JP2001207779A - Obstacle detecting device for boring tunnel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve obstacle detecting accuracy by surely detecting only a long size obstacle unexcavatable by a cutter in an obstacle detecting device for boring a tunnel. SOLUTION: A first detecting member 24 is arranged on the outer peripheral side of a cutter head 12. A second detecting member 25 is arranged on the inner peripheral side. When an obstacle H is the long size, since this obstacle H first collides with the first detecting member 24 and then collides with the second detecting member 25, in a colliding position of the obstacle H and the first and second detecting members 24, 25, a position of the obstacle H on three-dimensional coordinates is detected on the basis of turning angles θ1, θ2 of the cutter head 12 by a rotary encoder 50 and propelling strokes S1, S2 by a stroke sensor 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tunnel digging obstacle detecting device for detecting a long obstacle buried in the ground in front of a tunnel digging.

[0002]

2. Description of the Related Art In a general shield excavator, a cutter head having a large number of cutter bits is rotatably mounted at a front portion of an excavator body and can be driven to rotate by a drive motor. A plurality of shield jacks are arranged side by side in the circumferential direction at the rear portion of the excavator body, and an erector device is mounted. Therefore, while rotating the cutter head by the drive motor, the shield jack is extended and the excavator body is advanced by the reaction force against the existing segment, so that each cutter bit of the cutter head excavates the ground in front, With the excavation of the ground, the elector device assembles the segments on the inner peripheral surface of the existing tunnel, thereby constructing the tunnel.

By the way, if an unexpected obstacle, for example, a sheet pile or a reinforced concrete pile, is found in the ground in front of a tunnel during excavation, it cannot be crushed by a cutter bit of a shield excavator. The cutter bit will be damaged. Therefore, it is necessary to detect this obstacle during excavation and remove it. When detecting such an obstacle buried underground, electromagnetic waves are emitted forward from the cutter head, and electromagnetic waves reflected from the obstacle are received. Based on the reception level, the position of the obstacle is determined. Is detected. However, with such a method, the detection area is narrow, and it is not possible to perform highly accurate obstacle detection.

To detect an obstacle ahead during tunnel excavation, for example, Japanese Utility Model Laid-Open No. 4-108691 discloses a method.
Is disclosed in Japanese Patent Application Laid-Open Publication No. HEI 9-203 (1995). The “obstruction detection device for shield excavators” disclosed in this publication includes a cutter head provided rotatably at the front of a shield body, and a detection bit for detecting an obstacle in a face being cut by a hydraulic cylinder. It is provided so as to protrude more forward than before, and an obstacle is detected when a pressure fluctuation occurs in the hydraulic cylinder due to a load fluctuation acting on the detection bit.

[0005]

However, besides obstacles that cannot be crushed with a cutter bit, such as sheet piles and reinforced concrete piles, as well as gravel that is hard but can be sufficiently crushed even with a cutter bit, in the ground to be excavated. And so on. In the above-mentioned conventional "obstacle detecting device of a shield machine", when a detection bit collides with an obstacle, the obstacle is detected by a pressure fluctuation acting on a hydraulic cylinder due to the collision. As a result, even though hard gravel was mistakenly recognized as an obstacle, even though the cutter bit could be used to excavate, the worker went out of the machine and removed the obstacle, or installed a cutter to remove the obstacle. Alternatively, the obstacle is removed and replaced, and the work efficiency is reduced.

SUMMARY OF THE INVENTION The present invention solves such a problem. An obstacle detection system for tunnel excavation which improves the accuracy of obstacle detection by reliably detecting only a long obstacle which cannot be excavated by a cutter. It is intended to provide a device.

[0007]

According to a first aspect of the present invention, there is provided an obstacle detecting apparatus for a tunnel excavation, wherein the cutter head is rotatably mounted on a front portion of an excavator body. A first detection member mounted to be able to protrude and retract in the excavation direction, a second detection member mounted to be able to protrude and retreat in the excavation direction on the inner peripheral side of the cutter head, and when the first and second detection members protrude. Collision detection means for detecting a collision with an obstacle buried in the ground, rotation position detection means for detecting a rotation position of the cutter head, propulsion position detection means for detecting a propulsion position of the excavator body, Obstacle position detection means for obtaining the position of the obstacle based on the output results of the rotational position detection means and the propulsion position detection means when the first and second detection members collide with the obstacle. Characterized by Than it is.

In the obstacle detecting device for tunnel excavation according to the second aspect of the present invention, the first and second detecting members have spherical end portions, and can be freely retracted from the front surface of the cutter head by a hydraulic jack. It is characterized by having.

According to a third aspect of the present invention, in the tunnel excavation obstacle detecting apparatus, the collision detecting means rotates the cutter head and a pressure fluctuation in a hydraulic jack for moving the first and second detecting members. And a driving force fluctuation of the driving motor.

Further, in the obstacle detecting apparatus for tunnel excavation according to the present invention, the excavator body or the cutter head is provided with a radar detector for detecting an obstacle buried in the ground in front. It is characterized by:

Further, in the obstacle detecting device for tunnel excavation according to the invention of claim 5, when the obstacle is a long obstacle, when the first and second detection members are projected, the first and second detection members are first moved to the first position. The detection member collides with the long obstacle, and then the second detection member collides with the long obstacle.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic configuration showing an obstacle detecting device for tunnel excavation according to one embodiment of the present invention, FIG. 2 is a front view of a tunnel excavator equipped with the obstacle detecting device of this embodiment, and FIG. 2, FIG. 4 shows a cross section of a rotating spoke, FIG. 5 shows a VV cross section of FIG. 4, FIG. 6 shows a detection method using an obstacle detection device, and FIG. The flowchart of FIG.

In the tunnel excavation obstacle detecting device of the present embodiment, as shown in FIGS.
A cutter head 12 is rotatably mounted on the front of the unit 1, and can be driven to rotate by a drive motor 13. Then, five fixed spokes 15 a to 15 e and one rotating spoke 16 are radially mounted from a center ring 14 located at a central portion of the cutter head 12, and an outer peripheral portion is connected by an outer peripheral ring 17.

Each of the fixed spokes 15a to 15e has substantially the same configuration. As shown in FIGS. 2 and 3, a mounting base 19 is fixed to an upper portion of a box-shaped spoke body 18, and both sides of the mounting base 19 (see FIGS. A cutter bit 20 is rotatably mounted on a mounting pin 21 at the front and rear of the cutter head 12 in the rotation direction. This cutter bit 20 is a fixed spoke 1
Although a large number are mounted on both sides of the cutter head 12 along the radial direction of the cutter head 12, the mounting positions in the radial direction are slightly shifted for each of the fixed spokes 15a to 15e. Can be drilled.

A widened portion 22 is formed on the front surface of the fixed spoke 15b.
Is installed. Although not shown, the underground radar 23 has a transmission antenna for transmitting electromagnetic waves and a reception antenna for receiving reflected electromagnetic waves, and can detect the position of the obstacle H based on the reception level of the reception antenna. it can.

Further, on the front surface of the fixed spoke 15d,
A first detecting member 24 which can be moved in and out in the excavation direction is mounted at a radially outermost position of the cutter head 12, and a second detecting member 25 which can be moved in and out in the excavating direction is mounted at an innermost position. The first detection member 24 and the second detection member 25 have substantially the same configuration, and the detection member main body 26 having a cylindrical shape and a spherical end portion is attached to the mounting base 1 of the spoke main body 18.
9 is movably supported by a seal member 27 and a metal bearing 28, and is movable by a hydraulic jack 29 mounted in the spoke body 18. Then, during normal excavation, the hydraulic jack 29 contracts and the detecting member main body 2
6 is located behind the cutter bits 20 in the excavation direction, and when an obstacle H is detected, the hydraulic jack 29 is extended and the distal end of the detection member main body 26 is moved to the respective cutter bits 20.
It is located ahead of the excavation direction. In addition,
Grease is injected into the mounting portion of the sealing material 27 to enhance waterproofness.

On the other hand, in the rotary spoke 16, the sealing material 3 is attached to the center ring 14 by a rotary joint 30.
A base end of the rotary cylinder 33 is rotatably supported via the first and metal bearings 32, and a distal end of the rotary cylinder 33 is supported by a support ring 34 of the outer peripheral ring 17 via a seal material 35 and a metal bearing 36. It is rotatably supported. The drive shaft 38 of the hydraulic motor 37 mounted on the center ring 14 is fixed to the base end of the rotary cylinder 33. A slide cylinder 40 is movably supported by a support cylinder 39 fixed to the distal end side in the rotary cylinder 33 via a seal material 41 and a metal bearing 42. A hydraulic jack 43 is provided between them.

A cutter bit 44 is fixed to both sides of the outer peripheral portion of the rotary cylinder 33 (front and rear in the rotation direction of the cutter head 12), and a pile cutting bit 45 is spirally fixed along the longitudinal direction. A pile cutting bit 46 is attached to the tip of the slide cylinder 40 so as to be able to protrude and retract by a hydraulic jack (not shown). In addition, each pile cutting bit 45,
46 is set longer than the cutter bits 20 and 44. A lock device 47 is mounted on the center ring 14, and a movable lock pin 48 is fitted into a lock hole 49 of the rotary cylinder 33 so that the left and right cutter bits 44 are fitted.
The rotary cylinder 33 can be locked at a position where is located forward in the digging direction. In FIG. 4, the locking device 47 is described as being located on the side of the center ring 14 so that the structure can be understood in detail. However, in actuality, the locking device 47 is provided on the rear (rearward direction) side of the center ring 14. It is what is being done.

Therefore, when the excavator is normally used, the locking device 4
7, the rotary cylinder 33 is locked at a position where the cutter bit 44 is located in the forward direction in the excavation direction. By moving the cutter head 12 forward while rotating, the cutter bit 44 can excavate the ground in front. On the other hand, when cutting the obstacle H, the lock unit 47 unlocks the rotary cylinder 33 and drives the hydraulic motor 37 to rotate the rotary cylinder 33 at a high speed to move forward. The obstacle H buried therein can be cut.
At this time, the hydraulic jack 43 is extended and the slide cylinder 40 is extended.
Of the excavator main body 11 located behind the cutter head 12 by cutting the obstacle H outside the outer peripheral ring 17 by moving the
Can be facilitated.

Also, as shown in FIG.
Is mounted with a rotary encoder 50, which can detect the rotation angle of the cutter head 12. Furthermore,
A plurality of shield jacks 51 are arranged in the rear part of the excavator body 11 in the circumferential direction.
1 includes a stroke sensor 52 for detecting an operation stroke.
Is installed.

In this embodiment, the control device 53
The detection result of the underground radar 23, the fluctuation of the hydraulic pressure of the hydraulic jack 29 of the first detection member 24 and the second detection member 25, the fluctuation of the current of the drive motor, the detection result of the rotary encoder 50, the detection result of the stroke sensor 52 Is entered. As a result, the control device 53 can detect a collision between the first and second detection members 24 and 25 and the obstacle H from the fluctuation of the hydraulic pressure of each hydraulic jack 29 and the fluctuation of the current of the driving motor (collision detecting means). The position of the obstacle H can be obtained based on the detection results of the rotary encoder 50 and the stroke sensor 52 (obstacle position detecting means).

Here, the operation of the tunnel digging obstacle detecting device of the present embodiment will be specifically described with reference to the flowchart of FIG. In the tunnel excavator, the drive motor 13
While rotating the cutter head 12, the shield jack 51 is extended and the excavator body 11 is moved forward by the reaction force against the existing segment, and the cutter bits 20, 44.
Excavates the ground in front. At this time, underground radar 2
Activating 3 detects whether there is an obstacle H or the like in the ground in front of the vehicle. That is, as shown in FIG. 7, when the underground radar 23 detects an obstacle H or the like in the ground in front in step S1, the hydraulic jack 29 is extended in step S2 and the first detection member 24 and The second detection member 25 is made to protrude forward.

First, in step S3, it is determined whether the hydraulic jack 29 of the first detecting member 24 has a pressure fluctuation. In this case, as shown in FIGS. 1 and 2, if there is an obstacle H longer than the diameter of the cutter head 12,
It collides with the first detection member 24 before the detection member 25.
Then, if there is a pressure fluctuation in the hydraulic jack 29 of the first detecting member 24, in step S4, the load fluctuation of the rotational torque of the cutter head 12 at this time (the driving motor 13
Is determined to be greater than or equal to a predetermined value. That is, if the obstacle H colliding with the first detection member 24 is a mere gravel, it can be crushed by the cutter bits 20 and 44, and the load fluctuation is smaller than a predetermined value. On the other hand, if the obstacle H cannot be crushed by the cutter bits 20 and 44, such as a sheet pile or a reinforced concrete pile, the load fluctuation of the cutter head 12 becomes a predetermined value or more and it is determined that the obstacle H has occurred. The first detecting member 24 is immersed in the spoke 15d by contracting 29.

Then, in step S6, the controller 53
Is the rotation angle of the cutter head 12 by the rotary encoder 50, that is, the angle θ ₁ from the reference position to the collision position between the first detection member 24 and the obstacle H as shown in FIG.
With read, at step S7, read the propulsion stroke S ₁ of the tunneling machine by the stroke sensor 52, on the three-dimensional coordinates based on the rotational angle theta ₁ of the cutter head 12 and the propulsion stroke S ₁ first The collision position between the detection member 24 and the obstacle H is calculated.

Next, in step S8, similarly to step S3 described above, it is determined whether or not the hydraulic jack 29 of the second detecting member 25 has a pressure fluctuation. In S9, it is determined whether or not the load fluctuation (current value fluctuation of the drive motor 13) of the rotational torque of the cutter head 12 at this time is equal to or more than a predetermined value. If the load fluctuation is equal to or more than the predetermined value, a sheet pile, a reinforced concrete pile, or the like is used. Obstacles H that cannot be crushed by the cutter bits 20 and 44
Is determined, and in step S10, the hydraulic jack 29 is contracted so that the second detection member 25 is immersed in the spoke 15d.

Then, in step S11, the control device 5
3 is the rotary encoder 50 for the cutter head 12
The rotation angle, that is, as shown in FIG.
Angle θ to collision position between second detection member 25 and obstacle H
_TwoIs read, and in step S12, the stroke
The propulsion stroke S of the tunnel excavator by the sensor 52 _Two
And the rotation angle θ of the cutter head 12_TwoAnd push
Advance stroke S_TwoThe second inspection on the three-dimensional coordinates based on
The collision position between the knowledge member 25 and the obstacle H is calculated. Soshi
In step S13, the control device 53 determines that the obstacle H
Three-dimensional seat of the collision position with the first and second detection members 24 and 25
It is determined that there is an obstacle H on the straight line connecting the targets, and step S
At 14, the cutter head 1 according to the position of the obstacle H
2 is driven to crush the obstacle H.

That is, as shown in FIGS. 2 and 4, while the cutter head 12 is being rotated at a low speed, the lock pin 48 is pulled out of the lock hole 49 by the lock device 47 and the rotary cylinder 3 is rotated.
3 and the hydraulic jack 43 is extended to move the slide cylinder 40, and the pile cutting bit 46
To drive the hydraulic motor 37 to rotate the rotary cylinder 33 at high speed. When the excavator body 11 is advanced by extending the shield jack 51 in this state, a large number of pile cutting bits 4
Obstacle H in a state where 5, 46 are moving at high speed and rotating
, The obstacle H can be cut and crushed. In this case, by setting the rotation direction of the cutter head 12 and the rotation direction of the rotary cylinder 33 to be the same, the obstacle H
The contact speed of the pile cutting bits 45, 46 to the pile cutting bit is doubled. Further, since the pile cutting bits 45 and 46 are longer than the cutter bits 20 and 44 in the excavation direction, the cutter bits 20 and 44 do not come into contact with the obstacle H and are not damaged. Furthermore, since the pile cutting bit 46 cuts the obstacle H outside the outer peripheral ring 17, the excavator body 11 located behind the cutter head 12 can be easily propelled.

Although not described in the flowchart of FIG. 7, there is no pressure change in the hydraulic jack 29 of the first detecting member 24 in step S3.
When the pressure fluctuation occurs in the hydraulic jack 29 of No. 5,
The obstacle is judged to be gravel because it is not long. In addition, by setting the standby time in steps S8 and S9, even if the predetermined time has elapsed, the hydraulic jack 29 of the second detection member 25 does not change in pressure even if the predetermined time has elapsed, or the cutter head does not change in step S9. If there is no load fluctuation of the rotation torque of No. 12, the obstacle that collided with the first detection member 25 is not long and is determined to be gravel.

As described above, in the obstacle detecting device for tunnel excavation of the present embodiment, when the obstacle H is long,
The obstacle H first collides with the first detecting member 24 on the outer peripheral side of the cutter head 12 and then collides with the second detecting member 25 on the inner peripheral side, so that the obstacle H and the first and second detecting members 24 ,
25 based on the rotation angles θ ₁ , θ ₂ of the cutter head 12 by the rotary encoder 50 and the propulsion strokes S ₁ , S ₂ by the stroke sensor 52.
The position of the obstacle H on the dimensional coordinates is detected. Therefore, the detection accuracy can be improved by reliably detecting the long obstacle H without misidentifying it as gravel.

In the above-described embodiment, one rotary spoke 16 is provided on the cutter head 12, but two or more rotary spokes may be provided in consideration of the space for disposing the hydraulic motor 37. Further, the underground radar 23 is provided on the fixed spoke 15b, but may be provided on the excavator body 11. Furthermore, although the first and second detection members 24 and 25 are provided on the fixed spoke 15d, other fixed spokes may be provided. Alternatively, the first detection member 24 is provided on the fixed spoke 15a, and the second detection member is provided on the fixed spoke 15b. May be provided on the rotating spokes 16. The number of detection members may be three or more. In this case, it is desirable that the third detection member is provided at a middle portion in the longitudinal direction of the spoke.

In the above-described embodiment, the fluctuation of the hydraulic pressure of the hydraulic jack 29 of the first detecting member 24 and the second detecting member 25 and the fluctuation of the load of the driving motor 13 of the cutter head 12 (the fluctuation of the current value of the driving motor 13) are considered. Based on the determination, it was determined whether the obstacle H was mere gravel or an obstacle H that could not be crushed by the cutter bits 20 and 44, such as a sheet pile or a reinforced concrete pile. Only the hydraulic pressure fluctuation, or only the load fluctuation of the drive motor 13 may be used, and other conditions may be used.

Further, by rotating the rotary cylinder 33 at a high speed while rotating the cutter head 12 at a low speed, the obstacle H is cut by a large number of pile cutting bits 45 and 46.
By rotating the cutter head 12 within a predetermined angle range while the rotating cylinder 33 is rotating at a high speed, that is, reciprocatingly rotating, the rotating cylinder 33 is moved by the range where the obstacle H exists, and the pile cutting bits 45 and 46 are moved. When the obstacle H is at a position passing through the center of the cutter head 12, the rotary cylinder 33 stops the cutter head 12 at a position overlapping the obstacle H when the obstacle H passes through the center of the cutter head 12. The obstacle H may be cut by rotating only the rotating cylinder 33 at high speed. In this case, it is necessary to rotate the cutter head 12 every time a predetermined cutting time of the obstacle H elapses and to excavate the ground in front by the cutter bits 20 and 44.

[0034]

As described above in detail in the embodiment, according to the obstacle detecting apparatus for tunnel excavation of the first aspect of the present invention, the first detecting member and the inner peripheral side which can come and go on the outer peripheral side of the cutter head. And a second detection member which can be retracted and mounted, and collision detection means for detecting a collision with an obstacle buried underground when the first and second detection members protrude are provided. Since the position of the obstacle is obtained based on the rotation position of the cutter head and the propulsion position of the excavator body at the time of collision between the first and second detection members and the obstacle, if the obstacle is a long obstacle, This obstacle first collides with the first detection member on the outer circumference side, and then collides with the second detection member on the inner circumference side. Therefore, a long obstacle that cannot be excavated with the cutter based on the two collision positions is detected. Improve detection accuracy by reliably detecting position Door can be.

According to the obstacle detecting device for tunnel excavation according to the second aspect of the present invention, the distal end portions of the first and second detecting members are formed into spherical shapes so that they can protrude and retract from the front surface of the cutter head by the hydraulic jack. Regardless of the direction in which the detection member collides with the obstacle, the collision force of the obstacle can be reliably transmitted to the fluid pressure jack and detected.

According to the third aspect of the present invention, the collision detecting means includes the first and second collision detecting means.
Since the detection is performed based on the pressure fluctuation in the fluid pressure jack that causes the detection member to protrude and retract and the driving force fluctuation of the drive motor that rotates the cutter head, the obstacle is gravel that can be excavated with the cutter, It is possible to determine whether the sheet pile or the reinforced concrete pile cannot be crushed.

According to the obstacle detecting device for tunnel excavation of the fourth aspect of the present invention, the excavator body or the cutter head is provided with a radar detector for detecting an obstacle buried in the ground in front. By detecting the presence or absence of an obstacle in advance, the workability of the obstacle detection work can be improved.

According to the obstacle detecting device for tunnel excavation according to the fifth aspect of the present invention, when the obstacle is a long obstacle, when the first and second detecting members protrude, the first detecting is performed first. Since the member collides with the long obstacle and then the second detection member collides with the long obstacle, the detection accuracy is improved by reliably detecting the position of the long obstacle. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an obstacle detection device for tunnel excavation according to an embodiment of the present invention.

FIG. 2 is a front view of a tunnel excavator equipped with the obstacle detection device of the present embodiment.

FIG. 3 is a sectional view taken along the line III-III of FIG. 2;

FIG. 4 is a sectional view of a rotating spoke.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is an explanatory diagram of a detection method by the obstacle detection device.

FIG. 7 is a flowchart of a detection method by the obstacle detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Excavator main body 12 Cutter head 13 Drive motor 15a, 15b, 15c, 15d Fixed spoke 16 Rotating spoke 17 Outer ring 20 Cutter bit 23 Underground radar 24 First detection member 25 Second detection member 29 Hydraulic jack (fluid pressure jack) Reference Signs List 50 rotary encoder (rotational position detecting means) 51 shield jack 52 stroke sensor (propulsion position detecting means) 53 control device (collision detecting means, obstacle position detecting means) H Obstacle

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hisao Arai 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Kazuo Miyazawa 1-2-3 Shibaura, Minato-ku, Tokyo Shimizu Corporation Co., Ltd. (72) Inventor Minoru Suzuki 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Hiroshi Kazama 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation F Terms (reference) 2D054 BA03 GA17 GA62 GA65 GA81 GA84 GA92 2F069 AA04 BB40 GG01 GG04 GG06 GG20 GG58 GG59 HH02 HH15

Claims (5)

[Claims] 1. A first detecting member mounted on an outer peripheral side of a cutter head rotatably mounted on a front portion of an excavator body so as to be able to protrude and retract in an excavation direction, and a first detecting member on an inner peripheral side of the cutter head in an excavated direction. A second detection member mounted to be freely retractable;
And collision detection means for detecting a collision with an obstacle buried in the ground when the second detection member projects, rotation position detection means for detecting a rotation position of the cutter head, and a propulsion position of the excavator body. Propulsion position detecting means for detecting
And obstacle position detecting means for obtaining the position of the obstacle based on the output results of the rotational position detecting means and the propulsion position detecting means at the time of collision between the second detecting member and the obstacle. Obstacle detection device for tunnel excavation. 2. The obstacle detecting device for tunnel excavation according to claim 1, wherein the first and second detecting members have a spherical shape at their distal ends, and can be freely protruded and retracted from the front surface of the cutter head by a hydraulic jack. An obstacle detecting device for tunnel excavation. 3. The obstacle detecting device for tunnel excavation according to claim 1, wherein said collision detecting means rotationally drives a pressure fluctuation in a fluid pressure jack which causes said first and second detecting members to protrude and retract. An obstacle detecting device for tunnel excavation, which detects a driving force fluctuation of a driving motor. 4. The obstacle detecting device for tunnel excavation according to claim 1, wherein the excavator body or the cutter head is provided with a radar detector for detecting an obstacle buried in the ground in front. An obstacle detecting device for tunnel excavation, characterized by: 5. The obstacle detecting device for tunnel excavation according to claim 1, wherein when the obstacle is a long obstacle, the first detection is performed first when the first and second detection members protrude. An obstacle detection device for tunnel excavation, wherein a member collides with the long obstacle, and then the second detection member collides with the long obstacle.