JPH11222848A - Constructing method of cutoff earth retaining wall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the constructing method of an economical cutoff column- strip earth retaining wall, by which the cutoff column-strip sheathing wall can be built only in a section, in which cutoff properties are required. SOLUTION: Piles 21 are brought into contact with each other in a section in the depth direction, in which no cutoff properties is required, and an earth retaining wall 2 is constructed. The cross sections of the piles 21 are expansion- drilled on every other pile or the adjacent two piles are expansion-drilled in a section in the depth direction, in which cutoff properties are needed, one pile adjacent to the two piles is not expansion-drilled, and the next two piles are expansion-drilled and superposed and continued, thus building the earth retaining wall 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for constructing a water stoppage retaining wall.

[0002]

2. Description of the Related Art A conventional pillar-type water-blocking retaining wall has a method of constructing a wall surface by arranging a number of piles in a state of being overlapped to a certain extent. In this construction method, the diameter of each pile is the same from the pile head to the tip, and the piles are constructed by overlapping piles adjacent to each other in all cross sections.

[0003]

However, when looking at the actual state of formation of the stratum, sandy soil and cohesive soil are often in alternating layers, and groundwater flows mainly in the sandy soil layer. It is. Therefore, in order to make the retaining wall a high water-stopping performance, it is necessary to construct the wall surface by arranging the sandy soil layers with the flow of groundwater mainly in an overlapping state.
However, the conventionally known mountain retaining wall is a method in which the diameter from the pile head to the tip is all constant and is constructed by overlapping the adjacent piles by the same dimension over the entire length, so that it is necessary to construct a waterproof wall. It was uneconomical to build a water barrier on an uncontaminated clay layer.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and can be constructed only in a portion requiring water stoppage in consideration of the superposition of a water stoppage retaining wall. It is an object of the present invention to provide an economical construction method of a still water retaining wall.

[0005]

In order to achieve the above-mentioned object, a method of constructing a watertight retaining wall according to the present invention is to construct a retaining wall by adjoining a large number of piles underground. Method, in the section in the depth direction that does not require water stoppage, the pile and the pile are brought into contact to construct a retaining wall, and in the section in the depth direction that requires water stoppage, the pile and the pile Enlarging and drilling the cross section of every other pile, or enlarging and drilling two adjacent piles, without enlarging and drilling one adjacent pile, enlarging and drilling the next two piles, This is a method for constructing a water stoppage retaining wall in which a retaining wall is continuously constructed by overlapping.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for constructing a water stoppage retaining wall according to the present invention will be described below with reference to the drawings.

<A> Apparatus used In the construction method of the present invention, a drilling apparatus as shown in FIGS. 2 and 3 is used. That is, a screw head 12 is provided at the tip of the rotating rod 1, and a screw 11 is attached to the outer periphery of the rotating rod 1. An enlarged wing 13 having a larger diameter than the screw head 12 is attached between the screw head 12 at the tip and the screw 11 at the rear. This enlarged wing has its proximal end attached to the rod 1 with a pin 14. Normally, the expanding wing 13 is folded in parallel with the rod 1. When necessary, the expanding wing 13 is rotated 90 degrees about the pin 14 by supplying hydraulic pressure or other methods. Then, the expanding wing 13 protrudes toward the outer periphery,
This is a device capable of drilling a hole having a diameter larger than that of the screw head 12. A pipe 15 for feeding a hardening agent into the rotating rod 1 is pierced, and cement milk or mortar is discharged outward from the vicinity of the tip and mixed with the surrounding earth and sand to form a column of soil cement or mortar. The step of constructing the retaining wall is similar to a known method.

<B> Target Ground As described above, the target ground of the construction method of the present invention is:
It is a ground where permeable layers and impermeable layers are alternately present, such that sandy soil and cohesive soil are alternated. In such a ground, it is a method of constructing a pillar row retaining wall 2 by adjoining a large number of piles underground.

<C> Section in the depth direction of the water-impermeable layer The mountain retaining wall 2 is constructed using the above-described drilling device.
The soil condition has been determined by drilling in advance to determine where the clay layer and sand layer exist in the depth direction. For simplicity, a clay layer on the ground side, a sand layer in the middle,
A description will be given by taking as an example the ground in which clay layers are alternately provided below. (Figs. 1 and 4) Since the clay layer on the ground surface is impermeable ground, it is not necessary to construct the pile 21 adjacent to the pile 21 adjacent thereto. Therefore, excavation is performed with the diameter of the screw head 12 at the tip without using the enlarged wing 13 of the drilling device. As described above, in the section in the depth direction that does not require water stoppage, the pile 21 and the pile 21 are fixed within a range equal to the diameter of the screw head 12.
The dome wall 2 is constructed in such a manner that the contact is made at the contact point or slightly overlapped. Therefore, in this range, the water stoppage is poor, and the pillar row retaining wall 2 that can bear only the earth pressure can be constructed.

<D> Section in the depth direction of the water-permeable layer When the sand layer penetrates through the clay layer, the columnar mountain retaining wall 2 is required to be water-blocking in this section. For this reason, when reaching the section in the depth direction that requires water stoppage, the expanding wing 13 having a larger diameter than the screw head 12 is expanded by the action of hydraulic pressure or the like. Then, the hole is drilled to the range of the adjacent pile 21, and the cross-section of the pile 21 and the pile 21 can construct the water-stop columnar retaining wall 22 in a state where a part thereof is overlapped. The above-mentioned pile group inserts a core material such as H steel 3 or concrete pile 4 into the inside, and finishes the construction of the pillar row retaining wall 2. In this manner, in the depth direction of the pillar array retaining wall 2, only an arbitrary section is freely selected as the pillar retaining mountain wall 22 having the water blocking property, and the other sections are freely selected as the column retaining mountain retaining wall 2 having no water blocking property. Can be built.

[0011]

As described above, the method of constructing the watertight columnar mountain retaining wall of the present invention has the following effects. <a> Unlike the conventional pillar mountain retaining wall, there is no need to overlap the entire length with the same diameter. Only the section where groundwater is expected to flow out is constructed as a columnar retaining wall with water-blocking properties, and the other sections in the depth direction are constructed with simply non-water-blocking columnar retaining walls. Just do it. <B> Switching the structure according to the target ground,
It can be completed in one continuous process. Therefore, it is a construction method capable of shortening the work time of the construction and greatly reducing the construction cost. <C> The construction cost can be further reduced because the pillar canal can be constructed as a finely water-repellent pillar retaining wall in response to a change in the place where the outflow of groundwater is expected.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a method for constructing a water-blocking pillar row retaining wall of the present invention.

FIG. 2 is an explanatory view of a drilling device.

FIG. 3 is an explanatory view of a state where an enlarged wing of the drilling device is enlarged.

FIG. 4 is an explanatory view of another embodiment of the present invention.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toru Miyazawa 1-25-1, Nishishinjuku, Shinjuku-ku, Tokyo Taisei Construction Co., Ltd. No. 2 Tokyu Village 2-1421

Claims (2)

[Claims] 1. A method for constructing a retaining wall by placing a number of piles adjacent to each other in the ground, wherein the piles are brought into contact with each other in a section in a depth direction where water stoppage is not required. It is characterized by constructing a wall, drilling every other pile in the depth direction where water-stopping is required, drilling every other pile, and superimposing and continuously constructing a retaining wall. How to build a retaining wall. 2. The method for constructing a water-stopping retaining wall according to claim 1, wherein the pile is brought into contact with the pile to construct the retaining wall in a section in a depth direction that does not require water-stopping. In the depth direction where water is required, two adjacent piles are enlarged and drilled. The next adjacent pile is not enlarged and drilled, and the next two piles are enlarged and drilled. A method for constructing a still water retaining wall, comprising constructing a retaining wall continuously by overlapping.