JPS61162623A - Ground impregnation method - Google Patents

Abstract

PURPOSE:To perform optimum ground impregnation, by a method wherein, after an inorganic salt blended solution is poured into a ground, a water-glass blended solution is impregnated through a lower discharge port, and a multiple pipe is lifted up as said process is repeated. CONSTITUTION:After a double pipe A, formed a outer pipe 1 and an inner pipe 2, is penetrated into a ground down to a given depth, an inorganic salt blended solution, such as calcium chloride, is impregnated into a ground through an upper discharge port 4 of the outer pipe 1. By pouring a water-glass blended solution into a ground through a lower discharge port 3 of the inner pipe 2, inorganic salt is reacted with water-glass to prepare polyvalent metallic silicate, and a ground is solidified. The double pipe A is gradually lifted up to a given height, and a ground is improved through repetition of the above process. This enables free control of a pouring time of water-glass to the impregnated inorganic salt solution, and permits to perform optimum impregnation.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a ground injection method? , in detail, relates to a ground injection method that not only improves permeability but also produces homogeneous and strong solidified material.

[Prior art and its problems]

Generally, in order to achieve the purpose of ground injection, it is necessary to increase the permeability of the ground consolidation solution (grout) and increase the consolidation strength.

When consolidating the ground, a conventional method is known in which grout, which is water glass with an inorganic reactant added, is injected into the ground.

It has been difficult to simultaneously satisfy both the above-mentioned permeability and consolidation strength with water glass grout using such an inorganic reactant. In other words, in order to increase the consolidation strength, it is necessary to increase the water glass concentration and add a sufficient amount of reactant to the water glass to precipitate the silica content in the water glass. If the concentration of is high and the amount of reactant is large, gelation time becomes short and good permeability cannot be obtained. Also, if the amount of reactant is reduced,
Although the gelation time becomes longer, unreacted water glass remains in the gel and is eluted over a long period of time, which not only reduces the consolidation strength but also changes the quality of groundwater.

As a means to solve the above-mentioned problem, a construction method using injection pipe B shown in the third figure has been considered. As shown in the third figure, there are many strainers 10, 10...1 at the tip.
0 is drilled into the ground while injecting an aqueous solution of calcium chloride, and then pulled up while injecting water glass. Calcium may have deviated, or the timing of injection of water glass into the calcium chloride region may differ depending on the depth, so the diffusion state into the Sakai disk is not constant, and the solidification state is therefore non-uniform. 0 [Object of the Invention] The purpose of the present invention is to be able to control the injection timing of water glass to a pre-injected inorganic salt compound solution to a predetermined value for each injection stage, and as a result, the infiltration is reduced. The object of the present invention is to provide a ground injection method which improves the above-mentioned drawbacks and which not only improves the properties but also obtains a homogeneous and strong consolidated material. According to , multiple pipes with discharge ports at different locations along the axis are installed in the ground,
By injecting the inorganic salt mixture (secondary injection material) into the ground from the upper outlet and the water glass mixture (secondary injection material) from the lower outlet, and moving the multiple pipes upward, According to the present invention, the interval between the upper discharge port and the lower discharge port is determined to be constant, and the speed at which the injection stage is pulled upward, - the next injection is changed. The injection amount of the material or the injection amount of the secondary injection material can be controlled to any predetermined value, and a homogeneous and strong consolidated material can be obtained over a wide area in the ground. [Detailed description of the invention] Below, The present invention will be specifically explained using the accompanying drawings.

FIGS. 1(a), (b), (c) and (d) show process diagrams for carrying out process i of the present invention. A is a double tube used in the present invention, 1 is an outer tube, and 2 is an inner tube. 0 and 1 injected into the ground from
In Figure (b), the water glass mixture is fed from the inner pipe 2 and injected into the ground from the lower discharge port 3.

In Figure 1(c), the injection stage is changed by pulling up and moving the injection pipe A, and the inorganic salt mixture is injected into the ground from the upper discharge port 4 in the same way as in Figure 1(a). 4. FIG. 1(d) shows a state in which the water glass mixture is being injected from the lower discharge port 3, similar to the fa1 diagram (bl).

As shown in FIGS. 1(a) to (dl), the inorganic salt compound liquid is discharged from the upper discharge port 4 at a predetermined concentration and at a predetermined speed, and the water glass compound liquid is discharged from the lower discharge port 3. The liquid is discharged at a predetermined speed to achieve a predetermined concentration, and the injection tube A is raised at a predetermined speed.

In this manner, the present invention solidly consolidates the ground while changing the stage from the bottom to the top of the ground. .

In addition, in the present invention, the triple pipe shown in Fig. 2 can be used as a substitute for the double pipe shown in Fig. 1. In other words, in Fig. 2,
Inject the inorganic salt mixture through the outer tube 1 and the inorganic salt mixture through the port 1a, and water through the inlet port rb of the inner tube 1', and mix both outside the injection tube through the upper discharge ports 4' and 4', respectively. Then, the water glass mixture is sent from the inlet (2) of the inner pipe 2 and injected into the ground from the lower outlet 3.

Further, the injection pipe used in the present invention may be a double pipe in which a valve that can be moved up and down by fluid pressure is installed in the inner pipe line. (not shown).

The inorganic salts used in the present invention are, for example, as shown below, and among these, polyvalent metal salts are particularly preferred because they react with water glass to form insoluble polyvalent metal silicates.

Inorganic salts = (acidic salts, neutral salts, basic salts, etc.) calcium chloride, sodium chloride, agnesium chloride, potassium chloride,
Chlorides such as aluminum chloride, sulfates such as calcium sulfate, sodium sulfate, aluminum sulfate, aluminates such as sodium aluminate, potassium aluminate, hydrochlorides such as asimonium chloride, zinc chloride, aluminum chloride, sodium chlorate, Chlorates such as potassium chlorate, sodium perchlorate, potassium perchlorate, carbonic power 4
．． 4. Potassium carbonate 4, carbonates such as sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, calcium carbonate, magnesium carbonate, bisulfate)
Bisulfates such as IJum, potassium bisulfate, and ammonium bisulfate; bisulfites such as sodium bisulfite, potassium bisulfite, and ammonium bisulfite; silifluorosilicates such as sodium silicofluoride and potassium silicofluoride; alkaline earth metal salts; Silicates such as aluminum salts, borates such as sodium borate, potassium borate, ammonium borate, sodium hydrogen phosphate, potassium hydrogen phosphate,
Hydrogen phosphates such as ammonium hydrogen phosphate, bisulfates such as sodium pyrosulfate, potassium picosulfate, and ammonium pyrosulfate; pyrophosphates such as sodium birophosphate, potassium birophosphate, and ammonium birophosphate; sodium dichromate; Dichromates such as potassium chromate and ammonium dichromate, permanganates such as potassium permanganate and sodium permanganate, etc.

Also, as water glass, the molar ratio (5iOz/M*0)
:1.5-5.0 Alkali metal salt of silicic acid in any molar ratio including liquid water glass, anhydrous water glass, water-use water glass, crystalline water glass, etc., or an alkali metal salt of silicic acid and a silicic acid composition. Mixtures with any alkali may be used.

In addition, the water glass mixture liquid according to the present invention may contain, for example, a substance that does not react with water glass, such as sodium carbonate, but delays the reaction between water glass and the inorganic salt mixture liquid, or a substance that solidifies the ground even more, such as sulfate. A binding substance or phosphoric acid 2
A substance exhibiting a buffering effect such as sodium can also be used in combination.

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

Experimental method A comparative experiment was conducted by filling a large mold with a diameter of 2 ms and a height of 3 m and saturated with tap water. 01, Injection method 1-1 Strainer-injection method (Figure 3) ■-2 Double Pipe rod construction method (Figure 1) 2. Secondary injection material 2 1 A202330% solution.

2-2 CaCLB 3ON solution.

2-3 NaHCOs 3ON solution @2-4 Mixed with cement grout 100: Bortland cement 20#, remaining water.

' 2-5 Water glass-cement grout 10
0: Blend A@8 Confluence gelation time: 1 minute.

3. Secondary injection material (per IDO) No. 3-13 water glass Volume capacity % No. 3-23 water glass, 3 ot Sodium carbonate 3 Cooling water Rich 0 No. 3-33 water glass (Capital) Disodium phosphate in capacity 3. Carp water left ◇ 4. Injection amount and injection stage For both primary and secondary injections, the injection stages were set at 0.5 m intervals, and 50 tons per stage was injected.

Strainer: 5 people move the injection tube at a speed of 50 minutes per second, inject the next injection material at a rate of 101 per minute for each injection stage, and: do the same while pulling up the injection tube. The secondary injection material was injected at each injection stage at a rate of 10 t/min.

In addition, in the double pipe rod method, the upper discharge port is located 50 plots higher than the lower discharge port, and after first installing the double pipe in the ground, the primary injection material is pumped through the upper discharge port at a rate of 50 meters per minute. After injecting at a high speed, the secondary injection material was injected from the lower discharge port at a speed of 50 tons per minute, and the injection tube was pulled up 50 cm at a time and the above process was repeated. Table-1
Therefore, in 1-1, the interval between -water injection and secondary injection becomes longer in the upper part of the ground, and the permeation and reaction of primary injection and secondary injection do not occur in a regular, constant state at each injection stage. ,
Therefore, it can be seen that a homogeneous reaction was not carried out in the upper part #1. Therefore, unreacted water glass was significantly eluted, and the strength was also significantly reduced.

On the other hand, in 1-2, the injection stage moves from the bottom to the top, and the interval between the primary injection and the secondary injection can be maintained constant for each injection stage, and the -second injection material and the secondary injection material can be accurately measured. Since the water glass can penetrate and mix into the ground, a reliable reaction takes place.As a result, uniform and strong consolidation strength can be obtained from the top to the bottom of the ground, and there is little leaching of unreacted water glass. 0 Experimental results in which the strength increases significantly over time - 2 Table 2 shows the 0 results of a comparative test based on the difference in primary injection materials -
The 0 injection force formula shown in 2 is the same as the experimental result-1. The depth of sampling was carried out in the area where the secondary injection material had penetrated, rather than in the area where it had solidified.The depth of sampling was GL -2.0m.
As shown in Table 2x, 2-4.2-5, it is completely ineffective to use primary injection materials that do not penetrate between soil particles, or that gel and prevent salt from penetrating into the surrounding area. %, it can be seen that polyvalent metal salts are excellent as secondary injection materials.

Experimental Results-3 Table-3 shows the experimental results regarding the types of secondary injection materials. The injection method is the same as in Experimental Results-1. From Table 3, in the case of 3-2.3-3, the reaction between the primary injection material and the secondary injection material takes place slowly, resulting in homogeneous solidification. death,
Therefore, it can be seen that the consolidation strength is excellent.〇 [Effects of the Invention] As described above, the present invention uses multiple pipes to inject the inorganic salt mixture liquid from the upper outlet and the water glass mixture liquid from the lower outlet. Since the water glass is injected into the ground, the timing of injecting the water glass into the inorganic salt mixture that has been injected in advance can be controlled to a predetermined value for each injection stage. It is possible to obtain a strong consolidated product, and this invention is extremely useful in practice.

[Brief explanation of drawings]

Figures 1 (a), (b), (C), and (d) show process diagrams of the method of the present invention, Figure 2 shows an example of the triple pipe used in the present invention, and Figure 3 shows the conventional construction method. The injection pipe used in the construction method is shown. A, B... Injection tube, 1... Outer tube, 2... Inner tube, 1
'...middle pipe, 3...lower outlet, 4...upper outlet. Patent applicant: Reinforced Earthwork Engineering Co., Ltd.

Claims (1)

[Claims] Multiple pipes having discharge ports at different locations in the axial direction are installed in the ground, and the inorganic salt compound liquid is injected into the ground from the upper discharge port and the water glass compound liquid is injected from the bottom discharge port into the ground. A ground injection method characterized by changing the press-in stage in the injection by moving the pipe upward.