JPH05321511A - Construction method for underground vessel in weak ground - Google Patents

Abstract

PURPOSE:To make it possible to facilitate removable of surplus produced during construction by preventing the collapse of a drilling hole, securing the safety of workers with ease and protecting underground water from contamination pollution. CONSTITUTION:A spray nozzle-built-in triple pipe rod 5 is inserted into a guide hole 4 drilled in a weak ground. The surrounding ground is forcibly broken down by injecting high speed steam jet into the subsoil while a grout material 14 is injected thereinto simultaneously. The triple pipe rod 5 is pulled up while it is rotated. The foundation improvement which builds up a column-shaped solid body 1 by curing the grout material is executed, corresponding to the scale of an underground vessel to be built, Drilling holes 15 for construction are installed on a simple substance of a column-shaped solid body or a set of or chains of column-shaped solid bodies, thereby building an underground vessel 3 in the drilled holes 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing an underground container used for an underground storage tank, an underground heat storage tank, a starting shaft or a reaching shaft of a shield tunnel on soft ground.

[0002]

2. Description of the Related Art In the conventional method of constructing an underground container on soft ground, a mud excavation method is used to proceed with excavation while preventing collapsing of the excavation hole with stabilizing mud. An underground container is built inside the excavation hole.

However, in the mud excavation method, the collapse of the excavation hole is basically prevented only by the mud water. Therefore, if the excavation hole is left for a long time during the excavation or after the excavation, the excavation hole becomes unstable. Become. Depending on the properties of the ground, muddy water may escape from the drill hole, resulting in wasted expensive muddy water. Further, when the mud pressure in the borehole is excessively reduced by the lost mud, the groundwater is ejected or the borehole collapses, making it impossible to maintain the borehole.

That is, in the conventional method of providing the construction drilling hole by the mud drilling method, it is not easy to maintain the drilling hole,
Ensuring the safety of workers against collapse of drill holes is also a problem.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for constructing an underground container in soft ground, which can easily prevent the collapse of the excavation hole and thus ensure the safety of workers. Is.

[0006]

The method for constructing an underground container according to the present invention will be described below with reference to the reference numerals in the accompanying drawings. Implement ground improvement. In this ground improvement, a rod 5 with an injection nozzle is inserted into the guide hole 4 drilled in the ground 18, the surrounding ground is broken by the high-speed steam jet 13 and the grout material 14 is injected at the same time, and the rod 5 is rotated. While pulling, the grout material is hardened to form the columnar solidified body 1.

After the ground improvement is carried out according to the scale of the subterranean vessel 3 to be built, the excavation hole 15 is provided in the columnar solid body 1 or the aggregate of the columnar solid bodies in the improved soil, and the excavation hole 15 is formed.
The underground container 3 is built in, and the grout material 2 is filled between the underground container 3 and the excavation hole 15.

[0008]

The high-speed steam that is jetted laterally from the jet nozzle at the tip of the rod 5 toward the hole wall of the guide hole 4 by sequentially pulling up the rod 5 while rotating it from the bottom of the guide hole 4. The ground around the guide hole 4 is cut and crushed within a certain range by the jet flow 13. At the same time, the grout material 14 such as cement milk is ejected laterally from another injection nozzle of the rod 5 toward the ground component that is being destroyed and agitated. It is injected evenly.

The ground component is solidified by hardening the injected grout material 14, and the columnar solid 1 having a diameter much larger than the guide hole 4 is formed. The columnar consolidated body 1 has a high compressive strength, which improves the ground in the relevant portion. Only one columnar solid body 1 is formed if the underground container 3 to be built has a small diameter, and the construction excavation hole 15 is excavated concentrically with the columnar solid body 1. In this construction excavation hole 15, an underground container 3 having a bottom plate portion 3a in advance is built. The underground container 3 is firmly bonded and integrated with the columnar solidified body 1 by hardening the grout material 2 such as cement mortar filled between the underground hole 3 and the excavation hole 15.

When the diameter of the underground container 3 is relatively large, an aggregate of a plurality of columnar solidified bodies is formed. As shown in FIG. 5, it is desirable that the aggregate of the columnar solidified bodies 1 be formed by overlapping parts thereof, and that the excavation hole 15 for construction is excavated in the overlapping part. This ensures a necessary and sufficient ground support force for the underground container 3.
In the building excavation hole 15, the underground container 3 with the bottom plate portion 3a is built as described above. The underground container 3 has a drill hole 15
By hardening of the grout material 2 such as cement mortar filled between and, it is firmly bonded and integrated with the aggregate of the columnar solid bodies 1.

[0011]

EXAMPLE As shown in FIG. 1, after excavating the guide hole 4 in the soft ground 18 by an appropriate method such as a boring method,
As shown in FIG. 2, a rod 5 with an injection nozzle having a triple pipe structure is inserted into the guide hole 4. The high-speed steam jet 13 obtained by the high-pressure air from the compressor 11 and the high-pressure water from the high-pressure water pump 10 is jetted toward the ground portion around the guide hole 4 to destroy the ground portion and, at the same time, the grout pump. Pour grout material 14 from 12 into the agitated ground components. While continuing the destruction of the target ground portion and the injection of grout material, the rod 5 is rotated by the rotary drive unit 7 installed on the ground, and is gradually pulled up to the ground surface by a required heavy machine equipped on the turret 8.

It waits until the grout material 14 such as cement milk hardens and the columnar solidified body 1 is completed on the target ground portion. After confirming whether or not the columnar consolidated body 1 has a required strength by a boring inspection or the like, a shaft boring method suitable for an improved ground portion of the underground container 3, that is, the columnar consolidated body 1 And the open excavation method. After this excavation is completed, the bottom part 1 of the underground container 3
The underground container 3 is constructed by connecting 6 and the body portion 17 of the underground container 3 on the ground or in the excavation hole 15. Finally, the grout material 2 is filled between the underground container 3 and the hole wall of the excavation hole 15.
When the underground container 3 has a relatively small diameter and a relatively low height, it is possible to hang the one in which the bottom plate portion 16 and the body portion 17 are integrally configured from the beginning in the excavation hole 17.

When the underground container 3 to be built has a large diameter, a single columnar solidified body 1 or an assembly of a plurality of columnar solidified bodies 1 can no longer be adapted. Therefore, the ground improvement is continuously performed along the circumferential direction of the underground container 3. As a result, as shown in FIG. 7, a plurality of columnar consolidated bodies 1 are formed into a chain body in which two adjacent columnar consolidated bodies 1 partially overlap each other.

The building excavation hole 15 is provided in a chain shape so as to penetrate the overlapping portion of the chain of columnar solidified bodies 1 and the central portion of each columnar solidified body 1. Since the two adjacent construction holes partially overlap each other, when the last one is excavated, they will communicate in an annular shape as shown in FIG. Only the body portion 17 of the underground container 3 is built in this chain-shaped group of excavation holes for construction.
The body portion 17 is firmly bonded and integrated with the chain body of the columnar solidified body 1 by hardening the grout material 2 such as cement mortar filled between the body portion 17 and the excavation hole 15.

As shown in FIG. 11, the ground portion 18a on the inner side of the body portion 17 and the portion 1a of the columnar solidified body 1 leave a necessary rooting depth for the body portion 17 and are appropriately excavated. The entire surface is excavated by the construction method and shaft boring method.
By grouting a cement mortar or the like as shown in FIG.
The bottom plate portion 16 is formed. The bottom plate portion 16 can be made into a reinforced concrete structure by using concrete as the grout material, throwing the discarded concrete on the excavated bottom surface portion, and coating the rebar assembly installed on this with the grout material. When the underground container 3 is used as a starting shaft or a reaching shaft of a shield tunnel, a body part 17 adjacent to the bottom plate part 16 is provided with an entrance / exit of a required height and is connected to the tunnel body.

[0016]

As described above, in the construction method of the present invention, the rod 5 with the injection nozzle is inserted into the guide hole 4 formed in the ground 18.
And the simultaneous destruction of the surrounding ground by the high-speed steam jet 13 and the injection of the grout material 14 are proceeded simultaneously, and the rod 5 is pulled up while rotating, and the columnar solid body 1 having high strength is formed by hardening the grout material. By doing so, the construction excavation hole 15 is provided in the single unit of the columnar solid body 1, the aggregate of the columnar solid bodies 1 or the chain body according to the scale of the underground container 3 to be built. , Drilling holes for construction 15
Can do exactly without the risk of collapse.

Since the excavation hole 15 provided in the columnar solid body 1 is strong against collapse, maintenance of the excavation hole 15 after excavation is facilitated, and the construction period is delayed due to the addition of repair work for the collapsed excavation hole. No problem occurs.

As described above, since there is no danger of collapsing the excavation hole 15, measures for ensuring the safety of workers can be easily performed. In particular, in order to construct the bottom plate part of the large-diameter underground container 3, when excavating the entire inside of the body part 17, the existing body part 1
Since the pressure from the side is received by 7,
Internal excavation can be performed safely by the excavation method, etc., and security measures can be facilitated.

Further, since it is not necessary to use expensive stabilizing mud for preventing collapse of the construction excavation hole 15, it is possible to reduce the construction cost, and there is a problem of pollution pollution of groundwater by mud. Does not derive. Also, grout material 14
Since the injection range is the range destroyed by the high-speed steam-water jet 13, the ground improvement carried out in advance can be economically performed.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a stage in which a guide hole is provided ahead of soft ground in an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a stage in which the ground surrounding the guide hole is destroyed by the rod with the injection nozzle and the grout material is injected in the embodiment.

FIG. 3 is a vertical cross-sectional view showing a stage in which the grout material is hardened to form a columnar solidified body in the embodiment.

FIG. 4 is a vertical cross-sectional view showing a stage in which a columnar solidified body is provided with a construction excavation hole to construct an underground container in the embodiment.

FIG. 5 is a plan view when an underground container is built by providing a building excavation hole in an aggregate of columnar solidified bodies in another embodiment of the present invention.

6 is a cross-sectional view taken along the line AA of FIG.

FIG. 7 is a plan view showing a step of forming a chain of columnar solidified bodies in still another embodiment of the present invention.

8 is a cross-sectional view taken along line BB of FIG.

FIG. 9 is a plan view showing a stage in which a chain-shaped building excavation hole is provided in a chain of columnar solidified bodies in the example.

10 is a cross-sectional view taken along the line CC of FIG.

FIG. 11 is a plan view showing a stage in which an underground container is built in a chain-shaped excavation hole for building in the embodiment.

12 is a cross-sectional view taken along line DD of FIG.

[Explanation of symbols]

 1 columnar solidified body 2 grout material 3 underground container 4 guide hole 5 injection nozzle rod 6 mount 7 rotation drive unit 8 turret 9 triple pipe swivel 10 high pressure water pump 11 compressor 12 grout injection pump 13 high-speed steam jet 14 ground improvement Grout material 15 Drilling hole for construction 16 Bottom part of underground container 17 Body part of underground container 18 Soft ground

Claims (2)

[Claims] 1. A grout material by inserting a rod with an injection nozzle into a guide hole drilled in the ground, simultaneously causing destruction of the surrounding ground by a high-speed steam jet and injecting grout material, and pulling up while rotating the rod. Ground improvement by forming a columnar solidified body by hardening of concrete is carried out according to the scale of the underground container to be built, and a drilling hole for construction is provided in the columnar solidified body or aggregate of columnar solidified bodies in the improved ground. A method for constructing an underground container in soft ground, which comprises constructing an underground container in the excavation hole and filling a grout material between the underground container and the excavation hole. 2. A grout material is inserted by inserting a rod with an injection nozzle into a guide hole drilled in the ground, simultaneously causing destruction of the surrounding ground by a high-speed steam jet and injection of grout material, and pulling up while rotating the rod. Ground improvement to form columnar solidified bodies by hardening is continuously carried out along the circumferential direction of the underground container to be built, and the drilling holes for construction are linked to the chained body of columnar solidified bodies in the improved ground. , The body of the underground container is built in the chain-shaped drilling hole, grout material is filled between the body and the drilling hole, and the inner ground of the carcass is entirely excavated to a predetermined depth, and the grout is formed on the bottom surface of the drilling. A method for constructing an underground container in soft ground, in which a bottom material of the underground container is formed by placing a material.