JPH04238911A - Construction of underground continuous wall - Google Patents

Abstract

PURPOSE:To raise the accuracy of construction as well as the efficiency of operation by a method in which following pit groups are formed by lapping one ends of one-side pit groups in the non-connected part of the preceding pit group. CONSTITUTION:The ground is vertically excavated by using a multispindle excavator 8 having excavating rods 7 whose axes are arranged in parallel on the same plane. A hardening agent is injected to mix it with excavated soil with stirring to form connected preceding pit groups 2-1 and 2-2 with nonconnected portions, The nonconnected portion 3 between the pit groups 2-1 and 2-2 is excavated to forum following pit groups 2'-3 to construct an underground continuous wall consisting of the pit groups 2-1, 2'-3, and 2-2 which are connected to each other. At the pit 1 on one end of the one-side pit groups in the preceding pit groups 2-1 and 2-2, the pits on one ends of the following pit groups 2'-3 are overlapped for excavation.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing an underground continuous wall using a multi-axis excavator.

0002

[Problems to be Solved by the Invention] A construction method for constructing an underground continuous wall using a multi-shaft excavator having a plurality of parallel drilling rods whose axes lie in one plane is generally The ground is excavated vertically with a drilling rod, and solidified material is discharged from the tip of the drilling rod and mixed with the excavated soil.
A drill group consisting of a plurality of continuous drill holes was formed, and this drill group was successively used to construct an underground continuous wall made of a solidified mixture of solidified material and excavated soil.

[0003] The conventional construction methods described above include a continuous method in which a drill hole group consisting of a plurality of continuous drill holes is sequentially formed and constructed from one direction, and a continuous method in which a drill hole group is formed discontinuously and then a discontinuous portion is constructed. There was an intermittent method in which holes were constructed in succession with subsequent drilling groups.

In other words, in order to perform intermittent construction using a three-axis excavator, first drill three consecutive holes 1 as shown in Figure 4.
After forming the two drilling groups 2-1 and 2-2 discontinuously, the discontinuous portion 3 between the preceding drilling groups 2 and 2 is
Using an axial drilling machine, the two drilling rods on both ends are used to overlap the two holes 1 of the preceding drilling group 2 to form a trailing drilling group 2'-3, which is the preceding drilling group. There were 2,2 intervals in a row.

[0005] As mentioned above, in the conventional construction method, in order to homogenize the quality of the solidified material and improve continuity, one hole is repeatedly excavated between adjacent drilling groups, and the excavated soil and the solidified material are separated. Stirring and mixing were performed. However, once the mixing of the excavated soil and the solidification material has been completed, the mixture in the borehole has substantially sufficient strength, and there is little need to mix the soil and solidification material again.

[0006] The present invention has been made in view of the above-mentioned problems. The purpose is to reduce the number of duplicate drilling holes when constructing an underground continuous wall using the intermittent method.
It is possible to improve work efficiency and reduce material costs.
At the same time, we propose a construction method for underground continuous walls that can ensure the continuity of continuous walls.

[0007]

[Means for solving the problem] This underground continuous wall construction method involves excavating the ground vertically using a multi-axis excavator that has multiple parallel drilling rods whose axes lie on one plane. After discharging and stirring and mixing excavated soil and solidification material to form a plurality of discontinuous drilling groups consisting of a plurality of continuous drilling holes, a discontinuous portion between the two preceding drilling groups is formed. In the method of constructing an underground continuous wall that connects two preceding drilling groups by excavating a trailing hole group and connecting two preceding drilling groups, there is overlap in drilling at one end of one of the two preceding drilling groups. It is characterized by forming a group of subsequent drilling holes.

[0008]

[Embodiments] The following will explain the embodiments shown in the drawings. In this embodiment, an excavator having three drilling rods is used to construct a hole group consisting of three consecutive straight holes as a unit. The procedure for forming drill hole groups is shown in Figure 1(a).
Two preliminary drilling groups 2-1, 2-2 consisting of three drilling holes 1 along the position where an underground continuous wall is to be constructed, which are in a straight line in plan view.
are formed discontinuously at predetermined intervals. Thereafter, the discontinuous portion 3 between the preceding drilling groups 2-1 and 2-2 is excavated to form a subsequent drilling group 2'-3, thereby making the preceding drilling groups continuous. At this time, the holes 1 on one end side of one of the preceding hole group 2-1 are drilled redundantly. Similarly, a pre-drilling group 2-4 is formed with a predetermined interval between the pre-drilling group 2-2, and the discontinuous portion 3 is excavated by overlapping the drilled holes 1 at one end of the pre-drilling group 2-4. Row drilling group 2
'-5 is formed to connect the preceding drilling groups. This process is repeated to construct the underground continuous wall 4. FIG. 2 shows a three-shaft excavator 8 equipped with a drilling bit 5 at the tip, a stirring blade 6 around the shaft, and three drilling rods 7 that discharge solidified material liquid from the tips. The three drilling holes 1 form two continuous preceding drilling groups 2-1 and 2-2, and when the mixture 9 of excavated soil and solidification material in the drilling holes 1 is unhardened, a discontinuous part is formed. 3
This shows the state in which the trailing hole group 2'-3 is formed by drilling the hole group 2'-3.

The position of the drilling rod 7 at one end of the 3-axis excavator 8 is such that the drilling rod 7 at one end of the preceding drilling group 2-1 is redundantly drilled to form a trailing drilling group 2'-3. Drilling group 2-1, 2-2
Continuing.

FIG. 3 shows an embodiment in which a drilling group consisting of two holes is used as a unit using a two-shaft excavator having two drilling rods. In this example, the discontinuous portion 3 between the preceding drilling groups 2-1 and 2-2 consisting of two consecutive drilling holes 1 is overlapped with the drilling 1 at one end of one of the preceding drilling groups 2-1. drilling to form the trailing hole group 2'-3, and the preceding hole group 2-1, 2-
The two rooms are made continuous, and this process is repeated to construct an underground continuous wall.

[0011]

[Operation] This invention consists of the above structure. According to this method, only one hole is redundantly drilled between the preceding drilling group and the following drilling group, so the work efficiency is higher than the conventional method of drilling two holes redundantly. It is possible to improve this and reduce the amount of solidifying material used.

[0012] Furthermore, since the holes at one end of the preceding drilling group are drilled redundantly to form the subsequent drilling group, the accuracy of construction is high;
It is possible to closely connect drill holes and ensure high continuity of the continuous wall. Moreover, since a multi-axis excavator is used, even if there is hard ground or rock blocks, the plurality of excavation rods are mutually restrained and the axes can be prevented from bending.

[0013]

[Effects of the Invention] According to this method of constructing an underground continuous wall, using a multi-axis excavator, it is possible to improve work efficiency and reduce material costs, while at the same time ensuring high continuity of the continuous wall.

[Brief explanation of the drawing]

FIG. 1(a) is an explanatory plan view showing a procedure for constructing an underground continuous wall using a group of drilled holes formed using a three-axis excavator as a unit. (b) is a plan view of the constructed underground continuous wall.

FIG. 2(a) is a longitudinal sectional view showing a state in which a trailing hole group is formed between a preceding hole group. (b) is a cross-sectional view of (a).

FIG. 3(a) is an explanatory plan view showing a procedure for constructing an underground continuous wall using a group of drilled holes formed using a two-shaft excavator as a unit. (b) is a plan view of the constructed underground continuous wall.

FIG. 4 is an explanatory plan view showing a procedure for constructing an underground continuous wall using a group of drilled holes formed using a conventional three-axis excavator.

[Explanation of symbols]

1... Drilling hole, 2... Drilling group, 3... Discontinuous part, 4... Underground continuous wall, 5... Drilling bit, 6... Stirring blade, 7... Drilling rod,
8...3-shaft excavator, 9...mixture.

Claims (1)

[Claims] Claim 1: Vertically excavating the ground using a multi-axis excavator having a plurality of parallel drilling rods whose axes are in one plane, discharging a solidification material, and stirring and mixing the excavated soil and the solidification material. After forming a plurality of discontinuous drilling groups consisting of a plurality of continuous drilling holes, drilling a discontinuous portion between the two preceding drilling groups to form a subsequent drilling group, A method for constructing an underground continuous wall that connects two preceding drilling groups, characterized in that the drilling at one end of one of the two preceding drilling groups overlaps to form a subsequent drilling hole group. Continuous wall construction method.