.16 and 23) samples in Table 1. 5c
m, length l0C11) was cured in aqueous water, and the content of Sin in the curing water was measured.
Measure the cumulative total of leaching 5i01i1 against the amount of oz&g,
Oral changes in leaching rate were investigated. (Table-2) The numbers in Table-2 are leaching rate (%)/-axial compressive strength (kg/cIII
). Moreover, in Table-2, "-" represents collapse.

Table 2: 20% of aluminum chloride used as curing water in Experiment 2
A similar experiment was conducted using a 100% solution, and the results are shown in Table 3.

Table 3 Nandogel (consolidated standard sand) consolidated using 1tlo in the same manner as in Experiment 2 was cured with 20% by weight solution of various reactants, and the leaching rate of Sio after 28 days was determined. The strength was measured and the results are shown in Table 4.

Table 4: 100g of Portland cement was mixed into the curing water in the same manner as in Experiment 2, and then the mixed sand gel was cured. After 28 days, the unconfined compressive strength was measured to be 1.6k.
g/clII. This shows that no improvement effect regarding durability can be obtained.

X-kei Once using the same method as Experiment 5, mix 11 gelatinized product 100
(Yumata, cement made by crushing Jl and mixing it into the curing water)
100cII+ of water glass gel was crushed and mixed into curing water. The composition per 100 cd of cement-water glass gel is: 25 cc of No. 3 water glass, 50 g of water, and the rest.

When the unconfined compressive strength of these was measured after 28 days, Blending No. 11 showed 1.5 kg/cd, and cement-water glass gelatinized product showed 1.6 kg/cat.

None of these had any improvement in durability.

Large - Belly -1 After saturating the sand in the aquarium with a 20% calcium chloride solution, pour grout with a mixing ratio of 15.16 until it no longer soaks in with a water head difference of 30 cm, and after a period of time, check the size of the solids. When I investigated, the diameter was about 20cm for the composition number 15, and the diameter for the composition number 1.
6, a solidification diameter of approximately 45 cm was obtained, and the formulation Th16
shows a more significant penetration effect.

When a similar experiment was conducted using blend 1t19.20, the diameter of blend 19 was approximately 15 cm, and the diameter of blend NQ20 was approximately 231 cm.

From the above, it was found that under the same conditions, the permeation range is narrow when PI4 is neutral, whereas the permeation range is extremely wide when the pH is alkaline (pH 9 or higher). This is because if the injection liquid is a water glass mixture containing a gelling reactant and the pH is alkaline, the reaction between the reactant in the ground and the injection liquid will occur due to the presence of alkali in the injection liquid. This seems to be because it becomes more gradual.

Experiment 1 In the same manner as in Experiment 7, a 20% by volume aqueous No. 3 water glass solution and a grout of Mixture Arashi 21 were injected. In the former, the diameter is 1
While a heterogeneous solid of 0 to 25c+a was obtained,
In the latter case, a substantially spherical solid with a diameter of 30 cm was obtained.

Further, the unconfined compressive strength of the former was 5 kg/ed, while that of the latter was 9.5 kg/cal.

From the above, it can be seen that it is necessary for the injection liquid to be a compounded liquid having Pl(=9 or more) and containing a gelling reactant in order to achieve homogeneous and strong solidification.

Husband - 20% of the sand in the aquarium No. 3 water glass 't8? (
After injecting 20% calcium chloride 78 solution with a water head difference of 39 cm after being saturated with 100 ml, the strength of the solid around the injection hole was measured after - weeks, and the unconfined compressive strength was 2 kg/cIll. . Also, in the same way, after saturating the sand in the aquarium with the compounded liquid of Mixed Kan 21, before the compounded liquid gels, 20% chloride power is added. Master the night,
When we measured the strength of the solids around the injection hole after a week, we found that
It showed an unconfined compressive strength of 2.6 kg/cJ.

If you inject the water glass mixture and then inject the reactant, the reactant will push the water glass mixture outward, causing the water glass concentration around the injection tube to swell and reduce its strength. In the opposite case, as in Experiment 8, it can be seen that the reactant located around the injection tube gradually permeates into the solid body formed by the water glass mixture around the injection tube orally, and the reaction progresses.

After pouring 500 cc of cement grout (50 g of cement per 100 cc, remaining water) or cement-water glass grout (same as Experiment 6) into a water tank filled with sand, mix -10 grout in 11 in the same place. The unconfined compressive strength 28 days after the injection was determined to be 1 itl+, and the results are shown in Table 5.

Table 5 From Table 5, it can be seen that even if cement grout or cement water glass grout 1 is used as the primary material, the oral strength of the secondary injection (e) will not be improved.

[1] After saturating the sand in the aquarium with a 20% calcium chloride solution, we injected 500 cc of the cement grout and cement-water glass grout from Experiment 10, and excavated it after - weeks, but it solidified into veins. However, no overall solidification was obtained due to the early opening and infiltration of soil grains. In other words, it has been found that such a method does not improve the consolidation effect due to early penetration of soil grains.The non-cement based water glass grout with a pH of 9 or more according to the present invention has a molar ratio of water glass. It is any liquid water glass with a number of 1 to 5, and contains an arbitrary or sonic reactant such as an acid, a salt, or an organic reactant. It has been adjusted.

Further, the non-cement reactant mixture includes acids, acidic salts, organic reactants, salts exhibiting alkalinity (sodium bicarbonate, etc.), and polyvalent metal salts are particularly preferred.

These are specifically CaC1! , Mg(: alkaline earth metal salts such as β2, aluminum salts such as aluminum chloride and polyaluminum chloride, and other iron salts.

Specifically, the construction method of the present invention is carried out using the injection pipe shown in FIGS. 1 and 2.

First, as shown in FIG. 1(a), poling water is sent 1 from the lower discharge port 4 of the inner pipe 2 to drill a hole in the ground to a predetermined depth.

Next, as shown in FIG. 1 (1)), the primary injection material is sent through the outer pipe 1 and injected into the ground through the upper discharge port 3.
On the other hand, the secondary injection material is sent through the inner pipe 2 and injected into the ground from the lower discharge port 4, and the injection stage is moved from the bottom to the top, so that the secondary injection material is poured into the area where the primary injection material has been injected. Inject in layers. 5 is a metal crown.

Fig. 2 shows an example of another injection pipe.
As shown in Figure 2, when the reactant mixture is fed from the inner tube 2 and water is fed from the outer tube 1, the valve 7 is displaced downward by the flow pressure of the inner tube 2 and the upper discharge port 3 is opened. The lower outlet 4 is closed, and the reactant mixture is injected into the ground from the upper outlet 3.

Next, as shown in FIG. 2(b), the feeding of the reactant mixture from the inner tube 2 is stopped, and Pl (non-cement water glass grout of 9 or more) (secondary injection material) is poured from the outer tube 1. ), the valve 7 is moved upward by the elastic force of the spring 4, and at this time, the upper discharge port 3 is closed by the valve 7, and the lower discharge port 4 is opened, and the secondary injection material is It is injected into the ground from the lower discharge port 4.Then, by moving the injection stage from the bottom to the top, the secondary injection material is injected over the area where the primary injection material has been injected.6 is a check valve. be.

〔Effect of the invention〕

The present invention described above can have the following effects.

(1) The oral strength of water glass grout in the alkaline region, which has a long gelation time, is significantly improved, and the durability of the solid body is improved.

(2) Obtain a sufficiently wide range of penetration and consolidation effects.

(3) Preventing the secondary injection material from deviating outside the injection range and obtaining a homogeneous solidified body within a predetermined range.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 both show a specific example of an injection pipe for carrying out the construction method of the present invention. DESCRIPTION OF SYMBOLS 1...Outer pipe, 2...Inner pipe, 3...Upper outlet, 4...Lower outlet, 7...Valve, 8...
...Spring patent applicant: Reinforced Earth Engineering Co., Ltd.

Claims (1)

[Claims] (1) A non-cement based reactive agent mixture is injected into the ground in advance, and then a non-cement based water glass grout exhibiting alkalinity with a pH value of 9 or more is superimposed and injected into the injection area of this mixture. A ground injection method characterized by