JPS5825129B2 - Composite grouting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite injection method using multiple injection pipes, and more specifically, multiple injection pipes that can homogeneously and firmly consolidate or watertight heterogeneous ground with an excellent packer effect. Regarding the composite grouting method by.

Soft ground is usually formed by a complex interposition of coarse-grained soil and fine-grained soil, but such ground can be homogeneously consolidated by injecting grout into the ground. It is necessary.

In addition, due to environmental conservation and water quality conservation issues in recent construction work, it is desired from the viewpoint of pollution prevention that the injected water glass grout solidify reliably at the point where it is injected without deviating from the injection target area. There is.

The following methods are conventionally known as methods for consolidating soft ground.

(1) Rod injection method This method uses a water glass aqueous solution (liquid A) and a reactant aqueous solution (liquid B).
This method uses a Y-shaped pipe to merge these liquids and press-fit them into the ground. Although this is an excellent method with a very simple process, it has the following drawbacks.

In other words, a gap is created between the boring rod and the ground, and the grout either squirts out onto the ground surface from this gap or deviates into a large gap, which causes the cloud to penetrate into the fine-grained soil area. becomes difficult.

On the other hand, if the gelation time of the cloud is accelerated to prevent this gushing or deviation, the grout will mainly penetrate in veins, and it will still be difficult to penetrate into narrow areas.

(2) Double pipe injection method This uses water glass as liquid A and a gelling agent as liquid B, and these are combined at the tip of a double pipe inserted into the ground, resulting in gelation in a short time. This is a method of injecting grout with a composition that hardens, and the gelation time is short, so
Although it is possible to prevent grout from spewing out above the ground along the area around the rod, because the gelation time is short, it can only consolidate in rough areas in the form of veins, and cannot penetrate into thin areas or between soil particles. Can not.

When excavating this reservoir, spring water or collapse of earth and sand is likely to occur.

(3) One-shot injection method In this method, a grout that takes a long time to gel is adjusted in a mixer and then injected.

Therefore, this method does not require the above-mentioned merging operation, and the water glass and reactant can be precisely mixed in advance and injected in a so-called one-shot method.
Moreover, since it is a solution-type chemical, it can be uniformly injected even into fine-grained soil. However, with this method, the gelation time of the grout is long, so it has good permeability, but there are large voids in the ground and coarse-grained soil. This may cause the injected grout to concentrate in that area.

For this purpose, the injection pipe with the rubber sleeve inserted outside is installed in the ground in advance, and the gap between the hole wall and the injection pipe is filled with cement to fix the injection pipe, and then the inner pipe is moved up and down inside the injection pipe. first injection of cementitious grout, then
A method of performing shot injection as a secondary injection is used.

The purpose of the present invention is to solve the above-mentioned drawbacks of the conventional construction method by using an injection pipe consisting of a large number of pipes, and to solidify these complex coarse-grained soil parts and fine-grained soil parts thoroughly and integrate them as a whole. The object of the present invention is to provide a method for consolidating soft ground that can easily perform composite injection in one step.

In order to achieve the above-mentioned object, according to the present invention, in a composite grouting method in which a plurality of grouts with different permeability are injected into the ground through an injection pipe to solidify the ground, a multiple pipe is used as the injection pipe, The multiple pipes are moved to form a space in the ground at the tip of the multiple pipes, and among the multiple grouts with different permeability, grout with poor permeability is injected into this space, and then the grout with poor permeability is injected into this space. It is characterized by injecting a grout with good permeability in an overlapping manner in an area into which grout with poor permeability has been injected, and among the plurality of grouts with different permeability, at least the grout with good permeability is filled with grout with poor permeability. It is characterized in that it is injected into the ground through the inner pipe protrusion of the multi-pipe, and is injected into the ground by breaking the filling material.

Hereinafter, the present invention will be specifically explained in detail.

As described above, the present invention relates to an injection method that enables composite injection in which multiple types of grout having different permeability are injected in the same injection area in an overlapping manner, and the present invention relates to an injection method that enables composite injection in which multiple types of grout having different permeability are injected in the same injection area, and A method of filling a grout with poor permeability into the gap between the filling material and the injection hole wall, and then breaking the filling material and injecting a grout with good permeability through the inner tube protrusion located within the filling material. It is related to.

The basic scheme of the composite injection according to the present invention is as follows.

In order to prevent the injected grout from escaping from the voids around the injection pipe, it is better to shorten the gelation time, but in this case the grout can only penetrate in veins, and during excavation, spring water and
Causes landslides.

On the other hand, in order for the grout to penetrate between the soil particles, it is necessary to increase the gelation time, but this causes the grout to deviate from the voids around the injection pipe.

It is impossible to solve these contradictory problems with a single type of injection material, such as the conventional rod injection method or double front injection method.

The present invention solves these contradictory problems by using multiple tubes to provide grout with poor permeability with the function of filling the voids around the injection tube with light to form a packer, and using grout with good permeability to fill the gaps between soil particles. This problem was solved by focusing on sharing the function of infiltrating the two, and also made it possible to continuously perform such composite injection in one process.

In this way, the present invention can carry out composite injection in one step, and the injection pipe is pulled up during injection and is not left in the ground. Therefore, the construction is simple and does not take much time, and there is no need for an injection pipe. Since there is no waste, it is possible to improve the ground not only technically but also economically.

The present inventor completed the present invention based on the above-mentioned basic idea regarding composite injection, and by the following method, with a focus on forming a seal having a particularly reliable packer function.

■ Inserting a multilayer injection pipe into the ground, using multiple grouts with different permeability, and moving the injection stage by moving the injection pipe, injecting the grout with poor permeability into the ground first. This forms a compact seal with a packer effect in the gap between the injection pipe and the ground and the gap around the injection pipe resulting from the movement of the stage, thereby allowing the highly permeable grout to flow along the gap around the injection pipe. In addition to preventing leakage in advance, grout with poor permeability is press-fitted into rough or weak parts near the stage and at the interface between layers to prevent grout with good permeability from deviating outside the specified range. After the sealing treatment, the seal is broken into the area where the grout with poor permeability was injected, and the grout with good permeability is injected in an overlapping manner to penetrate into the narrow areas where the grout with poor permeability could not penetrate. The grout with good permeability penetrates between the particles and solidifies, making it sticky.Since the grout with good permeability does not deviate from the area around the injection pipe or the rough layer, it can reliably penetrate the area to be injected and solidify. It is possible to tie

(2) Among the grout with poor permeability and the grout with good permeability, the grout with at least a slightly better permeability is injected from the inner pipe protrusion of the multiple pipe.

(2) Before the grout with good permeability is injected from the protrusion of the inner pipe, the grout with poor permeability is filled into the gap between the protrusion of the inner pipe and the wall of the injection hole.

A filling with a tsuka effect is formed.

(2) The highly permeable grout is injected into the ground through the inner pipe protrusion located in the filler, breaking through the filler.

(2) The above-mentioned filler having the packer effect is usually formed by using grout or suspension type grout whose gel-forming time is within 30 seconds.

The basic principle of the present invention is shown in FIG.

Figure a is a sectional view showing the state of the multi-layered pipe from which the inner pipe having the discharge port is protruding, and the ground state immediately before injection.

1 is the outer tube, 2 is the inner tube, 2' is the inner tube protrusion, 3 is the injection hole wall, 4 is the gap between the injection tube and the injection hole wall, 4a is the inner tube protrusion and the injection hole wall. The gap 4b between the soil layers is a boundary between soil layers, a rough part, or a weak layer.

In Figure b, when only grout with better permeability than the inner pipe protrusion is injected through such an injection pipe, the state of penetration of the grout is shown by arrows, and the state of solidification is shown by diagonal lines.

The grout spreads non-uniformly through 4.4a and 4b, resulting in non-uniform solidification as shown by the diagonal lines in area B, or the injected liquid deviates from the target area.

For this reason, it is not possible to solidify a predetermined injection stage in a constant shape.

However, as shown in Figure C, grout with poor permeability,
For example, if you inject instant grout or suspension type grout that has a gelation time of less than 30 seconds, this grout can only penetrate into large voids, rough areas that tend to deviate, and weak areas, so 4.4a and 4b will be the main focus. A consolidated region A is formed.

Then, as shown in figure d, if you inject a grout with good permeability, such as a grout with a long gelation time or a solution-based grout, 4.4a and 4b are already filled, so
Due to the action of the injection pressure, some cracks 5 are formed in the lateral direction where the filler is most vulnerable, and these cracks serve as a new source of penetration between the soil particles.

In the injection surge to be injected, the parts that tend to deviate are already filled with grout with poor permeability, so the grout with good permeability solidifies in a certain shape as shown in area B shown by diagonal lines at a predetermined stage. .

By moving the injection pipe and changing the injection stage in this way, it is possible to form a homogeneously consolidated injection ground with no unconsolidated parts.

As mentioned above, in the composite injection method, it is important to reliably form a seal with a packer effect around the injection pipe, but in the present invention, it is important to form a seal with a packer effect around the injection pipe. It is possible to form a seal with a reliably constant thickness corresponding to the difference in diameter between the wall and the inner tube projection, which has a smaller diameter than the outer tube diameter.

For this reason, the present invention can have a complete packer function, and has therefore succeeded in forming reliable solids at each injection stage.

The grouts used in the present invention include suspension type grouts containing cement or other suspensions as active ingredients, water-soluble reactants, any water glass grouts using suspension reactants, grouts in the neutral range, and acidic grouts. A grout whose main material is a non-alkaline silicic acid aqueous solution obtained by adding water glass to the liquid, or any other grout can be used.

As a combination of multiple grouts with different permeability, the combination of grout with poor permeability and grout with good permeability is based on the following silk combination.

(b) A combination of grout with a short gelation time and grout with a longer gelation time.

(b) Combination of suspension type grout and solution type grout.

Grout with poor permeability refers to grout with better permeability than the grout with poor permeability described above.

For example, if the gelling time is longer than that of the applied grout with poor permeability, or if the grout with poor permeability is a suspension grout, it is called a solution grout.

Therefore, if the grout with poor permeability is a suspended instant setting grout, it may be possible to combine it with an instant setting solution type grout.

The above grout is formed by mixing or merging a plurality of injection materials constituting the grout.

For example, water glass grout is obtained by mixing or combining a plurality of injection materials, such as a water glass solution and a reactant aqueous solution.

A grout with a short gelation time and a grout with a longer gelation time can be combined by using the same type of water glass and reactant and changing the concentration, or grouts with different gelation times can be combined by using an inorganic reactant. It is also possible to combine a water glass grout using a reactant that easily reacts with water glass, such as , and a reactant that reacts slowly with water glass, such as an organic reactant.

Alternatively, they can be combined by adding or discontinuing a reactant mixture to the water glass and reactant mixture.

Especially gelling time as grout with short gelling time is 3.
Grouting within 0 seconds is particularly effective for creating an effective gel film in the gap between the injection pipe and the soil to form a seal with a packer effect.

This not only prevents the injection liquid from flowing through the injection pipe and spewing out above the ground when injection liquid with a long gelation time is subsequently injected, but also prevents the injection liquid from forming a gel film at the position of the injection liquid discharge hole. rupture, allowing the injection solution with a long gelation time to penetrate into the soil layer at that stage.

If the gelation time of the grout exceeds 30 seconds, the grout will spray out from around the injection pipe to the above ground, making it impossible to create a tight gel film seal between the injection pipes. When injecting grout with a long gelling time,
Injection at a specified depth is likely to become impossible due to spouting out onto the ground surface from between the injection pipes.

Grouts with poor permeability that have a short gelation time can be prepared by combining a reactant aqueous solution with a water glass aqueous solution, or by combining a mixed solution containing an alkaline agent, cement, etc. with an acidic or neutral water glass aqueous solution. It can be obtained by combining a liquid containing a reactant with a liquid containing glass and a reaction wall, or by combining a liquid containing an alkaline water glass and a reactant with a liquid mixture that exhibits an acidic value by mixing water glass and an acid. It will be done.

Examples of grout with good permeability include the above-mentioned suspension grout, a mixed or combined liquid of water glass and a reactant mixture, and an acidic or neutral water glass liquid.

Conversion between grout with poor permeability and grout with good permeability can be achieved by changing the formulation of the reactant aqueous solution that is mixed with the water glass aqueous solution and changing the gelation time, or by changing the gelation time from grout with good permeability to grout with good permeability. This is done by combining or interrupting the combination of rapidly setting reactive agents and grouts with good permeability and mixed liquids that exhibit a different pH.

Example of silk combination of grout with poor permeability and grout with good permeability (I) Grout with poor permeability ■'Liquid: 1" liquid mixture adjusted to pH 1 by adding water glass to acid Liquid: Water glass aqueous solution■' The formulation is set so that when the and I// liquids are combined, they gel in 3 seconds.

Water glass is added to grout sulfuric acid with good permeability, the pH is adjusted to 3, and the formulation is determined so that the gelation time is 1 hour.

When LIII is combined, a grout with poor permeability that has a gelling time of 2 seconds is changed, and when it is switched to ■ and ■ and combined with ■, it is converted to a grout with good permeability that has a gelling time of 5 minutes.

(3) ■Liquid: Mix No. 3 water glass into the sulfuric acid aqueous solution [S
iO2] is 7 molar, pH is 1.0, and gelation time is 15.
Adjust the time mixture.

■Liquid: Sodium bicarbonate 10% liquid ■Liquid: No. 3 water glass aqueous solution 20% liquid The combined liquid of LITf is a grout with poor permeability that has a gelation time of 2 seconds, and if the merging of the liquids is interrupted, it will gel. time is 1
Convert to a permeable grout for 5 hours.

Furthermore, when the liquid (①) is replaced with the liquid (②) from the combined solution of I and In solutions, the gelation time is 10 minutes, and the grout has good permeability and has a pH of 5.5.

Suspension ① and ② combined liquid are suspended type grouts with poor permeability that have a gelation time of 5 seconds, and if the merging of ① liquids is interrupted, a grout with good permeability that has a gelation time of 15 hours is produced. Convert to grout.

Also, change the liquid ■ of the combined liquid to the liquid ■ Convert to a solution-type grout with good permeability that has a gelation time of 10 minutes and a pH of 5.5.

The multiple tube in the present invention may be any injection tube that can form an inner tube protrusion in the ground, and the present invention is of course not limited by the structure of the multiple tube tip.

For example, a double front double tube with a drilled part such as a metal crown attached to either end of the inner or outer tube, or an injection tube with multiple channels arranged in parallel inside the tube. After drilling a hole to a predetermined depth with this injection tube, even if an inner tube protrusion is formed due to the relative displacement r in the axial direction of the inner and outer tubes, or a multiple tube in which an inner tube protrusion has been formed is polled. It may be installed inside the hole.

Alternatively, injection may be performed while rotating either the inner or outer tube.

In the present invention, the outer tube refers to a tube outside the multiplex tube, and the inner tube refers to any tube within the outer tube.

Further, the discharge hole for the injection material or grout may be formed in the side wall surface of the inner tube, or may be formed in the end portion of the inner tube or the outer tube.

Further, a check valve may be provided at the discharge port of the inner pipe or between the inner and outer pipes.

Regarding the mixing of the injection materials, a grout with poor permeability or a grout with good permeability may be formed before the multipipe is installed and injected into the ground through either the inner pipe or the outer pipe, respectively.

In addition, multiple types of injection materials are mixed at the tip of the injection pipe through either the inner or outer pipe to form grout with poor permeability or grout with good permeability, and are injected into the ground. It's okay.

Also, the space between the inner and outer tubes at the tip of the multiple tubes is closed so that grout with better permeability is discharged from the tip through the inner tube, and grout with lower permeability than the outer tube is injected. It's okay.

In any case, at least when injecting the grout with good permeability, the effect of the present invention can be achieved if the grout with good permeability is injected into the surrounding area through the protrusion of the inner pipe located in the filling with grout with poor permeability. can be obtained.

Furthermore, in the present invention, after a grout with a short gelation time is injected at each stage, a grout with a long gelation time is injected after gelation of the grout is completed, that is, after the flow has completely stopped. things can have a greater effect.

For example, if you inject grout that takes 5 seconds to gel, then wait 10 seconds to stop and then inject grout that takes more than 5 seconds, for example 10 minutes, the gel film will completely form at each stage. This is because grout, which takes a long time to gel after the seal is formed, breaks through the membrane at the injection depth and penetrates into the surrounding area.

As described above, the present invention is based on using multiple pipes and injecting multiple grouts with different permeabilities into the ground to be injected in a superimposed manner while changing the injection stage by moving the multiple pipes. This was born out of the conventional idea that ``it is desirable to improve the ground by injecting the gel time chemical solution that is most suitable for the type of soil layer that makes up the ground.'' This technique is essentially different from the "technique that attempts to selectively inject grout with the most suitable gel time for each soil layer."

The present invention starts from the viewpoint that in reality, there is likely to be an optimal gelling time for a certain soil layer constituting the injection ground.

In other words, each soil layer itself of each soil layer that makes up the ground is
Even if the soil quality and permeability are constant, in actual injection work, the injection hole is drilled vertically through each soil layer, creating a void around the injection pipe, so the permeability of the target soil layer remains constant. I can't help it.

Therefore, even if a chemical solution with a specific gelation time is injected, it will either deviate or partially solidify, so there is no such thing as an optimal gel time for that soil layer. be.

In this way, the inventor of the present invention avoided the foolish practice of forcing humans to force a specific gel time onto the ground, and instead injected multiple grouts with different gelation times into the target ground, overlapping the grouts, thereby achieving the desired result. The areas that accept grout with poor permeability solidify with it, and the areas that accept grout with good permeability solidify with it, so that the ground itself becomes the main body. It provides a technology that automatically consolidates the entire soil layer, and can be said to be an injection method that is compatible with the laws of nature.

As a result, it is possible to infiltrate the grout between particles and replace it with pore water without destroying the skeletal structure of the soil, which is the essence of the ground injection method, and solidify it by replacing it with pore water. It becomes possible to maintain continuity between bodies and prevent deformation of the ground and surrounding structures through low-pressure injection.

[Brief explanation of the drawing]

Figure 1a is a cross-sectional view showing the state of the multiple pipes with protruding inner pipes having discharge ports and the ground condition immediately before injection. FIG. 1C is a diagram showing the situation when only grout with poor permeability is injected, and FIG. 1D is a diagram showing the situation when both are injected. 1... Outer tube, 2... Bent inner tube, 2'... Bent inner tube protrusion, 3... Injection hole wall, 4, 4a, 4b, Curved, gap, 5・・・・・・Warisaki.

Claims (1)

[Claims] 1 In a composite grouting method in which multiple grouts with different permeability are injected into the ground through injection pipes to solidify the ground, multiple pipes are used as the injection pipes, and the multiple pipes are moved to form the tip of the multiple pipes. A space is formed in the ground, and among the plurality of grouts with different permeability, a grout with poor permeability is first injected around this space, and then a grout with good permeability is injected into the area into which the grout with poor permeability is injected. The grout is injected in a layered manner, and among the plurality of grouts with different permeability, at least the grout with good permeability is injected into the filling with the grout with poor permeability through the inner pipe protrusion of the multi-pipe. A composite grouting method characterized by the grouting method being injected into the ground by breaking the filling material between the grout and the grout.