JPH0610340A - Construction method of continuous underground wall using precast plate - Google Patents

Abstract

(57) [Summary] [Purpose] There is no risk of ground collapse, and the precast plate is securely buried to build a continuous underground wall without using a stabilizing solution for ground stabilization. [Configuration] Through-opening 1 of precast plate 10 for retaining soil
The earth auger 20 is passed through 1, 12, 13 and excavated by the earth auger 20, and the through openings 11, 12,
The excavated soil is discharged through 13.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method of constructing a continuous underground wall using a precast plate.

[0002]

2. Description of the Related Art Conventionally, in the construction of a continuous underground wall, a construction method is known in which a predetermined place is previously excavated, a rebar cage is installed in the excavation groove, and then concrete is poured. However, in this construction method, it is necessary to excavate the excavation groove with a stabilizing solution for ground stabilization in order to prevent the groove wall from collapsing during excavation. However, there are drawbacks such as that it must be disposed of as a product, and that a plant for preparing a stabilizing solution on site and quality control of the stabilizing solution are required.

As another method for constructing a continuous underground wall, there is known a construction method in which a predetermined place is previously excavated and a precast plate is erected in the excavation groove. However, this construction method has a drawback in that it is difficult to install due to friction with the ground when the precast plate is installed, in addition to the problems associated with the collapse of the groove wall and the stabilizing solution described above.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a stabilizing liquid for stabilizing the ground is not required to previously excavate a groove for constructing a continuous underground wall, and thus there is no fear of the groove wall collapsing. There is provided a method of constructing a continuous underground wall with a precast plate without the need to use.

[0005]

In the method of constructing a continuous underground wall using a precast plate according to the present invention, (a) an earth auger is passed through a through opening of a first precast plate for retaining soil, and The step of projecting from the lower end of the through opening of the precast plate 1 and the step of (b) excavating with the earth auger and carrying out excavated earth and sand through the through opening. In addition, in the method for constructing a continuous underground wall of the present invention, after performing the steps (a) and (b), (c) the earth auger is pulled out from the through opening and placed on the first precast plate. Placing a second precast plate, and (d) the first and second
Through an earth auger through the through opening of the precast plate to project the earth auger from the lower end of the through opening of the first precast plate, and (e) excavate by the earth auger and carry out excavated soil through the through opening. Step, and optionally the step (c),
The step of repeating (d) and (e) can be further performed.

When excavating with the earth auger, a foaming fluidizing agent may be supplied near the tip portion thereof, or the foaming fluidizing agent may be supplied through the earth auger.

[0007]

In the method of constructing a continuous underground wall of the present invention, the step (a)
In the step (b), the earth auger is protruded from the lower end of the through opening, and the earth auger is excavated by the earth auger in the step (b) and the excavated soil is carried out through the through opening of the precast plate. As a result, the precast plate serves as an earth retaining function during excavation and also serves as a carry-out port when the excavated soil is carried to the surface of the ground, and the precast plate is reliably buried in the soil as the excavation proceeds. .

As the excavation progressed, the earth auger was pulled out in the step (c) to remove the second precast plate into the first
It is placed on the precast plate of, the earth auger is projected through the through opening in the step (d), and the excavation is carried out in the step (e). It is possible to dig while discharging through the through opening.

On the other hand, if the foaming fluidizing agent is excavated while being supplied to the vicinity of the tip of the earth auger, the fluidity of the earth and sand is improved, and the earth and sand can be excavated smoothly and discharged to the ground through the through opening. You can Furthermore, part of the excavated soil mixed with the foaming fluidizing agent near the tip of the earth auger fills the gap between the precast plate and the ground, reducing the frictional resistance when the precast plate sinks, Prevent mountain collapse.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Referring to FIG. 1, a precast plate 10 for retaining earth is provided with three through openings 11, 12, and 13 and an earth auger 20 is attached thereto. The earth auger 20 is composed of three units in the illustrated example. That is, the first unit 21 includes a rotary shaft 21a that is passed through the through opening 11, a screw 21b that is fixed to the rotary shaft 21a and that is used for carrying excavated earth and sand, and a bit 21c that is attached to the tip of the rotary shaft 21a. The second unit 22 includes a rotary shaft 22a passed through the through opening 12 and a rotary shaft 22a.
And a screw 22b fixed to. The third unit 23 has the same configuration as the first unit 21 and has the same structure as the rotary shaft 2
3a, a screw 23b, and a bit 23c.

FIG. 2 is an enlarged view of a lower portion of the earth auger 20 which penetrates the precast plate 10 in the lower part of the precast plate 10. The lower part of the through opening 11 has a tapered surface 11a that expands downward as shown in the drawing, and expands in a radial shape like a brim, and at the lower end of the shaft 21a, there is more than the upper screw 21b-i. A large diameter screw 21b-ii is attached. The lower portions of the through openings 12 and 13 are also expanded similarly to the through opening 11, and the screws 22b and 23b having large diameters are attached (see FIG. 1).

Next, a method of constructing a continuous underground wall will be described with reference to FIGS. As shown in FIG. 1, the ground auger 20 is placed in the through openings 11, 12, 13 of the first precast plate 10.
Each of the units 21, 22, and 23 are mounted respectively, and protruded from the tips of the through openings 11, 12, and 13, and the rotary shaft 21a,
When bits 22a and 23a are respectively rotated, bits 21c and 23
c excavates the ground 30. Illustrated bits 21c, 23c
Since the excavation plane section is excavated in a rectangular shape, it is possible to excavate without leaving unexcavated areas. At the same time as the excavation, the excavated earth and sand will have large diameter screws 21b-ii (Fig. 2), 22
b, 23b (FIG. 1), each through opening 11, 12, 13
Ascends to the skirt-like widening at the lower end of the. Since the widening portion is in the shape of a burch, the excavated earth and sand are smoothly pushed into the through openings 11, 12, 13 along the screw and carried out upward through the through openings.

As shown in FIG. 3, at the stage where the first precast plate 10 is embedded, the earth auger 20 is pulled out, and the second precast plate 10-i is placed on the first precast plate 10. 10a (FIG. 1) is fixedly connected, the earth auger 20 is attached to the through openings of the first and second precast plates, and the same excavation is performed as described above.
The precast plate 10-i is embedded.

FIG. 3 schematically shows the construction of a continuous underground wall on the side of the buried first and second precast plates 10, 10-i. The third and fourth precast plates 10-ii and 10-iii are side joint members 10.
b (Fig. 1) via first and second precast plates 1
Fixedly connected to 0, 10-i and excavated in the same manner as described above. This operation is performed continuously to build a continuous underground wall.

The rotary shafts 21a, 22a, 23a of the respective units of the earth auger 20 are hollow, and a foaming fluidizing agent, for example, "OK-1" manufactured by Daiichi Kasei Sangyo Co., Ltd. (anionic surfactant main component). ) Is jetted from the tip through each rotary shaft, the fluidity of the earth and sand is improved, the excavation is smoothly performed, and the excavated earth and sand is easily carried out through the through openings 11, 12, 13. Further, a part of the excavated soil mixed with the foamy fluidizing agent enters between the ground 30 and the precast plates 10-ii and 10-iii 31, as shown in FIG. 3, and causes friction during settling of the precast plate. Reduce resistance. The discharged mixture of the foaming fluidizing agent and the earth and sand can be sprayed with an antifoaming agent and disposed of without pollution.

[0017]

According to the present invention, it is not necessary to excavate a groove for constructing a continuous underground wall in advance, and therefore, there is no risk of the groove wall collapsing and a stabilizing solution for stabilizing the ground is used. Without it, the precast plate can be surely buried along with the excavation.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view schematically showing the construction of a continuous underground wall using a precast plate according to the method of the present invention.

2 is a partial cross-sectional view taken along line 2-2 of FIG.

FIG. 3 is a schematic view showing a precast plate being continuously built by the method of the present invention.

[Explanation of symbols]

10, 10-i, 10-ii, 10-iii Precast plate 11, 12, 13 Through opening 20 Earth auger 21a, 22a, 23a Rotating shaft 21b, 22b, 23b Screw 21c, 23c Bit

Claims (4)

[Claims] 1. A step of: (a) passing an earth auger through a through opening of a first precast plate for earth retaining so that the earth auger protrudes from a lower end of the through opening of the first precast plate; and (b) the earth. A method of constructing a continuous underground wall using a precast plate, which comprises a step of excavating with an auger and carrying out excavated soil through the through opening. 2. After performing the steps (a) and (b), (c) the earth auger is pulled out from the through opening, and the second precast plate is placed on the first precast plate. And (d) a step of passing an earth auger through the through openings of the first and second precast plates to project the earth auger from the lower end of the through openings of the first precast plate, and (e) by the earth auger. The method according to claim 1, further comprising the steps of excavating and discharging excavated soil through the through opening, and repeating the steps (c), (d) and (e) if necessary. 3. The method according to claim 1, wherein a foaming fluidizing agent is supplied near the tip of the earth auger when excavating. 4. The method according to claim 3, wherein the foaming fluidizing agent is fed through the earth auger and near its tip.