JP3236544B2 - Method of forming tunnel support - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a support for a primary support on a wall excavated by a tunnel excavator.

[0002]

2. Description of the Related Art When a tunnel is excavated by a tunnel excavator, the excavated tunnel wall surface may fall off or fall down. A ring-shaped support made of H-section steel is assembled along with a lining member such as expanded metal or a wire mesh between the adjacent ring-shaped supports, and is loosened from the tunnel wall surface in the tunnel by the lining member. It forms a shoring that prevents the rock mass from collapsing.

[0003]

However, according to the above-mentioned prior art, since the assembling of the shoring is performed behind a tunnel excavator in which the excavated tunnel wall surface is exposed, a ring-shaped shoring member is required. There is a risk that the bedrock may collapse when assembling or stretching the lining member, which is extremely dangerous and that the work cannot be performed smoothly. For this reason, a rectangular frame formed by stretching a wire mesh body on a rectangular steel frame curved in an arc shape in the circumferential direction of the tunnel is connected circumferentially in the skin plate of the tunnel excavator to form a ring-shaped support body. After assembling, a method of forming a support by sending it to the tunnel excavation wall side has also been proposed.However, since the ring-shaped support body assembled in the skin plate has a smaller diameter than the tunnel excavation wall side, it has been proposed. A gap will be created between the support body and the tunnel excavation wall surface when it is sent out. Such a problem also occurs in the case of a small-diameter ring-shaped support assembled in a tunnel. Therefore, in order to fill the gap, it is necessary to re-form the ring-shaped support body to have a large diameter. However, at present, no specific means for implementing this has been found.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a small-diameter ring-shaped support body in which a plurality of rectangular frames are connected to each other in a tunnel excavator or a tunnel. It is an object of the present invention to provide a method for forming a tunnel support which can efficiently and accurately expand a diameter and closely contact a tunnel excavation wall surface.

[0005]

According to a first aspect of the present invention, there is provided a method of forming a tunnel support, comprising the steps of: excavating a tunnel in a rear end of a skin plate of a tunnel excavator; A ring-shaped support having a diameter smaller than the diameter of the tunnel excavation wall is assembled by connecting a plurality of rectangular frames that are curved in an arc along the wall direction, and then the tunnel excavator is moved backward.
The existing ring-shaped support body was expanded first.
Slide the rear end face on the front end face of the ring-shaped support body in the radial direction.
Capable to diameter of the small-diameter ring-shaped支保body by spaced between adjacent <br/> contact rectangular frame circumferentially in a state in the lower circumferential side of the tunnel pressed those of the outer peripheral surface thereof to the tunnel excavation wall It is characterized by contact.

According to a second aspect of the present invention, there is provided a tunnel excavation wall surface.
Connect a plurality of rectangular frames curved in an arc along the direction
A ring-shaped support with a diameter smaller than the diameter of the tunnel excavation wall.
When forming, form the lower periphery of this ring-shaped support
Inner peripheral edge of one of the rectangular frames adjacent to each other
A regulating plate that slides on the inner peripheral surface of the other rectangular frame
In addition, the opposite end of the other rectangular frame is
A small diameter ring-shaped support body with the inner peripheral surface of
After formation, separate these rectangular frames in the circumferential direction
By expanding the diameter of the small-diameter ring-shaped support body,
The surface is brought into contact with the tunnel excavation wall surface .

[0007] As described in claim 3 , a fall prevention body such as a wire netting is stretched over the rectangular frame forming the ring-shaped support body.

In the method for forming a tunnel support according to any one of claims 1 to 3 , the invention according to claim 4 is characterized in that:
The holding of the small-diameter ring-shaped support in the expanded state is performed by screwing a bolt through the opposing surface of one of the opposed rectangular frames and bringing the tip of the bolt into contact with the opposing surface of the other rectangular frame. It is characterized by the following.

[0009]

According to the first aspect of the present invention, first,
Multiple curved in an arc along the tunnel excavation wall
Because the rectangular frame is connected to form a ring-shaped support having a diameter smaller than the diameter of the tunnel excavation wall, a rectangular frame having a radius of curvature corresponding to the diameter of the excavation wall excavated by the tunnel excavator is used. A small-diameter ring-shaped support body can be assembled with high accuracy, and the small-diameter ring-shaped support body can be assembled in the rear end of the skin plate of the tunnel excavator.
Because it is an assembly, the ground surface of the tunnel excavation wall
Safe and efficient without being affected by falling or collapse
The ring-shaped support can be assembled easily, and
And push this small diameter ring-shaped support into a jack
Using the tunnel excavator from the skin plate backwards
Since it is sent out, it can be easily sent out to the tunnel excavation wall surface side having a diameter larger than the inner diameter of the skin plate.

[0010] Further, in the tunnel,
Since the expansion jacks and the like are interposed between the adjacent rectangular frames on the lower peripheral side and the pressing force is used to separate the rectangular frames in the circumferential direction, the rectangular frames to be separated from each other are formed.
Since the opposed parts are provided on the lower peripheral side of the tunnel, the enlarged work of the small-diameter ring-shaped支保body can be performed smoothly and surely
The pressing force is applied equally to all the rectangular frames constituting the ring-shaped support body, and the entire diameter of the small-diameter ring-shaped support body can be enlarged. The outer peripheral surface of the expanded ring-shaped support body is tunnel-excavated. It is possible to form a shoring that is entirely in contact with the wall surface.

In addition, the diameter of the small-diameter ring-shaped support is increased while the rear end of the ring-shaped support is slidably pressed in the diameter-expanding direction on the front end of the existing ring-shaped support. Therefore, it is possible to accurately increase the diameter of the small-diameter ring-shaped support body without separating the opposing portions of the rectangular frames adjacent to each other in the front-rear direction, and to smoothly perform the connection work with the existing ring-shaped support body.

According to the second aspect of the invention, in the rectangular frames of the ring-shaped support body which are separated from each other, the inner surface of one rectangular frame is opposed to the inner surface of the other rectangular frame facing the other rectangular frame .
Since the regulating plate to be in sliding contact with the surface is fixed, the regulating plate prevents the opposite end of the rectangular frame from bending and deforming in the inner diameter direction of the tunnel, thereby preventing the step from being formed. A good expanded ring-shaped support can be formed.

[0013] Further, since a fall prevention member such as a wire netting is stretched over the rectangular frame forming the ring-shaped support body as described in claim 3 , the rock formation from the tunnel excavation wall surface by the fall prevention member. In addition, the ring-shaped support body can be firmly integrated with the excavation wall through the collapse prevention body by spraying the concrete, and a tunnel support having excellent strength can be formed.

According to the fourth aspect of the invention, the small-diameter ring-shaped support is held in the expanded state by the one of the opposed ones.
Since the bolt is threaded through the opposing surface of the rectangular frame and the tip of the bolt is brought into contact with the opposing surface of the other rectangular frame , the ring-shaped support body can be firmly held in the expanded state.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a tunnel excavator according to a first embodiment of the present invention;
The tunnel excavation walls 2 drilled by a ring-shaped支保body 3A obtained by connecting together the front and rear facing surfaces together, which shows a state supporting the shoring consisting 3A · · · 3A, ring shoring The member 3A is assembled on the ring-shaped support body 3 having a small diameter in the skin plate 11 of the tunnel excavator 1, and is sequentially sent out to the tunnel excavation wall 2 side according to the excavation of the tunnel excavator 1, and is a diameter expanding means described later. The diameter is expanded by the expansion jack 4 and is sequentially pressed against the tunnel excavation wall surface 2.

The tunnel excavator 1 has a support member 12 disposed integrally with the skin plate 11 at a front end opening of a cylindrical skin plate 11, a rotatably supported support member 12 A cutter plate 13 driven to rotate by a drive motor (not shown) mounted in the member 12
A beam member 14 which is integrally fixed to the front end of the support member 12 at the rear end thereof and extends horizontally rearward from the rear end of the skin plate 11 through the central space of the skin plate 11; A front gripper 15 that is integrally attached to the upper, lower, left, and right sides of the support member 12 and can be extended and contracted by a jack 15a.
And a rear support 16 projecting downward from the lower surface of the rear end of the beam member 14 so as to be vertically expandable and contractable by a jack 16a, and a rear gripper slidably disposed along the lower surface of the beam member 14.
17 and a propulsion jack 18 connecting the support member 12 and the rear gripper 17. A cylindrical sliding frame 19 is slidably fitted on the beam body 14 and pushed up on the upper surface of the sliding frame 19. The jack 20 is fixed. An extrusion jack 5 for sending the small-diameter ring-shaped support body 3 backward is mounted on several inner peripheral surfaces of the skin plate 11.

The skin plate 11 includes a beam member 14.
The rear gripper 17 is integrally fixed to and supported on the outer peripheral surface of the beam body 14 via a connecting frame member 21 and the rear gripper 17 is disposed on the rear side of the beam body 14 projecting rearward from the skin plate 11. A beam receiver 22 slidable relative to the body 14 projects horizontally from both lower surfaces of the beam receiver 22 toward both side surfaces of the tunnel excavation wall surface 2 and both rear grippers 17, 17 and both rear surfaces of the support member 12. The parts are connected by the propulsion jacks 18, 18, respectively. Further, the sliding frame 19 and the beam receiver 22 are connected via a connecting jack 23. The earth and sand excavated by the cutter plate 13 is discharged rearward by a suitable carrying-out means such as a conveyor (not shown).

The tunnel excavator 1 having such a configuration
The ring-shaped support 3 having a small diameter assembled in the skin plate 11 is formed by connecting a plurality of rectangular frames 30 shown in FIG. This rectangular frame
Numeral 30 is formed by fixing the front and rear main girders 31, 32 curved in an arc shape along the inner peripheral surface of the skin plate 11 or the tunnel excavation wall surface 2 integrally by flat joint plates 33, 34 between both ends in the longitudinal direction. At the opening end on the outer peripheral end face side, a fall prevention body 40 made of a wire mesh formed by combining rod-shaped metal wires in a lattice shape is stretched and at the main girders 31, 32 and the joint plates 33, 34 at several places. The connection holes 35 and 36 are formed at equal intervals in the length direction.

As shown in FIGS. 6 to 8, the adjacent rectangular frames 30A and 30B forming the lower peripheral portion of the ring-shaped support body 3 are provided with the connecting holes 33 and 34 in the opposite joint plates 33 and 34, respectively. Screw hole members 6a and 6b penetrating the joint plates 33 and 34 are fixed together with 36, and the end faces of the push bolts 7 to be screwed into these screw hole members 6a and 6b face the end faces of the joint plates 33 and 34. It is configured to make contact with. Further, on the inner peripheral surface of the opposite ends of the main beams 31, 32 of the rectangular frames 30A, 30B, a bracket 4 for interposing an expansion jack 4 as expansion means is provided.
1 and 42 are detachably fixed by bolts 43, and the base end of the regulating plate 8 is fixed to the inner peripheral surface ends of the main beams 31 and 32 of one rectangular frame 30A as shown in FIG. As shown in FIGS. 7 and 8, the outer peripheral surface of the protruding portion of the regulating plate 8 protruding in the extending direction of the main girders 31 and 32 is attached to the inner peripheral surface of the other end of the main girder 31 of the other rectangular frame 30B. It is configured to make sliding contact. In FIG. 8, the expansion jack 4 interposed between the opposing ends of the other main girders 31, 32 of the rectangular frames 30A, 30B.
Is not shown.

The rectangular frames 30, 30A, 30 constructed as described above
After assembling a small-diameter ring-shaped support body 3 in the skin plate 11 of the tunnel excavator 1 using B, the diameter of the ring-shaped support body 3 is increased on the tunnel excavation wall surface 2 side to form a support. First, a small-diameter ring-shaped support 3 is assembled along the inner peripheral surface of the skin plate 11 in the rear end of the skin plate 11 of the tunnel excavator 1.

The ring-shaped support 3 is assembled by using a rectangular frame.
The joint plates 33, 34 which face each other with the main beams 31, 32 curved in an arc shape of 30, 30 facing in the circumferential direction are joined to each other to form a connection hole.
36, 36 are connected by bolts and nuts 37, 38. In this connection operation, an erector (not shown) provided in the skin plate 11 is used to support the rectangular frame 30 by the erector, and the rectangular frame 30 to be connected to the joint plates 33, 34 at both ends of the rectangular frame 30. , 30 are joined and connected by bolts and nuts 37, 38, respectively.

By connecting the plurality of rectangular frames 30 in this manner, a small-diameter ring-shaped support 3 along the inner peripheral surface of the skin plate 11 is assembled as shown in FIG. The rectangular frame 30A to be incorporated last along the inner surface of the lower peripheral portion of the skin plate 11 is connected by bolts and nuts to the joint plate 34 of the adjacent rectangular frame 30B that joins one joint plate 33 to the joint plate 33. As shown in FIG. 8, the other rectangular frame 30A is formed on the outer peripheral surface of the regulating plate 8 projecting from the inner peripheral surface end of the main girder 31 of the other rectangular frame 30A. The frame 30B is brought into sliding contact with and supported by the inner peripheral surface of the opposing end of the main girder 31.

In FIG. 4, the small-diameter ring-shaped support body 3 is assembled by four rectangular frames 30.
The ring-shaped support body 3 may be assembled with more than one rectangular frame. In short, the adjacent rectangular frames 30A, 30B constituting a part of the ring-shaped support body 3 disposed on the lower peripheral side of the skin plate 11 Without connecting the joint plates 33, 34 of
Alternatively, they may be released at small intervals.

After the small-diameter ring-shaped support body 3 is assembled in the skin plate 11 in this manner, the ring-shaped support body 3 is assembled.
The rod end of the jack 5 for extrusion is brought into contact with the front end face of the above to extend the lot of the jack 5 for extrusion, whereby the small-diameter ring-shaped support 3 is sent out to the tunnel excavation wall surface 2 side. At this time, after a tunnel of a certain length is excavated by the tunnel excavator 1, the small-diameter ring-shaped support body 3 may be sent out by the extruding jack 5 to the excavation wall surface 2 exposed behind the tunnel excavator 1 by the excavation. ,
The extrusion jack 5 may be relatively extended in accordance with the excavation of the tunnel excavator 1 and may be sent to the excavation wall surface 2 side.

The small-diameter ring-shaped support 3 sent out to the tunnel excavation wall 2 side receives the inner peripheral surface of the rectangular frame 30 on the upper peripheral side thereof by the push-up jack 20, and the skin plate
After moving backward from 11 and being completely fed to the tunnel excavation wall 2 side, the push-up jack 20 is further extended upward, thereby lifting the entire ring-shaped support body 3 to raise its upper peripheral portion. The outer peripheral surface of the side rectangular frame 30 is brought into contact with the upper peripheral wall surface of the tunnel excavation wall surface 2 as shown in FIG.

Next, the brackets fixed to the inner peripheral surfaces of the opposing portions of the main girder 31, 32 on both sides of the rectangular frames 30A, 30B which are not connected while the lifting of the ring-shaped support body 3 by the lifting jack 20 is maintained. Jack 4 for expanding diameter between 41 and 42
(In FIG. 8, one of the diameter expansion jacks is omitted), and the tip end of the push bolt 7 is screwed into the screw hole members 6a, 6b provided in the joint plates 33, 34 facing each other. Let it. Note that the expansion jack 4 and the push bolt 7 may be attached in the skin plate 11. The mounting of the brackets 41 and 42 may be performed in the skin plate 11 or may be performed after the small-diameter ring-shaped support body 3 is pushed out to the tunnel excavation wall surface 2 side as shown in the figure.

Thereafter, when the diameter-enlarging jack 4 is extended, the opposed joint plates 33 and 34 of the rectangular frames 30A and 30B are separated from each other, and the ring-shaped support body 3 having a small diameter expands accordingly. As shown in FIG. 7, the outer diameter of the ring-shaped support body 3A is entirely brought into contact with the excavation wall surface 2. At the time of this diameter expansion, the small-diameter ring-shaped support body 3 is pushed through a jack 5 for extrusion on the front end face of the existing expanded-diameter ring-shaped support body 3A that has been expanded first and supports the tunnel excavation wall surface 2. The diameter of the rectangular frames 30A, 30B of the small-diameter ring-shaped support body 3 is prevented from becoming staggered in the front-rear direction with each other, and the rectangular frames 30A, 30A are pressed.
B are joined so as to be slidable in the circumferential direction via the regulating plate 8, so that the regulating plate 8 is accurately enlarged in the radial direction using the regulating plate 8 as a guide.

The small-diameter ring-shaped support 3 is joined to the existing enlarged-diameter ring-shaped support 3A.
May be pressed directly by the push-out jack 5, but the push-out jack 5 is provided at a front portion of the skin plate 11 which does not hinder the operation of the elelectra, as shown in FIG. After assembling the next small-diameter ring-shaped support body 3 in the skin plate 11,
The small-diameter ring-shaped support body 3 sent out to the side is configured to be pressed by the pressing jack 5 via the small-diameter ring-shaped support body 3 in the skin plate 11. It should be noted that, instead of pressing against the existing enlarged-diameter ring-shaped support body 3A by the pushing jack 5, it may be pressed by pulling from the existing enlarged-diameter ring-shaped support body side. A small-diameter ring-shaped support body 3 may be slidably connected to the enlarged-diameter ring-shaped support body in the diameter-expanding direction.

As described above, when the small-diameter ring-shaped support 3 is expanded to the same diameter as the existing large-diameter ring-shaped support 3A by the expansion of the diameter-expanding jack 4, as shown in FIG. The push bolts 7 screwed into the screw hole members 6a, 6b provided on the joint plates 33, 34 of the rectangular frames 30A, 30B to be rotated are rotated in the screwing direction, and the ends of the push bolts 7 are opposed to the joint plates 33, 34. The surfaces are brought into contact with each other, and are maintained in the ring-shaped support body 3A whose diameter has been increased. It is to be noted that the push bolt 7 may be rotated to expand the small-diameter ring-shaped support body 3 due to the expansion of the diameter-expanding jack 23 so that the tip of the push bolt 7 always contacts the surfaces of the joint plates 33 and 34 facing each other. Alternatively, the rectangular frames 30A and 30B may be separated by the screwing force of the push bolt 7. In this case,
The diameter of the ring-shaped support body 3 can be expanded without using the diameter-expanding jack 4.

The bolts 37 are inserted into the connection holes 36, 36 of the opposed joint plates 33, 34 of the rectangular frames 30A, 30B separated from each other of the ring-shaped support body 3A whose diameter has been increased, and the nut 38 is screwed. The main girders 31, 32 of the front and rear ring-shaped supports 3A, 3A, which are connected and fixed and joined together as necessary, are also screwed with nuts by inserting bolts (not shown) into the connection holes 35, 35. On the other hand, the push-up jack 20 is advanced on the beam body 14 by the connecting jack 23 to support and push up the next small-diameter ring-shaped support body 3. The small-diameter ring-shaped support body is provided in the skin plate 11. After the assembling of the small-diameter ring-shaped support body 3, the small-diameter ring-shaped support body 3 is sent out to the tunnel excavation wall surface 2 side in the same manner as described above, and the diameter of the small-diameter ring-shaped support body 3 is increased. The excavation wall 2 is supported by expanding the assembly process and diameter. By repeating the steps and forms a 支保 Engineering for 支保 tunnel excavation wall.

In the above embodiment, the tunnel excavator 1
In the skin plate 11, the joint plates 33, 34 of the rectangular frames 30A, 30B opposed to each other are joined or separated without being connected, and the small-diameter ring-shaped support body 3 in which these rectangular frames 30A, 30B are integrally incorporated. After forming the ring-shaped support body 3, the ring-shaped support body 3 is sent out to the tunnel excavation wall surface 2 side. However, at least one of the rectangular frames 30A and 30B may be incorporated in the tunnel excavation wall surface 2 side.

FIGS. 9 to 11 show an embodiment of the present invention, in which the joint plates 33, 34 at both ends of the rectangular frame 30 are connected to the joint plates 33, 34 of the rectangular frames 30, 30B by bolts and nuts 37, 38 in the same manner as in the above embodiment. Three
3 and 34 are connected to each other, and the lower end joint plates 33 and 34 of the rectangular frames on both sides are spaced 39 without incorporating the rectangular frame 30A on the lower peripheral side.
A small C-shaped small diameter ring-shaped support 3 ′ that is free and is free from the problem is assembled. The small-diameter ring-shaped support body 3 ′ is sent out to the tunnel excavation wall surface 2 side by the pushing jack 5, and the rectangular frame 30 on the upper peripheral side thereof is supported by the pushing-up jack 20, and in the tunnel, as shown in FIG. The entire ring-shaped support 3 ′ is lifted by extending the push-up jack 20, and the outer peripheral surface of the rectangular frame 30 on the upper peripheral side is brought into contact with the upper peripheral wall of the excavation wall 2.

In this state, the rectangular frame 30A is inserted and interposed in the space 39 on the lower peripheral side of the small-diameter ring-shaped support 3 ', and the other joint plate 34 is connected to the joint plate of the rectangular frame 30 facing the other. 33
8, one joint plate 33 is connected to the joint plate 34 of the opposed rectangular frame 30B without being connected to the joint plate 34 of the rectangular frame 30B as shown in FIG. The outer peripheral surface of the regulating plate 8 projecting from the inner peripheral end of the girder 31 is slidably contacted with and supported by the inner peripheral surface of the opposite end of the main girder 31 of the other rectangular frame 30B.

Thereafter, the jack 4 for diameter enlargement is interposed between the brackets 41 and 42 fixed to the inner peripheral surfaces of the rectangular frames 30A and 30B, and the joint plates 33 and 34 facing each other.
The distal end of the push bolt 7 is screwed into the screw hole members 6a, 6b provided in the above, and the ring-shaped support body 3 having a small diameter is expanded while separating the joint plates 33, 34, so that FIGS. As shown in the figure, a large-diameter ring-shaped support body 3A whose outer peripheral surface is entirely in contact with the excavation wall surface 2 is provided. At the time of this diameter expansion, the small-diameter ring-shaped support body 3 is pushed through a jack 5 for extrusion on the front end face of the existing expanded-diameter ring-shaped support body 3A that has been expanded first and supports the tunnel excavation wall surface 2. The diameter of the rectangular frames 30A and 30B can be accurately enlarged in the radial direction by sliding the rectangular frames 30A and 30B in the circumferential direction via the regulating plate 8 while being pressed lightly.

As described above, the small-diameter ring-shaped support body 3 is replaced by the existing large-diameter ring-shaped support body by extending the diameter-expanding jack 4.
When the diameter is increased to the same diameter as 3A, the push bolt 7 screwed into the screw hole members 6a, 6b provided in the joint plates 33, 34 of the rectangular frames 30A, 30B in the screwing direction as in the above embodiment. , And the ends thereof are brought into contact with the opposing surfaces of the joint plates 33 and 34 facing each other, and are maintained in the ring-shaped support body 3A whose diameter has been increased. Thereafter, the opposing joint plates 33, 34 of the rectangular frames 30A, 30B are connected and fixed by inserting bolts 37 into the connection holes 35, 36 and screwing the nuts 38, and before and after joining, if necessary. The main girders 31, 32 of the ring-shaped supports 3A, 3A are also connected and fixed by inserting bolts (not shown) into the connection holes 35, 35 and screwing them with nuts.

In the excavation by the tunnel excavator 1, after the rear grippers 17, 17 are pressed against both side surfaces of the tunnel wall 2, the rear support 16 is contracted and separated from the bottom of the tunnel wall 2, and then the propulsion jack 18 is moved. The front gripper 15 is excavated on the wall surface 2 while the reaction force is supported on the tunnel wall surface 2 via the rear gripper 17 by extending the
It is excavated by the cutter plate 13 while being in sliding contact with. After excavating a tunnel of a certain length, the front gripper 15 is firmly pressed against the excavation wall 2 and the rear support 16
Is extended to be supported on the bottom surface of the excavation wall surface 2 and the rear gripper 17 is contracted, and then the propulsion jack 18 is contracted to advance the rear gripper 17 along the beam member 14 to the next crimping position.

In the above embodiment, after the ring-shaped support body 3 having a small diameter is assembled in the skin plate 11 of the tunnel excavator 1, the ring-shaped support body 3 is extruded toward the tunnel excavation wall surface 2 and expanded. The small diameter ring-shaped support body 3 may be assembled and enlarged at the rear side of the tunnel excavator 1 so that the outer peripheral surface of the ring-shaped support body 3 is brought into contact with the excavation wall surface 2. After assembling the small-diameter ring-shaped support body 3 in a tunnel other than the excavation according to 1, the diameter may be expanded. Further, in the above embodiment, after the ring-shaped support body 3 is brought into contact with the upper wall surface of the tunnel excavation wall surface 2 by the push-up jack 20, the diameter of the ring-shaped support body 3 is increased. It is also possible to temporarily place the small-diameter ring-shaped support body 3 on the bottom surface of the tunnel excavation wall surface 2 without using it, and then expand the diameter.

[Brief description of the drawings]

FIG. 1 is a simplified longitudinal side view of a tunnel excavator forming a support on an excavation wall surface,

FIG. 2 is a perspective view of a rectangular frame;

FIG. 3 is a perspective view of a joining rectangular frame;

FIG. 4 is a simplified front view of a small-diameter ring-shaped support body assembled in a skin plate;

FIG. 5 is a simplified front view of a small-diameter ring-shaped support body lifted in a tunnel excavation wall surface,

FIG. 6 is a simplified front view of a ring-shaped support body having an enlarged diameter;

FIG. 7 is a front view of a portion between the separated rectangular frames as viewed from the inner peripheral surface side;

FIG. 8 is an enlarged perspective view of a joint plate portion of a rectangular frame joined to each other,

FIG. 9 is a simplified front view of another form of the small-diameter ring-shaped support body assembled in the skin plate.

FIG. 10 is a simplified front view of a small-diameter ring-shaped support body lifted in a tunnel excavation wall surface,

FIG. 11 is a simplified front view of a ring-shaped support body having an enlarged diameter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tunnel excavator 2 Tunnel excavation wall 3 Small diameter ring-shaped support body 3A Expanded ring-shaped support body 4 Jack for expanding diameter 7 Push bolt 8 Restriction plate 11 Skin plate 14 Beam body 20 Push-up jack 30, 30A, 30B Rectangular Frame 31, 32 Main girder 33, 34 Joint plate

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-9-268898 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E21D 11/14 E21D 11/40

Claims (4)

(57) [Claims] 1. A rear end of a skin plate of a tunnel excavator.
And curved in an arc shape in a direction along the tunnel excavation walls in portion
A tunnel excavator after connecting a plurality of rectangular frames to assemble a ring-shaped support with a diameter smaller than the diameter of the tunnel excavation wall
From the back, and expand this ring-shaped support first.
The diameter of the rear end face is enlarged to the front end face of the existing ring-shaped support body
In the direction of the lower edge of the tunnel while being slidably pressed in the direction
Method of forming a tunnel shoring, characterized in that is brought into contact with the outer peripheral surface thereof by diameter of the small-diameter ring-shaped支保body tunneling wall by spacing between the rectangular frame adjacent in the circumferential direction. 2. An arc shape in a direction along a tunnel excavation wall surface.
By connecting a plurality of curved rectangular frames,
When forming a ring-shaped support with a smaller diameter than the diameter,
Rectangular frames forming the lower periphery of the ring-shaped support
At the end of the inner peripheral surface of one rectangular frame
A regulating plate to be brought into sliding contact with the inner peripheral surface is fixed, and this regulating plate
The inner peripheral surface of the opposite end of the other rectangular frame is slid on the outer peripheral surface of
After forming a small diameter ring-shaped support in the
By separating the rectangular frames of the small diameter in the circumferential direction.
The diameter of the support body is enlarged and its outer peripheral surface is
A method of forming a tunnel shoring , characterized by contacting the tunnel support. 3. A process according to claim 1 or請, characterized in that it is stretched to collapse preventing member in a rectangular frame to form a ring-shaped支保body
The method for forming a tunnel support according to claim 2 . Wherein the diameter state of the small-diameter ring-shaped shoring held, against the opposing surface of the by pass screw bolts on the opposing surface of one of the rectangular frame described above relative rectangular frame tip the other of the bolt 2. The method according to claim 1 , wherein the contact is performed by contact.
The method for forming a tunnel support according to claim 2 or 3 .