JPH02144500A - Construction of underground structure close to existing underground structure - Google Patents

Abstract

PURPOSE:To make it possible to avoid the influence of a newly constructed underground structure on an existing underground structure by inserting a large number of bar-shaped substances into a bedrock opposite to the newly constructed structure scheduled to construct to reinforce and improve the ground, and supporting the existing underground on the reinforced and improved ground. CONSTITUTION:After inserting bar-shaped substances 3 capable of extending to the inside of a bedrock from each of openings made on the ceiling surface of an existing tunnel 2, the end of each of the bar-shaped substances 3 to be exposed to the inside of the existing tunnel 2 is fixed to the existing tunnel 2. After insertion of the bar-shaped substances 3, the openings provided to the tunnel 2 are filled with a seal material such as mortar and the like to prevent underground water from getting into the tunnel. According to the constitution, the rigidity of the whole bedrock can be increased to reinforce and improve the ground.

Description

[Detailed Description of the Invention] <Industrial Application Field 5 The present invention relates to a construction technique for constructing a new underground structure such as a tunnel below an existing underground structure such as a tunnel or the foundation of a building. This invention relates to a method of constructing a new underground structure in close proximity to an existing underground structure, which allows new construction work to be carried out with minimal impact on the structure.

<Conventional Technology> Generally, when constructing a new tunnel (hereinafter referred to as a "new tunnel") below an existing tunnel, it becomes a problem to take measures to prevent deformation or destruction of the existing tunnel.

This is due to the subsidence of the supporting ground of the existing underground structure due to the excavation associated with the construction of the new tunnel.

We are currently taking the following measures to avoid such problems.

■Design with sufficient distance between the existing tunnel and the new tunnel so that the supporting ground of the existing tunnel is not affected.

■The new tunnel will use the shield construction method, which minimizes loosening of the surrounding ground.

■Improve and strengthen the ground surrounding the new tunnel using the one-liquid injection method.

<Problems to be solved by the present invention> The conventional countermeasure techniques described above have the following problems.

In the case of <A> ■, the larger the distance between the existing tunnel and the new tunnel, the less the impact on the existing tunnel, but on the other hand, the underground section cannot be used effectively.

Furthermore, there remains the problem that construction costs will increase as the depth of a new tunnel increases.

Cases 5 and 5 also have the problem of high construction costs.

Furthermore, although it would be possible to confirm the magnitude of the influence of the surrounding ground around the existing tunnel by constructing a new tunnel and the improvement effect of chemical injection, it is impossible to actually confirm this.

Therefore, the effectiveness of the improvement effects of shield construction methods and chemical injection can only be judged by whether or not the existing tunnels eventually become deformed or destroyed, and the existing tunnels are always exposed to the risk of deformation or destruction.

<Objective of the present invention> The present invention was made in order to improve the above-mentioned problems, and its purpose is to provide a method for constructing a new underground structure in close proximity to an existing underground structure as described below. do.

<A> A method of constructing a new underground structure close to an existing underground structure, which allows for effective use of underground space.

<Explanation> A method of constructing a new underground structure close to an existing underground structure, which can reduce construction costs.

(kuha) A method of constructing a new underground structure close to an existing underground structure that can reliably prevent deformation or destruction of the existing underground structure even if other structures around the newly constructed underground structure become loose.

<Means for Solving the Problems> When constructing a new underground structure near an existing underground structure, the present invention does not involve making improvements to other mountains surrounding the newly constructed underground structure. This is a construction method that improves the heating system. Specifically, it involves reinforcing the ground by inserting a large number of rod-shaped bodies into the ground surrounding the existing underground structure, on the opposite side of the new nearby structure that is scheduled to be constructed. By making improvements and supporting the existing underground structures on this reinforced and improved ground,
This is a construction method that minimizes the impact on existing structures caused by the construction of new underground structures.

<Configuration of the present invention> Next, one embodiment of the present invention will be described.

In this embodiment, a case will be described in which a new tunnel is constructed by crossing an existing tunnel below.

<B> Prior to construction of the new tunnel 1 by opening the hole on the side of the existing tunnel, reinforce the upper part of the existing tunnel 2 using the following procedure.

That is, as shown in FIG. 2, a large number of holes are bored in the ceiling surface of the existing tunnel 2.

The area to be drilled is not to cover the entire length of the existing tunnel 2, but to drill holes in the new tunnel 1, centering on the intersection with the new tunnel 1 to be constructed, as shown in Figure 1.3. This is a limited section that can cover the range 4 of loosening of other mountains that is expected due to construction.

<Exit> Insertion of rod-shaped bodies After inserting the rod-shaped bodies 3 into the ground through each opening made in the ceiling of the existing tunnel 2, insert the end of each rod-shaped body 3 exposed inside the existing tunnel 2 into the existing tunnel 2. Fixed to.

In principle, an extendable steel rod is used for the rod-shaped body 3, and a rock anchor construction method, an earth anchor construction method, etc. may be used in combination as necessary.

After inserting the rod-shaped body 3, the opening made in the existing tunnel 2 is filled with a sealing material such as mortar to prevent underground water from entering.

When a large number of groups of rod-shaped bodies 3 that did not exist before are inserted into the other piles above the existing tunnel 2, the rigidity of the rod-shaped bodies 3 is added to the rigidity of the other piles, increasing the rigidity of the whole mountain and improving the ground. Reinforcement improvements will be made.

Moreover, frictional resistance is generated between each of the many rod-shaped bodies 3 and other ridges,
The sum total of this frictional resistance becomes the supporting force of the existing tunnel 2.

<C> Insertion direction of the rod-shaped body The rod-shaped body 3 may be inserted directly above the existing tunnel 2, but it may be inserted at a certain angle to both sides so as to form a V-shape when viewed from the axial direction of the existing tunnel 2. May be inserted.

The insertion direction of the rod-shaped body 3 is selected in consideration of the geology of the ground where the existing tunnel 2 is to be improved, the supporting capacity of the existing tunnel 2, and the like.

<2> Construction of a new tunnel When the reinforcement and improvement work for the other mountain above the existing tunnel 2 is completed, approach the existing tunnel 2 and start construction of the new tunnel 1.

The new tunnel 1 intersects near the bottom of the existing tunnel 2 and continues to extend.

When constructing the new tunnel 1, in the case of conventional construction methods, it was natural to use the shield method, which has the least impact on the surrounding ground, and to use the chemical injection method in combination.

In the present invention, such conventional construction methods may not be adopted. Therefore, in the present invention, when constructing the new tunnel 1, the construction is not limited to the shield construction method, and any known construction method including the shield construction method can be employed.

Moreover, there is no need to improve the ground by injecting chemical solution into other mountains around the newly constructed tunnel 1 that intersects with the existing tunnel 2.

Even if the ground in loosening range 4 loosens, the descent of the existing tunnel 2 will be supported by the group of 3 rods inserted into the ground above the existing tunnel 2, as shown in Figure 3. There is no need to worry about subsidence, deformation, or damage to the existing tunnel 2.

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

(a) Since a large number of rod-shaped bodies serve as supporting members for the existing underground structure, it is possible to reliably prevent the existing underground structure from sinking, deforming, or being damaged due to the installation of a new underground structure.

<Exposure> Compared to conventional construction techniques, the planned new underground structure can be designed closer to the existing underground structure.

Therefore, underground space can be used effectively.

<C> Conventionally, when constructing a new underground structure near an existing underground structure, maximum efforts were made to avoid loosening of the ground on the side of the newly constructed underground structure.

On the other hand, in the present invention, the existing underground structure is supported by the ground above it, so unlike the conventional method, it is essential to reinforce the surrounding ground of the newly constructed underground structure and to adopt the shield method. Not a condition.

Moreover, the present invention only uses a rod-shaped body that is inserted over a limited area from within the existing underground structure, and does not require injection of chemical liquid.

Therefore, construction costs can be significantly reduced compared to conventional methods.

[Brief explanation of the drawing]

Fig. 1 2 Overall explanatory diagram after construction of the method according to the present invention Fig. 2: Cross-sectional view of the existing tunnel to explain the state of insertion of the Ia-shaped body Fig. 3: Front view of the tunnel after construction

Claims (1)

[Claims] (1) In the method of constructing a new underground structure in close proximity to an existing underground structure, it is necessary to conduct a survey from inside the existing underground structure to the surrounding area over a certain section centered on the intersection with the newly planned underground structure. A large number of rods are inserted into the ground to strengthen and improve the ground, each rod is fixed to the existing underground structure to support the existing underground structure, and then a new underground structure is constructed. , A method of constructing a new underground structure in close proximity to an existing underground structure.