JPS61134496A - Departure of shield excavator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for starting a shield tunneling machine.

[Prior art and problems]

Conventionally, when starting a shield excavator in rocky or sandy ground that is difficult to stand on its own, it is generally necessary to use soil consolidation methods such as chemical injection or freezing to strengthen the starting shaft. This was done by destroying or removing the opening of the shield to a size that would allow the shield tunneling machine to penetrate.

However, in this conventional construction method, the chemical solution has a
It is difficult to confirm the effects of freezing, and when the launch opening is destroyed or removed, the ground often collapses and flows into the launch shaft, causing the front ground to cave in and causing launch failures. However, there were problems such as the construction was complicated and the cost was high.

(Objective of the Invention) This invention was made in view of the above problems, and its purpose is to prevent the ground from collapsing and flowing in when starting a shield excavator in a ground that is difficult to stand on its own. It is an object of the present invention to provide a construction method that reliably prevents the occurrence of damage, is easy to construct, and is economically advantageous.

[Structure of the invention]

In order to achieve the above object, the present invention provides a group of ground reinforcement wire rods that can be cut by a shield excavator and has a large tensile resistance toward other mountains behind a position including at least the starting opening in a shield starting shaft. Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

In the ti1 diagram, 1 is the shield starting shaft.

Here, the shield launch shaft 1 is generally formed by a closed retaining wall. Earth retaining walls include steel sheet piles, column piles, diaphragm walls, caissons, etc., and this embodiment deals with diaphragm walls. .

First, the starting shaft 1 consists of an underground continuous wall 2 constructed by the muddy water construction method.

A fiber concrete wall 4 (hereinafter also referred to as a fiber mortar wall) is installed in the underground continuous wall 2 at a position where a launch opening 3 for penetrating a shield excavator (not shown) is to be defined.
is included.

When constructing the underground continuous wall 2, the fiber concrete wall body 4 is fixed integrally with the underground continuous wall 2 by incorporating it into reinforcing bars ff1 (not shown).

The fiber comfort wall 4 has a compressive strength of 100 kg/cJfffflf that can be cut with a shield excavator, and by mixing fibers such as glass fiber, it has sufficient bending strength to withstand external pressure from other mountains even though it is unreinforced. Use one with

Thereafter, the shield is excavated horizontally, diagonally upward, and in the required direction toward the ground behind the position of the starting port 3 made of the fiber concrete wall 4 in the shield starting shaft, for example, in the direction m in the shield excavation direction. A hole is formed diagonally downward using a drill pipe equipped with a drill bit at the tip using a caging vibrator. Then, at the same time as the drill pipe is pulled out, the wire rod 5 is inserted into the hole being drilled. Next, an assimilating agent is injected and filled between the wire rod 5 and the ground while pulling out the cage puffer pipe for preventing landslide from the inner circumferential wall of the borehole.

In this way, the wire rod 5n is placed on the ground behind.

Wire 5 cannot be cut by a shield excavator, and has a tensile strength of 11C.
-Jl11 bolts with high resistance are used for reinforcing bolts.

Glass fiber or synthetic fiber is suitable as the material for the bolt.

It should be noted that, depending on the condition of the ground behind, it is also possible to similarly arrange the wire 5 in the required direction from the position around the starting point toward other mountains behind. Not even.

In addition, 6 is a tunnel entrance wall, which is provided in a ring shape integrally with the underground continuous wall so that the shield IiI advancing machine can pass through.

Further, 7 is a reaction wall, 8 is a floor slab, and 9 is a cradle for a shield tunneling machine.

In this way, the shield tunneling machine is installed at a predetermined position within the starting shaft. Then, the shield excavator rotates the cutter disk, starts cutting the fiber concrete wall occupying the inside of the tunnel entrance wall 6, and starts the initial start.

After that, the shield excavator excavated the ground behind in accordance with the usual method, and the ground reinforced by the wire rod group started from the starting shaft without collapsing and flowing in (): In both cases, the wire rod 1
11 and then excavating Mt. Jllll.

〔Effect of the invention〕

As described above, according to the present invention, a group of ground reinforcing wire rods that can be cut by a shield excavator and have a high tensile resistance is installed in the shield starting shaft, at least including the starting opening, toward another mountain that is difficult to stand on its own in the back. By arranging it, it is possible to reliably prevent the ground from collapsing and flowing in when the shield excavator starts, and it is also easy to construct and can be said to be an economically advantageous construction method.

[Brief explanation of drawings]

FIG. 1 is a sectional view according to the second aspect of the present invention, showing a state in which wire rod groups are arranged before a shield tunneling machine is installed. ■・・Shield starting shaft 3・・Starting opening part 5・・Wire rod

Claims (1)

[Claims] A shield excavation machine characterized in that a group of ground reinforcing wire rods that can be cut by the shield excavation machine and have high tensile resistance are arranged in the shield starting shaft toward the ground behind at least a position including the starting opening part. How to start.