JP2006144357A - Column-row type continuous underground wall - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a column-row type continuous underground wall which facilitates drawing and reuse of cores, and pays attention to the circumferential environment. <P>SOLUTION: The column-row type continuous underground wall 1 is constructed by arranging columnar earth improvement bodies 3 which are each formed by mixing and agitating in-situ soil and a cement-based hardener, adjacently to each other in a lateral direction so as to form a column row. Each cylindrical earth improvement body 3 has the core 2 which is formed of an H-steel and arranged at the center thereof. The core 2 has sheet-type edge-cutting members 4 stuck to surfaces thereof, which is formed of a foamed biodegradable plastic. The edge-cutting member 4 is formed like a rolled tape having a width on the order of 200 to 400 mm, and a length on the order of 25 to 50 m, and has a biodegradable adhesive applied to one surface thereof. The thickness of the edge-cutting member 4 is on the order of 1 to 5 mm inclusive of the biodegradable adhesive applied thereto. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In the present invention, an in-situ soil is drilled by an auger excavator or the like, and a cement-based hardener is discharged from the auger and mixed with the in-situ soil to form a columnar ground improvement body. The present invention relates to a columnar continuous underground wall into which a core material is inserted.

The column-type continuous underground wall has less noise and vibration during construction, and has higher bending rigidity and better water-stopping properties than sheet pile-type retaining walls. It is used as a side wall of a structure.
On the other hand, the core material of the column-type continuous underground wall is often difficult to pull out and remove after completion of construction, so it often has to be left buried in the ground. It is an obstacle to burial work such as equipment piping. Further, from the viewpoint of reuse needs due to a significant increase in steel material costs accompanying an increase in international steel material demand, a column-type continuous underground wall in which the core material can be easily pulled out is desired.
For this reason, there are examples in which a friction cut material (covering material type) is attached to the surface of the core material, or grease or a lubricant is applied. In Patent Document 1, the surface of the steel pile is covered with a foamed resin material via a double-sided adhesive tape or resin film, and the foamed resin material remains in the ground improvement body when the steel pile is pulled out. An invention is disclosed in which a squeezed steel pile is pulled out.
JP 2003-193460 A (page 2-3, FIG. 1-5)

  However, since the method described in Patent Document 1 coats the foamed resin material on the surface of the steel pile via a double-sided adhesive tape or a resin film, there is a risk that the coating material may be peeled off when the core material is installed. Since the resin material is buried in the ground, it is not preferable from the viewpoint of protecting the global environment. In addition, in other conventional methods, soil cement adheres to the core material after it has been pulled out or the coating agent remains, which necessitates cleaning of the core material, and fine dust during the cleaning process. There is a risk of entering the eyes of a worker.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a columnar column-type continuous underground wall in which the core material can be easily pulled out and reused and is environmentally friendly.

In order to achieve the above object, the columnar continuous underground wall according to the present invention forms a columnar ground improvement body in the ground and inserts a core material into the ground improvement body. The wall is characterized in that an edge-cutting material formed by foaming a biodegradable plastic into a sheet shape is attached to the surface of the core material.
In the present invention, an edge cutting material in the form of a sheet obtained by foaming biodegradable plastic is stuck on the surface of the core material, and the edge cutting material is a soil cement when the core material is pulled out after completion of underground construction Since the fragile layer corresponding to the thickness of the edge-cutting material is formed between the ground improvement body and the core material, the core material can be easily pulled out. The pulling force is greatly influenced by the adhesion force and frictional force on the surface of the core material, but the adhesion force and frictional force are reduced by the brittle layer formed between the core material and the ground improvement body by the edge cutting material.
Moreover, since the edge cutting material made of biodegradable plastic is finally decomposed into carbon dioxide and water, it is not necessary to collect the edge cutting material even if the edge cutting material is scraped in the field. However, it is environmentally friendly without any hindrance to the columnar continuous underground wall.

Further, in the columnar row continuous underground wall according to the present invention, the edge cutting material may be adhered to the surface of the core material (excluding a portion exposed by excavation of the ground).
In the present invention, when the core material is partially exposed by excavating the ground on the front or back side of the columnar continuous underground wall after the formation of the columnar continuous underground wall, the edge cutting material is applied to the exposed portion of the core material. By not sticking, the construction period and construction cost can be reduced.

In the columnar continuous underground wall according to the present invention, the edge cutting material may be formed in a tape shape that is long in one direction, and a biodegradable adhesive may be applied to one surface thereof.
In the present invention, since the edge cutting material is in the form of a tape that is long in one direction, the edge cutting material can be easily attached in the longitudinal direction of the core material. Further, since the biodegradable adhesive is used as the adhesive, the cleaning work for reusing the core material can be largely omitted, and the cost for the core material drawing work can be reduced. Moreover, since the biodegradable pressure-sensitive adhesive has strong adhesiveness, the edge cutting material does not peel off when the core material is built.

Moreover, in the column-column type continuous underground wall which concerns on this invention, 1-5 mm is suitable for the thickness of the said edge cutting material in the state in which the biodegradable adhesive was apply | coated.
In the present invention, the amount of biodegradable plastic used can be reduced and the material cost can be reduced by foaming the biodegradable plastic into a sheet having a thickness of 1 to 5 mm. In addition, since it is a foam, it has cushioning properties, and is difficult to be damaged during work such as transportation and erection, and is easy to repair.

  According to the present invention, since the edge cutting material formed by foaming biodegradable plastic into a sheet shape is stuck on the surface of the core material, the core material can be easily pulled out and reused, and the environment is considered. A column-lined continuous underground wall can be realized.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a columnar continuous underground wall according to the present invention will be described based on the drawings.
FIG. 1 is a partial plan sectional view showing a first embodiment of a columnar continuous underground wall according to the present invention.
The columnar continuous underground wall 1 in the present embodiment is formed in a columnar row, with a columnar ground improvement body 3 formed by mixing and stirring an in-situ soil and a cement-based hardener adjoining the side. It is made.

A core material 2 made of H-shaped steel is inserted in the center of each columnar ground improvement body 3, and an edge cutting material made of foamed biodegradable plastic on the surface of the core material 2. 4 is affixed.
In addition, the core material 2 does not necessarily need to be inserted into each columnar ground improvement body 3, and may be disposed at appropriate intervals according to the ground.

The edge cutting material 4 is made of a biodegradable plastic as a main component and is in the form of a foamed tape having a width of about 200 to 400 mm and a length of about 25 to 50 m, and a biodegradable adhesive is applied to one surface thereof. Has been rolled. By using a biodegradable pressure-sensitive adhesive as an adhesive, the cleaning work for reusing the core material 2 can be largely omitted, and the biodegradable pressure-sensitive adhesive has strong adhesiveness. There is no worry that the edge cutting material 4 is peeled off when the core material 2 is installed.
Moreover, the thickness of the edge cutting material 4 is about 1-5 mm in the state by which the biodegradable adhesive was apply | coated.

Examples of biodegradable plastics include various conventionally known biodegradable plastic materials such as those produced by microorganisms containing polyhydroxybutyrate, polylactic acid, polybutylene succinate, polyvinyl alcohol, and the like. Any substance that can be decomposed into water and carbon dioxide by bacteria after a predetermined period of time in the soil, such as a chemical synthesis system, a natural product system using cellulose acetate, chitosan, starch, etc. as a component.
Although the cost of the biodegradable plastic itself is high, in the present invention, since the biodegradable plastic is used in the form of a foamed sheet, the amount used is small and the material cost can be reduced.

Next, the construction method of the columnar row continuous underground wall 1 will be described.
First, an in-situ soil is drilled with an auger excavator (not shown), and a cement-based hardener is discharged from the auger tip to mix and agitate the in-situ soil. Form.
On the other hand, an edge cutting material 4 is pasted in advance in the longitudinal direction of the core material 2 on the surface of the core material 2 made of H-shaped steel. Under the present circumstances, it is better to stick the adhesive tape which cut | disconnected the tape-shaped edge cutting material 4 to the side edge part 2a of a flange, and the lower end surface of the core material 2. FIG.
And before the ground improvement body 3 hardens | cures, the core material 2 is press-fitted vertically to the center part of the column-shaped ground improvement body 3. FIG. At this time, if the upper end portion of the core material 2 is projected on the ground, it can be used as a clue when the core material 2 is pulled out.
In addition, after adhering the edge-cutting material 4 to the core material 2, when the edge-cutting material 4 received damage, such as a tear, the adhesive tape which cut | disconnected the tape-shaped edge-cutting material 4 was stuck on the damaged part, and it repaired. Then, the core material 2 is installed.

  The means for pulling the core material 2 from the ground improvement body 3 is not particularly limited, but if a small and heavy lifting machine such as a rough terrain crane is used, it will be easy to carry out on-site, and it will be easy to carry out on the streets or in narrow areas. The core material 2 used in the above can also be reused.

  In the columnar row continuous underground wall 1 according to the present embodiment, since the edge cutting material 4 formed by foaming biodegradable plastic into a sheet shape is attached to the surface of the core material 2, after completion of the underground frame construction When the core material 2 is pulled out, the edge cut material 4 deteriorates by hydrolytic decomposition with a soil cement component or the like, and a brittle layer corresponding to the thickness of the edge cut material 4 is formed between the ground improvement body 3 and the core material 2. The core material 2 can be easily pulled out. Moreover, since the edge cutting material 4 made of biodegradable plastic is finally decomposed into carbon dioxide and water, it is not necessary to collect the edge cutting material 4 and it remains on the columnar continuous underground wall 1 even if it is left as it is. It is environmentally friendly with no hindrance.

FIG. 2 is a partial plan sectional view showing a second embodiment of the columnar continuous underground wall according to the present invention.
In this embodiment, the core material 2 is partially exposed by excavation of the ground after the columnar row continuous underground wall 11 is formed, and the core material 2 on the side to be excavated before the core material 2 is built. The edge cutting material 4 is stuck on the surface except the flange surface 2b.

  In the columnar continuous underground wall 11 according to the present embodiment, the flange surface 2b of the core member 2 exposed by excavation of the ground (including some ground improvement bodies 13) after the columnar continuous underground wall 11 is formed. By not sticking the edge cutting material 4, the construction period and construction cost can be reduced.

  As mentioned above, although embodiment of the column-column type continuous underground wall which concerns on this invention was described, this invention is not limited to said embodiment, In the range which does not deviate from the meaning, it can change suitably. For example, in the above embodiment, H-shaped steel is used as the core material, but the present invention is not limited to this shape, and a core material having another cross-sectional shape may be used. Moreover, in said embodiment, although it has set as the arrangement | positioning which overlapped the column-shaped ground improvement body, the wall-shaped ground improvement body without an unevenness | corrugation on the surface may be sufficient. In short, it is only necessary to obtain the desired function in the present invention.

It is a partial plane sectional view showing a first embodiment of a columnar row continuous underground wall according to the present invention. It is a fragmentary flat sectional view which shows 2nd embodiment of the column-column-type continuous underground wall which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 11 Column row type continuous underground wall 2 Core material 2a Side edge part 2b Flange surface 3, 13 Ground improvement body 4 Edge cutting material

Claims (4)

In the columnar continuous underground wall that forms a columnar ground improvement body in the ground and inserts a core material into the ground improvement body,
A columnar column-type continuous underground wall, wherein an edge-cutting material formed by foaming a biodegradable plastic into a sheet shape is attached to the surface of the core material.   The columnar row continuous underground wall according to claim 1, wherein the edge cutting material is adhered to a surface of the core material (excluding a portion exposed by excavation of the ground).   The columnar continuous underground wall according to claim 1 or 2, wherein the edge-cutting material is formed in a tape shape that is long in one direction, and a biodegradable adhesive is applied to one surface thereof.   The columnar continuous underground wall according to claim 3, wherein a thickness of the edge cutting member is 1 to 5 mm in a state where a biodegradable adhesive is applied.

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