JPH10280882A - Tunnel construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tunnel construction method using a simple and inexpensive timbering in place of a sheet pile method. SOLUTION: At the time of constructing a tunnel by a tunnel boring machine(TBM) 1, corresponding to the advance of the TBM 1 for one stroke, bar-like prelining members 11B, 11A for preventing a rock drop are inserted between the skin plate 12 of the TBM 1 and the boring surface 10 at spaces in the circumstantial direction. The prelining member 11B, 11A are supported by an extensible ring timbering 12 in the rear of the skin plate 2, and in such a condition, advanced while concrete 20 is sprayued to the boring surface to construct a timbering structure 100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a tunnel by using a tunnel boring machine (hereinafter abbreviated as "TBM").

[0002]

2. Description of the Related Art The TBM method is based on
High-speed excavation without support is possible, and its advantages can be fully exploited.However, excavation at cracked mountains where faults and small landslides are likely to occur and poor geology of fault crush zones are not good. The excavation will be performed while supporting the ground by means of all-around segments.

However, in this case, the installation position of the support is
In the TBM method, since rocks are located far behind the face, rocks in unstable geological areas fall out, and TBM excavation is carried out with the rocks resting on the upper part of the fuselage skin plate. You will fall into the mine.

Conventionally, tunnel support in the TBM method has been mainly based on a feed sheet pile method. That is, in the state where the above-mentioned rocks have fallen off after passing through the rear end of the TBM, a ring support or the like is assembled and installed on the excavated surface, and a sheet pile or the like is applied to this to construct a support structure.

[0005]

However, in the current feed sheet pile method, the problem remains in securing the quality of the tunnel because the excess digging increases and the slack area is allowed to progress. In addition, a lot of work time is required for unloading rocks that have fallen into the mine, setting up supports, and treating the ground at the collapse site.
There was a problem that the excavation speed of M became slow.

The present invention has been made in consideration of the above circumstances, and has as its object to provide a tunnel construction method using a simple and inexpensive support system that replaces the conventional sheet pile method.

[0007]

According to a first aspect of the present invention, when a tunnel is constructed by a tunnel boring machine, the skin plate and the excavation surface of the tunnel boring machine correspond to the excavation of the tunnel boring machine for one stroke. Insert a rod-shaped support material for rock fall prevention at intervals in the circumferential direction, and support the support material with an extendable ring support behind the skin plate. The support structure is constructed by spraying concrete on the excavated surface.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. According to the construction method of the present invention, since the shotcrete functions stably in the tunnel, the concrete is used as a basic member of the support, and the TBM body skin is formed by using a precedent material and an extendable ring support having an expansion function. Rocks and the like placed on the upper part of the plate are not dropped into the mine, but are held and fixed on the ground around the tunnel to stabilize it as a tunnel structure.

The construction procedure will be described in order with reference to FIGS. As shown in FIG. 1, the TBM 1 is provided with a cutter head 1A at the tip, a skin plate 2 at a rear fuselage, a thrust jack 3, a main gripper 4 and the like at a rear portion inside the machine. The TBM 1 projects the main gripper 4 on the pit wall, takes a reaction force therefrom, rotates the cutter head 1A while extending the thrust jack 3, and excavates one stroke. The rock on the skin plate 2 that has fallen from the excavation surface 10 during this excavation is held by the front support 11B simply supported by the extendable ring support 12 one ring before and the end of the skin plate 2. . This advance material 11
B is a rod-shaped member which is inserted between the skin plate 2 and the excavation surface 10 at an appropriate circumferential distance in advance before the excavation for one stroke of the TBM 1.

When the TBM 1 has excavated for one stroke, as shown in FIG. 2, an extensible ring support 12 is assembled just below the skin plate 2 of the TBM 1 so as to support the support 11B from below. This is fixed to the ring supporter 12 just before by a tie rod 16.

Next, as shown in FIG. 3, the next precedent material 11A is placed in a vacant space between the existing precedent materials 11B.
Insert. At this time, while using the extensible ring support 12 and the preceding receiving member 11B as a guide,
Using a driving device, the front receiving material 11A is inserted into the gap on the back surface of the skin plate 2. After inserting the front receiving material 11A, as shown in FIG. 4, the extendable ring support 12 is mechanically pushed upward to narrow the gap between the back ground and the ground as much as possible. A fixed key is sandwiched between the extendable mechanism 13 of the extendable ring support 12 as shown, and the ring support 12 is fixed.

Next, as shown in FIG. 5, the shotcrete 20 is sprayed on the excavation surface 10 to construct the support structure 100. In addition, according to the properties of the ground,
The shotcrete 20 may be sprayed after a lock bolt, an injection-type long precedenter, or the like is constructed in the gap between the holes A and 11B. In addition, spraying concrete may be sprayed to stabilize the stretchable mechanism 13.

The operations of driving the receiving members 11A and 11B, assembling the ring support 12 and spraying the shotcrete 20 are performed by using the multifunctional arm of the TBM support workstation 50 as shown in FIG. Can be done automatically. In such a case, each arm may be equipped with a preloading device driving device 51, a spraying device 52, and a support setter 53. In addition, when performing the injection type long tip receiving method, FIG.
As shown in the figure, a large number of small-hole pipe-shaped receiving members 61 may be inserted into the excavation surface 10 and mortar or the like may be injected into the ground from the holes of the receiving members 61.

Further, as the kind of the precedent material, for example, the kind shown in FIG. 9 can be considered. The first receiving material 71 shown in (a) is curved in the width direction.
A shell structure integrated with the ground can be formed in combination with shotcrete instead of the entire circumference segment. The receiving material 72 shown in (b) is also curved in the length direction, and functions to push up a large lump of rock that has fallen off during the TBM excavation to the ground side. When this front receiving material 72 is used together with a rock bolt, the rock is firmly held in the ground.
Can be fixed. The receiving material 73 shown in (c) has a chevron structure, and functions to prevent small lumps of rock falling onto the skin plate from sliding into gaps between the tunnel side wall and the bottom plate.

[0015]

As described above, according to the first aspect of the present invention, reliable support and high-speed excavation can be achieved in the ground where the surface falls, falls off, or slightly collapses in unstable geological parts. .
In addition, since the support system is based on shotcrete, tunnel quality can be ensured. In addition, the size, shape and arrangement of the precedent material can be appropriately selected and determined according to the size of the rock falling off on the skin plate and the state thereof, so that reliable economic construction is possible. Further, if a multifunctional arm or the like to be mounted on a TBM support workstation or the like is used, mechanical construction of the support can be performed.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a process explanatory view of a construction method according to the present invention, in which (a) is a side view and (b) is a front view.

2 (a) is a side view and FIG. 2 (b) is a front view.

FIGS. 3A and 3B are explanatory views of the next step of FIG. 2, wherein FIG. 3A is a side view and FIG.

FIGS. 4A and 4B are explanatory views of the next step of FIG. 3, wherein FIG. 4A is a side view and FIG.

FIGS. 5A and 5B are explanatory views of the next step of FIG. 4, wherein FIG. 5A is a side view and FIG.

FIG. 6 is a diagram showing a state where mechanical construction is being performed by a TBM support workstation in the construction method of the present invention.

FIG. 7 is a diagram showing a state in which another mechanical construction is being performed by a TBM support workstation in the construction method of the present invention.

FIG. 8 is an enlarged view of a stretchable portion of a ring support used for carrying out the construction method of the present invention.

9 (a) to 9 (c) are perspective views showing types of a precedent material used for carrying out the construction method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tunnel boring machine (TBM) 2 Skin plate 10 Drilling surface 11A, 11B, 61, 71, 72, 73 Preceding material 12 Stretchable ring support 20 Shotcrete

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Atsuyuki Kimura 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Kosuke Kamimi 2-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd.

Claims (1)

[Claims] When a tunnel is drilled by a tunnel boring machine, a rod-shaped rock-fall preventive plate is provided between a skin plate of the tunnel boring machine and an excavation surface in correspondence with excavation of the tunnel boring machine for one stroke. Insert the supporting members at intervals in the circumferential direction, support the supporting members behind the skin plate with an extendable ring support, and spray concrete on the excavated surface in this state to support the support structure. A tunnel construction method characterized by constructing a tunnel.