JP5140543B2 - Barrier wall construction method and ground purification method using the same - Google Patents

Description

  The present invention relates to a method for constructing a barrier wall and a method for purifying ground soil in the ground directly under a working structure.

Conventionally, as a method of constructing a barrier that isolates and blocks the ground contaminated by contaminants such as fluorine, arsenic, and heavy metals, the ground improvement material and soil are mechanically separated by a 3-axis large heavy machine installed on the ground surface. A method of stirring and mixing is known.
There is also a method in which a ground improvement material is slurried, sprayed into the ground by a heavy machine installed on the ground surface, and mixed with the ground soil.
JP 2004-298193 A JP 2006-159023 A JP 2006-314979 A

As a ground purification method using circulating water, a pumping well and an injection well are provided. Methods for purifying are known.
There is also a method of purifying the ground by arranging well pipes above and below the contaminated area and circulating water.
JP 2005-279548 A JP 2006-233712 A

Such a conventional method has the following problems.
<1> Of the methods for constructing a barrier wall in the ground, the method of stirring and kneading and jet mixing the ground with heavy machinery excavates the ground directly under the heavy machinery. For this reason, a space for installing heavy machinery is required above the ground, and when there is a structure in operation on the ground, it is difficult to construct a barrier on the ground below the structure.
<2> A method for purifying soil by providing a pumping well and an injection well is to provide a pumping well at a contaminated position. For this reason, when there is an existing structure on the ground of the contaminated position, it is difficult to provide a pumping well.
<3> The purification method that diffuses chemicals and the purification method that circulates water by arranging a well pipe do not take into account the diffusion route and circulation route, and the effect on the permeation and diffusion action of pollutants in the ground is It was limited.

  An object of the present invention is to provide a method for constructing a barrier wall and a method for purifying ground soil in the ground directly under a structure in operation.

The first invention of the present application, which has been made to achieve the above object, includes a shaft construction process for constructing a shaft, and a propulsion pipe provided with an injection improving device at the tip from the shaft to the ground in the horizontal direction. The excavation process of excavating the ground at a distance, and pulling out the propulsion pipe from the ground at the vertical shaft, and the ground improvement material is jetted and agitated from the jet improvement device located at the end to construct an improved body in the ground An improved body construction step, and the improved body construction step is repeated to construct a barrier wall construction method for constructing a barrier wall in which a plurality of the improved bodies are continuous in the vertical direction in the ground.
The second aspect of the present invention is the blocking wall construction method of the first invention, the vertical shaft was single build, from the shafts in the horizontal direction of the ground, along with building a curved barrier walls were constructed prior to Connecting the end of the preceding blocking wall and the end of the trailing blocking wall that forms a curve opposite to the curve of the preceding blocking wall constructed following the preceding blocking wall; and the shaft and the preceding blocking wall An enclosure area is formed in the ground by the downstream blocking wall, and a blocking wall construction method is provided.
According to a third invention of the present application, in the method for constructing a barrier wall according to the first invention, a plurality of the shafts are constructed, and a plurality of barrier walls are constructed from the shaft to the ground in the horizontal direction. The end of the wall is connected to the end of the trailing blocking wall constructed following the leading blocking wall, and is surrounded by the shaft, the leading blocking wall, and the trailing blocking wall in the ground. Provided is a method for constructing a barrier wall, characterized by forming an area.
The fourth invention of the present application is the barrier wall construction method of the second or third invention, wherein the improvement body construction step is repeated on the ground below the surrounding area, and a plurality of the improvement bodies are continuously arranged in the horizontal direction. A method for constructing a barrier wall is provided, which comprises constructing a bottom plate barrier wall.
A fifth invention of the present application is a method for purifying contaminated ground, wherein the contaminated ground is enclosed as an enclosed area by any of the methods of the second to fourth inventions, and is extended from the vertical shaft above the enclosed area. A water injection pipe is arranged, a drain pipe extending from the vertical shaft is arranged at a lower part of the Go area, water is poured from the water injection pipe into the ground, and the injected water passes through the Go area, and the drainage Disclosed as a drainage from a pipe and purifying the drainage is provided.

The present invention can obtain at least one of the following effects by means for solving the above-described problems.
<1> In order to construct a wall in the horizontal direction from the vertical shaft, even if there is a vertical site, even if the ground has a working structure in the upper part, it is non-open cut and has an adsorption / insolubility property You can build a wall.
<2> Since several barrier walls are constructed in the horizontal direction from the shaft and the contaminated ground is surrounded by the shaft and the barrier wall, even if there is a shaft site, even if the ground has a working structure in the upper part, The diffusion of the substance can be prevented.
<3> Since the bottom plate blocking wall is constructed in the lower part of the Go area, even if the contaminated ground is a water permeable layer, it can be reliably surrounded and the diffusion of pollutants can be prevented.
<4> Water injection pipes and drain pipes placed above and below the Go area are arranged horizontally from the vertical shaft, so even if the ground has a working structure at the top, it is possible to collect and purify pollutants. it can.
<5> Surrounded by a barrier wall and circulates and purifies water, so that a water circulation path can be secured while preventing the diffusion of contaminants by the barrier wall, and pollutants can be efficiently recovered and purified. it can.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[1] Configuration of the barrier wall The barrier wall 1 of the present invention is formed by continuously forming an improved body 11 formed horizontally from the vertical shaft 2 into the ground in the vertical direction to form a wall shape. (Figure 1)
The improved body 11 is obtained by injecting and stirring a ground improvement material into the excavated ground.

[2] Construction Method of Improved Body The improved body 11 is constructed by the propulsion unit 3 that excavates the ground and the propulsion pipe 4 that propels the propulsion unit 3 into the ground.
Hereinafter, the construction method of the improved body 11 will be described.
<1> Propulsion machine The propulsion machine 3 excavates the ground and injects and stirs the ground improvement material to improve and improve the ground.
The propulsion device 3 has a plurality of bits at the tip and includes an injection improving device 31. (Figure 2)
The injection improving device 31 is a device for injecting and stirring the ground improvement material at a high pressure.

<2> Propulsion pipe The propulsion pipe 4 is made of a steel pipe, and presses the shaft 3 into the ground to propel the propulsion unit 3.
The propulsion pipes 4 are arranged and connected to the rear of the propulsion unit 3 so that the necessary number is added.
For the connection between the propulsion unit 3 and the propulsion pipe 4, or the connection between the propulsion pipes 4, a means such as a connection by a bolt and a nut, a connection by welding, or the like can be adopted.
Inside the propulsion pipe 4, a mud pipe 41 for discharging mud and water is arranged, and mud and water in the ground can be discharged to the shaft 2 when the ground is improved.

<3> Propulsion The excavator 3 is excavated and propelled horizontally from the hole opened in the shaft 2 into the ground. (Figure 2)
A propulsion pipe 4 is connected to the rear of the propulsion unit 3 and propelled by a jack 5.
After propulsion for the length of the propulsion tube 4, the propulsion tube 4 is further connected to the rear of the propulsion tube 4 at the end and propelled.

<4> Pulling out After propelling for a desired distance, the propelling pipe 4 is pulled out from the ground by the jack 5. (Figure 3)
At the same time, from the injection improvement device 31 provided in the propulsion device 3, high-pressure water is injected around the excavation part to discharge mud from the mud pipe 41 while excavating, and the ground improvement material is injected and stirred. Then, the ground around the route that has been excavated is improved, and the improved body 11 is formed.
Since the improved body 11 is constructed by excavating and propelling the propulsion device 3 from the vertical shaft 2 in the horizontal direction, the improved body can be constructed without cutting even in the ground where there is a structure in operation on the ground. it can.
By including an adsorption / insolubilization substance in the ground improvement material injected from the injection improvement device 31, the improved body 11 to be constructed can have adsorption / insolubilization performance.

<5> Effect of mud discharge Unnecessary mud and water are discharged to the shaft 2 through the mud pipe 41.
By discharging the mud and water, the excavation part is filled with the ground improvement material, and the improved body 11 having strength can be constructed.
Moreover, since the mud and water which excavated can be reliably collect | recovered through the mud pipe 41, even if the ground is contaminated, secondary contamination can be prevented.

<6> Curve Propulsion The propulsion pipe 4 is made of a steel pipe, but the curved improvement body 11 is constructed by making a steel pipe that draws a predetermined curve such as a gentle curve or an S-shaped curve in the horizontal direction of the ground. You can also.
Thereby, the improved body 11 can be constructed while detouring the obstacle in the ground.

[3] Construction of barrier wall Next, a method for constructing the barrier wall using the above-described improved body will be described.
<1> Construction of vertical shaft The vertical shaft 2 is constructed by a known method such as a press-in caisson method.
Since the caisson that forms the outer wall of the shaft 2 is made of concrete, the shaft 2 itself has a function of blocking contaminated ground.

<2> Construction of the barrier wall The improved body 11a which is the uppermost part of the barrier wall 1 to be constructed is constructed by the propulsion unit 3 being horizontally driven from the shaft 2 and constructed by the method for constructing the improved body described above.
After the improved body 11a is constructed, the improved body 11b is constructed at a position below the improved body 11a and continuous with the improved body 11a. (Fig. 4)
Thus, the improvement body 11 is continuously constructed | assembled below and the interruption | blocking wall 1 is constructed | assembled.
Since the improved body 11 is constructed from the upper side, when the lower improved body 11 is constructed except for the improved body 11a, the upper side is always improved. Therefore, the ground collapse at the time of construction of the improved body 11 can be minimized, and the barrier wall 1 can be constructed efficiently.
Since the improved body 11 is constructed by spraying and stirring the ground improvement material, the blocking wall 1 made of the improved body 11 has a function of blocking contaminants.

<3> Side surface of contaminated soil When pollutants such as fluorine, arsenic, and heavy metals flow into the ground soil and become contaminated area A, so that it is almost the target across the contaminated area A in plan view, The shafts 2a and 2b are constructed.
And the surrounding area B is constructed so that the side walls of the contaminated area A are surrounded by the blocking walls 1a and 1b on the ground outside the contaminated area A from the vertical shafts 2a and 2b.
If the barrier wall 1a constructed from the vertical shaft 2a is constructed in advance, the end of the barrier wall 1b constructed downstream from the vertical shaft 2b is constructed so as to be connected and intersected in the ground. (Fig. 5)
By connecting the end portions, the shafts 2a and 2b and the blocking walls 1a and 1b are continuous, so that the pollutant can be contained by the surrounding area B, and the diffusion of the pollutant can be prevented.
When the ground below the contaminated area A is an impermeable layer, the pollutant does not diffuse to the impermeable layer. Therefore, the pollutant can be reliably contained by surrounding the side surface with the blocking wall 1.

<4> Side wall by curve propulsion When a site for constructing a plurality of vertical shafts 2 cannot be secured due to the shape of the structure on the ground, etc., curved barrier walls 1a, 1b are constructed from the vertical shaft 2, By constructing so as to connect and cross in the ground, it is possible to construct Go area B and contain the pollutants. (Fig. 6)

<5> Construction of Bottom Plate Barrier Wall Contaminant is constructed by enclosing the surrounding area B so that the contaminated area A is surrounded by the blocking walls 1a and 1b. May be formed continuously in the horizontal direction to construct the bottom plate blocking wall 6. (Fig. 7)
The bottom plate blocking wall 6 is constructed by forming the improved body 11 radially from the vertical shafts 2a and 2b and horizontally on the bottom surface of the surrounding area B.
By forming the bottom plate blocking wall 6 on the bottom surface of the surrounding area B, even if the ground below the contaminated area A is a water permeable layer, the bottom plate blocking wall 6 prevents contaminants from diffusing below the surrounding area B. can do.

[4] Ground Purification Method Next, a ground purification method using the blocking wall 1 will be described.
<1> Construction of Go Area First, the shaft 2, the blocking wall 1, and the bottom plate blocking wall 6 are built, and the contaminated area A is surrounded by the Go area B.

<2> Construction of Circulation Path Next, from the shaft 2, the water injection pipe 7 is installed on the ground above the Go area B, and the drain pipe 8 is installed on the ground below the Go area B. (Fig. 8)
When the bottom plate blocking wall 6 is present, the drain pipe 8 is installed near the lower end of the surrounding area B and above the bottom plate blocking wall 6.
The water injection pipe 7 and the drain pipe 8 are installed by propelling a horizontal boring or a steel pipe from the shaft 2.
When the surrounding area B is constructed by the vertical shafts 2a and 2b, the water injection pipes 7 are formed radially from one vertical shaft 2a, and the drainage pipes 8 are formed radially from the other vertical shaft 2b.
The water injection pipe 7 and the drain pipe 8 are connected to the purification plant 9 via the shafts 2a and 2b.
In this way, a circulation path composed of the Go area B, the drain pipe 8, the purification plant 9, and the water injection pipe 7 is constructed.

<3> Circulation Water supplied from the purification plant is supplied from the water injection pipe 7 to the upper part of the Go area B.
The water supplied to the Go area B moves downward from the upper side of the Go area B due to the pressure difference due to gravity and drainage from the drain pipe 8.
When moving from the upper side to the lower side, the water absorbs the pollutant, and the drain pipe 8 drains the water containing the pollutant.
The water containing the pollutant drained from the drain pipe 8 is purified by the purification plant 9 and then supplied from the water injection pipe 7 to the Go area B again.
Thus, the contaminated area A is gradually purified by circulating water in the circulation path.

[Other Examples]
In the above embodiment, the improved body 11 constituting the blocking wall 1 and the bottom plate blocking wall 6 is constructed by the propulsion unit 3 and the propulsion pipe 4, but can also be constructed by a conventionally known horizontal boring or the like.

Explanatory drawing of the barrier according to the present invention Explanatory drawing of construction method of improved body Explanatory drawing of construction method of improved body Illustration of how to build a barrier Illustration of barrier Illustration of barrier Illustration of bottom plate barrier Explanatory drawing of ground purification method

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Barrier wall 11 Improved body 2 Resistance 3 Propulsion machine 31 Injection improvement device 4 Propulsion pipe 41 Drainage pipe 5 Jack 6 Bottom plate barrier wall 7 Water injection pipe 8 Drainage pipe 9 Purification plant

Claims (5)

A shaft construction process to construct a shaft,
Excavation step of excavating a predetermined distance ground by propelling a propulsion pipe provided with an injection improvement device at the tip from the vertical shaft to the horizontal ground,
The propulsion pipe is pulled out from the ground at the shaft, and the ground improvement material is jetted and stirred from the injection improvement device located at the end, and an improved body is built in the ground ,
By repeating the improved body construction step, a barrier wall in which a plurality of the improved bodies are continuous in the vertical direction is constructed in the ground.
Barrier wall construction method. In the barrier wall construction method according to claim 1 ,
The pit was one building,
While constructing a curved barrier wall from the vertical shaft to the ground in the horizontal direction,
Connecting the end of the preceding blocking wall constructed in advance and the end of the trailing blocking wall forming a curve opposite to the curve of the preceding blocking wall constructed following the preceding blocking wall ;
A go area is formed in the ground by the shaft, the preceding blocking wall, and the trailing blocking wall.
Barrier wall construction method. In the barrier wall construction method according to claim 1,
Build a plurality of the shafts,
While constructing a plurality of barrier walls from the vertical shaft to the horizontal ground,
Connecting the end of the preceding blocking wall constructed in advance and the end of the subsequent blocking wall constructed following the preceding blocking wall;
A go area is formed in the ground by the shaft, the preceding blocking wall, and the trailing blocking wall.
Barrier wall construction method. In the barrier wall construction method according to claim 2 or claim 3,
On the ground below the Go area, the improved body construction step is repeated, and a plurality of the improved bodies are continuously constructed in the horizontal direction to construct a bottom plate blocking wall,
Barrier wall construction method. A purification method for contaminated ground,
Surrounding the contaminated ground as an enclosed area by the method according to any one of claims 2 to 4 ,
A water injection pipe extending from the shaft is arranged at the upper part of the Go area,
In the lower part of the Go area, arrange a drain pipe extending from the shaft,
Water is poured into the ground from the water injection pipe,
The injected water passes through the Go area and is discharged as drainage from the drain pipe.
Purifying the waste water,
Ground purification method.

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