JP2799899B2 - Structure and construction method of branch of underground tunnel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a branch portion of a plurality of underground horizontal tunnels having different heights, and relates to a structure of a branch portion performed through a vertical shaft and a method of constructing the branch portion. It is about.

<Conventional technology> When constructing a common ditch, water supply and sewerage in a city, a shield method and a propulsion method are often used.

This is because these construction methods are advantageous in that a pipeline can be constructed underground without affecting the ground.

<Problems to be solved by the present invention> However, even the above-mentioned method has the following problems, and the range of use has been limited.

<B> In many cases, the underground of an intersection becomes a branch of a pipeline.

However, many existing underground structures are often concentrated at intersections, and it is extremely difficult to open the ground to perform work.

<B> For that purpose, the freezing method of freezing the surrounding ground, reinforcing it, and opening it out is also used, but it is expensive and uneconomical.

<Object of the present invention> The present invention has been made to solve the above problems, and an object of the present invention is to provide the following structure and construction method of an underground tunnel.

<B> Structure and method that can work without affecting the ground even in places where underground structures such as intersections are concentrated <b> Economical compared to special methods such as freezing Structure and method that can be constructed <Means for solving the problems> That is, the present invention relates to a structure in which one horizontal tunnel constructed underground and horizontal tunnels having different heights are connected underground. The underground tunnel branch structure is composed of a shaft constructed downward from the bottom of one horizontal tunnel, and another tunnel connected through the lower part of the shaft.

Further, the present invention, after improving the ground around the horizontal tunnel constructed underground, reinforced the interior of the portion of the horizontal shaft planned to be constructed pits, dismantle the floor member of that portion, the surrounding ground exposed after dismantling This is a method of constructing an underground tunnel branch by excavating a shaft and protecting the inside of the shaft with concrete.

<Description of the present invention> Hereinafter, the present invention will be described in detail according to the order of construction.

<A> Construction of horizontal tunnel (Fig. 1) Horizontal tunnel 1 is underground by shield method and propulsion method
To build.

As a construction member of the tunnel 1, a pipe body such as a fume pipe and a concrete segment can be used. However, in order to facilitate the construction of the present method, it is efficient to use a steel pipe at least only in a planned pit area. The case will be described.

<B> Ground improvement (Fig. 2) The surrounding ground will be improved at the planned site for shaft construction.

For this purpose, a boring device 2 is installed in the horizontal tunnel 1, a hole is drilled in the ground through a wall surface, and a chemical solution is injected from the inside of the horizontal tunnel 1 to the surroundings.

<C> Reinforcement of steel pipe (Fig. 3) In preparation for dismantling the bottom of the horizontal tunnel 1, the surrounding area is reinforced.

As a method of reinforcement, for example, a pipe having a small diameter is driven outward to provide a pipe roof 3 to fix the upper part of the horizontal tunnel 1 and reinforce the upper part of the shaft during excavation.

Further, in order to reinforce the opening during excavation, the upper half of the horizontal tunnel is held from below by an arc-shaped ring 4 made of H steel.

Further, a horizontal girder 5 is stretched over the horizontal maximum diameter portion of the horizontal tunnel 1 to reinforce the periphery of the opening.

<D> Pit excavation (Fig. 4) The pit 6 is excavated under a safe condition by reinforcing the upper part.

As the excavation progresses, the surrounding wall surface is
Temporarily hold with earth retaining material such as.

A backfill material 8 is injected into the space between the liner plate 7 and the wall soil.

The horizontal cross-sectional shape of the shaft 6 can be constructed in a shape required at the site, such as a circle or a rectangle.

<E> Concrete work (Fig. 5) After excavation of the shaft 6 has been completed, reinforcing steel
After assembling the steel frame, concrete 9 is cast.

Further, the upper reinforcing material is removed, and concrete 9 is poured into the horizontal tunnel 1 from the inside to complete the structure as an integrated structure.

<F> How to use as a branch structure (Fig. 6) With the underground shaft 6 constructed in this way facing the side, a new tunnel 10 will be constructed at a different height in the future.

The branching is completed when the tip of the new tunnel 10 hits the wall surface of the shaft 6 constructed by the above method and opens.

<Effects of the Present Invention> The method of the present invention completes the branching of a plurality of tunnels having different heights by the above-described steps, so that the following effects can be achieved.

<B> This is a method in which a vertical shaft is once created in the ground without branching directly from the horizontal tunnel, and branching is performed through this shaft.

Therefore, as compared with a method in which branching is performed directly on the same narrow plane in a tunnel, the branching work has no effect on the main pipe in use, so that the work is extremely easy.

<B> When the branch path is completed, it is necessary to branch the tube group in use next, and since the branch section is provided with various devices, the structure becomes extremely complicated.

In that case, in the branch structure of the present invention, a large space is formed in the vertical direction, so that many new devices can be added.

Subsequent operation and inspection work of such a branching device is also easy.

[Brief description of the drawings]

 FIG. 1 to FIG. 6: explanatory diagrams of the work sequence of the present invention.

Claims (2)

(57) [Claims] Claims: 1. A structure for connecting one horizontal tunnel constructed underground to another horizontal tunnel having a different height, wherein the horizontal tunnel is constructed downward from the bottom of one horizontal tunnel. Underground tunnel branch structure consisting of a shaft and another tunnel connected through the lower part of the shaft 2. After improving the ground around a horizontal tunnel constructed underground, reinforcing the inside of a portion of the horizontal tunnel planned for vertical shaft construction, disassembling a floor member of the portion, and removing the surrounding ground on the exposed ground after dismantling. Of underground tunnel branch by excavating shaft while protecting concrete, and reinforcing the inside of shaft with concrete