JP2002194986A - Tie rod construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to obtain a sufficient anchorage effect without causing the deterioration of construction efficiency. SOLUTION: A tie rod construction method is employed when a loosening area A is expected to be in the area above a tunnel 10. When the tunnel 10 is constructed under the expected loosening area A, hollow, cylindrical sheath pipes 12 are buried in the ground 14. When the boring operation of the tunnel 10 proceeds and reaches the position where the sheath pipes are arranged, the lower end of the sheath pipes are exposed to the boring surface and an anchor 18 is inserted into each sheath pipe from the ground surface in the process of anchoring the both ends of the anchor to the ground side and to the tunnel 10 side, respectively, to suspend the loosening area A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tie rod method, and more particularly to a tie rod method employed when a loose area is assumed on an upper side of a tunnel to be constructed.

[0002]

2. Description of the Related Art In order to safely construct a tunnel under a bad ground where the top of the tunnel is largely settled, an auxiliary construction method of suspending the top of the tunnel upward is adopted.

In this type of auxiliary construction method, for example, as shown in FIG. 5, a lock bolt or a bolt which penetrates upward through the slack region 2 with respect to a slack region 2 assumed on the upper side of a tunnel 1 to be constructed. A method of burying a bolt material 3 such as a cable bolt is employed. However, such a conventional auxiliary method has a technical problem described below.

[0004]

That is, when suspending the slack region 2 by the conventional auxiliary method, if the slack region 2 is assumed to be large, the tip of the bolt member 3 is projected out of the slack region 2. Since the projecting portion is fixed, a very long bolt member 3 is required.

[0005] In addition, the embedding of the bolt material 3 by the conventional auxiliary method is an upward construction from the inside of the tunnel 1.
There is a problem that a fixing material such as mortar for fixing the bolt member 3 falls down by its own weight and a sufficient fixing effect cannot be obtained.

Further, since the bolt material 3 is buried from the inside of the tunnel 1, the length of the bolt material 3 which can be used is limited by the diameter of the tunnel or the like. During the burial work, since the tunnel construction is temporarily interrupted, the construction work of the tunnel 1 is greatly affected, which is one of the factors that greatly reduces the construction efficiency.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a tie rod method capable of obtaining a sufficient fixing effect without lowering the construction efficiency. Is to do.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a drilling method in which, before excavation of a tunnel, the drilling penetrates an assumed loose area and a lower end reaches into the excavation surface of the tunnel. Excavation from the ground surface side, a hollow tubular sheath pipe is installed in the borehole, the excavation of the tunnel reaches the installation position of the sheath pipe, the lower end is exposed to the excavation surface, An anchor body was inserted into the sheath tube, and upper and lower ends thereof were fixed to the ground surface side and the inside of the tunnel, and the slack area was suspended by the anchor body.

[0009] According to the tie rod method constructed as described above, before excavation of the tunnel, a drill hole that penetrates the assumed loose area and whose lower end reaches the excavation surface of the tunnel is excavated from the surface of the ground. A hollow tubular sheath tube is installed in the hole, and tunnel excavation reaches the installation position of the sheath tube,
When the lower end is exposed on the excavation surface, the anchor body is inserted into the sheath pipe, and the upper and lower ends are fixed on the ground surface side and the inside of the tunnel, and the slack area is suspended by the anchor body. Can be performed safely.

In this case, the work of inserting the anchor body can be performed from the ground surface side, and the fixing of the end is also performed on the ground surface side and in the tunnel.
There is no problem of the fixing material falling under its own weight, and a sufficient fixing effect can be obtained.

[0011] The anchor body may have an upper end fixed to a bearing plate installed on the ground surface and a lower end fixed to a steel arch support of the tunnel.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1 to 4 show one embodiment of a tie rod method according to the present invention. The tie rod method shown in the figure is a method applied when a loose area A is assumed on the upper side of the tunnel 10 to be constructed.

In the case of this embodiment, the assumed loose area A
Is a tunnel 10 for soft ground, bad ground, low earth cover, etc.
For example, in the case where it is confirmed by a preliminary ground survey or the like, or when it is a loose area generated by tunnel excavation and the tunnel 10 needs to be constructed below the assumed loose area A, Before excavation of the tunnel 10, as shown in FIG.
Is buried in the ground 14.

As the sheath tube 12, a hollow tube such as a steel tube or a rigid PVC tube is used. The sheath tube 12 penetrates through the slack area A from the surface side so that the lower end reaches the excavation surface of the tunnel 10 to be constructed. Next, a hole 16 corresponding to this length is excavated, and the sheath tubes 12 are respectively installed in the excavated holes 16.

In this case, the bore 16 is formed by, for example, percussion drilling. In order to securely fix the sheath tube 12 in the bore 16, a hole is formed between the sheath tube 12 and the inner surface of the bore 16. A solidifying material such as CB mortar may be filled.

A plurality of such sheath tubes 12 are arranged at appropriate intervals in the vertical and horizontal directions in consideration of the length of the loose area A along the axial direction of the tunnel 10 and the width along the cross-sectional direction. Set up.

Then, as shown in FIG.
When the excavation proceeds and reaches the installation position of the sheath tube 12 and the lower end side of the sheath tube 12 is exposed on the excavation surface, the anchor body 18 is inserted and fixed in the following procedure.

The anchor body 18 is, for example, an anchor bolt having a threaded portion at each end, and is provided with each sheath tube 12.
Inside is inserted from the ground side. At this time, the bearing plate 20 is installed on the ground surface side.

In the case of this embodiment, the supporting plate 20
Is formed by an RC structure, and has an area covering the upper surface of the sheath tube 12. On the other hand, when the tunnel 10 is excavated, the steel arch-like support 22
Is installed.

In this embodiment, the anchor body 18 inserted into each sheath tube 12 is fixed at its upper end to a supporting plate 20 provided on the ground surface, and its lower end is formed in an arched shape installed in the tunnel 10. It is fixed on the shoring 22.

FIGS. 3 and 4 show details of the fixing state. FIG. 3 shows a fixing structure for the fixing plate 20 on the upper side, and an arch-shaped support 22 on the lower side.
Are shown, respectively.

The supporting plate 20 is provided with a through hole 20a through which the sheath tube 12 can be inserted. The end of the sheath tube 12 is inserted into the through hole 20a. The upper end side of the anchor body 18 protrudes upward from the upper end edge of the sheath tube 12.

A nut 28 is screwed to the upper projecting end of the anchor body 18 with a washer plate 24 and a spherical base 26 interposed therebetween. By screwing and screwing the nut 28, the washer plate 24 is pressed against the support plate 20, whereby the upper end side of the anchor body 18 is fixed to the support plate 20.

On the other hand, a pair of supporting channel members 30 are provided between the pair of supporting members 22 adjacent to each other in the axial direction of the arch so as to face each other. The lower end of the body 18 is inserted, and the lower end of the anchor 18 protrudes below the channel member 30.

Then, at the lower protruding end of the anchor body 18,
The washer plate 24 and the spherical pedestal 26
The washer plate 24 is pressed against the channel material 30 by screwing the nut 28 to fix the lower end side of the anchor body 18 to the arch-shaped support 22.

When both ends of the anchor body 18 are fixed to the ground surface and the inside of the tunnel 10 in this manner, the slack area A is suspended on the bearing plate 20 via the anchor body 18.

According to the tie rod method constructed as described above, before excavation of the tunnel 10,
A drilling hole 16 whose lower end reaches the excavation surface of the tunnel 10 is excavated from the ground surface side, and the sheath tube 12 is installed in the drilling hole 16, and the excavation of the tunnel 10 reaches the installation position of the sheath tube 12. When the lower end is exposed on the excavation surface, the sheath tube 1
Since the anchor body 18 is inserted into the inside 2 and its upper and lower ends are fixed to the ground surface and the inside of the tunnel 10 to suspend the loose area A, the tunnel 10 can be excavated or constructed safely.

In this case, the operation of installing the sheath tube 12 can be performed completely separately from the operation of constructing the tunnel 10, and can be performed in advance.
It can be performed from the ground surface separately from the excavation work of the tunnel 10 and the like, and the suspension work in the loose area A hardly affects the construction efficiency of the tunnel 10.

Further, since both ends of the anchor body 18 are fixed on the ground surface side and in the tunnel 10, there is no problem such as falling of the fixing material by its own weight, and a sufficient fixing effect can be obtained.

[0030]

As described above in detail, according to the tie rod method of the present invention, a sufficient fixing effect can be obtained without lowering the construction efficiency.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of an initial step of a tie rod method according to the present invention.

FIG. 2 is an explanatory view of a step performed subsequently to FIG. 2;

FIG. 3 is a detailed view of a fixing structure at both ends of the anchor body shown in FIG. 2;

FIG. 4 is a side view of a main part of FIG. 3;

FIG. 5 is an explanatory view of a conventional method of suspending a loose area.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Tunnel 12 Sheath pipe 14 Ground 16 Drilling hole 18 Anchor body 20 Bearing plate 22 Arch support

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiromitsu Miyazaki 1-10-19 Higashisakura, Higashi-ku, Nagoya-shi, Aichi F-term in Obayashi-gumi Nagoya Branch Co., Ltd. 2D041 GA01 GD02 2D054 AC20 FA07

Claims (2)

[Claims] Before excavation of a tunnel, a drill hole is drilled from the surface side, the lower end of which penetrates an assumed loose area and reaches the excavation surface of the tunnel, and a hollow cylindrical hole is formed in the drill hole. A sheath pipe is installed, and when the tunnel excavation reaches the installation position of the sheath pipe and the lower end thereof is exposed on the excavation surface, an anchor body is inserted into the sheath pipe and the upper and lower ends thereof are grounded. A tie rod method, wherein the loose area is suspended on the front side and in the tunnel, and the anchor body is suspended by the anchor body. 2. The anchor body according to claim 1, wherein an upper end of the anchor is fixed to a bearing plate installed on the ground surface, and a lower end of the anchor is fixed to a steel arch support of the tunnel. Tie rod method.