JPS61159484A - Grouting method - Google Patents

Abstract

PURPOSE:To precipitate waterglass component as gel to thereby prevent strength from being lowered, by introducing waterglass grout into the ground which has been previously penetrated with an inorg. salt-contg. soln. CONSTITUTION:An injection hole 1 is dug in the ground and a casing 2 is inserted into the hole. The discharging hole 3 of an injection pipe 5 is covered with a rubber 4, the pipe 5 is inserted into the hole, the space between the casing 2 and the pipe 5 is sealed by sleeve grout 6 and the casing 6 is drawn out. A strainer pipe 8 provided with a packer 7 is inserted into the pipe 5 and an injection material of an inorg. salt-contg. soln. is injected by means of a pump. An injection material of waterglass grout whose pH is alkaline is injected and caused to gel.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a ground injection method using water glass whose pH is alkaline.

[Prior art and its problems]

Conventionally, a method of adding a reactive agent to water glass and injecting it into the ground has been used to solidify the ground, but water glass
Since the gelation time is the shortest in the vicinity of weak alkalinity, that is, in the vicinity of pH 8 to 9, it was not possible to add enough reactant to neutralize this.

Therefore, unreacted water glass remains in the grout, and when this is injected into the ground, the strength decreases or the water glass is leached into the ground water. In particular, in water glass grout using an inorganic reactant, the above-mentioned phenomenon due to insufficient reactant is noticeable, and for this reason, the water glass and reactant must be combined in the injection pipe and injected in a short gelation time, resulting in OBJECT OF THE INVENTION The purpose of the present invention is to completely gel the injected water glass by allowing a sufficient amount of the inorganic salt reactant to act on the water glass. An object of the present invention is to provide a ground injection method that can precipitate water glass as a substance, thereby preventing a decrease in strength and also preventing leaching of water glass from the groundwater core. According to the method, the injection material of an inorganic salt mixed solution is infiltrated into the ground to be injected in advance, and then the injection material of PE (alkaline earth metal drained glass grout) is press-fitted into the ground.

[Detailed description of the invention]

The present invention will be specifically described in detail below.

In the present invention, first, the injection material of the inorganic salt mixture is infiltrated into the ground to be injected in advance. Next, an injection material of water glass grout whose pH is alkaline is injected into the ground to be injected.The pH of this water glass grout is in the alkaline range, and although it gels, it is neutralized to the amount of water glass. It contains only an insufficient amount of reactant.

However, because there is too little reactant, sufficient gelation time is maintained for penetration. When such water glass grout is injected into the ground into which an inorganic salt mixture has been injected in advance as described above, the water glass grout permeates into an area equivalent to a large amount of water, and after permeation, it gradually becomes present in the soil particles. It reacts with the injection material containing the inorganic salt mixture, and is completely solidified without leaving any unreacted parts, and does not cause any deterioration in strength.

The reactants for water glass grout in the present invention are acids (inorganic acids, organic acids, etc.), salts (inorganic salts,
Any organic salt, basic salt, neutral salt, acid salt, etc.) esters, aldehydes, amides, alcohols, alkalis such as lime, etc. can be used.

[Reactant]

Esters: Fatty acid esters of alcohols such as ethyl acetate, methyl acetate, butyl acetate, and amyl acetate.

Fatty acid esters of polyhydric alcohols such as ethylene glycol diacetate, glycerine triacetate, and succinic acid diester. (Total ester) Intramolecular ester such as δ-butyrolactone and ε-caprolactone. (Cyclic esters: lactones) ethylene glycol monoacetate, ethylene glycol monoacetate, ethylene glycol monopropionate, glycerin monoformate, glycerin monoacetate, glycerin monopropionate, glycerin diformate, Polyhydric alcohol partial esters such as glycerin diacetate, sorbitol monoformate, sorbitol monoacetate, glycolic acid monoacetate, low polymerization partially saponified vinyl acetate, and the like. Carbonates such as cyclic carbonates such as diacetoxyethylene ethylene carbonate (ethylene carbonate), propylene carbonate (propylene carbonate), and glycerin carbonate.

Aldehydes: glyoxal, succinic dialdehyde, malondialdehyde, succinic aldehyde, glutardialdehyde,
Dialdehydes such as furfural dialdehyde.

Amides: formamide, dimethylformamide, acetamide,
Dimethylacetamide, propionamide, butyramide, acrylamide, malondiamide, pyrrolidone, caprolactam, etc.

Alcohols: Ethyl alcohol, methyl alcohol, amyl alcohol, chrycerin, polyvinyl alcohol, etc., monohydric or polyhydric alcohols, or synthetic polymeric alcohols 0 Acids: Inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid, formic acid, acetic acid, etc. 07
Acids, organic acids such as succinic acid, maleic acid, tartaric acid, etc. Inorganic salts: (acidic salts, neutral salts, basic salts, etc.) Chlorides such as calcium chloride, sodium chloride, magnesium chloride, chloride power 1 and aluminum chloride, Sulfates such as calcium sulfate, sodium sulfate, aluminum sulfate, aluminates such as aluminate sorter, potassium aluminate,
Hydrochlorides such as ammonium chloride, zinc chloride, aluminum chloride, chlorates such as sodium chlorate, potassium chlorate, sodium perchlorate, potassium perchlorate, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, carbonates such as potassium carbonate, ammonium bicarbonate, calcium carbonate, and magnesium carbonate; bisulfates such as sodium bisulfate, potassium bisulfate, and ammonium bisulfate; bisulfites such as sodium bisulfite, potassium bisulfite, and ammonium bisulfite; Silicates such as sodium silicofluoride and potassium silicofluoride, silicates such as alkali metal salts and aluminum salts, borates such as sodium borate, potassium borate, and ammonium borate, sodium hydrogen phosphate, hydrogen phosphate potassium,
Hydrogen phosphates such as ammonium hydrogen phosphate; bisulfates such as sodium pyrosulfate, potassium pyrosulfate, and ammonium pyrosulfate; pyrophosphates such as sodium birophosphate, potassium pyrophosphate, and ammonium pyrophosphate; sodium dichromate; Dichromates such as potassium chromate and ammonium dichromate, permanganates such as potassium permanganate and sodium permanganate, etc.

Organic salts: acetic acid, succinic acid, formic acid, sodium formate, etc.

〔others〕

Quicklime, alumina, iron oxide, red sea bream oxide, etc., metal oxides, slag, fly ash, calcium silicate, cement, etc. Ca, At, Mg km,
carbon dioxide gas.

As water glass, the molar ratio (5iOz/'l1v120
): 1.5-5.0 liquid water glass, anhydrous water glass,
It refers to an alkali metal salt of silicic acid in any molar ratio, including hydrous water glass, crystalline water glass, etc., or a mixture of an alkali metal salt of silicic acid and silicic acid or any alkali.

In addition, the water glass grout using the above-mentioned playing material is a mixed aqueous solution of water glass and a reactant, or a mixture of a water glass aqueous solution and a reactant aqueous solution, and can be gelled by itself.
The H value is in the alkaline range (PH value higher than 8).

Further, the inorganic salts used in the present invention are those listed above, but polyvalent metal salts are particularly suitable from the viewpoint of increasing strength. Further, the inorganic salt compounded liquid in the present invention can also be used in combination with other above-mentioned reactants.

Hereinafter, the present invention will be explained in more detail through experiments. 〇 Experimental method A comparative experiment was conducted by filling a large mold with a diameter of 2 ml and a height of 3 m with mountain sand and saturating it with tap water. 01, Injection method 1-1 Rondo injection 1-2 Double tube rod injection (Figure-1) 1-3 Double tube double packer injection (Figure-2) 2, -Next injection material 2- I Atx (804)s 20% mixed solution 2
-2 CaC2z 20X combination liquid 2-3
NaHCO3 20% mixture 2-4 Cement grout (per 100cc) Portland cement 120f Water: remaining 2-5 Water glass -
Cement grout (same as 3-1) 3, secondary injection material (1
Formulation per 00CC) Gelation time of A-8 combined liquid: 1 minute. P
Gelation time of H11, 8° and 8 combined liquid: 3 minutes.

PH11.2゜ Gelation time of A-8 confluence: 3 minutes.

PL (11,0°4, injection amount) For both primary and secondary injections, the injection stage was moved from bottom to top at intervals of 5 m (L), and 5 Ot was injected per stage.

For comparison, in the case of only secondary injection material, the injection amount per stage was set to 10010. Experimental results - 1 The experimental results of the strength test with and without primary injection are shown in Table 1. From this point on, primary injection was performed. It can be seen that when there is no injection, the strength decreases drastically, but when the second injection is performed, the strength increases dramatically.

Table 1: Also, collect 1000- of the solidified bodies, cure 10 in distilled water for four days, and then increase the curing amount of 5i02 in the curing water by +111.
The determined results are shown in Table 1. The strength decrease from this is 51
It can be seen that this is due to the elution of 0.02, and it can be seen that when the second injection is performed, the elution amount decreases significantly, so that the strength does not decrease.

Experimental Results-2 Table-2 shows the results of a comparison of injection methods.0 Table-2 Table-2 shows that if rod injection is used, it is difficult to ensure that the primary injection material penetrates at each injection stage. Compared to the relatively small effect, when using a double tube (or triple tube) injection and injecting the primary injection in advance at each predetermined stage and then performing the secondary injection, the effect is extremely excellent. I know it will work.

Experimental results-3 Table-3 shows the experimental results regarding the types of primary injection materials. Table 3 shows that polyvalent metal salts are especially excellent as primary injection materials. This is thought to be due to the formation of insoluble polyvalent metal silicate.

Table 3 Also, the results of the 8i0z elution test conducted in the same manner as Experiment 1 also showed that when polyvalent metal salts were used as the primary injection material, Si
This showed that the amount of O2 elution was small.

Experimental Results-4 A comparison was made between the use of cement grout or water glass-cement grout and the use of an inorganic salt mixture as the primary injection, and the results are shown in Table-4.Table-4 Table-4 is- Secondary injection has better permeability than secondary injection,
This shows that it is effective for the first time.0 This is because if the permeability of the -next injection is poor, the secondary injection does not penetrate between the soil particles where it can penetrate. This is because they cannot react. In other words, using cement grout or water glass-cement grout as the secondary injection only fills rough areas and no chemical reaction with the secondary injection material can be expected, whereas using an inorganic salt mixture as the primary injection It is used to cause a reaction between the secondary injection material and the soil particles, and it can be seen that the meaning is different from using cement grout or water glass-cement gelaud as the primary injection material.

Therefore, before carrying out the present invention, cement grout, water glass-cement grout, suspension grout such as lime, or flash setting grout is injected into the ground to fill the rough areas. If the present invention is carried out, the primary injection material of the present invention can penetrate between soil particles homogeneously, so that the reaction between the secondary injection material and the primary injection material can be performed more accurately. A construction example will be explained in detail using the attached FIGS. 1 and 2.

In order to ensure that these primary press-in materials are distributed in advance at each injection stage, the primary press-in materials are introduced into the ground through the injection pipe (Fig. Inject the secondary injection material overlappingly after injection, or use a multi-tube rod to overlap and inject the secondary injection material before the primary injection material injected dissipates outside the designated area. There are ways to do this. (Figure 2).

To explain FIG. 1, first, an injection hole 1 is drilled in a predetermined ground and a casing 2 is inserted. Next, after inserting the injection pipe 5 surrounded by the rubber 4 into the discharge hole 30, the space between the casing 2 and the press-fit pipe 5 is filled with sleeve grout 6, and the casing 2 is pulled out. - Insert the pipe 8 into the press-fit tube 5 and inject the next ground injection agent from the injection pump (not shown). Then,
After this injection is completed, a secondary grouting agent is injected.

To explain FIG. 2, FIG. 2(a) shows a situation in which poling water is sent from the lower discharge port 12 of the inner pipe 10 to drill a hole to a predetermined depth using a double pipe.

13 is a metal crown. Thereafter, as shown in FIG. 2(b), the primary injection material is sent through the outer pipe 9 and press-fitted into the ground through the upper discharge port 11, while the secondary injection material is sent through the inner pipe 10 and into the ground through the lower discharge port 12. By moving from the bottom of the injection stage to the top while injecting, the secondary injection material is superimposed and injected into the area where the primary injection material was press-fitted.

In addition to the injection tube shown in Fig. 2, an injection tube with a valve attached to the tip of the inner tube that can be moved up and down by fluid pressure in the direction of the pipe is used, and the primary injection material is injected from the upper discharge port by switching the valve. Next, a secondary injection material can also be injected from the lower discharge port.

〔Effect of the invention〕

As described above, in the present invention, the water glass grout with an alkaline pH is injected after the inorganic salt mixture has penetrated into the ground to be injected in advance. The salt reactant acts in the ground to completely precipitate water glass as a gel, thereby preventing a decrease in strength and also preventing water glass from leaching into groundwater.

[Brief explanation of drawings]

Both FIGS. 1 and 2 show a specific example of an injection pipe for carrying out the construction method of the present invention, and FIG. (b) shows a process diagram of the method of the present invention. 1... Injection hole, 3... Discharge port, 5... Injection pipe, 9
...outer pipe, 10...inner pipe, 11...upper discharge port,
12...Lower discharge port. Patent applicant: Reinforced Soil Engineering Co., Ltd. Sen 2g

Claims (1)

[Claims] The injection material of the inorganic salt mixture is infiltrated into the ground to be injected in advance, and then the injection material of water glass grout with an alkaline pH is injected into the ground. Ground injection method to consolidate.