JPH03293500A - Construction method for large underground space - 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 <Industrial Application Field> The present invention relates to a construction technique for effectively utilizing underground space and forming a large underground space.

<Prior Art> The following two methods are currently known as construction methods for forming large underground spaces.

One method is to construct a spiral tunnel around an underground cavity, drive rock bolts into the ground from inside the tunnel to counteract the stress of the ground, and excavate the area surrounded by the spiral tunnel to create an underground tunnel. It is a method of constructing large spaces.

Another method is to form a lining that matches the outline of an underground cavity while adjoining a plurality of shield tunnels, and then excavate the inside of the lining to construct a large underground space.

The two differ in that the former construction method constructs adjacent tunnels with a certain distance between them, while the latter construction method constructs adjacent tunnels adjacent to each other.

<Problems to be Solved by the Present Invention> The conventional construction techniques for large underground spaces described above have the following problems.

<B> In the construction method using a spiral tunnel, the spiral tunnel does not directly serve as a lining, so a separate lining construction work is required.

Furthermore, since the spiral tunnel does not exhibit any water-stopping function during excavation work, a separate water-stopping work is required.

<Entrance> In the case of a method of constructing tunnels adjacent to each other, high construction accuracy is required for each tunnel.

If each tunnel is constructed incorrectly, it may be difficult to close or it may become impossible to construct.

Compared to the case of spiral tunnels, the number of tunnels to be constructed increases, and it is difficult to connect adjacent tunnels in a strong and waterproof manner.

<Objective of the present invention> The present invention has been made to solve the above problems, and its purpose is to solve the problems described above.
Moreover, it is an object of the present invention to provide a construction method for a large underground space that is excellent in workability and economy.

<Means for solving the problem> That is, the present invention constructs a shaft that reaches both ends of a large underground space to be constructed, and from inside the shaft, a plurality of independent Build a leading tunnel, improve the ground around the leading tunnel, then build a trailing tunnel while excavating each of the improved ground, improve the ground around the trailing tunnel, and integrate it with the leading tunnel. This is a construction method for large underground spaces, in which an improved layer is formed, the inside of the outer shell, which is made up of multiple tunnels and a reinforcing layer connecting each tunnel, is excavated, and the inner surface of the outer shell is then lined.

<Description of the present invention> The present invention will be described below with reference to the drawings.

<B> Construction of shafts (Figure 1) Construct shafts 1 and 2 that reach both ends of the large underground space to be constructed.

<Entrance> Construction of the outer shell (Figs. 1 to 3) While the shield machine 3 is moved back and forth between the shafts 1 and 2, a plurality of shield tunnels 4 are constructed along the outer periphery of the large underground space.

One or more shield machines 3 may be used, or a single shield machine that can construct a plurality of tunnels at the same time may be used.

Adjacent shield tunnels 4.4 do not need to be constructed with particularly high precision as in the past, and it is sufficient that they have approximately equal intervals.

The reason will be explained later.

Next, after constructing each shield tunnel 4, this tunnel 4
Surrounding underground tunnels 4 by injection method etc.
The group forms an outer shell 6.

That is, each shielded outer shell 6 is constructed independently.
form.

A more preferable construction method for the outer shell 6 is to construct shield tunnels 4a and 4b every other or more number of shield tunnels, as shown in FIG.
, 4b are constructed with reinforcing layers 5a and 5b on the surrounding ground.

Then, a shield tunnel (not shown) was constructed behind the shield machine 3 by making the shield machine 4 dig between the previously constructed shield tunnels 4a and 4b while excavating a part of each reinforcing layer 5a and 5b. Thereafter, the ground is improved from within this shield tunnel to construct a reinforcing layer 5c as shown by the dashed line and to integrate it with the reinforcing layers 5a and 5b.

As described above, in the present invention, even if the construction accuracy of each shield tunnel 4 is somewhat low, it can be compensated for by widening and narrowing the formation range of the reinforcing layer 5, so there is no need to construct shield tunnels with high precision as in the conventional case.

Further, when constructing the reinforcing layer 5, if an auxiliary method such as rock bolts is used in combination, the connecting portions of each reinforcing layer 5 can be connected more strongly.

<C> Excavation (Figure 4) Once the construction work of the outer shell 6 has been improved, the interior of the outer shell 6 is excavated.

At this time, the vertical shaft 1.2 shown in the 11th ffl will be used as a space for excavating and discharging soil.

<2> - Method lining (Fig. 4) A primary lining 7 such as shotcrete is applied to the inner surface of the outer shell 6 exposed by the excavation.

This prevents the outer shell 6 from collapsing during excavation.

Note that the primary cover may be omitted depending on conditions such as the cross-sectional diameter and cross-sectional shape of the outer shell 6.

<E> Lining (Fig. 5) After the excavation work inside the outer shell 6 is completed, lining concrete 8 is poured over the entire inner peripheral surface of the outer shell 6 to obtain a large underground space.

<Other Examples> Although the above embodiment describes the case where the shield tunnel 4 is constructed using the shield construction method, the tunnel may be constructed using the thrust construction method.

Further, in the above embodiment, the case where the cross-sectional shape is a horizontally long ellipse has been described, but the large space can be constructed in any shape such as a circle or a rectangle.

<Effects of the Present Invention> Since the present invention is as described above, the following effects can be obtained.

<B> By connecting independent tunnels with an improved layer, a continuous outer shell can be constructed.

Therefore, high precision is not required in the construction of each tunnel.

〈口〉 Since excavation is carried out after constructing a continuous shell, the safety of excavation work is further improved.

Furthermore, by using the spraying method in combination, reliability against collapse when the underground space is opened is further improved.

<C> Compared to the conventional method of constructing many tunnels adjacent to each other, the number of tunnels can be reduced.

Therefore, it is advantageous in terms of construction period and construction cost compared to conventional construction methods.

<2> The interior space of each tunnel can be used as space for piping, wiring, and drainage channels.

[Brief explanation of drawings]

Figure 1: An explanatory diagram of an embodiment of the present invention, showing a cross-sectional view of the underground part. Figure 2: A cross-sectional view of the outer shell constructed around a large underground space. Figure 3: A method of constructing the outer shell. Figure 4: Cross-sectional view of the outer shell showing the excavation process inside the shell Figure 5: Cross-sectional view of the large underground space where construction has been completed National policy 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) Construct a shaft that reaches both ends of the large underground space to be constructed, construct multiple independent preceding tunnels from within the shaft along the perimeter of the large underground space to be constructed, and The ground is improved, and then each of the above-mentioned improved ground is excavated to construct a trailing tunnel, and the ground around the trailing tunnel is improved to form an improved layer that is integrated with the leading tunnel, and multiple tunnels and A construction method for large underground spaces that involves excavating the inside of the outer shell, which is made up of reinforcing layers that connect each tunnel, and then lining the inner surface of the outer shell.