JPH10231700A - Method for building tunnel timbering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten working time spent between the building of timbering and the expansion of bags and introduction of preload, to prevent soft areas of the ground around the tunnel from expanding at an early stage, and to ensure the safety of work. SOLUTION: To build the timbering 2 along the circumference of the excavation cross section of a tunnel, after bags 4, 6 for introducing preload are built along the circumference of the timbering 2, the timbering 2 is installed along the circumference of the excavation cross section of the tunnel. In a method for building the timbering 2, bag displacement prevention members 3 are provided at the working face on the circumference of the timbering 2 and the edges on the opposite side or both edges.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for erection of a tunnel supporter.

[0002]

2. Description of the Related Art In recent years, in tunnel construction, there has been an increasing number of constructions on collapsed soils having a structure on the top or a thin covering. In the case of such a construction, a precedent construction method is adopted for the purpose of preventing the advance loosening of the ground and the collapse of the face and the top end.

As shown in FIG. 3, in the pre-receiving method, a plurality of pre-receiving steel members "a" are driven in front of the cutting face along the outer periphery of the excavated cross section of the tunnel, and a steel arch is inserted inside the pre-receiving steel members "a" group. This is a method of digging by shoring a support b or the like.

Conventionally, in this prior receiving method, after the support b is erected, the bag c is pushed into the gap between the outer peripheral surface of the support b and the ground, and the mortar d is filled in the bag c. In addition, a method of introducing a preload into the surrounding mountain is also performed.

[0005]

The conventional method of introducing a preload is excellent in that the loosening of the ground and the collapse of the face and the top can be reliably prevented, but the following problems are encountered. Unresolved. <B> The work of pushing the bag into the narrow gap between the outer peripheral surface of the support and the ground requires labor, and the time required for the work becomes long.

<B> The pushed-in bag is stopped by the support with only the rubber band. However, when the bag is inflated, the rubber band may come off and the bag may be shifted from the support or fall. Wasted time such as fixing and reattachment was required.

<C> Due to the delay in the operation described in (a) and (b) above, a long time elapses before the mortar is injected into the bag and the preload is introduced. Therefore, at the time when the slope of the characteristic curve becomes the largest in the initial stage of excavation, that is, at the time when the progress of the loosening is the most intense, the progress of the loose area around the tunnel around the tunnel cannot be suppressed.

<4> The pushing operation of the bag body is a dangerous operation immediately below the face because the worker manually rides on an aerial work vehicle.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and shortens the working time from the work of erecting a supporter to inflating a bag and introducing a preload. In addition, it is an object of the present invention to provide a method for installing a tunnel shoring capable of suppressing the progress of a loose area in the ground around the tunnel at an early stage and securing work safety.

[0010]

As a means for solving the above-mentioned problems, in a method of erection of a shoring along a perimeter of an excavated cross section of a tunnel, a bag for introducing a preload is provided on an outer peripheral surface of the shoring. After the deployment, a method of erection of a tunnel shoring is provided, wherein the shoring is erected along the outer periphery of the excavated cross section of the tunnel.

Further, in the above-described method for mounting a tunnel support, the slip prevention member for the bag body is protruded at an edge or both edges of the outer peripheral surface of the support opposite to the face. Provide a method of building tunnel support.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

<A> Driving of Precedent Steel Material As shown in FIG. 1, prior to tunnel excavation, a plurality of precedent steel materials 1 are driven along the outer periphery of the excavation section. As the first steel material 1, a steel pipe, an H-shaped steel, or the like is used.

The driving direction of the front receiving steel material 1 is parallel or slightly inclined with respect to the axis of the tunnel, and is driven in front of the face or inserted after excavation. Then, one end side of the front receiving steel material 1 is a predetermined length from the face face (the length at which the shoring can be installed).
Protrude into the tunnel.

<B> Shoring The shoring 2 is for directly supporting the roof formed by the first group of steel members. For the support 2, a steel arch support as shown in FIG. 1 is used. In principle, steel arch supports are embedded in concrete lining.

There are various types of steel arch supports,
Use appropriate ones considering the geology, cross-sectional shape, excavation method, lining method, etc. of the tunnel. As the steel material to be used, I type, H type, V type, rail and the like are used.

<C> Displacement Prevention Member The displacement prevention member 3 is provided on the outer peripheral surface of the support 2 to prevent the bag body from being displaced or dropped. For example, FIG.
It is conceivable that an angle steel material as shown in FIG. 1 is welded in advance along the both edges of the support 2 before embedding the support.

Although various shapes such as a rod-like body and a plate-like body can be adopted as the slip prevention member 3, the shape is such that the bag is not damaged by the slip prevention member 3 when the bag is inflated. Also,
The height of the slip prevention member 3 from the outer peripheral surface of the support 2 is set in consideration of the size of the bag when inflated and the like so that a sufficient slip prevention effect can be obtained when the bag is inflated. Further, it is necessary to provide a strength that does not cause deformation due to the expansion pressure of the bag.

In the case of FIG. 2, the slip prevention member 3 is
This is the case where it is provided on both edges of the outer peripheral surface, but it may also be provided only on the edge 21 opposite to the face. In this case, the face side of the bag is supported by the face face of the tunnel.

In addition to the case where the slip preventing member 3 is provided intermittently as shown in FIG. 2, there may be a case where it is provided continuously along the outer peripheral surface of the support 2. The slip prevention member 3 may be attached by bolting instead of welding, or may be formed integrally with the support 2 in advance.

<D> Upper Bag 4 The upper bag 4 is a flexible bag disposed between the roof formed by the first group of steel members and the support 2. The upper bag body 4 may be constituted by an integral body communicating over the entire length, a body whose inside is divided into a plurality of rooms, or a plurality of independent bag bodies.

The material of the upper bag body 4 is filled with mortar, so that the mortar can be prevented from flowing out, and a material having air permeability that allows only air to be discharged to the outside is used. For example, it is good to form with a fine cloth. Further, the mortar may be formed of a material having a dehydrating property (a coarse cloth or the like) so that only water in the mortar can be discharged.

When the upper bag 4 is formed of a water-blocking member such as rubber, it is preferable to connect an exhaust pipe to release air in the bag when filling the mortar to the outside. In addition, it is good to open a mortar inlet at an appropriate place in the upper bag body 4 and to make this inlet a check valve structure.

<E> Attachment of the upper bag to the shoring Before the shoring of the shoring 2, the upper sack 4 is attached to the outer peripheral surface of the shoring 2 at a low place such as on the floor away from the face. Attach. The structure in which the upper bag body 4 is attached to the support 2 is not particularly limited because various structures can be considered. As an example, it is conceivable that the upper bag body 4 and the shoring 2 are restrained at appropriate intervals by a stop band 5 formed of an elastic member such as rubber.

<F> Embankment / Embedment of upper bag body The embankment 2 to which the upper bag body 4 is mounted in advance is installed inside a portion of the group of first steel members protruding into the tunnel. At this time, the bottom bag 6 may be provided below the leg 22 of the support 2. The bottom bag 6 has the same material and configuration as the upper bag 4.

<G> Mortar Pressure Injection When the setting of each member is completed, the mortar 7 is injected under pressure into the upper bag body 4 and the bottom bag body 6. As a result, the upper bag body 4 and the bottom bag body 6 are inflated, so that the preload can be introduced into the surrounding ground, and the progress of the loose area around the tunnel surrounding ground can be suppressed. Then, under such a safe face condition, the excavation of the tunnel is advanced.

[0026]

Since the present invention has been described above,
The following effects can be obtained. <B> After the bag is attached to the shoring, the shoring is erected, so that the erection work is facilitated and the time required for the operation can be reduced.

<B> Since the bag body is not likely to be displaced or dropped from the support when inflated by the displacement prevention member, it is not necessary to waste time for displacing or reattaching the bag.

<C> Since the work can be sped up as described above, the work time from injecting the mortar into the bag and introducing the preload can be shortened. Therefore, it is possible to suppress the progress of the loose area around the tunnel at an early stage. Therefore,
Prevention of loosening of the ground and prevention of collapse of the face and top end can be ensured, and the influence on the upper structure can be reduced.

<D> Since the work of attaching the bag body to the shoring work can be performed at a low place such as on the floor away from the face, safety of the work can be ensured.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is an explanatory view of an example of a slip prevention member.

FIG. 3 is an explanatory view of a conventional technique.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshihiko Aoki 1-25-1, Nishishinjuku, Shinjuku-ku, Tokyo Taisei Corporation

Claims (3)

[Claims] 1. A method of erection along a perimeter of an excavation section of a tunnel, comprising: providing a bag for introducing a preload on an outer peripheral surface of the support; A method of building a tunnel shoring, characterized in that it is built. 2. The method for erection of a tunnel shoring according to claim 1, wherein a member for preventing displacement of the bag body is protruded from an edge of the outer peripheral surface of the shoring opposite to the face. How to build tunnel support. 3. The tunnel supporting method according to claim 1, wherein the bag body is prevented from slipping at both edges of an outer peripheral surface of the supporting structure. How to build the shoring.