JP2940424B2 - Forward search device for tunnel machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forward exploration device for a tunnel machine, and more particularly, to a cutting face of a tunnel excavation work which obtains a reaction force of excavation from an outer ground or a back lining body. The present invention relates to a forward search device for a tunnel excavator provided in a tunnel excavator having a trunk having a cutter head to excavate and for exploring the state of the ground ahead in accordance with the excavation work by the tunnel excavator.

[0002]

2. Description of the Related Art Conventionally, for example, a tunnel boring machine (hereinafter referred to as “TB”) has been used as a machine for excavating and forming a mountain tunnel by mechanical excavation without blasting.
M ”. ), A tunnel machine having a body provided with a cutter head for excavating a face is known.

That is, this tunnel machine generally includes, for example, a front body having a cutter head for excavating a face and a front gripper protruding outward and pressing the ground on the outer periphery; A rear body portion provided with a main gripper slidably connected to the main body and protruding outward and pressing the ground at an outer periphery, and a thrust for connecting the rear body portion and the front body portion so as to extend and contract. The thrust jack is extended and the tunnel body is excavated by the cutter head of the front body, while the main gripper on the rear body is protruded to obtain the excavation reaction force from the ground on the outer periphery. The process of protruding the front gripper of the torso and obtaining the support reaction force from the ground on the outer periphery, retreating the main gripper of the rear torso, contracting the thrust jack and pulling the rear torso is repeated. Accordingly, those going by excavating a tunnel in a so-called inchworm-like.

[0004] Further, according to this tunnel machine, not only the ground in which the ground around the rock formation etc. is stabilized and the fixed reaction force by each gripper can be easily obtained, but also the geological conditions such as the fault crush zone and the soft formation. Even when it is necessary to excavate and form a tunnel through poor ground,
Equipped with a device for mounting a lining body such as a segment that covers the inner peripheral surface of the tunnel, and a shield jack for obtaining the propulsion reaction force from the installed lining body. Tunnel excavators that employ a so-called shield mechanism that can be used have also been developed.

According to the construction method using these tunnel excavators, there is an advantage in that the construction speed and ease of work are superior to other tunnel construction methods, but the shield excavation method used in the shield construction method is used. Because it does not work in a closed work space like a machine,
When encountering a soft stratum such as a crush zone without taking any precautionary measures, tunnel excavation work becomes difficult, not only requires much time and labor for restoration work, but also the use of tunnel excavator In some cases, it becomes impossible to change the construction method.

Therefore, in order to perform a tunnel excavation work while taking advantage of the excellent features of a tunnel excavator such as a TBM, information on the ground in front of the face is accurately grasped, and ground conditions such as shredding zones are poor. When the ground is discovered, it is necessary to perform excavation work while taking countermeasures against the ground in advance.

[0007] Then, as exploration method for obtaining information of the ground, conventionally, in general, and elastic wave exploration method, electromagnetic exploration method, the Rayleigh wave exploration method, various physical exploration methods such as electrical resistance probe method Although it is known, it has not yet been put to practical use as a means for accurately exploring the state of the ground ahead of a tunnel machine such as a TBM as information useful for excavation work by the tunnel machine. .

On the other hand, as an alternative to the above-mentioned physical exploration method for accurately exploring the ground in front of the tunnel excavator, there is a method of directly boring the ground in front to directly obtain the state of the ground. is there. According to this exploration method,
A part of the actual ground can be observed by hand, and the ground can be determined with high reliability from various data at the time of drilling.

[0009]

However, in the above-described conventional method for exploring the ground in front of a tunnel excavator by boring, when the inside of the excavated cross section of the tunnel excavator is inspected by this method, troubles during drilling and the like may occur. However, there is a risk that a steel boring rod or the like remains in the excavated section, and if such a steel material is left behind, there is a risk that damage to the cutter may increase and hinder the excavation work. It is customary to remove the boring work.

That is, in the conventional method for exploring the ground by boring, as shown in FIG. 5, a section excavated by a tunnel excavator 60 is removed, and a boring rod 6 is diagonally forwardly moved.
Although the exploration was performed by driving 1 or the like, in such a method, a point farther from the actual excavation point was explored as going deeper, and an accurate survey result which is a reference for the excavation work of the tunnel 62 was obtained. In addition to being unable to obtain, there is a problem that work cannot be performed efficiently because the drilling distance becomes long.

A boring device 63 for boring is also provided.
Is generally provided on and used on a tunnel excavator 60, a work table 64 or a work vehicle tow base 65 that subsequently moves forward with the tunnel excavator 60, and therefore, the boring rod 62 is used in an oblique direction. While the ground exploration work is being performed by driving the tunnel excavator, the excavation work by the tunnel excavator 60 must be stopped, so that the excavation speed of the tunnel excavator 60 is impaired.

Further, even if the boring rod 62 and the like can be driven into the excavated cross section of the tunnel and the excavation work by the tunnel excavator 60 and the exploration of the ground in front are performed, the excavation speed by the tunnel excavator 60 is not increased. Since it changes randomly depending on the state of the ground, such as the hardness of the ground to be ground, the boring drill 63 is simply attached to the tunnel excavator 60 or the work carriage 64 following the boring machine for boring work. There is a problem that the drilling operation cannot be performed at a suitable predetermined speed, and thus it is not possible to accurately collect various data at the time of drilling necessary for exploration and determination of the ground.

The present invention has been made in order to solve such a problem, and it has become possible to perform the ground exploration by drilling in a tunnel excavation section, and to perform the excavation work by a tunnel excavator in parallel. In addition to being able to perform ground exploration work, even when the tunneling speed of the tunneling machine fluctuates randomly,
An object of the present invention is to provide a forward search device for a tunnel excavator that can obtain accurate ground information efficiently and quickly by performing a drilling operation at a predetermined speed suitable for a boring operation.

Further, the present invention provides a tunnel excavator which does not impede the excavation work even when a casing which is a device for boring operation, which is cast and inserted into a tunnel excavation section, remains in the cross section. It is an object of the present invention to provide a forward search device.

[0015]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and the gist of the present invention is to obtain a tunnel excavation work by obtaining an excavation reaction force from an outer ground or a back lining body. The excavator is provided on a tunnel excavator consisting of a telescopic body with a cutter head that excavates the facet at the tip of the tunnel excavator. A forward exploration device, wherein the forward exploration device is installed through a through hole formed in a cutter head of the tunnel excavator and is inserted into a ground in front of the tunnel excavator; and A drilling machine provided with a drilling bit, a relay rod and a driving device for driving, a drilling machine guide for sliding the drilling machine along the axial direction of the tunnel, and the tunnel A slide synchro device that holds a relative stop state of the drilling machine guide in the tunnel pit by retracting the drilling machine guide by an amount of advance with respect to the excavating movement of the drilling machine. In the forward exploration device of the tunnel machine.

Further, in the forward search device for a tunnel excavator according to the present invention, the slide synchronizing device is connected to a slide synchronizing base on which the drilling machine guide is mounted and the tunnel excavator moving excavatingly or a subsequent bogie thereof. Preferably, one end is attached and the other end is attached to the slide synchro base, and the synchro cylinder is configured to extend and contract in synchronization with the forward movement of the tunnel excavator.

Further, the slide synchro base may be provided with a guide slide device for adjusting a position of the mounted drilling machine guide.

Further, the drilling machine guide may be provided with a bit pressure adjusting device for adjusting the driving pressure of the casing by the drilling bit of the drilling machine.

In the forward exploration device for a tunnel machine according to the present invention, the casing, which is cast and inserted into the front ground, is made of a fiber-reinforced resin that can be cut by the cutter head, except for its tip. Is preferred.

Further, the casing is provided with a casing shoe having a stepped portion projecting inward at a tip end thereof, and the drilling machine is provided between the drilling bit and the relay rod. A guide device having a stepped portion of the casing shoe and a stepped portion that abuts and locks from the inside of the casing toward the front is provided, and as the drilling bit and the relay rod advance during drilling work, the guide is provided. By pushing the casing forward by the abutting engagement between the stepped portion of the device and the stepped portion of the casing shoe, the casing can be driven and inserted into the ground.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. As shown in FIG. 1, a forward search device 20 of a tunnel excavator according to this embodiment performs an excavation operation of a tunnel 30 while obtaining an excavation reaction force from ground on an outer periphery via grippers 14 and 16. Telescopic body 13 with cutter head 12 for digging face
The tunnel excavator 10 is provided for exploring the state of the ground ahead of the face in parallel with the excavation work by the tunnel excavator 10.

Here, the tunnel machine 10 is provided with a TB
M, a front body 15 having a cutter head 12 for excavating a face and a front gripper 14 protruding outward and pressing the outer peripheral ground, and sliding on the front body 15. A rear trunk portion 17 having a main gripper 16 movably connected and protruding outward to press against the ground at the outer periphery; and a thrust linking the rear trunk portion 17 and the front trunk portion 15 so as to extend and contract. The thrust jack 18 is extended and the tunnel 30 is excavated by the cutter head 12 of the front body 15 while the main gripper 16 of the rear body 17 is protruded to obtain the excavation reaction force from the surrounding ground. Thereafter, the main gripper 16 of the rear body 17 is retracted to protrude the front gripper 14 of the front body 15 and obtain the support reaction force from the ground on the outer periphery, and the thrust jack 18 is moved back. By repeating the step of drawing the rear body portion 17 by condensation, in which slide into excavating a tunnel 30 in a so-called inchworm-like.

The forward search device 20 of this embodiment
The main body portion is installed on a TBM rear bogie tow rack 11 that connects to a working bogie 19 that follows the tunnel boring machine 10 and moves forward with the excavation movement thereof.
As shown in FIG. 2, a casing 22 mainly driven into the ground in front of the tunnel excavator 10 through a through hole 21 formed in the cutter head 12 of the tunnel excavator 10, and the casing 22. Drilling bit 2 arranged at the tip of casing 22 for placing
3. Relay rod 2 disposed inside casing 22
4, a drilling machine 25 provided with a driving device 28 for imparting impact rotation to the relay rod 24 and the drilling bit 23, and a drilling machine for sliding the drilling machine 25 along the axial direction of the tunnel 30. The drilling machine guide 26 and the drilling machine guide 26 are moved backward by the amount of advance for the excavating movement of the tunnel boring machine 10, so that the tunnel 10
And a slide synchronizing device 27 for maintaining a relative stop state in the mine.

Casing 2 to be cast and inserted into the ground in front
2 is a cutter head 12 made of fiber reinforced resin (FRP) or the like.
Is formed by forming a member which is easy to cut by a tubular shape, and while a unit rod having a predetermined length is successively added together with the driving operation, a tunnel is formed through a through hole 21 formed in the cutter head 12. The drill bit is inserted into the ground in front of the excavator 10, and a drill bit 23
A casing shoe 50 made of a steel pipe is attached so as to be able to withstand the impact and wear at the time of drilling. As shown in FIG. 3, the casing shoe 50 has a stepped portion 29 which protrudes inward over the entire circumference by increasing the thickness at the distal end thereof.
Is formed, and the casing opening 31 formed in the stepped portion 29 has a pilot bit 3 constituting the drill bit 23 as described later.
2 and the eccentric reamer 33 can be taken in and out. The operation of extending the unit rod of the casing 22 is performed by the discharge head 40.
, And between this and the existing casing 22,
This is performed by connecting a unit rod having a length substantially equal to the unit rod length of the relay rod 24.

A drilling machine 25 for driving the casing 22 into the ground at the front thereof includes a drill bit 23 disposed at the tip of the casing 22 and a drilling bit 23.
A relay rod 24 disposed in the inside of the device, and a driving device 28 for performing impact rotation on the relay rod 24 and the drill bit 23.
And a connecting portion between the relay rod 24 and the drill bit 23.
The guide device 34, the extension rod 35, and the wing coupling 36 are interposed and arranged.

The drill bit 23 is formed, for example, in Japanese Patent Publication No. 51-2.
Pilot bit 32 having a configuration similar to that described in JP-A-5101 and having a cutting blade on the tip end surface.
And an eccentric reamer 33 attached to the pilot bit 32 so as to be rotatable and slidable while being laterally moved in the center position relative to the pilot bit 32 by being inserted through the bit axis of the pilot bit 32, as shown in FIG. )
As shown in (b) and (b), the unidirectional rotation of the pilot bit 32 via the relay rod 24 causes the eccentric reamer 33 to slide laterally while sliding relative to the pilot bit 32 to remove the shoulder. The pilot bit 32 is fixed to the pilot bit 32 via the locking member and rotates. The cutting blade provided on the shoulder portion causes a cross section larger than the cut cross section of the pilot bit 32, that is, a cross section larger than the cross section of the casing 22. Drilling can be performed on the cross section (see (a)). The rotation of the pilot bit 32 in the other direction via the relay rod 24 causes the eccentric reamer 3 to rotate.
3 releases the engagement with the pilot bit 32 and slides in the opposite direction while rotating and sliding with respect to the pilot bit 32, and as shown in FIG.
2 and the protruding shoulder is retracted, whereby the drill bit 23 can be collected into the casing 22 through the casing sink opening 31.

The guide device 34 subsequent to the drill bit 23 is formed of a steel cylinder having a size capable of sliding in the casing 22, and the front portion thereof has a casing sink opening 31 of the casing shoe 50. The stepped portion 29 of the casing shoe 50 and the stepped portion 37 that comes into contact with the inside of the casing 22 are formed. The guide device 34 functions as a guide for aligning the center position of the pilot bit 32 and the relay rod 24 with the center position of the casing 22, and the outer peripheral surface of the guide device 34 A notch groove 38 is formed to extend to the end face, and cutting earth and sand can flow into the casing 22 through the notch groove 38.
In addition, the guide device 34 can reduce the impact force from the setting device 28 via the relay rod 24 by the stepped portion 37 abutting against the stepped portion 29 of the casing shoe 50 from inside the casing 22. This is transmitted to the shoe 50, whereby the shoe 50 is pushed into the ground of the casing 22.

The relay rod 24 disposed inside the casing 22 is extended to the driving device 28 of the drilling machine 25 by connecting a unit rod made of, for example, steel via a sleeve 39. In order to transmit the rotation and impact force of the driving device 28 to the guide device 34 and the drill bit 23, the device is connected and fixed to the driving device 28.

The connecting portions of the above members are connected by a rope screw between the drill bit 23 and the guide device 34 and between the guide device 34 and the extension rod 35, and between the extension rod 35 and the wing coupling 36. The wing coupling 36 is connected to the wing coupling 36 with a T screw which is easier to loosen than a rope screw, so that the tip of the drill bit 23 or the like is less likely to come off.

As the driving device 28 for driving the relay rod 24 and the drill bit 23, various known devices for driving a rock or the like can be used.
A function is provided in which the relay rod 24 and the drill bit 23 can be easily driven into a hard ground such as a rock while giving a rotation and a hit to the drill bit 23.

Then, as shown in FIG. 2, the drilling machine 25 includes a slide base 41 on which the driving device 28 is mounted.
Slides along a drilling machine guide 26 arranged along the axial direction of the tunnel 30, penetrates the through-hole 21 formed in the cutter head 12, and passes through the relay rod 24, the drilling bit 23, The casing 22 pushed forward by these components is accurately driven and inserted into the ground in front of the tunnel machine 10.

That is, a drilling machine slide winch 42 is provided before and after the drilling machine guide 26, and a wire 43 whose one end is fixed to a front part and a rear part of a slide base 41 is connected to the drilling machine guide 26. The boring machine 25 is wound around a slide winch 42 and can be slid along the boring machine guide 26 by driving the boring machine slide winch 42. In the drilling machine guide 26, a hydraulic cylinder 45 for adjusting the bit pressure is provided between the front and rear drilling machine slide winches 42, and before and after this, a wire 43 wound around the drilling machine slide winch 42 is provided. At the same time, a bit pressure adjustment sensor 44 is interposed at a position where the wire 43 is attached to the front portion of the slide base 41, and data from the bit pressure adjustment sensor 44 is transmitted to a proportional electromagnetic sensor for controlling a cylinder. The cutting pressure of the ground by the cutting bit 23 can be kept constant by controlling the hydraulic cylinder 45 for adjusting the bit pressure by feeding to the valve. That is, this makes it possible to eliminate an operator's operation error and facilitate automatic excavation.

The drilling machine guide 26 is mounted on a slide synchronizing base 46 constituting a slide synchronizing device 27, and is connected to a TBM rear bogie towing rack 11 for connecting a succeeding bogie following the tunnel excavator 10. It is arranged in.

The slide synchro base 46 has wheels and the like on its bottom surface and is configured to be slidable on the towing stand 11.
A synchro cylinder 48 constituting the slide synchro device 27 is provided. That is, one end of the synchro cylinder 48 is connected to the slide synchro base 46.
The other end is fixed to the towing stand 11 by, for example, a pin connection or the like, and in conjunction with the thrust jack 18 (see FIG. 1) of the tunnel machine 10, the thrust jack 18 extends to retreat the slide synchro base 46. With this configuration, the drilling machine guide 26 mounted on the tunneling machine is retracted, and the drilling machine guide 26 can maintain a relatively stopped state in the tunnel pit even during the excavation work by the tunnel excavator 10. Has become.

Further, a guide slide winch 49 is provided on the slide synchro base 46, whereby the wire 52 having both ends fixed to the drilling machine guide 26 is wound or unwound, thereby forming the drilling machine guide 26. The position can be moved, and the position of the drilling machine 25 can be adjusted and the slide width can be given a margin.

According to the forward exploration device 20 of the tunnel excavator of this embodiment, in the drilling operation, the impact rotation or rotational energy generated by the drilling machine 25 is transmitted to the relay rod 24, and the drilling bit is further transmitted. 23, water, air, air bubbles and the like fed through a through hole formed in the center of the relay rod 24 are jetted from the tip of the drill bit 23, and these jetted water and the like are crushed or The excavated earth and sand is discharged by flowing the cut earth and sand into the casing through the cutout groove 38 formed on the outer peripheral surface of the guide device 32.

Here, the drilling operation is performed by the tunnel excavator 10.
Is performed by directly driving the relay rod 24, the drill bit 23, or the casing 22 into the ground in front of the tunnel excavator 10 in the excavation cross section through the through hole 21 formed in the cutter head 12 in the excavation. Therefore, while obtaining accurate survey results targeting the actual excavated ground,
The drilling distance can be kept to a necessary minimum.

Also, during the excavation work by the tunnel excavator 10, the drilling machine guide 26 is relatively stopped in the tunnel shaft by the action of the slide synchronizing device 27 including the slide synchronizing base 46 and the synchronizing cylinder 48. The drilling speed of the drilling machine 25 can be maintained even when the excavation speed of the tunnel excavator 10 randomly changes depending on the state of the ground such as the hardness of the ground to be excavated. It can be maintained at a predetermined speed suitable for the work, whereby it is possible to accurately collect various data at the time of drilling necessary for exploration and determination of the ground, and also during excavation work by the tunnel excavator 10 A boring operation can be easily performed in parallel with this operation.

Further, when the casing 22 is inserted and driven into the ground, the casing 22 is pushed into the ground by abutting engagement between the stepped portion 37 of the guide device 32 and the stepped portion 29 of the casing shoe 50. Since it is carried out in the form, it can be carried out without damaging the casing 22 and joints thereof and while inserting the casing 22 with high precision. Further, since the eccentric reamer 33 of the drill bit 23 performs the drilling operation with a diameter larger than the outer diameter of the casing 22, the pushing operation of the casing 22 into the ground by the pushing can be easily performed. it can.

Further, since the casing 22 is made of a member such as FRP, which can be easily cut by the cutter head 12, the casing 22 may be left in the ground. Even when the position deviates from the through hole 21, the excavation work can be performed without any trouble while cutting and removing the same by the cutter head 12.

The drill bit 23, the guide device 3
2. The extension rod 35, the wing coupling 36, the relay rod 24, etc. can be collected after the drilling operation, but the drill bit 23, the guide device 32, the extension rod 35, the wing coupling 36 are not too large members. Therefore, even when the connection portion is detached and left in the ground, it is possible to sufficiently cope with the situation when the tunnel excavator 10 reaches the point where these are left.

[0042]

As described above in detail, according to the forward search device for a tunnel excavator of the present invention, the ground can be searched by boring in the tunnel excavation section in the tunnel excavation direction. This reduces the length of boring and provides more accurate information on the ground in front of the boring.The slide synchro device allows boring even when the tunnel excavation speed fluctuates randomly. The drilling operation can be performed at a suitable predetermined speed, whereby the ground exploration operation can be easily performed in parallel with the excavation operation by the tunnel excavator. That is, prior to the excavation work by the tunnel machine, information on the ground in front can be obtained accurately, efficiently, and quickly.

If the casing to be cast and inserted is made of a fiber reinforced resin that can be cut by a cutter head, even if the casing remains in the excavated cross section,
The excavation work can be performed without damaging the cutter head and causing a trouble in the work.

Further, if the casing is configured to be driven into the ground by being pushed forward by pushing the casing forward through the abutting engagement between the stepped portion of the guide device and the stepped portion of the casing shoe, The casing can be accurately inserted and cast into the ground without damaging the casing and its joints.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a forward search device for a tunnel machine according to an embodiment of the present invention.

FIG. 2 is a side view showing a configuration of a forward search device for a tunnel machine according to an embodiment of the present invention.

FIG. 3 is a side view showing details of configurations of a casing, a drill bit, a relay rod, and the like.

FIG. 4 (a) is an explanatory view showing a situation where a drilling operation is being performed by a cutting bit, and FIG. 4 (b) is an explanatory view showing a situation where a cutting bit is collected in a casing.

FIG. 5 is an explanatory view showing a conventional method for searching ahead of a tunnel excavator by boring.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Tunnel excavator 11 TBM construction trolley traction stand 12 Cutter head 13 Body 18 Thrust jack 20 Forward search device 21 Through hole 22 Casing 23 Drilling bit 24 Relay rod 25 Drilling machine 26 Drilling machine guide 27 Slide synchro device 28 Driving Installation device 29 Stepped portion (casing shoe) 30 Tunnel 34 Guide device 37 Stepped portion (guide device) 44 Bit pressure adjustment sensor 45 Bit pressure adjustment cylinder 46 Synchro slide base 48 Synchro cylinder 50 Casing shoe

Claims (6)

(57) [Claims] 1. A tunnel excavator comprising a telescoping trunk having a cutter head for excavating a face at a tip for excavating a tunnel by obtaining excavation reaction force from an outer ground or a back lining body. And a forward search device of the tunnel excavator for exploring the state of the ground ahead in accordance with the excavation work by the tunnel excavator, the forward search device having an opening formed in a cutter head of the tunnel excavator. Through a through hole, a casing that is driven into the ground in front of the tunnel excavator, and a drilling machine equipped with a drill bit, a relay rod, and a driving device, for driving the casing, A drilling machine guide for slidingly moving the drilling machine along the axial direction of the tunnel, and by retracting the drilling machine guide by an advance amount with respect to the excavation movement of the tunnel excavator. Front locator of tunnel boring machine characterized by comprising the slide synchronizer and for retaining the relative standstill in a tunnel underground of the drilling machine guide. 2. The slide synchronization device according to claim 1, wherein one end of the slide synchronization base is mounted on the slide synchronization base on which the drilling machine guide is mounted, and the other end of the tunnel excavation machine or a trailing bogie thereof. The forward search device for a tunnel excavator according to claim 1, further comprising a synchro cylinder attached to a base and extending and contracting in synchronization with the forward movement of the tunnel excavator. 3. The forward search device for a tunnel machine according to claim 2, wherein a guide slide device for adjusting a position of the drilling machine guide mounted is provided on the slide synchro base. 4. The drilling machine guide according to claim 1, wherein said drilling machine guide includes a bit pressure adjusting device for adjusting a driving pressure of a casing by a drilling bit of the drilling machine. A forward search device for a tunnel machine described in Crab. 5. A casing, which is cast and inserted into the front ground, is made of a fiber-reinforced resin that can be cut by the cutter head except for a tip portion thereof. A forward exploration device for a tunnel machine according to any one of the above. 6. The casing shoe further comprises a casing shoe having a stepped portion projecting inward at a distal end thereof, and the drilling machine is arranged such that the casing shoe is disposed between the drilling bit and a relay rod. A guide device having a stepped portion and a stepped portion that abuts and locks forward from inside the casing, and with the advancement of the drill bit and the relay rod during drilling work, the guide device of the guide device is provided. 6. The casing according to claim 1, wherein the casing is pushed into the ground by pushing the casing forward in a state where the stepped portion and the stepped portion of the casing shoe are in contact with each other. A forward search device for a tunnel machine described in Crab.