JP2003074289A - Excavating construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow safe tunnel excavation in a short period of time by constituting an excavation cycle without considering timbering when excavating a main pit in excavation work of particularly a mountain tunnel of large cross section. SOLUTION: Prior to the main pit construction of the tunnel 1, a guide pit 2 is first excavated near the top part of the tunnel 1. Excavated pits 3, etc., curved in arch shape are excavated by an excavating tool from the internal wall of the guide pit 2 downward to the outside within a vertical plane to a tunnel axis, and at the same time, bent steel pipes 4 are inserted and installed in the excavated pits 3. After the insertion and installation of the bent steel pipes 4, a chemical solution or the like is injected into a surrounding rock-bed to stabilize the surrounding natural ground, and the main pit of the tunnel 1 is excavated using the bent steel pipes 4, etc., as timbering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending boring method for driving a curved steel pipe while excavating an arch-shaped curved excavation shaft.

[0002]

2. Description of the Related Art Recently, a new excavation technique has been demanded for excavation work of a mountain tunnel having a large cross section. In such a construction method, when excavating the main shaft, the excavation cycle can be assembled without considering the support, and it is required that the tunnel excavation can be performed safely and in a short period of time.

[0003]

In order to solve the above problems and achieve such an object, the present invention is to excavate a tunnel near the top of the tunnel before the main tunnel construction. The curved steel pipe is inserted into and installed in the excavation pit while excavating the excavation pit curved in an arch shape in the plane perpendicular to the tunnel axis from the inner wall of the tunnel with the excavation tool. After insertion and installation, the surrounding rocks will be stabilized by injecting chemicals etc. into the surrounding rock mass, and the main shaft of the tunnel will be excavated using this curved steel pipe as a support. Therefore, according to such a construction method, since the bent steel pipe as the support work is installed before the excavation of the main shaft, the excavation cycle can be assembled without considering the support during the excavation of the main shaft, Tunnel excavation can be performed safely and in a short period of time.

Here, as an excavating tool for constructing a steel pipe while excavating an excavation pit in the ground in this manner, for example, a substantially cylindrical casing top integrally attached to the tip of an excavating pipe, and the casing top A drilling tool, which is rotatably inserted and has a drilling bit that projects at the tip of the casing top and drills the ground, and in particular, this drilling bit has a bit head whose outer diameter expands and contracts with rotation. A so-called diameter-expanding bit is conventionally known. With such a diameter-expanding bit, the bit head projecting from the tip of the casing top is expanded in diameter during excavation, and the excavation pipe is advanced together with the casing top while excavating the ground by the rotational impact force applied to the bit head. On the other hand, after the drilling pipe is built, by rotating the bit head in the opposite direction to reduce the diameter, only the drilling bit can be pulled out from the drilling pipe while leaving the casing top and the drilling pipe in the ground. You can

However, such a drilling tool including a diameter-expanding bit is premised to be used for building a straight tubular drilling pipe straight into the ground, and the rotation axis of the drilling bit is It is coaxial with the central axis of the drill pipe, that is, the central axis of the outer diameter portion of the casing top. Therefore, in the above-mentioned construction method, if such an excavating tool is simply attached to the tip of a bent steel pipe used as an excavating pipe, the curved steel pipe is curved, so that The distance between the inner circumference and the outer circumference of the bent steel pipe becomes smaller on the bending direction side as the bending steel pipe is built, and conversely increases on the opposite side of the bending steel pipe so that it is guided by this. The bent steel pipe will be built while shifting to the opposite side of the bending direction. Along with this, the excavation tool attached to the tip of the bent steel pipe also shifts to the opposite side of the curving direction to excavate the excavation pit. There is a problem that it is difficult to accurately control the direction of bending of the curved steel pipe to be built in and accurately install the curved steel pipe at a predetermined position.

Therefore, the present invention further provides the excavation tool as the excavation tool, in order to excavate a curved excavation shaft and accurately install a bent steel pipe in a predetermined position while controlling the direction of excavation. A substantially cylindrical casing top integrally attached to the tip of a bent steel pipe used as a pipe; and a digging bit that is rotatably inserted into this casing top and protrudes at the tip of the casing top to dig the ground, It is characterized in that an excavating tool in which the rotation axis of the excavation bit is eccentric with respect to the central axis of the outer diameter portion of the casing top is used. However, according to the drilling tool having such a configuration, since the rotation axis of the drilling bit is eccentric with respect to the center axis of the outer diameter portion of the casing top, the centerline of the drilling pit to be drilled by the drilling bit is also It will be eccentric with respect to the center line of the drilling pipe built with the casing top, whereby the distance between the inner circumference of the drilling pit and the outer circumference of the drilling pipe is on the eccentric side of the rotation axis of the drilling bit, It will be larger than the opposite side.

Therefore, for example, in the above construction method,
Steel pipe (drilling pipe) that bends in the eccentric direction of this drilling bit
By setting it on the same side as the curving direction of the curved steel pipe, it is possible to prevent the curved steel pipe from being built by shifting to the opposite side of the curving direction, and the drill bit at the tip of this curved steel pipe also has a curved steel pipe. The excavation direction can be controlled so that it bends towards the bending direction to be installed. Here, in order to decenter the rotation axis of the drill bit with respect to the central axis of the casing top in this way, for example, the central axis of the inner diameter portion of the casing top may be decentered with respect to the central axis line of the outer diameter portion. It suffices to adopt such a configuration, and thus the drilling bit itself can be used as it is, such as the conventionally known diameter-expanding bit.

[0008]

1 to 5 show an embodiment of the present invention. In the present embodiment, as shown in FIG. 1, prior to the main construction of the tunnel 1, the tunnel 1 is first
The tunnel 2 was excavated near the top of the, and from the inner wall of this tunnel 2,
The excavation shaft 3 curved in an arch shape is excavated by an excavation tool toward the outside downward in a plane perpendicular to the tunnel axis, and the bent steel pipe 4 is inserted and installed in the excavation shaft 3. After the bending steel pipe 4 is inserted and installed, the surrounding rock is stabilized by injecting a chemical solution or the like into the surrounding rock, and the main shaft of the tunnel 1 is excavated by using the bending steel pipe 4 as a supporting structure. go. Therefore, according to such a construction method, since the bent steel pipes 4 as the support work are installed before the excavation of the main shaft, the excavation cycle can be assembled without considering the support during the excavation of the main shaft. In addition, it is possible to excavate the tunnel safely and in a short period of time.

2 to 4 show a drilling tool according to an embodiment of the present invention. As shown in FIG. 2, in this drilling tool, a substantially cylindrical casing top 12 is integrally attached to the tip of a bent steel pipe 11 used as a drilling pipe by welding or the like, and in the casing top 12, a substantially circular outline is formed. An excavation bit 15 having a bit head 14 at the tip of a columnar device 13 is inserted with the bit head 14 protruding from the tip of the casing top 12. Also, this drill bit 1
A hammer 16 for giving a striking force to the bit head 14 is connected to the rear end of the hammer 5 via the device 13, and further to the rear end side of the hammer 16 are screw augers via universal joints 17 ... 1
8 ... are sequentially connected, and this screw auger 18
Rotational force is applied to the bit head 14 from the device 13 via.

Here, the excavating bit 15 is the above-mentioned diameter-expanding bit in which the outer diameter of the bit head 14 expands and contracts as the excavating bit 15 rotates. That is, in this excavating bit 15, the bit head 14 is composed of a plurality of blocks 20 ... In which a large number of chips 19 ... Are planted on the tip surface, and these blocks 20. Drill bit 15
Is rotatably mounted around an axis slightly distant from the rotation axis O on the outer peripheral side in the radial direction, and when the excavation bit 15 is rotated in the excavation rotation direction about the rotation axis O, the block is rotated. 20 ... are rotated and positioned so that the outer diameter from the rotation axis O increases, and conversely, the drill bit 1
When 5 is rotated in the direction opposite to the excavation rotation direction, the blocks 20 ... Are rotated and positioned so that the outer diameter from the rotation axis O contracts. Further, the dust powder generated by the excavation bit 15 excavating the ground is introduced into the bent steel pipe 11 from between the device 13 and the casing top 12 by the exhaust gas discharged from the tip of the device 13, and screwed. As the auger 18 rotates, it is sent to the rear end side and discharged.

Further, as shown in FIGS. 3 and 4, the casing top 12 having a substantially cylindrical shape has an outer diameter portion 12A having an outer diameter equal to that of the bent steel pipe 11, and the outer diameter portion 12A. A step portion 12B to which the bent steel pipe 11 is joined by welding or the like is formed at the rear end.
On the other hand, the inner diameter portion 12C of the casing top 12 is sized so that the device 13 of the excavating bit 15 can be rotatably fitted therein, and therefore the casing top 1
With the excavation bit 15 inserted in the inside 2, the rotation axis O of the excavation bit 15 is arranged coaxially with the central axis X of the inner diameter portion 12C. And this casing top 12
The central axis X of the inner diameter portion 12C is parallel to the central axis Y of the outer diameter portion 12A, and is arranged at a position eccentric by the eccentric amount e.
The rotation axis O of the casing is also the outer diameter portion 12A of the casing top 12.
It is arranged at a position eccentric by the above-mentioned eccentric amount e with respect to the central axis Y of.

On the rear end side of the inner diameter portion 12C of the casing top 12, a circular cross section which is coaxial with the central axis Y of the outer diameter portion 12A and has a radius larger than the inner diameter portion 12C by the eccentric amount e. The enlarged diameter portion 12D of the inner diameter portion 12C is formed so that the inner diameter portion 12C has a central axis X of the inner diameter portion 12C when viewed from the central axis X, Y direction as shown in FIG. The outer diameter portion 12A is arranged so as to be inscribed in a direction eccentric to the central axis Y of the outer diameter portion 12A (hereinafter referred to as an eccentric direction). Further, a portion between the inner diameter portion 12C and the enlarged diameter portion 12D is a tapered surface 12E which gradually becomes wider from the eccentric direction side toward the opposite side about the central axes X and Y, and further, the inner diameter portion 1
The tip end side of 2C is a tapered surface 12F that expands in diameter toward the tip end side around the central axis Y.

The excavating tool thus constructed is attached to the tip of the bent steel pipe 11 in the above-mentioned construction method,
The excavation device provided in the guide shaft 2 excavates an excavation shaft 3 curved in an arch shape in a plane perpendicular to the tunnel axis from the inner wall of the guide shaft 2, while the excavation shaft 3 is bent. Used to insert and install the steel pipe 11.
Here, for example, as shown in FIG. 5, in this excavation device, a base 22 provided with a rail 21 that is installed in an excavation pit 3 and curved substantially parallel to the curved steel pipe 11 is provided with the rail 21. It is installed in the guide hole 2 toward the inner wall 2A side (the left side in FIG. 4) where the pit 3 is to be formed, and the entrance (insertion portion) 23 of the bent steel pipe 11 and the guide roller 24 are provided on the inner wall 2A side of the base 22. Pipe clamp 25,
A welding device 26 is provided, a propulsion device 27 is provided on the opposite side of the welding device 26 so as to be able to move forward and backward along the rail 21, and a pedestal 28 for the bent steel pipe 11 is provided at the center of the base 22. It is configured as

The bent steel pipe 11 having the above-mentioned excavation tool attached to the tip of the excavator is held at the rear end thereof by the propulsion unit 27 and can be advanced along the rail 21 integrally with the propulsion unit 27. At the same time, the screw auger 18 inserted therein is connected to a rotating device (not shown) built in the propulsion unit 27, so that the screw auger 18 can rotate via the universal joint 17. And, with this rotating device, the screw auger 18
While rotating the excavating bit 15 of the excavating tool via the hammer, the hammer 16 applies a striking force to the excavating bit 15 to excavate the excavation pit 3 and the propulsion device 27 is advanced to move the screw auger 18 together. The curved steel pipe 11 is guided by the guide rollers 24 and is built into the excavation pit 3 from the entrance 23.

Further, when one bent steel pipe 11 is built in the digging pit 3 in this way, the rear end of the bent steel pipe 11 is held by the pipe clamp 25 and the propulsion device 27 is detached and retracted. As shown in FIG. 5, the next bent steel pipe 11 having the screw auger 18 inserted therein is placed on the pedestal 28. After connecting the screw augers 18 and 18 to each other, the bent steel pipes 11 and 1 are connected.
1 is joined by the welding device 26, and further the propulsion device 27 is connected to the rear end of the bent steel pipe 11 placed on the pedestal 28, and the bent steel pipe 11 is formed while the excavation pit 3 is formed in the same manner as above. By inserting and repeating such an operation one by one, a large number of bent steel pipes 11 ... Further, after the predetermined number of bent steel pipes 11 are built in this way, the excavation bit 15 is rotated in the direction opposite to the excavation rotation direction via the screw augers 18 to contract the outer diameter of the blocks 20. With the bent steel pipe 11 left behind, the propulsion device 27 is retracted, the excavation bit 15 and the hammer 16 and the screw augers 18 are pulled out one by one and removed, and only the bent steel pipe 11 ... Form the work.

In the excavating tool having the above construction, however, the rotational axis O of the excavating bit 15 is eccentric with respect to the central axis Y of the outer diameter portion 12A of the casing top 12 attached to the tip of the bent steel pipe 11. Since the eccentric direction of the rotation axis O is set to the bending direction of the bent steel pipe 11, the center line of the digging pit 3 to be digged by the digging bit 15 is also the center of the bent steel pipe 11 built with the casing top 12. The curved line is eccentric to the curved line side, so that the distance between the inner circumference of the excavation mine 3 and the outer circumference of the curved steel pipe 11 is opposite to the curved direction side of the curved steel pipe 11. Will be larger than. Therefore, the bending steel pipe 11 is bent by the propulsion device 27.
When the curved steel pipe 11 is built, the space between the curved steel pipe 11 and the digging pit 3 does not become smaller, and therefore, as the curved steel pipe 11 is built, the gap is shifted to the opposite side to the curved direction. In addition to being able to prevent it, the excavation bit 15 at the tip of the bent steel pipe 11 is also controlled in its excavation direction so as to be guided in the bending direction of the bent steel pipe 11. It becomes possible to form the excavation pit 3 in accordance with the curvature of the steel pipes 11 and bend the steel pipes 11 ...

Further, in this embodiment, when the rotation axis O of the excavating bit 15 is eccentric with respect to the center axis Y of the outer diameter portion 12A of the casing top 12 in this way, the center axis line of the inner diameter portion 12C of the casing top 12 is X is made eccentric with respect to the central axis Y of the outer diameter portion 12A. Therefore, according to the present embodiment, it is possible to use a conventionally known well-known diameter-expanding bit or the like for the excavating bit 15 itself, and the excavating tool which is relatively inexpensive while exhibiting the above-described operational effects. Can be provided. In this embodiment, the diameter-expanding bit is used as the excavating bit 15 as described above, but when the ground to be excavated is likely to collapse, for example, a general down-the-hole bit or the like can be used. Is.

[0018]

As described above, according to the present invention,
Since a bent steel pipe is installed as a support work before excavation of the main pit, the excavation cycle can be assembled without considering the support during excavation of the main pit, and tunnel excavation can be performed safely and in a short period of time. Can be Further, the excavation direction of the excavation bit can be controlled in accordance with the curve of the excavation pipe, which allows the excavation pipe to be accurately and reliably inserted and installed at a predetermined position.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of an embodiment of the present invention.

FIG. 2 shows a drilling tool according to an embodiment of the present invention and a drilling pipe (bent steel pipe 1 attached with the drilling tool.
It is a sectional side view of 1).

FIG. 3 is a casing top 12 of the drilling tool shown in FIG.
FIG.

FIG. 4 is a casing top 12 of the drilling tool shown in FIG.
FIG.

FIG. 5 is a diagram showing an excavating device when the construction method of the embodiment is performed by the excavating tool shown in FIG. 2.

[Explanation of symbols]

2 resistance 2A Inner wall of guide 2 11 Bent steel pipe (drilling pipe) 12 casing top 12A Outer diameter of casing top 12 12C Inner diameter of casing top 12 13 devices 14 bit head 15 drill bits 16 Hammer 18 screw auger 22 base 27 propulsion machine O Axis of rotation of drill bit 15 X Center axis of the inner diameter portion 12C of the casing top 12 Y Center axis of outer diameter portion 12A of casing top 12 eccentricity of center axis X with respect to center axis Y

Continued front page    (72) Inventor Hirochika Wakimoto             1528, Nakashinden, Yokoi, Kobe-cho, Anpachi-gun, Gifu Prefecture             Address Mitsubishi Materials Corporation Gifu Factory             Within (72) Inventor Shigeru Sato             1528, Nakashinden, Yokoi, Kobe-cho, Anpachi-gun, Gifu Prefecture             Address Mitsubishi Materials Corporation Gifu Factory             Within F term (reference) 2D054 AC15 AC18 AD32 FA02

Claims (8)

[Claims] 1. Prior to the main construction of the tunnel, a tunnel is first excavated near the top of the tunnel, and from the inner wall of the tunnel,
An excavation method characterized in that a curved steel pipe is inserted into and installed in an excavation pit that is curved in an arch shape in a plane perpendicular to the tunnel axis by using an excavation tool. 2. The main shaft of the tunnel is excavated using the bent steel pipe as a support work by injecting a chemical liquid or the like into the surrounding rock after inserting and installing the bent steel pipe. The excavation method described in 1. 3. The drilling tool according to claim 1, wherein a substantially cylindrical casing top is integrally attached to the tip of the bent steel pipe by welding or the like, and a bit head is provided in the casing top at the tip of a device having a substantially cylindrical outer shape. And a hammer having a hammer that applies a striking force to the bit head through the device at the rear end of the drill bit. The screw auger is sequentially connected to the rear end side of the hammer via universal joints, and the rotating force is applied to the bit head from the device via the screw auger. The drilling tool configured as described above is installed in the guide hole by the drilling device provided in the guide hole. The method according to claim 1 or 2, wherein the curved steel pipe is inserted into and installed in the excavation pit while excavating the excavation pit curved in an arch shape in a plane perpendicular to the tunnel axis. The excavation method according to Item 2. 4. The excavation device according to claim 1, wherein a base provided with a rail that is installed substantially parallel to the bent steel pipe installed in the excavation shaft is such that the rail faces the inner wall side where the excavation shaft is formed. It is installed in the guideway, and the bent steel pipe entrance, guide roller, pipe clamp, and welding device are provided on the inner wall side of the base, and the propulsion device moves back and forth along the rail on the opposite side. The excavator is provided with a bendable steel pipe pedestal in the center of the base. Held
While being able to advance integrally with the propulsion unit along the rail, the screw auger inserted therein is connected to a rotating device built in the propulsion unit,
It is possible to rotate via the universal joint,
While rotating the excavating bit of the excavating tool via the screw auger by this rotating device, while striking the excavating pit by giving a striking force to the excavating bit by the hammer, by moving the propulsion device forward, The excavation method according to claim 3, wherein the bent steel pipe is guided from the guide roller and is built into the excavation hole from the entrance. 5. When one of the bent steel pipes is built in an excavation pit, the rear end of the bent steel pipe is held by the pipe clamp and the propulsion unit is removed and retracted, and a screw auger is inserted inside. Place the next bent steel pipe on the pedestal, connect the screw augers to each other, join the bent steel pipe with a welding device, and connect the above-mentioned propulsion device to the rear end of the bent steel pipe placed on the pedestal. 5. The excavation method according to claim 4, wherein the bent steel pipe is inserted while forming a digging pit, and the bent steel pipe is successively built by repeating such an operation one by one. 6. The excavating bit is a diameter-expanding bit in which the outer diameter of the bit head expands and contracts in accordance with the rotation of the excavating bit, and after a predetermined number of bent steel pipes have been built in, the screw auger is used. Rotate the drill bit in the direction opposite to the drill rotation direction to shrink the outer diameter, then with the bent steel pipe left, retract the propulsion device and pull out the drill bit and hammer a screw auger one by one to remove. The excavation method according to claim 4 or 5, wherein a support structure is formed in which only the bent steel pipe is built in the mine. 7. A substantially cylindrical casing top integrally provided at the tip of the bent steel pipe used as an excavation pipe as the excavation tool, and rotatably inserted into the casing top and protruding at the tip of the casing top. 7. A drilling tool for drilling the ground by using a drilling tool, wherein a rotary axis of the drilling bit is eccentric with respect to a central axis of an outer diameter portion of the casing top. The excavation method described in any one of 1. 8. The axis of rotation of the drill bit is coaxial with the center axis of the inner diameter of the casing top, and the center axis of the inner diameter is relative to the center axis of the outer diameter of the casing top. The excavation method according to claim 7, wherein the excavation method is eccentric.