JP2001131952A - Injecting method of ground improving agent and injecting device used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure the strength of the ground by preventing an injected chemical from intruding in a uninjection area and hardening to sufficiently inject the chemical in the ground. SOLUTION: An expansible packer 1 having liquid permeability is used, and prior to the injection of the chemical through an injection pipe 2, a permeable injecting material 33 having a relatively short hardening time is injected into the packer 1 to expand the packer 1. The permeable injecting material 33 is leaked from the expanded packer 1, injected into a ground 30 and hardened. When the chemical 34a is injected to an injection space 37 through the injection pipe 2, the chemical 34a permeates into the ground 30. However, the hardened layer of the injecting material 33 forms a barrier wall to prevent the chemical 34a from penetrating into the uninjected circumference of the space 37 and hardened, so that the penetration of the chemical 34b to be injected later to the ground 30 is never prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for injecting a ground improvement material used for ground improvement work for liquefaction countermeasures and the like.

[0002]

2. Description of the Related Art For example, in the case of a ground composed of a gravel layer, there is a possibility that a liquefaction phenomenon may occur due to the occurrence of an earthquake or the like. Be taken. This method is called an injection method, in which an injection device is inserted into an excavation hole, a chemical solution as a ground improvement material is injected, and this is penetrated into the ground and hardened to strengthen the ground.

FIG. 6 is a sectional view showing a sleeve injection method which is an example of a conventional injection method. In the figure, 101
Is a ground made of a gravel layer, 102 is a drilling hole excavated in the ground 101, and 103 is an injection device inserted into the drilling hole 102. The injection device 103 includes a sleeve pipe 104 and an injection pipe 105 inserted into the inside of the sleeve pipe 104. The sleeve pipe 104 has a chemical liquid inlet 106 formed therein. Cylindrical rubber sleeve 10 to cover
7 is mounted on the outer periphery. The rubber sleeve 107 has a slit 108 formed therein. Further, the injection pipe 105 is provided with a rubber
9 and 110, and a discharge port 111 for the chemical solution.
Is provided. Reference numeral 112 denotes a sealing material filled between the sleeve pipe 104 and the excavation hole 103, and reference numeral 113 denotes a seal material injected from the slit 108 of the rubber sleeve 107.
01 is a chemical solution injected into the interior of the device.

[0004] Next, the construction procedure of the ground improvement work using the above-described pouring device 103 will be described. First, an excavation hole 102 is formed in the ground 101 by boring.
This boring is performed using a casing pipe (not shown). When boring is performed to a predetermined depth and the casing pipe is buried in the soil, a sealing material 112 such as CB (cement / bentonite) is then injected into the casing pipe. Subsequently, the sleeve pipe 104
Is inserted into the casing pipe, and the casing pipe is pulled out from the excavation hole 102 before the sealing material 112 is hardened. As a result, as shown in the figure, the sealant 112 is filled between the sleeve pipe 104 and the borehole 102.

[0005] Next, the injection pipe 105 is inserted into the sleeve pipe 104. Then, a chemical solution is introduced into the injection pipe 105 from the outside, and when this chemical solution is ejected from the discharge port 111 through the injection port 106 and the slit 108 at a predetermined pressure, a crack is generated in the sealant 112 by the pressure. Therefore,
The injected chemical solution 113 passes through the crack and
The ground 101 is reinforced by permeating the first gravel layer and hardening the permeated chemical solution 113.

However, in the above-mentioned conventional method, the sealing material 11 is provided between the sleeve pipe 104 and the drill hole 102.
2 is interposed, and the chemical solution 113 is injected into the ground 101 through the cracks in the sealing material 112.
3 has a disadvantage that the permeation area is small and the permeation takes time. However, in order to shorten the infiltration time, the injection amount of the chemical should be increased, but if the injection amount is too large, the injection pressure may cause the ground 101 such as a gravel layer to collapse. Has limitations.

[0007] On the other hand, a construction method is considered in which an injection space is formed between the packers by expanding the packer, and a chemical solution is injected into this space and penetrates into the ground. FIG. 7 shows this method, in which an injection device provided with a packer 1 and an injection pipe 2 is inserted into an excavation hole 31 formed in the ground 30 as shown in FIG. Inject gas or other gas to expand the packer 1,
An injection space 37 isolated by the packer 1 is formed. Thereafter, a chemical solution is supplied to the injection pipe 2 and injected into the injection space 37 from the discharge port 22 to allow the chemical solution 34 to penetrate into the ground 30 as shown in FIG.

According to this, a wide injection space 37 is formed between the injection pipe 22 and the ground 30, and the chemical solution 34 injected into the injection space 37 comes into direct contact with the ground 30 with a wide contact area and quickly penetrates. Therefore, a large amount of the chemical solution 34 can be injected into the injection space 37 without breaking the ground 30, and the injection speed can be increased to improve construction efficiency.

[0009]

In the construction method shown in FIG. 7, in order to prevent the ground 30 from being lifted by the injection pressure of the chemical solution 34, the chemical solution 34 is not simultaneously injected into each of the injection spaces 37. For example, a two-stage construction may be performed, in which every other injection is initially performed and then the remaining part is injected. When the ground 30 is composed of a plurality of layers, there may be a case where a construction is performed in which a chemical solution is individually injected under conditions suitable for each layer. In such a case, if the chemical solution injected first penetrates into the periphery of the space where no chemical solution is injected and hardens, the chemical solution injected later is impeded from penetrating into the ground, and the permeation diameter becomes small, which is satisfactory. The required ground strength cannot be obtained.

[0010] Therefore, a main object of the present invention is to prevent the injected chemical liquid from entering the uninjected area and harden, and ensure that the chemical liquid to be injected later penetrates sufficiently into the ground to secure the strength of the ground. Is to do.

[0011]

In order to solve the above-mentioned problems, a method for injecting a ground improvement material according to the present invention uses an expandable packer having liquid permeability and compares the curing time inside the packer. Injecting a ground-improving material from a pouring pipe after injecting a short permeable injection material to expand the packer, penetrating the injection material into the ground through the packer and hardening the material.

In this manner, a hardened layer of the injection material is formed on the ground around the packer, and the hardened layer serves as a partition wall, thereby preventing the ground improvement material to be subsequently injected from entering the non-injected region. Can be blocked.

Further, in the injection method of the present invention, it is preferable that the permeable injection material is injected into the inside of the packer so as to penetrate into the ground, and then the suspension type injection material is injected into the packer and cured. By doing so, the packer is filled with the filling material therein and firmly adheres to the ground, so that the ground improvement material injected into the filling space can be prevented from leaking into the adjacent filling space.

Further, in the injection device of the present invention, it is preferable to perform a water stopping process such as rubberization on both sides of the packer. By doing so, the permeable injection material filled in the packer oozes out only from the portion in contact with the ground, and permeates the ground without waste.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. FIG. 1 is a view showing an apparatus for injecting a ground improvement material according to the present invention, wherein (a) is a front sectional view,
(B) is a side sectional view. In the figure, reference numeral 1 denotes an inflatable packer provided at a predetermined interval, and 2 denotes a ground improvement material injection pipe provided continuously with the packer 1, and a plurality of these pipes are provided alternately. The packer 1 is provided with a main body 3 which is caulked and fixed at both ends to fixtures 5a, 5b by caulking rings 4a, 4b, respectively. The main body 3 is made of a material having liquid permeability, and a cloth is used here. In addition, although the fixtures 5a and 5b are formed of resin such as plastic, they may be formed of metal instead.

Inside the packer 1, a hose 6 for supplying a fluid for expanding the packer 1 and a hose 7 for supplying a ground improvement material to the injection pipe 2 are accommodated. , 7 are inserted into a flexible pipe 12 made of a flexible resin material. Both ends of the flexible pipe 12 are fixed to the fixtures 5 a and 5 b by caulking 13.

The injection pipe 2 includes a flexible strainer 20 having a plurality of discharge ports 22 for injecting the ground improvement material on a peripheral surface thereof, and a mesh sheet 23 mounted on an outer periphery of the flexible strainer 20. Fixing tools 5 at both ends by caulking 21a, 21b
a, 5b. Flexible strainer 2
Numeral 0 is made of a flexible resin material like the flexible pipe 12, whereby the whole becomes a flexible device and can be wound up. The mesh sheet 23 is
It is made of a thin resin material in which mesh-like pores are formed such that sand in the soil does not enter the inside. The hoses 6 and 7 that communicate with the hoses 6 and 7 in the packer 1 are housed inside the injection pipe 2.

As shown in FIG. 1 (b), a plurality of hoses 6 and hoses 7 are housed inside one packer 1 and injection pipe 2, respectively. Provided, each hose 6 is independent so that fluid can be individually supplied to the corresponding packer 1. On the other hand, the hoses 7 are also provided corresponding to the respective injection pipes 2, and the respective hoses 7 are independent so that the ground improvement material can be individually supplied to the corresponding injection pipes 2.

As shown in FIG. 1 (a), the hose 6 inside the packer 1 has a fixture 5a at one end and a fixture 5b at the other end.
And a passage 6a formed in the fixture 5a.
And is connected to a passage 6b formed in the fixture 5b. Also, the hose 7 has one end supported by the fixture 5a and the other end supported by the fixture 5b, and is connected to a passage 7a formed in the fixture 5a.
It is connected to a passage 7b formed in the fixture 5b. According to such a structure, the length of the packer 1 can be freely adjusted at the manufacturing stage according to the geology.

On the other hand, the hose 6 inside the injection pipe 2 has one end supported by the fixture 5b and the other end supported by the fixture 5a, respectively.
It is connected to the passage 6b formed in the fixture 5b, communicates with the hose 6 inside the packer 1, and is connected to the passage 6a formed in the fixture 5a. The hose 7 inside the injection pipe 2 is also supported at one end by the fixture 5b and at the other end by the fixture 5a, and connected to the passage 7b formed in the fixture 5b.
And is connected to a passage 7a formed in the fixture 5a. According to such a structure, the length of the injection pipe 2 and thus the distance between the packers 1 can be freely adjusted in the manufacturing stage according to the geology.

Thus, the hose 6 and the passages 6a, 6
b forms an expansion fluid supply passage, and the hose 7 and the passages 7a and 7b form a ground improvement material supply passage. One of the passages 6a in the fixture 5a has an opening 8 at an end thereof communicating with the internal space 9 of the packer 1, and is supplied from the hose 6 and the passages 6a and 6b corresponding to the packer 1. The expansion fluid is sent from the opening 8 into the internal space 9 to expand the packer 1. Therefore, the plurality of packers 1 can be individually inflated by the fluid supplied from the independently provided inflation fluid supply path. In this case, the hoses 6 and 7 are connected to the flexible pipe 1
2 protects the packer 1 from internal pressure. A check valve 10 is provided in front of the opening 8 of the passage 6a.

On the other hand, one of the passages 7b in the fixture 5b has an opening 11 at its end communicating with the internal space 24 of the injection pipe 2, and the hose 7 and the passage 7a corresponding to the injection pipe 2 are provided. , 7b supplied from the ground improvement material
1 to the internal space 24 and is discharged from the discharge port 22. Therefore, the plurality of injection pipes 2 can individually discharge the ground improvement material supplied from the ground improvement material supply passages provided independently corresponding to the respective injection pipes 2.

Next, a description will be given of a pouring method in the case of performing a ground improvement work using the pouring apparatus having the above-described configuration. FIG. 2 is a process chart showing an example of the injection method according to the present invention. First, as shown in FIG. 2A, the injection device shown in FIG. 1 is vertically inserted into an excavation hole 31 formed in the ground 30 by boring. Reference numeral 32 denotes a pipe through which the above-described hoses 6 and 7 are inserted. Here, since the ground 30 is formed of a gravel layer, boring using a casing pipe (not shown) is preferable to form the excavation hole 31. The depth of the excavation hole 31 is, for example, 15 m to 20 m, and the hole diameter is, for example, about 12 cm.

Next, when the injection material is supplied from the outside of the pipe 32 through the hose 6, as shown in FIG.
3 is injected and filled into the inside of the packer 1 from the opening 8, whereby the packer 1 expands. Here, a permeable injection material having a relatively short curing time (gel time) is supplied as the injection material. As such an injection material, for example, a water glass type, a silica sol type or a silica type injection material is used. In addition, since the check valve 10 is provided in front of the opening 8, the injection material 33 filled in the packer 1 does not flow backward.

When the packing material 1 is filled and the packer 1 expands, the packer 1 comes into close contact with the inner surface of the excavation hole 31 as shown in FIG. An injection space 37 into which the material is injected is formed.
Further, as described above, since the main body 3 of the packer 1 is made of cloth, as shown in FIG. 3, the filling material 33 filled in the portion in contact with the ground seeps through the main body 3. The exuded injection material 33 permeates into the gravel layer of the ground 30 as shown in FIG. In this case, the setting time of the injection material 33 is short, and the injection material 33 is hardened in about several minutes. This hardened layer has a permeation diameter of, for example, 0.5 m to 1 m, and serves to prevent the ground improvement material described later from invading another region.

In a preferred embodiment, a suspension type injection material is supplied from outside the pipe 32 through the hose 6 and the injection material 35 is opened through the opening 8 as shown in FIG.
And then into the packer 1 and filled. Such a suspension type injection material 35 is, for example, LW (Labires Wasserglas) which is a mixture of water glass and a cement suspension.
Is recommended. Since the curing time of the LW is about 30 seconds to 3 minutes, the injection material 35 filled in the packer 1 is cured in a short time. Here, since the cement is mixed in the injecting material 35, the fabric of the main body 3 of the packer 1 is clogged with the cement, and the water glass can be prevented from seeping out through the fabric. Thus, the injection material 3
The packer 1 filled with 5 is pressed against the inner wall of the borehole 31 to shield adjacent injection spaces 37 from each other.
It also has the function of reinforcing the ground 30.

Next, a ground improvement material is supplied from the outside of the pipe 32 through the hose 7 and is fed into the internal space 24 of the injection pipe 2 from the opening 11 through the passage 7b in FIG. The liquid is discharged from the discharge port 22 through the mesh sheet 23 and injected into the injection space 37. In this case, the ground improvement material may be injected into all the injection spaces 37 at the same time. However, in this case, the water pressure in the ground 30 may be too high and the ground 30 may be lifted, as shown in FIG. , For example, 1
It is preferable to inject a ground improvement material every other ground. The ground improvement material injected into the injection space 37 is prevented from leaking into the adjacent injection space 37 with the packer 1 serving as a partition.

As the ground improvement material, it is preferable to use a durable, highly permeable chemical such as a solution type water glass system, a silica sol system, or an ultrafine silica system having a long curing time.

The chemical solution 34a injected into the injection space 37 is
As shown in FIG. 2 (c), it penetrates into the gravel layer on the ground 30.
Here, the sealing material 112 as shown in FIG.
Does not exist, and the vertical dimension of the injection space 37 can be set to, for example, about 0.75 m to 1 m.
Solution 34a injected into the ground 30 directly over a large contact area.
And has high permeability.
It quickly permeates the ground 30.

Subsequently, the remaining injection space 3 where the chemical solution has not been injected yet.
7, the same chemical solution 34b as the chemical solution 34a is injected in the same manner as described above. Here, when the previously injected chemical solution 34a enters the periphery of the space 37 into which the chemical solution has not been injected and hardens, the penetration of the chemical solution 34b which is injected later is impeded, but as shown in FIG. A hardened layer of the injecting material 33 is present around the surrounding area, so that the hardened layer serves as a partition wall and can prevent the chemical solution 34a from entering the non-injected region.

The chemical solution 34b injected later penetrates into the ground 30 as shown in FIG. 2D similarly to the previous chemical solution 34a, and the chemical solutions 34a and 34b (collectively indicated by 34) are finally formed. Then, as shown in FIG. 2 (e), it penetrates into a wide area around the excavation hole 31 and hardens. Thereby, the gravel layer of the ground 30 is solidified and strengthened by the chemical solution 34. And since the chemical liquid 34 is durable and does not deteriorate over a long period of time, it exerts great power in liquefaction countermeasures.

Although FIG. 2 shows an example in which the ground 30 is composed of a single gravel layer, when the ground 30 is composed of a plurality of layers, the injection conditions (chemical solution) suitable for the geology of each layer are used. , Injection speed, injection pressure, etc.).

FIGS. 5A and 5B show another embodiment of the packer used in the above-mentioned method, in which FIG. 5A is a front view and FIG. 5B is a sectional view. Here, both sides of the cloth main body 3 of the packer 1 are coated with rubbers 36a and 36b to perform a water stopping process. With such a structure,
Since the injected material 33 filled in the packer 1 oozes out only from the portion in contact with the ground 30, the injected material 33 can be permeated into the ground 30 without waste. In addition, as the water stopping process, a resin may be coated instead of the rubberization as described above. Or, instead of these, Packer 1
May be formed of a resin material, and only the middle portion may be formed of a cloth. Further, as the material of the packer 1, other than cloth, a material in which a small-diameter hole is provided in leather, rubber, vinyl, or the like to impart liquid permeability may be used.

In the above-described embodiment, an example in which a plurality of injection tubes 2 are provided has been described. However, the present invention can be applied to a single injection tube 2. In addition, FIG. 2 shows a case where the excavation hole 31 is formed by performing vertical boring. However, when performing liquefaction countermeasures immediately below an existing structure such as a tank, the drilling is performed obliquely from the side of the structure. Drilling holes 31 may be formed by boring.

[0035]

According to the present invention, before the ground improvement material is injected, a hardened layer of the injection material is formed around the packer, and this hardened layer serves as a partition to the unimplanted region of the ground improvement material. Can be prevented, and the ground improvement material injected later can be sufficiently penetrated to secure a strong ground.

Further, after the permeable impregnating material has penetrated into the ground, the suspension-type injecting material is injected into the packer and hardened, so that the packer is firmly adhered to the ground and injected into the pouring space. It is possible to prevent the ground improvement material from leaking into the adjacent injection space.

Further, by performing the water stopping process on both sides of the packer, the injected material filled in the packer oozes out only from the portion in contact with the ground, so that the injected material can permeate the ground without waste.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an injection device used in the method of the present invention.

FIG. 2 is a process diagram showing a method for injecting a ground improvement material according to the present invention.

FIG. 3 is a cross-sectional view of a packer filled with a permeable filler.

FIG. 4 is a cross-sectional view of a packer filled with a suspension type injection material.

FIG. 5 is a view showing another embodiment of the packer.

FIG. 6 is a cross-sectional view showing an example of a conventional injection method.

FIG. 7 is a process chart showing an injection method by infiltration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Packer 2 Injection pipe 22 Discharge port 30 Ground 31 Drilling hole 33 Permeable injection material 34 Chemical solution (ground improvement material) 35 Suspension type injection material 36a, 36b Rubber 37 Injection space

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shiro Yamamoto 2-2-2 Matsuzaki-cho, Abeno-ku, Osaka-shi, Osaka Prefecture Inside Okumura Gumi Co., Ltd. No. 6 Co., Ltd. Osaka Waterproof Construction Co., Ltd. (72) Inventor Atsushi Shiotani 7-6, Nasashimachi, Tennoji-ku, Osaka City, Osaka Prefecture Co., Ltd. Osaka Waterproof Construction Co., Ltd. F term (reference) 2D040 AA00 AB01 AC03 CA02 CA10 CB03 DA02 DA05 DA12 DB01 DC02

Claims (3)

[Claims] 1. A packer having liquid permeability and being expandable and an injection pipe provided continuously with the packer and having a discharge port for soil improvement material are inserted into a drilling hole in the ground, and the inside of the packer is inserted. Injecting a relatively short curing time into a permeable injection material to expand the packer, penetrating the injection material into the ground through the packer and hardening, and then injecting a ground improvement material from the discharge port of the injection pipe. A ground improvement material injection method characterized by the following. 2. Injection of the soil improvement material according to claim 1, wherein after the permeable injection material is injected into the packer and infiltrated into the ground, the suspension type injection material is injected into the packer and hardened. Construction method. 3. A pouring device provided with a packer and a pouring pipe used in the pouring method according to claim 1, wherein both sides of the packer are subjected to a water-stopping process. apparatus.