JPH1122385A - Tunnel excavation machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate manufacture, efficiently perform excavation work and spraying work of concrete for an excavation wall face and make biting-in of a rock piece on an expansion and contraction actuation part difficult. SOLUTION: A skin plate is formed on a single drum and blocked by a slide plate 5 before and behind slidably provided on the rear inner peripheral face of the skin plate 1. The skin plate 1 is advanced and excavation of a tunnel is performed by mounting a rear gripper 7 on the inner peripheral face of the slide plate 5 and extending a pipe jack 8 in a state where application is performed on a tunnel excavation wall face T. After excavation of a constant long tunnel, the pipe jack 8 is contracted and a ring member 6 mounting the rear gripper 7 is advanced up to a next position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a tunnel excavator for excavating a tunnel in rock.

[0002]

2. Description of the Related Art As shown in FIG. 12, a conventional excavator for excavating a tunnel in a collapsible rock mass containing a lot of fragile rocky parts such as cracks and crushed zones covers the entire wall of the tunnel excavation wall as shown in FIG. The shielded cylindrical skin plate is divided into a front trunk A and a rear trunk B, and the front part of the rear trunk B is slidably fitted inside the rear inner peripheral surface of the front trunk A and connected to each other so as to be extendable and contractible. A front gripper D is mounted on the front body A, and a rear gripper E is mounted on the rear body B, respectively.
It is widely known that a cutter head F is disposed at the front end of the opening of the front trunk A, the front and rear trunks A and B are connected by a thrust jack G, and a shield jack H is mounted in the rear trunk B. ing.

When excavating hard rock with relatively stable rock quality, the rear gripper D is fixed to and supported by the tunnel wall by extending the rear gripper D and pressing it against the tunnel excavation wall. In this state, the front trunk A is advanced by extending the thrust jack G, excavated by the cutter head F, and the excavated tunnel wall is covered with shotcrete. If the rear gripper D cannot be pressed against the tunnel wall due to the collapsible rock, the segment S
The tunnel is excavated by applying a reaction force to the segment S to extend the shield jack H.

[0004]

However, according to the above-described tunnel excavator, since the skin plate is divided into the front body A and the rear body B, these longitudinal movements A and B are separated from each other. To telescopically connect to each other, it is necessary to form the telescopic portion E as described above, and there is a problem that the production and processing thereof require a considerable amount of time. In addition, the rear trunk B is attached to the front trunk A side. When pulling, the gap of the telescopic portion E that opens rearward is likely to cause excavation slips and exfoliated rock pieces, and the whole rear body B is drawn, so the work is slow and careful. In this case, the work efficiency is reduced, and it is difficult to remove rock pieces and the like that have entered the telescopic unit E.

Further, at the time of excavation, the rear trunk B is fixed to the tunnel excavation wall surface via the rear gripper D while the front trunk A
During the tunnel excavation, the concrete wall cannot be sprayed because the excavated wall is not exposed, and when the rear trunk B is pulled after the tunnel of a certain length is excavated. There is a problem that the workability is poor because the lining with the shotcrete is performed on the tunnel excavation wall exposed to the outside.

In the case of collapsible rock, as described above, the segment S is assembled behind the tunnel excavator. Excavation is performed by taking a reaction force on the segment S and propelling the entire tunnel excavator. , It is necessary to use a shield jack H for propelling the segment S with a reaction force.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to make a skin plate into a single body without dividing it into front and rear bodies, to facilitate manufacture and processing, and to make rock pieces and the like. It is an object of the present invention to provide a tunnel excavator having a structure in which the digging phenomenon does not easily occur, and capable of performing excavation work and lining work with shotcrete efficiently.

[0008]

In order to achieve the above object, the invention according to claim 1 comprises a cylindrical skin plate, a digging means provided at a front end of the skin plate, and a front and rear surface of the skin plate. A front gripper and a rear gripper, which are respectively provided so as to be able to protrude and retract toward a tunnel excavation wall surface through an opening provided in the skin plate.
One end is connected to the front gripper side and the other end is connected to the rear gripper side, and a propulsion jack is formed, and an opening part of the opening part where the rear gripper appears and retracts is formed in a long hole so as to move the rear gripper forward and backward. I have.

In the tunnel excavator according to the first aspect of the present invention, a ring-shaped member is disposed in the skin plate so as to be movable back and forth, and the rear gripper is mounted on the ring-shaped member. The other end of the propulsion jack is connected to the ring-shaped member.

According to a third aspect of the present invention, in the tunnel excavator according to the first or second aspect, the opening of the skin plate is closed and the inner peripheral surface of the skin plate is slid. A movable slide plate is provided.

[0011]

[Operation and Effect] The rear gripper is projected from the opening provided at the rear part of the skin plate and is pressed against the tunnel excavation wall surface to support the propulsion reaction force on the tunnel excavation wall surface and retreat the front gripper from the tunnel excavation wall surface. . In this state, when the propulsion jack is extended and the excavating means is operated, the propulsion jack is extended and the entire skin plate is propelled in a state in which a reaction force is supported by the rear gripper pressed against the tunnel excavation wall, and the excavating means is used. The rock face on the face side is excavated. At this time, the opening that faces the rear gripper toward the tunnel excavation wall moves its rear edge forward to a position where it abuts or approaches the rear gripper in accordance with the propulsion of the skin plate. Tunnels are excavated.

Further, as described above, when the tunnel is excavated by the excavating means while the skin plate is advanced by the propulsion jack, the tunnel excavation wall surface is exposed rearward from the rear end of the skin plate moving according to the excavation. In parallel with the tunnel excavation process, lining work by spraying concrete on the tunnel excavation wall surface can be performed.

In this way, after excavating a tunnel of a certain length, the front gripper is pressed against the tunnel excavation wall,
The rear gripper is released from the tunnel excavation wall surface by being pressed and immersed in the opening, and then the propulsion jack is contracted to advance the rear gripper in the opening provided at the rear of the skin plate, thereby leading the front edge of the opening. Pull back to the position where it comes into contact with or close to. Then, as described above, the rear gripper is pressed against the tunnel excavation wall surface again, and the front gripper is released from the pressure contact with the tunnel excavation wall surface to be immersed in the skin plate, and the propulsion jack is extended to advance the skin plate. In this way, a tunnel of a certain length is excavated.

As described above, since the opening is provided at the rear portion of the skin plate having a single body and the rear gripper is relatively moved back and forth within the opening, the structure is simple and the production and processing are simple. Not only becomes easier, but also, as described above, the skin plate is excavated by the excavation means provided in the front end opening while the entire skin plate is propelled. , And lining work by spraying concrete on the tunnel excavation wall at the same time as the excavation process,
In addition, after excavating a tunnel of a certain length, to move the rear gripper to the next excavation position, instead of advancing the rear body as in the conventional case, the propulsion jack is contracted to pull the rear gripper forward. Therefore, the pulling can be smoothly and promptly performed, and therefore, the tunnel can be efficiently constructed while improving the workability of the lining work.

Further, in such a tunnel excavation work, the invention according to claim 2 is characterized in that the rear gripper is mounted on a ring-shaped member disposed in a rear portion of the skin plate so as to be movable back and forth, and the ring-shaped member is mounted on the ring-shaped member. Since the other end of the propulsion jack is connected, the propulsion reaction force of the propulsion jack can be uniformly received by the rear gripper via the ring-shaped member, so that the reaction force receiving area can be widened. By connecting the propulsion jacks at predetermined intervals in the circumferential direction on the front end surface of the ring-shaped member, the skin plate can be smoothly propelled with a small number of propulsion jacks. Can be widened to enable a smooth operation.

In addition, in a collapsible rock mass in which a sufficient reaction force cannot be supported on the tunnel wall by the rear gripper,
When assembling the segment behind the tunnel excavator instead of lining by spraying concrete, the rear end face of the ring-shaped member is received by the front end face of the segment without using a shield jack as in the conventional case. By extending the propulsion jack in this state, the skin plate can be advanced to excavate the tunnel.

Further, since the opening can be closed by the ring-shaped member, it is possible to prevent rock fragments and earth and sand from falling into the skin plate through the opening through the opening from the wall surface of the tunnel excavation. The ring-shaped member can be smoothly moved back and forth along the inner peripheral surface of the skin plate by the propulsion jack, so that the rear gripper mounted on the ring-shaped member can be accurately and quickly moved to a predetermined position. The rear gripper is moved back and forth in the opening provided in a part of the skin plate, unlike the telescopic part where the front and rear bodies are fitted together, so that rock fragments and earth and sand enter the skin plate The likelihood of
Even if it bites, it can be easily removed from the skin plate.

In the tunnel excavator according to the first or second aspect, the invention according to the third aspect is characterized in that a slide plate is slidably disposed on an inner peripheral surface of the skin plate, and the slide plate is provided with the slide plate. Since the opening of the skin plate is configured to be closed, the slide plate is in sliding contact with the inner peripheral surface of the skin plate. It is possible to reliably prevent the fall of earth and sand and the like into the plate, and furthermore, the length of the ring-shaped member can be made shorter than the opening so that the movement in the front-rear direction can be performed lightly. Things.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a tunnel excavator. The tunnel excavator has a cylindrical skin plate having a fixed length. 1, a cutter plate 2a having a plurality of roller cutters 2b protruding from a front surface rotatably disposed at a front end opening of the skin plate 1, and a rotation drive mechanism (not shown) for the cutter plate 2a. Excavating means 2, several front grippers 3 mounted on the inner peripheral surface of the front part of the skin plate 1 at regular intervals in the circumferential direction, and constant in the circumferential direction at several places on the rear part of the skin plate 1. The opening 4 made of a rectangular elongated hole provided at each interval (two sides in the figure) and the inner surface of the rear part of the skin plate 1 are slidably fitted in the length direction and the circumferential direction. A short cylindrical slide plug with the opening 4 closed And over bets 5, a ring-shaped member 6 of a short tube shape slidably fitted into the inner peripheral surface of the slide plate 5, the ring-shaped member in correspondence with the respective openings 4 6
The rear gripper 7 is attached at a constant interval (two sides in the figure) in the circumferential direction, and one end is connected to the front side of the skin plate 1 and the other end is integrally formed with the front end face of the ring-shaped member 6. And a plurality of propulsion jacks 8 connected to each other.

A partition 9 is stretched in the front of the skin plate 1, and the cutter plate 2 a is provided on the front side of the partition 9.
Are rotatably supported, and front gripper storage portions 10 are integrally fixed to the outer peripheral portion of the front surface of the partition wall 9 at predetermined intervals in the circumferential direction, and the front gripper 3 is attached to each storage portion 10 to hold the gripper portion. 3a is disposed so as to be freely protruded and retracted toward the tunnel excavation wall surface T through an opening hole 11 formed in the skin plate 1.

The opening portions 4 facing the rear grippers 7 are provided at regular intervals in the circumferential direction at the rear of the skin plate 1, that is, on both sides in FIG. Is formed to be equal to or greater than the sum of the length of one excavation for excavating the skin plate 1 and the width of the rear gripper 7 in the front-rear direction, and the opening width in the circumferential direction is the width that the rear gripper 7 can be inserted. Is formed.

The slide plate 5 is interposed between the inner peripheral surface of the skin plate 1 and the outer peripheral surface of the ring-shaped member 6 to close all the openings 4 from the inner peripheral surface side of the skin plate 1 and has a length. An opening hole 12 having a size through which the gripper portion 7a of each of the rear grippers 7 can be inserted is formed on two sides on both sides at the center in the vertical direction. The length between the front edge of the opening 12 and the front end of the slide plate 5;
The length between the rear edge of the slide plate 5 and the rear end of the slide plate 5 is equal to or longer than the length of one excavation for propelling the skin plate 1 for excavation. The length between the rear ends of the slide plates 5 is equal to or longer than the length between the rear end of the opening 12 provided in the slide plate 5 and the rear end of the slide plate 5. The slide plate 5 is the skin plate 1
The seal 4 is in sliding contact with the inner peripheral surface of the front and rear ends of the opening 4 over the entire circumference.

The ring-shaped member 6 is provided with storage portions 13 for the rear grippers 7 at two positions in the circumferential direction at the central portion in the longitudinal direction thereof so as to face the openings 4. The rear grippers 7 are provided in the storage portions 13. The gripper portion 7a is mounted so as to be able to protrude and retract toward the tunnel excavation wall surface T. The openings 4 provided in the skin plate 1 are provided in three or four directions at the rear end of the skin plate 1, and corresponding to each opening 4, three directions or at the center of the ring-shaped member 6 are provided. The rear grippers 7 may be mounted on four sides, and an opening 12 through which the gripper portion 7a of the rear gripper 7 can be inserted may be provided on three or four sides at the center of the slide plate 5.

A plurality of (six in the figure) propulsion jacks 8 are arranged at regular intervals in the circumferential direction along the inner peripheral surface of the skin plate 1 between the partition wall 9 and the ring-shaped member 6. One end (front end) is connected to and fixed to the outer periphery of the rear surface of the partition wall 9 and the other end (rear end) is connected to the ring-shaped member 6.
Are integrally connected to the front end face of the The propulsion jack 8 has a stroke equal to or longer than one excavation length.

In order to excavate a tunnel in the rocky ground by the tunnel excavator constructed as described above, the propulsion jack 8 is contracted to the maximum immediately before the start of excavation, and the contraction causes the ring-shaped member 6 to move forward. The rear gripper 7 attached to the ring-shaped member 6 is located inside the front end of the opening 4 of the skin plate 1 and presses the gripper portion 7a to the tunnel excavation wall surface T. Note that the gripper portion 7a of the rear gripper 7 is engaged with the opening hole 12 of the slide plate 5 in an inserted state, so that when the propulsion jack 8 contracts, the slide plate 5 slides on the inner peripheral surface of the skin plate 1. It advances integrally with the ring-shaped member 6 and the rear gripper 7.

The rear gripper 7 is located within the front end of the opening 4 of the skin plate 1 and presses the gripper portion 7a thereof to the tunnel excavation wall surface T, and excavates the front gripper 3 in a state where the crimping of the front gripper 3 to the excavation wall surface T is released. When the propulsion jack 8 is gradually extended while rotating the cutter plate 2a of the means 2, the skin plate 1 moves forward by supporting the reaction force on the excavation wall surface T on which the rear gripper 7 is pressed, and the cutter plate 2a moves the cutting face. Rock is excavated. At this time, as the skin plate 1 advances, the opening 4 through which the rear gripper 7 is inserted also advances integrally, so that the rear gripper 7 relatively moves to the rear end side of the opening 4 and advances along the excavation. Tunnel excavation wall T from the rear end
Is exposed, concrete C is sprayed on the excavated wall surface T to perform lining.

Thus, the propulsion jack 8 is extended, and the rear end of the opening 4 of the skin plate 1 is moved to the rear gripper 7.
When the tunnel of a certain length is excavated by moving forward until reaching the back of the vehicle, the operation of the propulsion jack 8 is stopped,
Thereafter, the gripper portion 3a of the front gripper 3 is extended in the radial direction to be pressed against the tunnel excavation wall T, while the gripper portion 7a of the rear gripper 7 is contracted to release the pressure from the excavation wall T. Shrink.

When the propulsion jack 8 is contracted, the ring-shaped member 6 is pulled forward, and the rear gripper 7 attached to the ring-shaped member 6 moves the opening 4 of the skin plate 1.
, And the slide plate 5 also advances while slidingly contacting the inner peripheral surface of the skin plate 1 integrally with the rear gripper 7. At this time, in the conventional tunnel excavator, since the rear body is advanced together with the rear gripper, it must be gradually advanced while paying attention to whether rocks and earth and sand do not collapse from the exposed tunnel excavation wall T as the rear body advances. However, in the tunnel excavator of the present invention, when the rear gripper 7 is advanced, the skin plate 1 does not move at all, and only the ring-shaped member 6 to which the rear gripper 7 is attached needs to be pulled. Can be performed quickly by contracting the propulsion jack 8 at the maximum speed, and the preparation for the next tunnel excavation can be efficiently performed. Further, even if the rear gripper 7 is moved between the front and rear ends in the opening 4, the opening 4 is always kept closed by the slide plate 5, and the rock pieces or the like fall or enter the skin plate 1. Can be prevented.

After the rear gripper 7 is moved into the front end of the opening 4 of the skin plate 1, the gripper portion 7a of the rear gripper 7 is again pressed against the tunnel excavation wall surface T as described above, while the front gripper 3 is pressed again. After unraveling, the propulsion jack 8 is gradually extended while rotating the cutter plate 2a of the excavating means 2 to excavate a tunnel of a fixed length.

Next, in the case of a collapsed rock mass in which the rear gripper 7 cannot support a sufficient reaction force on the tunnel excavation wall T, a segment S is assembled behind the tunnel excavator instead of lining by spraying concrete. As shown in FIG. 4, the segment S excavates while supporting the reaction force of the entire tunnel excavator. That is, the rear gripper 7 attached to the ring-shaped member 6 by contracting the propulsion jack 8 is positioned within the front end of the opening 4 of the skin plate 1, and the rear end surface of the ring-shaped member 6 is already assembled. The cutter plate 2a of the excavating means 2 is brought into contact with and received by the front end face, and retracts the grippers of the front gripper 3 and the rear gripper 7 so as to be separated from the excavation wall T.
By extending the propulsion jack 8 while rotating the skin, the propulsion reaction force is supported by the segment S via the ring-shaped member 6 and the skin plate 1 is advanced to excavate the tunnel.

When a tunnel of a predetermined length is excavated in this way, the rear gripper 7 reaches the rear end of the opening 4 of the skin plate 1 as described above, and then the gripper portion 3a of the front gripper 3 is tunneled. After being pressed against the excavated wall surface T, the propulsion jack 8 is contracted to remove the ring-shaped member 6 having the rear gripper 7 from the rear gripper 7.
Of the skin plate 1 until it reaches the front end of the opening 4. As the ring-shaped member 6 advances, a space is formed in the rear end of the skin plate between the ring-shaped member 6 and the front end of the segment S. After assembling the next segment S in this space, the space is formed again as described above. The rear end of the ring-shaped member 6 abuts against and receives the front end surface of the segment S to extend the propulsion jack 8, thereby excavating a tunnel of a fixed length.

As described above, when the tunnel is excavated while the segment S supports the propulsion reaction force, the gripper portion 7a of the rear gripper 7 is moved from the opening hole 12 of the slide plate 5 in the radial direction as shown in FIG. When the slide plate 5 is retracted into the storage portion 13 of the ring-shaped member 6 and the slide plate 5 is rotated in the circumferential direction,
Is covered on the inner peripheral surface of the skin plate 1, and the opening 4 of the skin plate 1 is completely closed by the slide plate 5. In this state, the propulsion jack 8 is extended to excavate the tunnel while propelling the skin plate 1 as described above, and after excavating a tunnel of a predetermined length, the propulsion jack 8 is contracted to thereby remove the ring-shaped member 6.
At this time, the slide plate 5
Is maintained in contact with the inner peripheral surface of the skin plate 1, and the ring-shaped member 6 extends along the inner peripheral surface of the slide plate 5.
Moves back and forth.

To enable the ring-shaped member 6 to move back and forth along its inner peripheral surface without moving the slide plate 5, the sliding contact force of the slide plate 5 on the skin plate 1 is controlled by the slide plate 5 and the ring-shaped member 6. Larger than the sliding contact force with the slide plate 5
The inner peripheral surface of the skin plate 1 may be rotatable only in the circumferential direction without being able to move in the length direction, and the rotating operation of the slide plate 5 in the circumferential direction may be performed by the propulsion jack 8,
If several jacks connected to the front end of the slide plate 5 are arranged on the inner peripheral surface of the skin plate 1 between the eight positions, the slide plate 5 can be rotated in the circumferential direction by these jacks. Good. In addition, a plurality of friction wheels that are rotated by a motor are mounted on the front end of the ring-shaped member 6, and these friction wheels are brought into sliding contact with the inner peripheral surface of the slide plate 5 between the adjacent propulsion jacks 8,8. Alternatively, the slide plate 5 may be rotated in the circumferential direction by the rotation of the friction wheel. Such a friction wheel may be disposed on the inner peripheral surface side of the skin plate 1.

Thus, the opening 4 of the skin plate 1
When the ring-shaped member 6 is moved back and forth along the inner peripheral surface of the slide plate 5 in which the opening is closed, the rear gripper 7 attached to the ring-shaped member 6 is not restricted by the front and rear ends of the opening 4. The ring-shaped member 6 can be moved back and forth over the above length, so that the extension length of the propulsion jack 8 can be increased to increase the length of one tunnel excavation, and the ring-shaped member 6 is pulled forward. In this case, the space between the ring-shaped member 6 and the segment S can be widened, and the assembling work of the segment S can be performed easily and efficiently.

The slide plate 5 does not necessarily need to be configured to rotate in the circumferential direction. The slide plate 5 is integrally formed with the ring-shaped member 6 as in the case of the above-described tunnel excavation in which concrete is sprayed on the tunnel excavation wall surface T. May be moved back and forth. In this case, as described above, the gripper portion 7a of the rear gripper 7 is connected to the opening hole 12 of the slide plate 5.
It is not necessary to lock the slide plate 5 with the ring-shaped member 6 by inserting the gripper portion 7a through the opening hole 12.
The slide plate 5 is integrally fixed to the outer peripheral surface of the skin plate 1 by moving the ring-shaped member 6 back and forth.
May be configured to be slidably moved on the inner peripheral surface of the.

In the above embodiment, the slide plate 5 is formed in a short cylindrical shape. However, the slide plate 5 is formed in a flat rectangular slide plate 5A having a constant width and length corresponding to each opening 4 of the skin plate 1. You may keep it. 6 to 8
The slide plate 5A comprises a curved plate having a constant width and a constant length curved along the inner peripheral surface of the skin plate 1, and the width thereof is slightly smaller than the width of the opening 4. The opening 4 is large enough to close the opening 4 from the inside of the skin plate 1 and has the same length as the short cylindrical slide plate 5 in the above embodiment. At the center in the length direction of the slide plate 5A, an opening hole 12 having a size through which the gripper portion 7a of the rear gripper 7 attached to the ring-shaped member 6 can be inserted is provided as in the above-described embodiment. Although the slide plate 5A is integrally fixed to the outer peripheral surface of the ring-shaped member 6, the slide plate 5A is slidably moved forward and backward integrally by locking the gripper portion 7a of the rear gripper 7 with the opening hole 12. You may leave.

A step 16 on which a seal packing 15 is mounted is provided on the inner surface of the skin plate 1 at the four peripheral edges of the opening 4, and the slide plate 5 A slides on the seal packing 15. . Other configurations are the same as those of the above embodiment, and the same portions are denoted by the same reference numerals and description thereof will be omitted.

With this configuration, when the tunnel is excavated, the gripper portion 7a of the rear gripper 7 is pressed against the tunnel excavation wall T and the front gripper 3 is released from the pressure on the tunnel excavation wall T as in the above embodiment. By extending the propulsion jack 8 connected to the front end face of the ring-shaped member 6 on which the rear gripper 7 is mounted, the tunnel is excavated by the excavating means 2 while the skin plate 1 is moved forward. After excavation of the tunnel, the front gripper 3 is moved to the tunnel excavation wall T
The ring-shaped member 6 is advanced to the next position by compressing the rear gripper 7 and contracting the propulsion jack 8.

In any of the above embodiments, the slide plate 5 is used to close the opening 4 of the skin plate 1.
However, the opening 4 can be closed by a ring-shaped member without using such a slide plate 5.

FIGS. 9 to 11 show one embodiment of the present invention.
A ring-shaped member 6A having a length (dimension between front and rear ends) formed at the rear inner peripheral surface of the skin plate 1 having the opening 4 at the same length as the slide plate 5 is provided so as to be movable back and forth. doing. In the ring-shaped member 6A, a rear gripper 7 having a gripper portion 7a which can be protruded and retracted through the opening 4 is attached to a portion of the skin plate 1 opposed to the opening 4 at the center in the longitudinal direction thereof. 7 is a movable closing member that can freely move in and out of the tunnel excavation wall T at small intervals in the front-rear direction on the front and rear sides of
Twenty are arranged.

The movable closing member 20 has a width in the circumferential direction of the tunnel equal to the width of the gripper portion 7a of the rear gripper 7, and a distal end surface facing the tunnel excavation wall T is formed in an arc shape along the excavation wall T. It is made of curved plate material,
The distal end surface of each movable closing member 20 arranged in parallel on the front side of the rear gripper 7 is formed on an inclined end surface 21 inclined inward toward the front, while each movable closing member 20 arranged on the rear side of the rear gripper 7. The tip end surface of 20 is formed on an inclined end surface 22 inclined inward toward the rear.

The ring-shaped member 6A is formed hollow,
Partition walls 23 are provided at regular intervals in the longitudinal direction with the rear gripper 7 as a center, and the movable closing member 20 is provided between the adjacent partition walls 23 and 23 so that the movable closing member 20 can freely move in and out in and out using the partition wall 23 as a guide.
Is inserted. Further, a spring 24 is interposed between the inner end surface of each movable closing member 20 and the inner bottom surface of the ring-shaped member 6A, and the movable closing member 20 is constantly pressed by the spring 24 toward the tunnel excavation wall T side. At the same time, a bolt body 25 is fixed to the inner end surface of each movable closing member 20 to project the bolt body 25 from the inner peripheral surface of the ring-shaped member 6A, and a nut 26 is screwed to the protruding end portion. Is screwed and screwed back to adjust the length of protrusion of the movable closing member 20 from the outer surface of the ring-shaped member 6A. The ring-shaped member 6A has its front end face integrally connected to the rear end of the propulsion jack 8 as in the above embodiment. Other configurations of the tunnel excavator are the same as those in the above-described embodiment.

In order to excavate a tunnel in the rocky ground by the tunnel excavator constructed as described above, the propulsion jack 8 is in the state of being contracted to the maximum immediately before the start of excavation, and the contraction causes the ring-shaped member 6A to move. As shown in FIG. 9, the rear gripper 7, which is pulled forward and attached to the ring-shaped member 6A,
, The gripper portion 7a is pressed against the tunnel excavation wall surface T and the movable closing member 20 on the front side from the rear gripper 7 is sunk inward against the force of the spring 24,
The front end surface is in contact with the inner peripheral surface of the skin plate 1. On the other hand, the rear movable closing member 20
Protrudes into the opening 4 of the skin plate 1 and closes the opening 4 with the tip end surface and the outer end surface of the partition wall 23 of the ring-shaped member 6 to prevent rock pieces and the like from falling into the skin plate 1. doing.

In this state, the skin plate 1 is advanced by extending the propulsion jack 8 in the same manner as in the above embodiment, and the tunnel is dug by the excavating means 2. As the skin plate 1 advances, the opening 4 is formed. The rear end edge of the movable closing member 20 moves forward while sliding on the inclined end surface 22 of the movable closing member 20 disposed on the rear side of the rear gripper 7, and the sliding contact force causes the movable closing member 20 to oppose the force of the spring 24. The skin plate 1 is brought into contact with the inner peripheral surface of the skin plate 1 with its leading end surface in sliding contact. At this time, even if rock pieces, earth and sand, etc. are present on the inclined end face 22 of the movable closing member 20, the rock plate is pushed outward on the inclined end face 21 by the advance of the rear end edge of the opening 4 and is pushed outward. There is no danger of digging into the interior. On the other hand, the movable closing member 20 disposed on the front side of the rear gripper 7 projects by the force of the spring 24 while sliding the inclined end face 21 against the front end edge of the opening 4 and closes the front of the opening 4.

Thus, when a tunnel of a predetermined length is excavated by the excavating means 2 while the skin plate 1 is advanced, the gripper portion 7a of the rear gripper 7 reaches the rear end edge of the opening 4 and is movable rearward from the rear gripper 7. While all the closing members 20 are in a housed state in which the front end surface thereof is in contact with the inner peripheral surface of the skin plate 1, all the movable closing members 20 on the front side from the rear gripper 7 project into the opening portion 4 and 4 is closed. When the next tunnel is excavated from this state, after the crimping of the gripper portion 7a of the rear gripper 7 against the excavation wall T is released, the propulsion jack 8 is contracted so that the ring-shaped member 6A is moved to the front edge of the opening 4 by the gripper portion 7a. , The movable closing member 20 on the front side from the rear gripper 7 is immersed inward while sliding its inclined end surface 21 against the front edge of the opening 4. At this time, even if rock pieces, earth and sand, etc. are present on the inclined end face 21 of the movable closing member 20, the rock piece is pushed outward on the inclined end face 21 by the front edge of the opening 4 and cuts into the skin plate 1. There is no fear. On the other hand, the rear movable closing member 20
Protrudes into the opening 4 to close the opening 4. Hereinafter, a tunnel of a certain length is excavated in a similar manner.

In the above description, the rear gripper is mounted on the ring-shaped member. However, the present invention is not limited to this. A beam body is mounted rearward from the partition wall 9 and this is used as a reaction force. The rear gripper may be pressed against the excavation wall.

[Brief description of the drawings]

FIG. 1 is a simplified cross-sectional view of a tunnel excavator;

FIG. 2 is a simplified side view thereof,

FIG. 3 is a vertical front view of a rear gripper portion,

FIG. 4 is a simplified cross-sectional view showing a state in which a reaction force is supported by a segment;

FIG. 5 is a longitudinal sectional front view showing a state in which a slide plate is rotated in a circumferential direction.

FIG. 6 is a cross-sectional view of a ring-shaped member showing another embodiment of the present invention.

FIG. 7 is a longitudinal sectional view thereof,

FIG. 8 is a side view thereof,

FIG. 9 is a cross-sectional view of a ring-shaped member showing still another embodiment of the present invention;

FIG. 10 is a simplified longitudinal front view thereof,

FIG. 11 is a side view thereof,

FIG. 12 is a simplified vertical side view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Skin plate 2 Excavation means 3 Front gripper 4 Opening 5 Slide plate 6 Ring-shaped member 7 Rear gripper 8 Propulsion jack

Claims (3)

[Claims] 1. A skin plate having a cylindrical shape, a digging means provided at a front end of the skin plate, and a front and rear portion of the skin plate facing an excavation wall surface of a tunnel through an opening provided in the skin plate. The front gripper and the rear gripper are provided so as to be freely retractable, and a propulsion jack having one end connected to the front gripper side and the other end connected to the rear gripper side. A tunnel excavator characterized in that the rear gripper is formed in a long hole so as to move back and forth. 2. The rear gripper is mounted on a ring-shaped member disposed in the skin plate so as to be movable back and forth, and the other end of the propulsion jack is connected to the ring-shaped member. Item 4. A tunnel excavator according to item 1. 3. The slide plate according to claim 1, wherein a slide plate is provided to close the opening of the skin plate and to be slidable with respect to an inner peripheral surface of the skin plate. Tunnel excavator.