JP2708142B2 - Hard rock tunnel excavator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard rock tunnel excavator (hereinafter simply referred to as a tunnel excavator). In more detail, tunnels can be excavated even in hard rock areas such as mountains, and there is no special need to assemble segments according to the situation, and a unique drilling is used to fix the excavated tunnel wall and fix itself. The present invention relates to a tunnel excavator capable of excavating with a gripper.

[0002]

2. Description of the Related Art In recent years, railways, roads,
Demand for tunnels for headraces, waterways, etc. is increasing. BACKGROUND ART Conventionally, a shield excavator for a soft soil layer and a tunnel excavator for a hard rock soil layer are generally used in a mechanized construction method for tunnel excavation. The tunnel excavator, which is also the object of the present invention, uses a hard bedrock to propel the excavated pit wall with its own gripper, and fixes the excavator itself to the pit wall to support the reaction force of the excavation advance. It is configured to receive. In addition, as a feature of the configuration and operation of the tunnel excavator, the rotation of the cutter disk for excavation is often limited to one direction due to restrictions on the arrangement of the roller bits and the arrangement of the excavation slip inlet.

A conventional tunnel excavator is disclosed in Japanese Patent Publication No. 62-32.
No. 319 discloses this in detail.

Recently, there has been a demand for a tunnel excavator to bend and excavate. As described in the above-mentioned publication, a plurality of fuselage bodies are connected so as to be able to bend, and a direction control jack and a detail jack are used. A configuration in which these bodies are bent is created.

[0005] The tunnel excavator described in the above publication comprises a front trunk, a middle trunk and a rear trunk, and between the front trunk and the middle trunk and between the middle trunk and the rear trunk, each of the trunk ends has a body end. It is configured to be loosely fitted and bendable by pin connection. A seal member is provided in the gap between the fitted bodies.

[0006]

The above-mentioned tunnel excavator has a structure in which the trunks are simply loosely fitted and pin-coupled to each other. One of the directions is reduced and the other side is enlarged by 180 °, so that such a variation is accommodated by the deformation of the sealing member. As a result, when the bending angle between the trunks is increased, the one gap is reduced in proportion thereto, and a strong compressive force acts on the sealing member to damage the sealing member, thereby promoting the deterioration. Becomes large and the sealing function is lost.

Further, since the cutter disk rotates in only one direction as described above, a relative displacement in the circumferential direction occurs due to the rolling (so-called torsion) between the trunks due to the rotational reaction force during excavation.

The present invention has been made to solve such a problem, and provides a tunnel excavator capable of forming a large bending angle by forming a so-called spherical joint between the trunks, and has such a configuration. Another object of the present invention is to provide a tunnel excavator provided with a conventional correction mechanism for circumferential relative displacement.

[0009]

[0010]

[0011]

The excavator according to the first aspect of the present invention is configured such that a plurality of cylindrical trunks are fitted to each other via a seal member at the ends thereof and a joint mechanism is provided. A jack for eliminating relative displacement in the circumferential direction of the two trunks is supported at one end by the one trunk while the other end is supported by the other trunk in a state deviated from the center of the trunk. Hard rock tunnel excavator,
The joint mechanism is disposed at two positions in one diameter direction at the fitted both ends, and each joint mechanism is provided at one trunk end and has a first bracket having a long hole in a trunk axis direction and the other bracket. A second bracket having a long hole in the circumferential direction of the body provided at the body end of the body, and both brackets are overlapped with a gap therebetween, and a pin member is provided so as to penetrate the two long holes. I have.

According to the excavator of the first aspect , when the jack causes the jack to rotate coaxially so as to eliminate the relative displacement in the circumferential direction, the pin member guides along the elongated hole in the body circumferential direction of the bracket. This allows smooth rolling correction, and also allows bending in the direction perpendicular to the pin member by the gap between the brackets and the elongated hole in the body axis direction. This is achieved by a simple mechanism.

[0013] In the excavator according to the second aspect of the present invention, a plurality of cylindrical trunks are flexibly connected via a joint mechanism, and a jack for eliminating relative displacement of the two trunks in the circumferential direction is provided. A hard rock tunnel excavator having one end supported by one body and the other end supported by the other body in an off-center state, wherein the joint mechanism has a substantially partially spherical shape over the entire circumference. At least one body end portion, and the other body end portion provided with a seal member fitted to the one body end portion and in contact with the surface of the partially spherical body end portion over the entire circumference. A pin coupling mechanism disposed at two locations in one diameter direction in the fitting portion, the pin coupling mechanism comprising a first bracket having a circular hole disposed at one body end and the other Second bracket having a long hole in the circumferential direction of the body disposed at the body end The brackets are overlapped with each other, and the pin members penetrate the holes.

According to the excavator of the second aspect, a sharp curve excavation becomes possible by increasing the function maintenance limit angle of the seal member when the trunk is bent around the pin, and the smooth excavation between the trunks is possible. Rolling correction can be performed.

[0015]

[0016]

In the excavator according to the third aspect of the present invention, a plurality of cylindrical trunks are flexibly connected via a joint mechanism, and a jack for eliminating relative displacement of the two trunks in the circumferential direction is provided. A hard rock tunnel excavator having one end supported by one body and the other end supported by the other body in an off-center state, wherein the joint mechanism has a substantially partially spherical shape over the entire circumference. At least one body end portion, and the other body end portion provided with a seal member fitted to the one body end portion and in contact with the surface of the partially spherical body end portion over the entire circumference. A pin coupling mechanism disposed at two locations in one diameter direction in the fitting portion, the pin coupling mechanism having a trunk axially long hole disposed at one trunk end. A bracket having a long hole in the circumferential direction of the body provided at the other end of the body. The two brackets are arranged such that the two brackets overlap with a gap therebetween, and that the pin member penetrates into the long holes.

[0018] According to the excavator of the third aspect, a sharp curve excavation becomes possible by increasing the function maintenance limit angle of the seal member at the time of bending between the trunks around the pin, and the gap between the brackets can be formed. And the elongated hole in the body axial direction allows the pin member to bend in the axial direction as well.
In addition, since the pin member is guided along the elongated hole in the body circumferential direction of the bracket, smooth rolling correction is possible, and the above-described action is simultaneously achieved by the simple mechanism of the partial spherical surface, the bracket, and the pin member. .

In the excavator according to the first and third aspects , the pin is provided with a pair of stoppers which can be fitted on both sides of a pin member penetrating into the center in the elongated hole in the trunk axis direction. By fitting the stopper when bending around the member, it becomes possible to position the pin member at an appropriate position on the partial spherical surface of the trunk end, and as a result, the seals at both ends in the direction perpendicular to the bending center line This is preferable in that the function is also maintained soundly.

[0020]

Next, an embodiment of an excavator according to the present invention will be described with reference to the drawings.

FIG. 1 is a side sectional view showing an embodiment of the excavator according to the present invention, FIG. 2 is a side sectional view showing the excavator shown in FIG. 1 in an extended state, and FIG. FIG. 4 is a perspective view showing one embodiment, FIG. 4 is a plan view of the joint member of FIG. 3, FIG.
FIG. 6 is a sectional view taken along line AA of the joint member of FIG. 3, FIG. 6 is a sectional view taken along line AA of the joint member of FIG. 3 with a stopper attached, FIG. 7 is a perspective view showing the stopper in FIG. FIG. 4 is a schematic plan view showing the excavator when bent in the horizontal direction, (a) when the stopper is mounted, and (b) when the stopper is not mounted;
9 is a cross-sectional view taken along line AA of the joint member of FIG. 3 at the time of bending in the vertical direction. FIG. 10 is a cross-sectional view taken along line AA of the joint member of FIG. FIG. 12 is a sectional view taken along line AA of the joint member of FIG. 3, and FIG. 12 is a sectional view of FIG.
13 is a schematic cross-sectional view taken along line B, FIG. 13 is a cross-sectional view taken along line CC of the joint member of FIG. 3 in the rolling correction operation process, and FIG. 14 is a cross-sectional view taken along line DD of FIG. .

The excavator 1 shown in FIG. 1 is a three-body excavator comprising a front body 2, a middle body 3 and a rear body 4. Each of the cylinders 2, 3, and 4 is flexibly connected via a first joint member 5 and a second joint member 6, respectively. A cutter disk 7 is mounted on the entire end surface of the front body 2, and the cutter disk 7 is provided with a number of excavating roller bits 8 and a cutter bit (not shown).
The cutter disk 7 is rotated by a drive motor 9 via a pinion gear 10 fitted on its output shaft, a ring gear 11 meshing with the pinion gear 10, and a support cylinder 12 connected to the ring gear 11. A plurality (four in this embodiment) of front grippers 13 are provided at equal intervals in the circumferential direction of the front body 2. The front gripper 13 is provided for the purpose of fixing the excavator 1 in a tunnel by protruding radially outward and stretching a pit wall, similarly to a rear gripper 18 described later.

The middle body 3 is nested with its inner cylinder 3a and outer cylinder 3b, and can be expanded and contracted by a thrust jack 14 having one end connected to the front body 2 and the other end connected to the rear body 4. It is configured as follows. This figure shows a contracted state, and FIG. 2 shows an extended state. As shown, the inner cylinder 3a is connected to the front body 2 by a first joint member 5, and the outer cylinder 3b is connected to the rear body by a second joint member 6. The expansion and contraction of the middle body 3 is performed while the key member 15 fixed to the inner cylinder 3a is guided by a key groove member 16 formed in the outer cylinder 3b. As will be described later, the outer cylinder 3b can be relatively rotated by the second joint member 6 with respect to the rear trunk 4 within a range of the elongated hole 25a in the trunk circumferential direction (see FIGS. 3 to 13). A seal member 17 for watertight sealing between the outer cylinder 3b and the inner cylinder 3a is mounted on the inner diameter side of the front end of the outer cylinder 3b.

Although not shown, between the front body 2 and the middle body 3, a plurality of so-called direction control jacks for bending the two bodies 2 and 3 are provided over the entire circumference as in the prior art. Have been. Further, although not shown, a screw conveyor or a belt conveyor for discharging excavated earth and sand and rocks backward is provided.

As described above, the rear barrel 4 is provided with two rear grippers 18 in one diameter direction. The rear gripper 18 is configured to project the contact portion 18b outward in the radial direction by the four gripper jacks 18a. Further, two rolling jacks 19 for rotating the rear trunk 4 relative to the front trunk 2 and the middle trunk inner cylinder 3a in the circumferential direction are provided (see also FIG. 12). One end of the rolling jack 19 is pin-connected to the rear body 4,
The other end is pin-connected to the outer cylinder 3b of the middle body 3. Therefore, if the spreader of the rolling jack 19 expands and contracts, the rear trunk 4 and the outer cylinder 3b rotate relatively around the trunk axis, and as a result, the front trunk 2 is moved to the rear trunk 4 via the key member 15 and the key groove member 16. Rotate relative to it. In this manner, the relative displacement of the front body 2 and the rear body 4 around the body axis caused by the reaction force of the excavation rotation of the cutter disk 7 can be eliminated.

The excavator 1 of this embodiment is equipped with a propulsion jack 20. The propulsion jack 20, like a shield machine, is provided for pushing the assembled segment and for causing the excavator 1 to move forward by its reaction. In this way, the excavator 1 can select the advance by the grippers 13, 18 and the thrust jack 14, or the advance by the propulsion jack 20, and the advance by using both simultaneously according to the environmental conditions.

Next, referring to FIGS.
The second joint member 6 that connects the outer cylinder 3b and the rear trunk 4 will be described.

In FIG. 3, reference numeral 21 denotes a spherical cylindrical member fixed to the rear end of the outer cylinder 3b. The spherical outer surface of the spherical cylindrical member 21 has a substantially spherical shape as a whole as is clear from FIG. Reference numeral 22 denotes a support member disposed on the inner peripheral surface of the front end of the rear trunk 4, and a seal ring 23 is mounted on the entire periphery adjacent to the support member 22. In the present embodiment, as shown in FIG. 13, the support member 22 is arranged not along the entire circumference but along the inner circumferential direction of the rear trunk 4 at a predetermined interval. Of course, it may be extended in an annular shape over the entire circumference. The support member 22 is usually made of metal, and plays a role of supporting the inner trunk 3. The gap between the support member 22 and the spherical cylindrical member 21 is very small in the diameter direction. Reference numeral 24 denotes a first bracket having a U-shaped cross section disposed on the inner peripheral surface of the spherical cylindrical member 21, and is provided at two locations in the diameter direction of the spherical cylindrical member 21. Reference numeral 25 denotes a second bracket which engages the first bracket 24 with a slight gap S (see FIG. 5), and is fixed to the reaction force receiving plate 26 of the rear trunk 4.
The second brackets 25 are also provided at two positions in the diameter direction of the rear trunk 4 so as to correspond to the first brackets 24.
As is clear from FIGS. 4 and 5, the first bracket 2
A long hole 24a in the trunk axis direction is formed in 4 and a long hole 25a in the trunk circumferential direction is formed in the second bracket 25. And the pin 27 is penetrated in the state where both long holes 24a and 25a overlap at right angles. The middle trunk 3 and the rear trunk 4 can be bent around the pin 27 (see also FIG. 1). Usually, the second joint member 6 is disposed at the uppermost end and the lowermost end of the trunk, so that the middle trunk 3 and the rear trunk 4 can be bent in a horizontal plane. 28 is a lid member. Reference numeral 29 denotes a stopper which can abut on the leading edge of the spherical cylindrical member 21 and is fixed to the reaction force receiving plate 26 over the entire circumference.

[0029] FIG. 6 is a range of the restraining member 30 (the claims cylinder axis direction of the long hole 24a of the first bracket 24
(Corresponding to the stopper referred to as “stopper”) is shown. This restraining member 30 is a pair of members having a shape as shown in FIG. Then, in a state where the pin 27 penetrates into the center of the elongated hole 24a, the two pairs of restraining members 30
On both sides. By doing so, the pin 27 is positioned exactly at the center of the spherical cylindrical member 21 in the trunk axis direction, in other words, at the position where the spherical surface is bulged most outward. As a result, when the middle trunk 3 and the rear trunk 4 are bent around the pin, the portion where the relative movement between the support member 22 and the spherical cylindrical member 21 is the largest, that is, both ends in the horizontal plane in the diametric direction (FIG. 8), the support member 22 is always in contact with the spherical cylindrical member 21 (see FIG. 8A), and the function of the seal ring 23 is maintained in a healthy state. That is, theoretically, the distance between the support member 22 and the outer surface of the spherical cylindrical member 21 does not change due to the bending of the trunks. However, when the position of the pin 27 is shifted from the center of the elongated hole 24a in the trunk axis direction of the first bracket 24 and is located, for example, on the rear end side without attaching the restraining member 30 (FIG.
8) when the middle trunk 3 and the rear trunk 4 are bent.
As shown in (b), the gap between the support member 22 and thus the seal ring 23 and the outer surface of the spherical cylindrical member 21 becomes large. The restraining member 30 is mounted to prevent such a situation.

It is desirable that the restraining member 30 is mounted only when the bending is performed about the pin 27 (bending in a horizontal plane). This is because the excavator 1 can be bent up and down using the elongated hole 24a in the trunk axis direction. That is, as shown in FIG.
The second bracket and the second bracket can be mutually inclined using the gap S therebetween, and accordingly, the pin 27 can also be inclined along the elongated hole 24a in the trunk axis direction. Also in this case, the contact between the support member 22 and the spherical cylindrical member 21 is maintained, so that the function of the seal ring 23 is maintained sound.

FIG. 10 shows a process in which the front body 2 is advanced by the extension of the thrust jack 14 while excavating (the middle body 3
May extend during the extension operation), at the completion of the extension operation, or during the process in which the rear trunk 4 is drawn toward the front trunk 2 due to the contraction of the thrust jack 14 (the process in which the middle trunk 3 is contracted). The state of the two joint members 6 is shown.

At this time, the pin 27 abuts on the rear end of the elongated hole 24a in the body axis direction, and the position of the support member 22 is slightly shifted from the center of the spherical cylindrical member 21 in the body axis direction. If so, there is no problem with the sealing function.

FIG. 11 shows the state of the second joint member 6 at the time when the operation of pulling the rear trunk 4 by the contraction of the thrust jack 14 is completed. At this time, the tip of the spherical cylindrical member 21 contacts the stopper 29 before the pin 27 contacts the front end of the long hole 24a. As shown, a small gap T is formed between the front end of the elongated hole 24a and the pin 27. Thus, the positions and dimensions of the brackets 24 and 25, the elongated hole 24a, and the stopper 29 are set. By doing so, the impact force on the pin 27 when the pulling operation is completed is avoided, and the pin 27 and the brackets 24 and 25 are protected. It is not necessary to consider the impact force particularly during the contraction process, the extension process, or the completion of the extension operation (see FIG. 10).

On the other hand, as described above, the elongated hole 25a in the circumferential direction of the second bracket 25 is formed by the pin 27 due to the rotational reaction force during excavation.
In addition to protecting the brackets 24 and 25, the relative rotational displacement between the front trunk 2 and the rear trunk 4 caused by rolling causes the rear trunk 4 and the front trunk 2 to be relatively rotated by the rolling jack 19 as shown in FIG. It is formed so as to be able to be modified. In FIG. 12, first, the outer cylinder 3b of the middle body connected to the front body via the inner cylinder, the key member, and the key groove member is rotationally displaced in the direction of arrow M by the rotational reaction force during excavation. The displacement is eliminated and corrected by relatively rotating the rear trunk 4 in the direction of arrow M and the outer cylinder 3b in the direction of arrow N by extending the rolling jack 19.

In this case, as shown in FIG. 13, even if the front trunk 2 and the rear trunk 4 rotate relative to each other by receiving a rotational reaction force during excavation (see a two-dot chain line in the figure), the pin 27 remains Since the pin 27 moves relative to the inside of the elongated hole 25a in the body circumferential direction, the bracket 27 is also attached to the pin 27.
No load acts on 4 and 25. Then, the pin 27 is returned by the rolling jack 19 to the original position substantially at the center of the elongated hole 25a in the body circumferential direction (see the solid line in the figure). As described above, by the second joint member 6 having a simple configuration,
In particular, it is possible to correct the displacement by rolling as well as bending up and down and left and right without receiving an excessive load.

FIG. 14 shows a first joint member 5 between the front body 2 and the inner cylinder 3a of the middle body. This joint member 5 also
Like the second joint member 6, it is usually arranged at the uppermost end and the lowermost end of the trunk, so that the front trunk 2 and the middle trunk 3 can be bent in a horizontal plane. Also, like the second joint member 6,
A spherical cylindrical member 31, a support member 32, a seal ring 33,
First bracket 34, second bracket 35 and pin 3
6, the brackets 34, 35 are provided with circular pin holes 34a, 35a instead of long holes.
The first joint member 5 cannot be expected to bend in the vertical direction like the second joint member 6, but in the case of a three-body excavator, the first joint member 5 is provided between the front trunk and the middle trunk or between the middle trunk and the rear trunk. If the second joint member 6 is provided and the other is provided with the first joint member 5, a bending angle of about 5 ° becomes possible. Of course, both parts may be equipped with the second joint member 6. However, it is generally difficult for a tunnel excavator to arrange a rolling jack near the front fuselage. Therefore, between the front trunk and the middle trunk, the one in which the long hole 25 in the trunk circumferential direction of the second joint member 6 is replaced with a circular pin hole is provided, and the second joint member 6 is directly held between the middle trunk and the rear trunk. It may be equipped. Either the first joint member 5 may be provided between any of the cylinders, or the second joint member 6 may be replaced with a circular pin hole in the circumferential direction of the second joint member 6 between any of the cylinders. However, a large bending angle can be obtained. As described above, if the spherical cylindrical member is mounted, a large bending angle can be obtained even when the long holes of the first bracket and the second bracket are used in place of the circular holes so as to have various combinations.

Even if the spherical cylindrical member is not mounted, the simple structure of the second joint mechanism enables smooth rolling correction and bending between the trunks without receiving a large load.

[0038]

According to the present invention, since the cylinders are connected to each other by a so-called spherical joint, the function maintenance limit angle of the seal member becomes large when the cylinders are bent around the pins. That is, since a large bending angle is possible, a sharp curve excavation becomes possible. Since the pin member is guided along the elongated hole in the torso direction, smooth rolling correction is possible, and the gap between the brackets and the elongated hole in the torso axial direction allow bending in the direction perpendicular to the pin member. Becomes possible,
Moreover, these functions are simultaneously achieved by a simple mechanism of the bracket and the pin member.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of an excavator according to the present invention.

FIG. 2 is a side sectional view showing the excavator of FIG. 1 in an extended state.

FIG. 3 is a perspective view showing one embodiment of a joint member in the excavator of FIG. 1;

FIG. 4 is a plan view of the joint member of FIG. 3;

FIG. 5 is a cross-sectional view taken along line AA of the joint member of FIG. 3;

FIG. 6 shows the joint member A of FIG. 3 fitted with a stopper.
FIG. 4 is a cross-sectional view taken along a line A.

FIG. 7 is a perspective view showing a stopper in FIG. 6;

FIGS. 8A and 8B are schematic plan views showing the excavator when bending in the horizontal direction, in which FIG. 8A shows a state in which a stopper is mounted and FIG.

9 is a cross-sectional view of the joint member of FIG. 3 taken along line AA when bent in a vertical direction.

10 is a cross-sectional view of the joint member of FIG. 3 taken along the line AA in a rear trunk pulling process.

11 is a cross-sectional view of the joint member of FIG. 3 taken along the line AA when the rear trunk pulling is completed.

FIG. 12 shows the rolling jack in FIG.
FIG. 3 is a schematic sectional view taken along line BB of FIG.

FIG. 13 is a sectional view taken along line CC of the joint member of FIG. 3 in a rolling correction operation process.

FIG. 14 is a cross-sectional view of another embodiment of the coupling member, taken along line DD in FIG. 1;
It is a line sectional view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Excavator 2 ... Front trunk 3 ... Middle trunk 3a ... Inner cylinder 3b ... Outer cylinder 4 ... Rear trunk 5 ... First joint member 6 ... Second joint member 21, 31 ... spherical cylindrical member 22, 32 ... support member 23, 33 ... seal ring 24, 34 ... first bracket 25, 35 ... first bracket 27, 36 ... pin 29: stopper 30: restraint member

Claims (4)

(57) [Claims] 1. A plurality of cylindrical cylinders are flexibly connected to each other by a fitting mechanism and a joint mechanism at end portions of the cylinders via a seal member, thereby eliminating relative displacement of the two cylinders in the circumferential direction. A hard rock tunnel excavator having one end supported by one body and the other end supported by the other body in a state in which the jack is shifted from the center of the body. The two joints are disposed at two positions in one diameter direction at both ends, and each joint mechanism is disposed at the first bracket having a long hole in the trunk axis direction disposed at one trunk end and at the other trunk end. A hard rock tunnel excavator, comprising: a second bracket having an elongated hole in a trunk circumferential direction, wherein both brackets overlap with a gap therebetween, and a pin member is disposed to penetrate the elongated holes. 2. A plurality of cylindrical cylinders are flexibly connected via a joint mechanism, and a jack for eliminating relative displacement of the two cylinders in the circumferential direction is one end of which is off the center of the cylinder. A hard rock tunnel excavator supported by a torso and having the other end supported by the other torso, wherein the joint mechanism has at least one torso portion formed substantially partially spherical over the entire circumference. And a second body end provided with a seal member fitted to the one body end and in contact with the partial spherical body end surface over the entire circumference; A pin bracket having a circular hole provided at one of the body ends, and a body circumference provided at the other body end. It consists of a second bracket with a long hole in the direction, and both brackets With each other becomes, hard rock tunnel boring machine comprising the two holes in the pin member is disposed to penetrate. 3. A plurality of cylindrical cylinders are flexibly connected via a joint mechanism, and a jack for eliminating relative displacement in the circumferential direction of both cylinders is provided with one end of the jack off the center of the cylinder. A hard rock tunnel excavator supported by a torso and having the other end supported by the other torso, wherein the joint mechanism has at least one torso portion formed substantially partially spherical over the entire circumference. And a second body end provided with a seal member fitted to the one body end and in contact with the partial spherical body end surface over the entire circumference; A pin coupling mechanism disposed at two places, the pin coupling mechanism being disposed at a first bracket having an elongated hole in a trunk axial direction disposed at one trunk end and at the other trunk end. And a second bracket having an elongated hole in the torso direction. With Tsu door overlap with a gap,
A hard rock tunnel excavator comprising a pin member penetrating into the slots. Wherein in said cylinder axis direction of the long hole, hard rock tunnel boring machine of the central pair of stoppers is provided, which can fitted on both sides of the penetration pin whose member comprising claim 1 or 3 wherein.