JPH09165991A - Branch tunnel excavation pit mouth wall structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to prevent a pit mouth wall from being turned together by the turning of a disk-shaped cutter board and excavate definitely the pit mouth wall when launching a branch tunnel excavation shield excavating machine from a disk-shaped pit mouth wall closed with a low strength concrete- made pit wall mouth wall. SOLUTION: While a locked recessed area 6, which is expanding a part of a pit mouth 1 in the dia-expanding direction, is provided on an excavated ground of a permanent tunnel T in a disk-shaped pit mouth 1, a projected area, which is fitted in the aforesaid locked recessed area 6 in a part of a disk-shaped outer peripheral surface of a low strength concrete-made pit mouth wall 7 which has blocked this disk-shaped pit mouth 1. When the pit mouth wall 7 is crushed with a disk-shaped cutter board 8 of a branch tunnel excavation shield excavating machine S, the projected area, which is fitted in and locked with the aforesaid locked recessed area 6, prevents the pit mouth wall 7 from turning together with a disk-shaped cutter board 4 and crushes all the pit mouth wall 7 definitely, thereby enabling the branch tunnel 11 to be excavated with the branch tunnel excavation shield excavating machine S.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a wellhead wall for excavating a branch tunnel from a desired portion of a tunnel when lining the tunnel.

[0002]

When excavating a branch tunnel from a part of a main tunnel using a built tunnel as a main tunnel, as shown in FIG. 8, a main tunnel lining 2 formed by assembling steel segments in advance is used. A circular tunnel opening 1 for starting a branch tunnel is provided in a part of this, and the well opening 1 is closed by a low strength concrete well wall 7 and a circular cutter plate 8 for excavating a branch tunnel is provided on the back side of the well wall 7. After incorporating the above, the circular cutter 8 is inserted into the shield tunnel excavator S for branch tunnel excavation during excavation of the branch tunnel.
After the shield excavator S is started, the circular cutter plate 8 is rotated to crush the wellhead wall 7 and then the branch tunnel is excavated.

[0003]

However, since the conventional wellhead wall 7 has a structure in which the circular peripheral end face is fixed to the inner peripheral wall surface of the circular wellhead 1 by adhesion or the like, shield excavation for branch tunnel excavation is performed. When the excavating bit of the circular cutter plate 8 is rotated while biting into the wellhead wall at the time of starting the machine S to cut and crush the wellhole wall, the rotational torque of the circular cutter plate 8 causes the wellhole 1 and the wellhead wall 7 to rotate. The peripheral end face of the wellhead wall 7 is separated from the inner peripheral wall surface of the wellhead 1 by overcoming the sticking force of the wellhole, and the whole wellhead wall rotates integrally with the circular cutter plate 8 so that the wellhead wall 7 can be crushed by the circular cutter plate 8. There was a problem of disappearing.

Such a problem can be solved by connecting and fixing the outer peripheral end portion of the wellhead wall to the inner peripheral wall surface of the wellhead with bolts, but then the bolts prevent the circular cutter from cutting the wellhead wall. Therefore, the entire wall of the wellhead cannot be cut or removed. The present invention provides a structure of a wellhead wall for excavating a branch tunnel, which can completely solve such a problem.

[0005]

The structure of a wellhead wall for excavating a branch tunnel according to the present invention has a predetermined structure for a main tunnel lining formed by assembling a steel segment on a wall surface for excavating the tunnel in a circumferential direction and a longitudinal direction. A circular wellhead for branch tunnel excavation that penetrates from the inside of the tunnel to the wall surface of the tunnel excavation is provided at this location, and this circular wellhead is made of a material that can be crushed by the cutter plate of the shield excavator for branch tunnel excavation. In the pit wall for branch tunnel excavation that is closed by a wall, a locking recess that expands in the radial direction is formed in a part of the pit on the wall surface of the tunnel, and the circular shape of the pit wall is formed in this locking recess. When cutting the wellhead wall with a circular cutter from inside the tunnel by fitting the protruding part protruding from a part of the periphery, the wellhead wall maintains a fixed state without rotating with the circular cutter. To cutting, in which are configured to smoothly perform the crushing.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION During the construction of this tunnel, when a position where a branch tunnel is to be constructed is reached and the tunnel lining is to be carried out on that portion, a rectangular steel segment curved in the tunnel circumferential direction is used for the tunnel. Assembling the lining for one ring in the circumferential direction and assembling the lining for several rings in the length direction of the tunnel to form the circular wellhead wall of the branch tunnel by part of these lining segments. . That is, an arc-shaped cutout part that becomes a part of a wellhead and an edge wall plate protruding toward the main tunnel side are formed on the edge of the cutout part in a part of the steel segment, and a circular shape is formed in the arc-shaped cutout part. A low-strength concrete block that can be cut by a cutter plate is installed with its arcuate end face in close contact with the edge wall plate, and a lining segment for several rings is assembled in the tunnel length direction using this steel segment. As a result, a circular wellhead wall is formed by the low-strength concrete blocks joined to each other, and the circular arc-shaped notches of the lining segments are circumferentially continuous to form a circular wellhead. An outer surface of the wellhead wall on the tunnel excavation ground side has the same curved surface as the curved shape of the lining segment, while an inner surface of the tunnel side has a flat surface. The pit wall counteracts earth pressure and stabilizes the lining such as temporary water stoppage until the water stoppage treatment by filling the low-strength material.

Further, in the wellhead wall, a locking recess which is stepwise expanded in the radial expansion direction is formed on the wall surface side of the tunnel in the edge wall plate of a part of the lining segment. A part of the low-strength concrete block mounted on the above is projected in the radial expansion direction, and the projecting portion is fitted into the locking recess. Therefore, when starting the shield excavator for branch tunnel excavation, when cutting the wellhead wall while rotating the circular cutter plate, the rotation of the circular cutter plate causes the wellhead wall to try to rotate integrally with the locking recess. The fitted protruding portion reliably blocks and the circular cutter plate enables smooth cutting and crushing. Further, in the lining segment, locking recesses are formed only in the lining segments arranged at both ends in the tunnel length direction, and the concrete block corresponding to the lining segment is provided with a projecting portion. By fitting the projecting portion in the locking recess, the wellhead wall can be cut and crushed to the end by the circular cutter plate.

[0008] Further, connecting holes are formed between the joint ends of the concrete blocks so as to communicate with each other in an oblique direction from the inner surface of one block into the other block, and a cutter plate is provided between these connecting holes. A crushable resin connecting member is inserted and adhered to connect the blocks together, and similarly, a connection hole is provided at the end edge of the concrete block facing the lining segment, and a cutter plate is provided in this connection hole. Insert a resin connecting member that can be crushed by
The block is integrally bonded to the lining segment by gluing. Therefore, the concrete blocks are integrated with each other and the opposing end portions of the concrete block and the lining segment are easily and firmly connected to each other, and at the time of excavating the branch tunnel, the resin connecting member is crushed by the circular cutter plate while digging the wellhead. The wall can be cut.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a concrete embodiment of the present invention will be described with reference to the drawings. In FIG. 1 and FIG. A tunnel tunnel forming pit formed by a part of the lining segment 2 of the main tunnel T. A constant length of the main tunnel T is excavated every time the main tunnel T is excavated by a shield excavator (not shown) for excavating the main tunnel. When a plurality of curved rectangular steel segments 2 are assembled in the circumferential direction to form a lining for one ring, and when this lining is sequentially formed for several rings in the tunnel length direction, Steel segment 2 provided with arcuate notches 3a, 3b, ... 3e each having a shape obtained by dividing the wellhead 1 in the lengthwise direction of the tunnel T
It is formed by these arcuate notches 3a, 3b ... 3e which are continuous by assembling a, 2b ... 2e.

That is, when the circular wellhead 1 is divided in the tunnel length direction by the lining width for one ring of the main tunnel T, and this divided portion is formed by a part of the lining segment 2, the main tunnel tunnel The steel segments 2a, 2e assembled on both end sides of the wellhead in the longitudinal direction have a shape in which arcuate arcuately curved notches 3a, 3e are provided on the opposite end surface sides thereof, and these steel segments 2a , 2e between the linings for one ring, the upper and lower circumferential steel segments 2b, 2b; 2c, 2c;
The opposing end faces of 2d are formed into arcuate cutouts 3b, 3c, 3d which are part of the outer peripheral end face of the circular wellhead 1, and the arcuate end edges of these cutouts 3a to 3e are continuous and circular. Therefore, the wellhead 1 is formed in the space surrounded by the circular edge.

Further, the arcuate notches 3a to 3e of the steel segments 2a to 2e are provided with edge wall plates 4a to 4e of a certain height toward the main tunnel T side at the edges of the notches. There is. The edge wall plates 4a to 4e form the peripheral wall of the frame-shaped lining segment together with the peripheral wall plates 5a to 5e projecting toward the main tunnel T side in each of the steel segments 2a to 2e. In addition, as shown in FIGS. 4 and 7, the steel segments 2a and 2e arranged at both ends of the wellhead 1 in the tunnel length direction extend from the arcuate notches 3a and 3e to the edge wall plate 4a, respectively. The engaging recess 6 having a triangular shape on the front surface is formed so as to project in a radial direction in a stepwise manner with respect to 4e. The locking recess 6 is formed from the cutouts 3a and 3e to the edge wall plate.
Wall plate 6a bent at right angles to 4a and 4e and the wall plate
It is formed from an L-shaped surrounding wall plate 6b protruding from the tip of 6a toward the excavated ground side at a right angle, and one end of the surrounding wall plate 6b is connected to the surrounding wall plates 5a and 5e, respectively.

The steel segments 2a and 2e arranged at both ends of the wellhead 1 have arcuate cutouts 3a and 3e.
Low-strength concrete block 7 with the same shape as the cutout
a and 7e are fitted into the rectangular steel segments 2a and 2e, respectively, as a part of the rectangular steel segments 2a and 2e, and the flat side end faces of these low-strength concrete blocks 7a and 7e form one long side of the steel segment. In addition, these low strength concrete blocks 2a, 2e on the ground side of the tunnel excavation
Is formed integrally with a triangular protrusion 7f which is fitted in the locking recess 6 by projecting a part of the protrusion in the radial direction.

Further, in the wellhead 1 between these low-strength concrete blocks 7a, 7e, a low-strength concrete block long in the tunnel circumferential direction having a shape divided in the tunnel length direction for each width of the steel segment 2 is formed. 7b, 7c, 7d are joined in a state where the opposite end faces perpendicular to each other are joined and the upper and lower arc-shaped end faces of each block are closely attached to the end faces of the arc-shaped edge wall plates 4b to 4d of the upper and lower steel segments facing each other. Therefore, when the steel segments 2a to 2e are combined, the wellhead wall 7 that closes the wellhead 1 with these low-strength concrete blocks (hereinafter simply referred to as blocks) 7a to 7e.
Is formed. The outer surface of the wellhead wall 7 on the side of the tunnel excavation ground is formed into a curved surface curved in an arc shape, while the inner surface of the tunnel side is formed into a flat surface in the vertical direction.

Further, in the blocks 7a to 7e forming the wellhead wall 7, except for the block 7e located at the end of the tunnel T in the excavation direction, the other blocks 7a to 7d are used for excavating the tunnel. As shown in FIGS. 1 and 3, a horizontal through-hole 10 is formed in the shield machine S for receiving the propulsion jacks so as to penetrate the blocks 7a to 7d over the entire width. At the time of constructing the lining of T, the reaction force receiving member 11 having rigidity of substantially the same length as the through holes is sequentially provided in these through holes that communicate with each other in the horizontal direction every time the blocks 7a to 7d are assembled. Inserted while connecting with screws and screw holes, the front end surface of the reaction force receiving member receives the propulsion jack of the shield excavator for excavation of the tunnel T, and these reaction forces are applied to the already assembled steel segment side. Support the propulsion reaction force through the receiving member However, the tunnel T is configured to be dug forward. The reaction force receiving member 11 is extracted from the through hole 10 and removed before the rearmost steel segment 2e is assembled.

Further, as shown in FIG. 1, the joint side end portions of the blocks joined to each other are joined end faces of the two blocks from the inner surface of one block toward the main tunnel T toward the other block. Connection holes 12 and 12 of appropriate depth that intersect with each other and communicate with each other in a straight line are provided. From inside the main tunnel T inside the connection holes 12 and 12, by a circular cutter plate 8 for excavating a branch tunnel. By inserting a connecting member 9 made of a synthetic resin material mainly composed of crushable glass fibers and filling the connection holes 12 and 12 with an adhesive such as urethane foam, they are joined to each other through the connecting member 9. The blocks are connected together. The connection holes 12 and 12 may be provided in each of the blocks 7a to 7e in advance, and after being assembled to the wellhead wall 7, the connection holes 12 and 12 are bored from inside the tunnel T by using an appropriate punching tool. Good.

On the other hand, the steel segment 2 in which the blocks 7a to 7e and the arcuate curved edges of these blocks are joined together
In the same manner as above between the edge wall plates of the block, straight connecting holes 13 and 14 communicating with each other are respectively formed in the arc-shaped curved end portions of the block and the edge wall plate of the steel segment 2 in which the end portions are joined. The tunnel T is provided inside the connection holes 13 and 14.
From inside, insert a connecting member 9 made of a synthetic resin material mainly composed of glass fiber that can be crushed by a circular cutter plate 8 for excavating a branch tunnel, and fill the connection holes 13 and 14 with an adhesive such as urethane foam. Are connected to each other via the connecting member 9.

The circular cutter plate 8 for excavating a branch tunnel is, as shown in FIG. 1, a low-strength concrete block 7a.
Divided pieces 8a, 8b ...
-It is formed by integrally connecting 8e to each other with bolts 15. As shown in FIG. 3, the circular cutter plate 8 is arranged at a small distance from the inner surface of the wellhead wall 7 facing the inside of the main tunnel T, and the circular outer peripheral end surface thereof is outside the wellhead 1. Bolts 17 are detachably connected to the inner peripheral surface of the wellhead ring member 16 protruding from the periphery toward the inside of the main tunnel T. Then, the low-strength waterproof material 18 made of mortar is filled and solidified in the void portion formed by the gap portion between the facing surfaces of the wellhead wall 7 and the circular cutter plate 8.

In order to mount the circular cutter plate 8 on the wellhead ring member 16, a divided piece of the circular cutter plate 8 may be arranged on the back side of each block of the wellhead wall 7 each time it is formed. After forming the wellhead wall 7, the divided pieces 8a to 8e of the circular cutter plate 8 are formed.
Round cutter plate 8 that is connected by bolts 15 while combining
And the circular cutter plate 8 may be fixed to the wellhead ring 16 by bolts 17. The circular cutter plate 8
A filling member made of sponge is fitted into the gap between the outer peripheral end surface of the hole and the inner peripheral surface of the wellhead ring member 16 to form a water blocking material 18a.
Are prevented from leaking into the tunnel T.

After the pit wall 7 for advancing the branch tunnel is formed in this way, the fixing bolt 17 of the circular cutter plate 8 is removed from the pit ring member 16 and the circular cutter plate 8 is passed through the main tunnel T when the branch tunnel T1 is constructed. A skin plate 19 having substantially the same outer diameter, a drive device 20, other constituent members of a shield excavator for branch tunnel excavation, a bearing frame 21, and the like are loaded, and as shown in FIG. The drive device 20 is fixed to the back surface of the partition wall 23 which is installed on the abutment 22 so as to face the back surface of the circular cutter plate 8 and is stretched in the opening of the skin plate 19, and its rotation axis is set at the center of the partition wall 23. The part is penetrated and projected forward.

Further, the propulsion jacks 24 are attached to the skin plate at a plurality of positions, and the propulsion jacks 24 are communicated with the earth and sand intake chamber 25 formed between the cutter plate 8 and the partition wall 23 and sent to the rear surface of the partition wall 23, the mud pipe 26, Connect 27. After that, the propelling jack 24 is brought into contact with the bearing frame 21 fixed to the lining of the tunnel T, and the propeller jack 24 is extended to advance the skin plate. The central portion of the back surface of the plate 8 is integrally connected and fixed to form a shield excavator S1 for excavating a branch tunnel.

Next, while supplying muddy water from the mud pipe 26 to the earth and sand intake chamber 25, the shield excavator S1 is slightly retracted to separate the front surface of the circular cutter plate 8 from the low strength water blocking material 18, and then When the shield jack excavator S1 is propelled by extending the propelling jack 24 while rotating the circular cutter plate 8, the excavating bit protruding from the front surface of the circular cutter plate 8 causes the low-strength water blocking material 18 to move to the concrete wellhead. While cutting into the wall 7, the low strength waterproof material 18 and the concrete wellhead wall 7 are cut and crushed.

At this time, the wellhead wall 7 and the peripheral edge wall plates 4a and 4e of the steel segment around the wellhead wall 7 are connected by the connecting member 9, but the connecting member 9 is broken by the rotational force of the circular cutter plate 8. Then, a situation occurs in which the wellhead wall 7 tries to rotate together with the circular cutter plate 8. However, since a protrusion 7f is provided on a part of the outer periphery of the wellhead wall 7 on the tunnel excavation wall surface side, and the protrusion 7f is fitted in the locking recess 6 provided in the steel segments 2a, 2e, it is circular. Despite the rotation of the cutter plate 8, the mine wall 7 is prevented from co-rotating by the locking force between the projecting portion 7f and the locking recess 6, and the shield excavator S1
Wellhead wall 7 by circular cutter plate 8 which rotates with the propulsion of
Is surely cut and crushed to the end.

This concrete crushed piece is a circular cutter plate 8
It is taken into the earth and sand intake room 25 through the intake provided in. After cutting the pit wall 7, as shown in FIG. 9, the ground on the front side is subsequently excavated by the shield excavator S1 and the segment 28 is assembled in the rear skin plate. It is to build T1. In addition, in the above embodiments, the protrusions 7f are formed on a part of the blocks 7a and 7e assembled on both ends of the wellhead 1.
However, a protrusion may be provided in a part of another block, and a locking recess for fitting the protrusion to a steel segment corresponding to the protrusion may be provided.

[0024]

As described above, according to the structure of the wellhead wall for excavating the branch tunnel of the present invention, the main tunnel lining formed by assembling the steel segment on the wall surface for excavating the main tunnel in the circumferential direction and the length direction is formed. A circular wellhead for branch tunnel excavation that penetrates from the inside of the tunnel to the wall surface of the tunnel excavation is provided at a predetermined location. In the pit wall for branch tunnel excavation that is closed, a locking recess that is enlarged in the radial direction is formed in a part of the pit on the wall surface side of this tunnel, and the circular recess of the pit wall is formed in this locking recess. Since the protruding part protruding from a part is fitted, it is circular when cutting the wellhead wall while rotating the circular cutter plate when starting the shield excavator for branch tunnel excavation. It is possible to reliably prevent the wellhead wall from trying to rotate integrally by the rotation of the tab plate by the protrusion fitted into the locking recess, and further, the protrusion of the wellhead wall is provided on the tunnel excavation wall surface side. Therefore, the rotation of the wellhead wall can be prevented until all the wellhead wall is cut by the circular cutter plate, so that the excavation work of the branch tunnel can be performed smoothly and efficiently.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing a state in which a wellhead wall and a cutter plate are arranged at a wellhead,

[Fig. 2] Simplified back view of the tunnel excavation wall surface,

FIG. 3 is an enlarged vertical side view,

FIG. 4 is a front view of a steel segment disposed on the end side of the wellhead,

FIG. 5 is a rear view of the

FIG. 6 is a side view thereof,

7 is a sectional view taken along line AA in FIG.

FIG. 8 is a simplified vertical sectional side view showing a state in which a shield excavator for branch tunnel excavation is provided,

FIG. 9 is a simplified vertical cross-sectional side view showing a state where a branch tunnel is being dug.

[Explanation of symbols]

 1 Wellhead 2a-2e Steel segment 3a-3e Arcuate notch 4a-4e Edge wall plate 6 Locking recess 7a-7e Low-strength concrete block 7 Wellhead wall 8 Circular cutter plate 9 Connecting member

Claims (5)

[Claims] 1. A branch tunnel excavation that penetrates between the tunnel excavation wall surface from inside the main tunnel at a predetermined location of the main tunnel lining formed by assembling steel segments in the tunnel excavation wall surface in the circumferential direction and the length direction. There is a circular wellhead for the tunnel tunnel, and the circular wellhead is closed by a wellhole wall made of a material that can be crushed by the cutter plate of the shield excavator for branch tunnel excavation. A locking recess enlarged in the radial direction is formed in a part of the wellhead on the wall surface side, and a protrusion protruding from a part of the circular periphery of the wellhead wall is fitted into this locking recess. The structure of the wellhead wall for excavating a branch tunnel, which is characterized in that 2. A lining segment is formed with an arcuate notch forming a part of a wellhead and an edge wall plate projecting toward the main tunnel side at the edge of the notch. The circular wellhead is formed by the edge wall plates of the notches that are continuous in the circumferential direction with each other by combining the segments,
In addition, a locking recess that is enlarged stepwise in the direction of diameter expansion is formed on the wall surface side of the tunnel excavation in the edge wall plate of a part of the lining segment, and the wellhead wall is formed in the tunnel length direction of the lining segment Is formed by combining a plurality of divided concrete blocks for each width, and a part of the concrete blocks is provided with a protruding portion protruding from a part of the circular peripheral edge of the wellhead wall, and the protruding portion is provided with the locking recess. The structure of a wellhead wall for excavating a branch tunnel according to claim 1, characterized in that 3. A locking recess is formed only in the lining segment of the lining segment, which is disposed at both ends in the tunnel length direction, and a projecting portion is formed on a concrete block corresponding to the lining segment. The structure of a wellhead wall for excavating a branch tunnel according to claim 2, wherein the projecting portion is provided and fitted in the locking recess. 4. A connection hole is provided between the joint ends of the concrete blocks so as to communicate with each other diagonally from the inner surface of one block toward the inside of the other block, and a cutter plate is provided between these connection holes. The structure of a wellhead wall for excavating a branch tunnel according to claim 2, characterized in that a crushable resin connecting member is inserted and adhered to integrally connect the blocks. 5. A connection hole is provided at an end edge portion of the concrete block facing the lining segment, and a resin connecting member that can be crushed by a cutter plate is inserted into the connection hole and adhered to the block to be integrated with the lining segment. The structure of the wellhead wall for excavating a branch tunnel according to claim 2, characterized in that the structure is connected to the.