JPH0637766B2 - Ground injection method - Google Patents

Description

[Field of Industrial Application] The present invention relates to a ground pouring method using a non-cement type water glass grout, and in particular, a deficiency of a reactant is supplied in the ground to leach silica. The present invention relates to a ground pouring method for obtaining a solidified body having a reduced amount and thereby improved durability.

[Public technology and its problems]

Non-cement-based water glass grout that exhibits alkalinity has good permeability and penetrates even between fine soil particles.
Widely used as a solidifying agent for ground injection.

However, in this type of grout, the amount of the reactant added must be small in order to maintain good permeability, and therefore a large amount of unreacted water glass remains and a high-strength solidified body can be obtained. Not only that, but also the silica content is leached out for a long period of time and durability cannot be obtained.

A method is also known in which a reactive agent is injected into the ground in advance, and then neutral water glass grout is injected into this injection region. However, in this method, since the gelling time of the neutral water glass grout is short, it is difficult for the grout to permeate between the soil particles, so that the reaction between the grout and the reactive agent does not easily occur in the fine-grained soil portion in the ground, and The improvement of grain ground is insufficient.

Further, a method is also known in which a strainer injection pipe is driven when water glass is injected, and the injection pipe is pulled up while injecting calcium chloride through the injection pipe to cause the water glass and calcium chloride to react in the ground. However, in this method, high-viscosity water glass is extruded to the outside when calcium chloride is injected, and the solidification by water glass and calcium chloride becomes nonuniform in a certain range around the injection pipe.

[Object of the Invention]

An object of the present invention is to solidify a non-cement-based water glass grout to replenish a shortage of the solidifying reactant in the ground to reduce the leaching of silica and thereby improve the solidification of durability. It is an object of the present invention to provide a ground pouring method for forming a body and improving the above-mentioned drawbacks existing in the known art.

[Main points of the invention]

In order to achieve the above-mentioned object, according to the present invention, a multiple injection pipe having a plurality of outlets at different upper and lower positions is inserted into the ground, and then this injection pipe is moved upward to change the injection stage. While discharging, a non-cement-based reactive agent mixture liquid is discharged from the upper discharge port, and a mixture liquid of PH9 or more containing water glass as an active ingredient is discharged from the lower discharge port,
As a result, the compounded liquid containing the water glass as an active ingredient is allowed to permeate into the region where the reagent compounded liquid has already permeated.

[Specific Description of the Invention]

The background of the completion of the present invention is as follows.

(1) When the sand gel solidified with the non-cement-based water glass grout in the alkaline region is immersed in curing water, the silica content of the water glass is leached out with time, and the strength is significantly reduced with time. In particular, when the amount of the reaction agent is reduced to prolong the gelation time, it will disintegrate within several tens of days. However, even with such a sand gel, the strength does not decrease in the curing water containing the non-cement type reaction agent-containing solution, but rather the strength increases with time.

(2) Even if the sandle is cured in a cement solidified product or a cement-water glass gelled product, improvement in strength cannot be obtained.

(3) A non-cement-type reactive agent mixture liquid is preliminarily permeated into a water tank filled with sand, and then a non-cement-type neutral water glass grout and an alkaline non-cement-type water glass grout with a pH of 9 or more (these are all the same. When the same gel time was injected at the same concentration of water glass) at the same injection pressure, the latter had a significantly larger permeation range.

(4) A non-cement-based reaction mixture was preliminarily impregnated in a water tank filled with sand, and then a water-glass aqueous solution and an alkaline non-cement-based water glass grout with a pH of 9 or more were injected under the same conditions as in the above (3). However, the latter obtained a solidified body having a solidification strength that 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-based water glass grouts were each infiltrated, and then the reactant aqueous solution was injected before these gelled, a homogeneous solidified body could not be obtained depending on the injection area, and sufficient strength was also obtained. I couldn't do it.

(6) When the non-cement-based reactive agent-mixing liquid was preliminarily impregnated into a water tank filled with sand, and then non-cement-based water glass grout exhibiting an alkalinity of PH9 or higher was injected under the same conditions as described above, it was found to be homogeneous and A solidified body with significantly improved daily strength was obtained.

(7) Cement grout or cement-water glass grout was previously poured into a water tank filled with sand, and then non-cement water glass grout exhibiting an alkalinity of PH9 or higher was injected under the same conditions as described above. No daily strength improvement of the conjunctiva was achieved.

(8) A non-cement-based reactant aqueous solution was preliminarily impregnated in a water tank filled with sand, and then cement-based grout or cement-water glass grout was injected under the same conditions as described above. Only sand gel was obtained.

The above-mentioned objects of the present invention are based on the background of (1) to (8) above. (A) A non-cement-based reactive agent compounding liquid has been previously injected into the ground as a primary injection, and (b) this compounding liquid is then injected. The non-cement-based water glass grout exhibiting an alkalinity of PH9 or more, which is mixed with the reactive agent, is superposed and injected as the secondary injection in the injection area of (2) and (2). This is achieved by using a multiple injection tube having a plurality of discharge ports at different locations.

That is, for the purpose described above, the multiple injection pipe is inserted into the ground, and then the injection pipe is moved upward to change the injection stage while performing the primary injection (a) from the upper discharge port and the lower discharge. This is achieved by overlapping secondary injections from the outlet.

In the above-mentioned present invention, when the primary injection material and the secondary injection material are directly mixed, a momentary setting state occurs, and although the inter-soil particle infiltration cannot be expected, the primary injection material is the injection pressure of the secondary injection material. It is pushed to the outer peripheral part by and is replaced by the secondary injection material and becomes covered with the secondary injection material. This is the same as the state where the solidified material of the secondary injection material is immersed in the reaction material mixture liquid at the time when the secondary injection material gels. Then, with the passage of time, the reactive agent penetrates into the solidified body of the secondary injection material and the unreacted water glass in the solidified body reacts with the reactive agent, and as a result, all the water glass in the solidified body is completely removed. And the polymerization of the silica component progresses over time, and the strength of the solidified body is enhanced.

Therefore, the primary injection material in the present invention is a non-cement-based reactive compounding liquid, and the secondary injection material is P.
A non-cement-based water glass grout exhibiting an alkalinity of H9 or higher is necessary for causing a reaction between soil particles, which allows the reaction of the primary injection material and the secondary injection material in the fine-grained soil layer. It will be possible.

The method of the present invention is specifically carried out using the injection pipe shown in FIGS. 1 and 2.

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

Then, as shown in FIG. 1 (b), the primary injection material is sent from the outer pipe 1 and injected into the ground through the upper discharge port 3, while the secondary injection material is sent through the inner pipe 2. Lower discharge port 4
While further pouring into the ground, the pouring stage is moved from the bottom to the top to superimpose the secondary pouring material on the region where the primary pouring material has been injected. 5 is a metal crown.

FIG. 2 is an example of another injection pipe. First, FIG. 2 (a)
As shown in FIG. 3, when the reagent mixture liquid is sent from the inner pipe 2 and the water is sent from the outer pipe 1, the valve 7 is displaced downward by the flow pressure of the inner pipe 2 to open the upper discharge port 3 and at the same time discharge the lower portion. The outlet 4 is closed, and the reactant mixture is injected into the ground through the upper outlet 3. Then, as shown in FIG. 2 (b), the feeding of the reaction mixture solution from the inner pipe 2 is stopped, and the non-cement-based water glass grout (secondary injection material) of PH9 or more is fed from the outer pipe 1. When the liquid is sent, the valve 7 moves 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, so that the secondary injection material is injected into the lower discharge port 4. Is injected into the ground. Then
By moving the injection stage from the bottom to the top, the secondary injection material is overlapped and injected into the area where the primary injection material is injected.
6 is a check valve.

In the injection pipe described above, the space between the upper and lower discharge ports 3 and 4 is
cm or more, preferably 30 cm or more, 4 m or less, preferably 3
It is within m. If the distance is 10 cm or less, it is not preferable because the injection material is always merged when the injection materials are simultaneously injected from the upper and lower discharge parts 3 and 4, and if the distance is 4 m or less, it is shown in FIG. In the initial injection stage as described above, it becomes difficult for the injection material from the upper and lower discharge ports 3 and 4 to communicate with each other through the space around the injection pipe.

Further, the method of the present invention is applied to FIGS. 3 (a), (b) and (c).
Will be specifically described. A is a multiple injection tube,
It is inserted into the ground. As shown in FIG. 3A, when the primary injection material is injected from the upper ejection port 3 and the secondary injection material is injected from the lower ejection port 4, the lower ejection port 4 is initially filled.
The secondary injection material from the above flows into the vicinity of the upper discharge port 3 through the gap 9, and both are mixed and reacted to form a quick-setting grout. Then, as shown in FIG. 3B, the grout has a gap 9 around the injection tube with the upper discharge port 3 as the center.
And permeates into the rough and weak parts of the ground, gels, and the ground is restrained by the gelled material B. After that, when the above-mentioned infiltration decreases, the primary injecting material and the secondary injecting material respectively infiltrate independently, the infiltration region C of the reaction material (primary injecting material) is formed in the upper ground, and the water glass mixture in the lower ground. A liquid (secondary injection material) permeation region D is formed.

That is, at this stage, in the vicinity of the upper discharge port 3, the gap 9 around the injection pipe and the rough portion of the ground have already been filled with the gelled substance B of the quick-setting grout, so that the primary injection material itself has a low viscosity. It penetrates into the coarse-grained soil portion without deviating to fill the voids between the soil particles without forming a solidifying agent, and forms a permeation region C of the reactant. On the other hand, in the secondary injection material discharged from the lower discharge port 4, since the voids above it are already filled with the gelled substance B of the quick-setting grout, the soil particles around the lower discharge port 4 do not deviate upward. It permeates between them to form a permeation region D of the water glass formulation liquid.

Next, while the multiple injection pipe A is moved upward and the injection stage is changed, the primary injection material is injected from the upper discharge port 3 and the secondary injection material is injected from the lower discharge port 4, respectively, as shown in FIG. 3 (C). As shown, the water-glass compounded liquid that is the secondary injection material is discharged from the lower discharge port 4 to the permeation area C of the reactant that has been previously permeated with the primary injection material, and the penetration area E is formed. In this case, the water-glass compounding liquid, which is the secondary injecting agent, penetrates the primary injecting agent (reactant compounding liquid) in the pores of the soil particles while pushing it out by the injection pressure. Although a gelled product is produced by the contact of the mixed solution, most of the voids between the soil particles are replaced by the water glass mixed solution by the water glass mixed solution which is sent out one after another.

As a result, a cylindrical permeation region E filled with the water glass compounding liquid is formed around the injection pipe A, gelling occurs on the peripheral surface thereof by the reaction with the reaction agent, and the outer side thereof is mixed with the reaction agent. A penetrating region F is created which is filled with liquid. However, the viscosity of the reaction mixture liquid is lower than that of the water glass mixture liquid, so that it penetrates into the permeation region E of the water glass mixture liquid from the outside for a long period of time to react with the unreacted silica content in the water glass mixture liquid. Eventually, all silica is completely gelled. In the method of the present invention, the final stage is the solidification reaction between the permeation region E around the injection pipe with the water glass compounding liquid and the reactant compounding liquid F existing outside thereof. This phenomenon at the final stage is extremely important from the viewpoint of improving durability.

Hereinafter, the present invention will be described in detail with reference to experimental examples.

Experiment 1 PH and gelation time of a mixed solution of water glass No. 3 and a reactant were measured, and the results are shown in Table 1.

Experiment 2 Test specimens (diameter 5 cm, length 5 cm, length) obtained by consolidating standard sand using the samples of formulation Nos. 6, 10, 13, 16 and 23 in Table-1.
The 10 cm) was measured SiO ₂ content of curing water and cured in tap water, thereby leaching for SiO ₂ the total amount of the consolidation chemical Si
The cumulative amount of O ₂ was measured to examine the daily change in the leaching rate.
(Table-2) The numbers in Table-2 are the leaching rate (%) / uniaxial compressive strength (kg / cm ² ). Moreover, in Table 2, "-" represents collapse.

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

Experiment 4 In the same manner as in Experiment 2, sand gel (consolidated standard sand), which was consolidated using formulation No. 10 was cured with 20 wt% solutions of various reactants, and the leaching rate of SiO ₂ after 28 days was measured. The strength was measured and the results are shown in Table 4.

Experiment 5 Portland cement in curing water was treated in the same manner as Experiment 2.
After mixing 100g, cure the formulation No. 10 sand gel,
Uniaxial compressive strength measured 28 days later was 1.6 kg / cm ²
showed that. From this, it is understood that the improvement effect on durability cannot be obtained.

Experiment 6 Using the same method as in Experiment 5, 00 cm ³ of the gelled product of formulation No. 11 was crushed and mixed in the curing water. In addition, 100 cm ³ of cement-water glass gel was crushed and mixed in curing water. Cement-water glass gelling composition per 100 cm ^{3 of} water glass No. 3 25 cc cement 50 g water balance.

When the uniaxial compressive strength of these materials was measured after 28 days, the compound No. 11 showed 1.5 kg / cm ² , and the cement-water glass gelation product showed 1.6 kg / cm ² . None of these could achieve the effect of improving durability.

Experiment 7 After saturating the sand in the water tank with 20% calcium chloride solution, injecting grout of the compound No. 15 and 16 until the water no longer penetrates with a head difference of 30 cm, and one week later, the size of the solid was examined. , Compound No. 15 has a diameter of about 20 cm, and compound No. 16 has a diameter of about 45 cm.
A consolidation diameter of cm was obtained, and Compound No. 16 shows a remarkable penetration effect.

When the same experiment was conducted using the compound Nos. 19 and 20, the diameter of the compound No. 19 was about 15 cm, and the diameter of the compound No. 20 was about 23 cm.

From the above, it was found that, under the same conditions, the permeation range was narrow when the pH was neutral, whereas the permeation range was extremely wide when the pH was 9 or higher. This is because the injection liquid is a water glass compounded liquid containing a gelling reaction agent and
When is alkaline, it is considered that the reaction between the reaction agent in the ground and the injecting liquid becomes slow due to the presence of the alkali in the injecting liquid.

Experiment 8 In the same manner as in Experiment 7, 20% by volume aqueous solution of No. 3 water glass and grout of formulation No. 21 were injected. Diameter 10 in the former
Inhomogeneous aggregates of ~ 25 cm were obtained, whereas the latter produced almost spherical aggregates with a diameter of 30 cm. The former uniaxial compressive strength was 5 kg / cm ² , whereas the latter one was 9.5 kg / cm ² .

From the above, it can be seen that the injected liquid is a mixed liquid having a pH of 9 or more and containing a gelling reaction agent in order to uniformly and firmly solidify.

Experiment 9 Saturate the sand in the water tank with 20% by volume aqueous solution of No. 3 water glass
After injecting a 20% calcium chloride solution with a water head difference of 30 cm, the strength of the solidified body around the injection hole was measured one week later, and it showed a uniaxial compressive strength of ² kg / cm ² . Similarly, after saturating the sand in the water tank with the formulation liquid of formulation No. 21, inject 20% calcium chloride solution before the formulation liquid gels and solidify around the injection hole one week later. When the body strength was measured, it showed a uniaxial compressive strength of 2.6 kg / cm ² .

When the reactant is injected after injecting the water glass mixture from this, the water glass mixture is extruded by the reactant to the outside, and the water glass concentration around the injection pipe becomes thin and the strength becomes low. In the opposite case as in Experiment 8, it can be seen that the reaction agent located in the peripheral portion gradually permeates the inside of the solidified body of the water glass compounded liquid around the injection pipe and the reaction proceeds.

Experiment 10 After injecting 500 gr of cement grout (50 g of cement per 100 cc, remaining water) or cement-water glass grout (same as in Experiment 6) into a water tank filled with sand, 1 grout of compound No. 10 was placed in the same place. After the injection, one week after the drilling, the uniaxial compressive strength was measured 28 days after the injection, and the results are shown in Table-5.

From Table-5, it can be seen that even if cement grout or cement-water glass grout is used as the primary injection material, the daily strength of the secondary injection material is not improved.

Experiment 11 After saturating the sand in the water tank with a 20% calcium chloride solution, 500 cc of cement grout and cement-water glass grout of Experiment 10 were injected and excavated one week later. No solids were obtained due to infiltration between soil particles. That is, it was found that such a method does not improve the consolidation effect due to the infiltration of soil particles.

The non-cement-based water glass compounded liquid having a pH of 9 or more according to the present invention is an arbitrary liquid water glass having a water glass molar ratio of 1 to 5, and further, an optional reaction agent such as an acid, a salt or an organic reaction agent. Is contained, or the reaction time and pH are adjusted by alkali or acid.

Further, the non-cement-based reaction mixture is an acid, an acid salt, an organic reaction agent, a salt exhibiting alkalinity (sodium bicarbonate, etc.), lime, etc., but a multi-valued metal salt is particularly preferable. Specific examples thereof include alkaline earth metal salts such as CaCl ₂ , MgCl ₂ , calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium sulfate and calcium phosphate, aluminum salts such as aluminum chloride and polyaluminum chloride, and other iron. For example, salt.

Example In a fine or coarse sand ground in Tokyo, using the injection pipe of FIG. 1, a calcium chloride compounded liquid of 20% concentration as the primary injection material is supplied from the upper discharge port 3 and as the secondary injection material. The compounding solution of compounding No. 10 is simultaneously injected from the lower discharge port 4 at an injection rate of 10 minutes per minute, and the injection stage is moved upward from below while pulling up the injection tube A at a rate of 10 cm per minute. Turned. The interval between the upper and lower discharge ports 3 and 4 was 1 m. The injection depth was set to GL-15 to 0 m, and the infiltration consolidation state of the GL-10 to -5 m section was investigated 10 days after the injection.

As a result, the rough part is filled with the instantaneous setting grout in a pulse shape,
A solid body with a substantially circular cross section is obtained, and the cross-sectional area is about 3
It was m ² . The uniaxial compressive strength of the solidified body near GL-7m was 6 to 7 kg / m ₂ . The water permeability test of the solid was 3.5 × 10 ^{−5 to} 4.2 × 10 ⁻⁶ / cm ² . From this, it is understood that the method of the present invention produced a uniform and strong solid body with a certain size.

〔The invention's effect〕

 The present invention described above can achieve the following effects.

(1) The daily strength of water glass grout in the alkaline region where the gelation time is long is significantly improved, and the durability of the solidified body is improved.

(2) Construction is extremely easy.

(3) The secondary injection material is prevented from deviating outside the injection range, and a homogeneous solidified body is obtained within a predetermined range.

[Brief description of drawings]

1 (a) and 1 (b) and FIGS. 2 (a) and 2 (b) each show a specific example of an injection tube and an injection state for carrying out the method of the present invention. 3 (a), (b), (c)
Shows an explanatory view of the permeation and consolidation state of the method of the present invention. 1 ... Outer pipe, 2 ... Inner pipe, 3 ... Upper discharge port, 4 ... Lower discharge port, 7 ... Valve, 8 ... Spring, 9 ... Gap, A
…… Injection tube, B ・ ・ ・ Gelted substance of quick-setting grout, C ……
Penetration area of reactant, D ... Penetration area of water glass compounded liquid,
E: Cylindrical permeation area, F: Reagent mixture

Claims (1)

[Claims] 1. A multi-injection pipe having a plurality of outlets at different upper and lower positions is inserted into the ground, and then the inlet pipes are moved upward to change the injecting stage and the non-cement system from the upper outlet. It is characterized in that the reagent mixture liquid is discharged and a mixture liquid of PH9 or more containing water glass as an active ingredient is discharged from the lower discharge port, whereby the water mixture is introduced into an area where the reagent mixture liquid has already permeated. A ground injection method characterized by infiltrating a compounded liquid containing glass as an active ingredient.