JP3195552B2 - Tunnel construction method and tunnel excavator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a tunnel while covering the excavated peripheral wall with shotcrete and a tunnel excavator.

[0002]

2. Description of the Related Art TBM (tunnel boring machine), which excavates a bedrock in its entire cross section, includes a thrust jack for propulsion and a gripper jack for taking a reaction force on an excavated wall surface even when a skin excavator does not have a skin plate. Due to the jack device and the belt conveyor etc. that discharges excavated waste from the chamber to the rear inside the machine, the lining work to support the excavated wall with shotcrete is not possible because the inside of the machine is narrow. This is generally performed in a space behind the TBM having a large work space.

[0003] On the other hand, a ground having a thin clay layer or a crush zone or a crack developed therein is brittle against external pressure. When such a ground is excavated by a TBM, the excavated wall surface is required during a support operation behind the TBM. Skin fall (collapse) due to loosening of
Not only is it necessary to remove the fallen earth and sand and to repair the walls, but it is also uneconomical due to the loss of materials for restoration, and furthermore, the work environment deteriorated due to the revolved shotcrete. There are problems such as the necessity of removing the rebound material.

[0004]

As a cause of the above-mentioned skin drop, the peripheral wall surface excavated by the cutter plate is T-shaped.
Relaxation until it is exposed to the rear of the BM, pressing force by the front and main grippers of the TBM, and sliding contact between the body of the TBM and the excavation wall due to rapid direction control, Is not captured by the scraper provided on the cutter plate and remains on the excavated wall surface. To excavate the ground where large-scale skinning is expected, the ground in front of the cutter plate is improved in advance, but relatively small-scale skinning as described above tends to occur. It is not only uneconomical to perform such improvement of the ground on the ground, but also there is a problem that the working efficiency is significantly reduced.

The present invention has been made in view of the above problems, and has as its object to lay concrete on a peripheral wall immediately after being excavated by a cutter plate so as to support the peripheral wall. The present invention provides a tunnel construction method capable of performing construction smoothly and accurately without causing skin fall due to loosening of an excavation wall surface, and a tunnel excavator used in this method.

[0006]

In order to achieve the above object, a tunnel construction method according to a first aspect of the present invention is directed to a tunnel excavating part having a rotary cutter plate disposed at a front end thereof in a tunnel length direction. A step of excavating a tunnel having a larger diameter than the excavated portion by the rotary cutter plate while advancing the excavated portion with the propulsion portion elastically connected to the tunnel supported on the peripheral wall surface of the tunnel; co If by blowing a concrete drilling wall from the rear side of the cutter plate during excavation step through an opening in the radial direction are provided on the back outer peripheral wall of the cutter plate forming the concrete lining layer
At the rear end of the opening.
And cutting the thick portion of the concrete lining layer
To form a concrete lining layer with an inside diameter that can pass through
And while the excavated portion is supported by the already hardened concrete lining layer after this process , the process of releasing the support of the propelled portion from the tunnel peripheral wall surface and drawing the propelled portion toward the excavated portion is repeatedly performed. It is characterized by the following.

A second aspect of the present invention relates to another tunnel construction method according to the present invention, which is connected to an excavated portion having a rotary cutter plate disposed at a front end so as to be able to expand and contract in the tunnel length direction. A step of excavating a tunnel having a larger diameter than the excavated portion by the rotary cutter plate while advancing the excavated portion while supporting the propelled portion on the tunnel peripheral wall surface; Retracting the excavation section, and spraying concrete from the back side of the cutter plate to the excavation wall surface through a radial opening provided in the outer peripheral wall portion of the back surface of the cutter plate after the retreat of the excavation section. Forming the excavation part and moving the excavation part forward.After this step, the excavation part is supported by the already hardened concrete lining layer, and while the support of the propulsion part from the tunnel peripheral wall surface is released, the propulsion part is removed. It is characterized in repeatedly performing steps to draw the cut portion.

In the invention according to claim 2 ,
The invention according to Claim 3 is characterized in that concrete is sprayed onto the excavated wall surface from the back side of the cutter plate through a radial opening provided in the rear peripheral wall portion of the cutter plate to form a concrete lining layer, and the opening portion is formed. A step of cutting a thick portion of the concrete lining layer with a shaping cutter protruding from the rear end side to shape the concrete lining layer into an inner diameter through which the excavated portion can pass. . In any of the above methods, as described in claim 4 , the concrete may be sprayed only at necessary places on the excavated wall according to the rock quality.

According to a fifth aspect of the present invention, there is provided a tunnel excavator for performing the above-described tunnel construction method, wherein the excavation unit includes a front gripper which can be extended and contracted in a radial direction of a tunnel to be excavated, and the excavation unit. A thrust jack is provided at the rear of the propulsion unit via a thrust jack so as to be extendable and contractible in the tunnel length direction and has a rear gripper which is extendable and contractible in the tunnel radial direction. A cutter plate rotatably supported and provided with a digging blade in a tunnel traveling direction and a digging blade in a tunnel radial direction, and a rotation driving unit for the cutter plate and an unloading unit for excavating shears provided in the digging portion. a tunneling machine comprising comprising, on its front end with are arranged pivotally moving the concrete spray nozzle to face the tunnel peripheral wall surface in the circumferential direction within the opening The rear side of the opening, and the cutter plate
Swivels together and sprays on the excavation wall by the spray nozzle
Shaping cutter to cut the laid concrete lining
It has a mounting structure.

[0010] In the above-mentioned tunnel excavator, the invention according to claim 6 is characterized in that the shaping cutter is configured so that the protruding length from the outer peripheral wall portion of the cutter plate toward the excavation wall surface can be adjusted. .

[0011]

[Action] After the rear gripper is extended and pressed against the digging wall side to support the propulsion unit on the digging wall surface,
The excavation section is advanced by extending the thrust jack by taking a reaction force on the support section, and the front ground is excavated by a tunnel lengthwise excavation blade protruding from a rotary cutter plate attached to the front end of the excavation section. Excavation and excavation of the ground on the outer periphery of the cutter plate by a tunnel radial cutting edge protruding from the outer peripheral edge of the cutter plate to make the entire circumference of the tunnel or at least the upper half of the tunnel larger in diameter than the planned diameter. Excavate.

Further, during the excavation of the tunnel, the concrete plate is excavated from the concrete spray nozzle provided in the space on the back side of the cutter plate through the radial opening provided in the outer peripheral wall of the cutter plate. Concrete is sprayed on the immediately following excavation wall to form a concrete lining layer thicker than a predetermined thickness. In this concrete spraying operation, the openings are provided at small intervals in the circumferential direction on the outer peripheral wall of the cutter plate, while the concrete outlet of the nozzle facing the opening is reciprocated in the circumferential direction. Therefore, the concrete lining layer can be applied to at least the upper peripheral portion of the excavation wall surface. Further, the concrete lining layer is cut and shaped into a concrete lining layer having a predetermined thickness with a smooth surface by a shaping cutter protruding from a rear end side of the opening of the cutter plate that excavates while rotating. A gap is provided between the inner peripheral surface of the concrete lining layer and the excavated portion, through which the excavated portion and the propulsion portion can pass.

If the opening provided in the outer peripheral wall of the cutter plate is formed between rib flats provided radially at regular intervals in the circumferential direction over the entire periphery of the outer peripheral wall, the upper peripheral portion is formed. The rebound material of shotcrete falling into the back space of the cutter plate through the opening between the adjacent rib plates on the side of the part, the cut pieces cut by the shaping cutter, or the rock pieces that have fallen down are disposed in the space. Rebound material and rock mass pieces that have been received and unacceptable on the unloading start end of the unloading means consisting of a belt conveyer are stored between adjacent rib plates on the lower peripheral side and excavated. At the same time, after being lifted up by the rib plate according to the rotation of the cutter plate, it is dropped downward and received on the unloading start end of the unloading means.

After excavating a tunnel of a certain length in this way, the front gripper of the excavated portion is extended in the radial direction and pressed against the already hardened concrete lining layer of the excavated wall to support the excavated portion, The rear gripper of the propulsion unit is contracted to release the support of the propulsion unit against the concrete lining layer already constructed on the excavation wall surface, and then the thrust jack is contracted to draw the propulsion unit toward the excavation unit by a certain length. Thereafter, while the propulsion unit is again supported on the excavation wall side, the support on the excavation unit side is released, and then the thrust jack is gradually extended while excavating the ground by the rotary cutter plate and the peripheral wall surface immediately after excavation. Of the sprayed concrete lining layer, and shaping the concrete lining layer by a shaping cutter.

[0015] constant in such a tunnel construction method without spraying of the concrete during tunnel boring by the cutter plate, in the invention according to the claims 2 and 3, first, the cutter plate is advanced drilling unit After excavating the long tunnel, the excavated part was once retracted to the original excavation position, and then concrete was sprayed on the excavated wall from the spray nozzle through the opening provided in the outer peripheral wall on the back side of the cutter plate. A thick concrete lining layer is formed, and then the excavating part is advanced while rotating the cutter plate, and the concrete lining layer is formed into a digging part by a shaping cutter projecting from the rear end side of the opening. It may be shaped so as to have an inside diameter that allows the propulsion to pass.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, a specific embodiment of the present invention will be described.
M) is a longitudinal sectional side view of the tunnel excavator. The tunnel excavator has a front body 1 having a circular cross section as an excavation part in which a cutter plate 3 is rotatably mounted on a front end opening, and a rear part of the front body 1. A rear body 2 having a circular cross section, which is a propulsion section connected to an end portion so as to be extendable and contractible in the length direction of the tunnel, a thrust jack 4 connecting the front and rear body sections 1 and 2, and a front and rear body section 1 and 2 , A front gripper 5 and a rear gripper 6 respectively provided on the outer peripheral wall 3a of the cutter plate 3 and an opening 10 radially penetrating therethrough.
A concrete supply pipe 8 having a concrete spray nozzle 7 for spraying concrete on the tunnel excavation wall surface T facing the inner peripheral surface of the rear outer peripheral wall portion 3a at the rear side, and protrudingly provided on the rear end side of the opening 10. It comprises a shaping cutter 11, a rotation driving means 9 for the cutter plate 3, and a belt conveyor 12 which is an excavating chip discharging means.

The front body 1 has a front and rear partition plate in its front part.
The front gripper 5, which extends and contracts in the radial direction of the tunnel by means of a jack 15 at several places on the peripheral wall of the front body 1 between the front and rear bulkheads 13 and 14, is cut from the front body 1 by excavation wall T. It is attached so that it can appear and disappear toward. On the front surface of the cutter plate 3 disposed at the front end opening of the front body 1, an excavating blade comprising a central portion and a plurality of roller cutters for excavating the front ground at predetermined intervals in an outer circumferential direction from the central portion. 16
The cutter plate 3 is provided with a tunnel radially excavating blade 17 projecting obliquely forward toward the tunnel radial direction at regular intervals in the circumferential direction at the outer peripheral edge of the cutter plate 3. The excavating blade 17 in the tunnel radial direction is made expandable and contractable in the tunnel radial direction by a jack (not shown) so that the protruding length thereof can be adjusted. As shown in FIG. 2, the cutter plate 3 is provided with an excavation shear inlet 18 penetrating between the front and rear surfaces of the cutter plate 3 along a cutting blade 16 mounted in a radial direction.

Further, the outer peripheral portion of the cutter plate 3 is provided integrally with the outer peripheral wall portion 3a having a ring-shaped cross section and projecting rearward. Excavation chamber 19 for excavating the space surrounded by the inner peripheral surface of
The rib plates 20, 20,... 20 are arranged radially at regular intervals in the circumferential direction and are adjacent to the central portion in the longitudinal direction of the outer peripheral wall 3a, as shown in FIG. The openings 10 penetrating from the inner peripheral surface to the outer peripheral surface of the outer peripheral wall 3a are provided between the rib plates 20 at intervals of the thickness of the rib plate 20.

That is, the front end and the rear end of the outer peripheral wall 3a of the cutter plate 3 are separated at an interval in the front-rear direction, and the vertical length of the separated portion is between the inner and outer peripheral surfaces of the outer peripheral wall 3a. A plurality of rib plates 20 having a thickness substantially equal to the thickness of the rib plate 20 are radially arranged, and the front and rear end surfaces of the rib plate 20 are integrally fixed to the opposing surfaces of the front and rear ends of the outer peripheral portion 3a, and the adjacent rib plates 20 This has a structure in which the opening 10 is provided between 20. Further, a plurality of the above-mentioned shaping cutters are provided at regular intervals in the circumferential direction on the rear end outer peripheral surface of the outer peripheral wall 3a on the rear end side of the opening 10.
11 protrudes from the outer peripheral surface of the outer peripheral wall 3a. The shaping cutter 11 is configured such that a protruding length from the outer peripheral wall portion 3a toward the excavation wall surface T can be adjusted by a jack (not shown), similarly to the tunnel radial direction excavation blade 17 mounted on the cutter plate 3. ing. The outer end surface of the rib plate 20 is provided so as to be substantially flush with the outer peripheral surface of the outer peripheral wall 3a of the cutter plate 3. An internal gear 22 is fixed to the inner peripheral portion of the outer peripheral wall 3a of the cutter plate 3 via a ring member 21 via a ring member 21. Are rotatably supported between the inner and outer annular members 23 and 24 projecting therefrom.

The concrete spray nozzle 7 is integrated with the tip of a concrete supply pipe 8 rotatably inserted and supported in the center of the front partition plate 13 so that the pipe axis is aligned with the rotation center line of the cutter plate 3. The concrete supply pipe 8 is bent at a right angle from the tip of the concrete supply pipe 8 toward the opening 10 provided on the outer peripheral wall 3a of the cutter plate 3 so that the tip of the nozzle is positioned at the center of the inner opening end of the opening 10. Department. The tip of the concrete supply pipe 8 provided with the concrete spray nozzle 7 is rotated in the left-right direction by a motor 25 with a speed reducer mounted on the back of the central part of the front partition wall 13. The nozzle tip is configured to reciprocate in the circumferential direction along the inner peripheral surface of the outer peripheral wall 3a of the cutter plate 3. A universal joint 26 is provided on the back side of the motor 25 with a speed reducer.
Thus, the distal end of the contact supply pipe 8 is configured to be rotatable with respect to the rear side.

On the other hand, the rear trunk portion 2 has its front outer peripheral surface fitted to the rear peripheral inner peripheral surface of the front trunk portion 1 so as to be slidable back and forth, and has annular front and rear partition plates 27 and 28 therein. Is stretched,
The thrust jack 4 is provided at regular intervals in the circumferential direction between opposing surfaces of the front partition plate 27 and the rear partition plate 14 of the front body portion 1.
, And both ends of the thrust jack 4 are connected to opposing surfaces of the partition plates 14 and 27. In addition, rear trunk 2
The rear gripper 6, which expands and contracts in the tunnel radial direction by a jack (not shown), is mounted between the front and rear partition plates 27 and 28 so as to be able to protrude and retract from the rear trunk portion 2 toward the excavation wall surface T.
The rear grippers 6 are provided on both sides or the upper and lower portions of the rear body 2.

The rotation driving means 9 of the cutter plate 3 includes a cutter plate rotation driving motor 9a fixed between the front and rear partition plates 13 and 14 of the front body portion 1, and a small gear fixed to the rotation shaft of the motor 9a.
9b, wherein the small gear 9b is meshed with an internal gear 22 fixed to the back surface of the cutter plate 3;
The cutter plate 3 is rotated via the small gear 9b and the internal gear 22 by driving the 9a. Further, the belt conveyor 10 serving as the excavated waste discharging means has its front end disposed at the rear of the excavated waste intake chamber 19 of the cutter plate 3,
From the front end, the front and rear partition plates 13 and 14 of the front body 1 are pierced to the rear body 2 in a state of being inclined obliquely upward and toward the rear body 2, and on the front end of the belt conveyor 10. A hopper 29 that opens upward is provided.

A method of constructing a tunnel by the tunnel excavator constructed as described above will be described. The front gripper 5 of the front body 1 is press-bonded to a concrete lining layer C 'already formed on an excavation wall T described later. In this state, the thrust jack 4 is contracted to pull the rear trunk 2 toward the front trunk 1, and then the rear gripper 6 of the rear trunk 2 is pushed out in the tunnel radial direction by the extension of the jack, as shown in FIG.
As shown in (1), pressure is applied to the concrete lining layer C 'already constructed on the excavation wall T. Thus, the rear gripper 6
After the rear body 2 is supported on the inner peripheral surface of the contact lining layer C ′ through the, the front gripper 5 is contracted to release the pressure bonding to the concrete lining layer C ′, and the cutter plate rotation drive motor 9a is driven. When the cutter plate 3 is driven to rotate and the thrust jack 4 is extended, the propulsion reaction force of the front body 1 is supported on the concrete lining layer C 'side, and the cutter plate 3 is advanced while the front body 1 is advanced. As shown in FIG. 4, a constant length tunnel is excavated by a cutting blade 16 projecting in the tunnel length direction and a cutting blade 17 projecting in the tunnel radial direction. At this time, the excavation blade 17
Is adjusted by a jack, and the outer diameter of the tunnel excavation wall T excavated by the excavation blade 17 is set to a desired diameter that is larger than a predetermined diameter.

Further, during the excavation of the tunnel of a certain length, the concrete is supplied to the concrete supply pipe 8 so that the spray nozzle 7 allows the radial opening 10 formed in the outer peripheral wall 3a of the cutter plate 3 to be formed. Concrete is sprayed on the excavated wall surface T immediately after being excavated by the cutter plate 3 to form a concrete lining layer C having a thickness greater than a predetermined thickness. Concrete spraying by the spray nozzle 7 through the opening 10 is performed because the opening 10 is provided continuously over the entire circumference of the outer peripheral wall 3a of the cutter plate 3 via the thickness of the rib plate 20. In spite of the rotation of the cutter plate 3, always keep the spray nozzle 7 in one of the openings.
It can be carried out in a state of facing the excavation wall T side through 10, and the spray nozzle 7 is reciprocated to the left and right to perform only the places that require support according to the rock quality, or at least The concrete lining layer C is constructed on the upper half of the excavation wall T.

As described above, while the tunnel is excavated by the cutter plate 3 by the advancement of the front body portion 1, the concrete lining layer C constructed on the excavated wall surface T immediately after the excavation continues to the opening 10 of the cutter plate 3 It is cut and shaped into a concrete lining layer C ′ having a predetermined thickness by a shaping cutter 11 protruding from a rear portion. That is, since the cutter plate 3 excavates while rotating, the shaping cutter 11 also advances while integrally rotating in the circumferential direction of the excavation wall surface T, and moves the concrete lining layer C in the circumferential direction and the length direction of the tunnel. It is shaped into a concrete lining layer C 'having a smooth surface and a constant thickness, and the front and rear body parts 1 and 2 are formed between the inner peripheral surface of the concrete lining layer C' and the outer peripheral surface of the front body part 1. It is possible to pass through and secure a gap.

The shear excavated by the cutter plate 3 is:
The cutter plate 3 is taken from the sediment inlet 18 into the
Opening 10 between adjacent rib plates 20, 20 on the lower peripheral side
On the other hand, the rebound material and the rock pieces falling off the skin due to the spraying of the concrete from the spray nozzle 7 and the shavings by the shaping cutter 11 are formed in the opening provided in the outer peripheral wall 3a of the cutter plate 3. While falling through 10 and partly being received in the hopper 29, unacceptable rebound material and rock pieces that have fallen off are accommodated in the lower peripheral side opening 10 of the cutter plate 3 together with the above-mentioned excavation shears. After being lifted up by the plate surface of the rib plate 20 in accordance with the rotation of the cutter plate 3, when the plate surface of the rib plate 20 is inclined downward, it falls down from the rib plate 20 and falls down to And is placed on the conveyance start end of the belt conveyor 12 from the lower end of the opening, and is conveyed backward by the belt conveyor 10.

After the excavation of the tunnel of a certain length and the construction of the concrete lining layer C 'of a certain thickness on the excavation wall surface T, the rotation of the cutter plate 3 is stopped and the front gripper 5 of the front body 1 is extended. The rear body 2 is pressed against the excavated wall surface T or the concrete lining layer C ′ constructed on the excavated wall surface T, and then the rear gripper 6 of the rear body 2 is contracted, and then the thrust jack 4 is contracted. Is pulled toward the front body side by a certain length (see FIG. 6). Thereafter, while the rear body 2 is again supported on the excavation wall surface side, the support on the front body side is released, and then the rotary cutter plate 3 is gradually extended while the thrust jack 4 is gradually extended.
Excavation of the ground and formation of the sprayed concrete lining layer C on the peripheral wall surface immediately after the excavation, shaping of the concrete lining layer by the shaping cutter 11, and repeating this process to build a tunnel. .

In the above tunnel construction method, a sprayed concrete lining layer C 'having a constant thickness is formed on the excavated wall surface T together with the excavation of the tunnel. The tunnel can also be built by separately performing the construction process of C '. The method of constructing this tunnel will be described. The thrust jack 4 is contracted to pull the rear trunk 2 toward the front trunk 1, and the rear gripper 6 of the rear trunk 2 is extended to be supported on the excavation wall T side. By rotating the cutter plate 3 and extending the thrust jack 4, the excavating blade 16 protruding from the cutter plate 3 in the tunnel length direction and projecting in the tunnel radial direction on the cutter plate 3 while moving the front body 1. With the drilling blade 17 installed, a tunnel having a constant length larger than the planned diameter is drilled as shown in FIG.

Thereafter, by contracting the thrust jack 4, the front body 1 is temporarily retracted to the excavation start position as shown in FIG. In this state, concrete is sprayed from the spray nozzle 7 to the excavated wall surface T immediately after being excavated by the cutter plate 3 through a radial opening 10 provided in the outer peripheral wall portion 3a of the cutter plate 3, and a thickness greater than a predetermined thickness. The thick concrete lining layer C is formed. At this time, the spraying nozzle 7 is reciprocated to the left and right to perform only the portion that requires support according to the rock quality, or the concrete lining layer C is constructed at least in the upper half of the excavation wall T. .

After the concrete lining layer C is applied to the excavated wall surface T where spraying can be performed from the opening 10, the thrust jack 4
, The front body 1 is advanced, and the cutter plate 3
The concrete lining layer C continuous to the concrete lining layer C is constructed by spraying the concrete from the spray nozzle 7 to the excavation wall T on the front side through the opening 10 while rotating the concrete lining. The layer C is cut into a concrete lining layer C ′ having a predetermined thickness by a shaping cutter 11 protruding from a rear portion of the opening 10 of the cutter plate 3.
It is shaped (see FIG. 9).

When the cutter plate 3 reaches the face face, the forward movement of the front body 1 is stopped, and the front gripper 5 of the front body 1 is extended to extend the excavated wall surface T or the concrete formed on the excavated wall surface T. Crimping to the lining layer C ', then
After the rear gripper 6 of the rear trunk 2 is contracted, the thrust jack 4 is contracted to pull the rear trunk 2 toward the front trunk by a certain length. Thereafter, the rear trunk portion 2 is again supported on the excavation wall surface side, while the support of the front trunk portion side is released, and then, while the thrust jack 4 is gradually extended, a tunnel of a fixed length is excavated by the rotary cutter plate 3. Then, after retracting the front body 1 to the original excavation position, formation of the sprayed concrete lining layer C and shaping of the concrete lining layer by the shaping cutter 11 while moving the cutter plate 3 are performed. By repeating this process, a tunnel is constructed.

In this tunnel construction method,
After excavating a tunnel of a certain length by the cutter plate 3, the cutter plate 3 is once retracted, so that the concrete can be sprayed on the excavation wall T from the spray nozzle 7 during the retreat. The shears excavated by the cutter plate 3 are taken into the intake chamber 19 from the earth and sand intake port 18 and stored in the opening 10 between the adjacent rib plates 20 on the lower peripheral side of the cutter plate 3. After being scraped up by the rib plate 20 as described above, it is thrown into the hopper 29, and similarly, the rebound material and the rock mass pieces that fall off the skin by the spraying of the concrete from the spraying nozzle 7, and the shaping cutter 11 Of the cutter plate 3
3a, is dropped through the opening 10 provided in the lower hopper, is taken up by the rib plate 20 in accordance with the rotation of the cutter plate 3, and then falls downward to drop the hopper. It is received in the inside 20, is placed on the transport start end of the belt conveyor 12 from the lower end of the opening, and is conveyed backward by the belt conveyor 12 .

[0033]

As described above, according to the present invention, a large-diameter tunnel is excavated by a tunnel excavator and the excavated portion of the tunnel excavator is once retracted and then moved forward during or after excavation. Because concrete is sprayed on the excavation wall through the opening provided in the outer peripheral wall of the back face of the rotating cutter plate, concrete is sprayed on the excavation wall immediately after excavation on the excavation part side of the tunnel excavator. The spray support can be applied before the excavation wall is loosened, so that the concrete lining with a desired thickness and good quality can be prevented from falling off, and the dust generated when the concrete is sprayed can be diffused into the machine. There is no work environment.

Further, a thick lining layer is formed on the excavated wall by spraying concrete, and the lining layer is formed into a concrete lining layer having a constant thickness by a shaping cutter projecting from the rear end side of the opening. Because it is shaped into
The inner surface can be efficiently formed into a uniform concrete lining layer having a constant thickness and a uniform thickness. The concrete lining layer hardened to a certain thickness is present on the propulsion portion side of the tunnel excavator, and the propulsion is performed. The work on the part side can be performed safely and efficiently, and the rear gripper of the propulsion part can be securely pressed and supported on the flat inner peripheral surface of the concrete lining layer, so that the tunnel excavation work can be performed smoothly. is there.

In the outer peripheral wall portion integrally provided on the back side of the cutter plate, openings penetrating in the radial direction are provided at regular intervals in the circumferential direction and are surrounded by the outer peripheral wall portion. Since the concrete spray nozzle whose tip faces the above-mentioned opening is disposed so as to be pivotable in the circumferential direction in the space, the concrete spray nozzle is circumferentially moved along the inner peripheral surface of the outer peripheral wall. The concrete can be sprayed smoothly on the excavated wall surface through the opening while reciprocatingly rotating, and the lining layer of the sprayed concrete can be efficiently constructed.

In addition, since the opening is formed between the rib plates provided radially at regular intervals in the circumferential direction on the outer peripheral wall, the opening is cut by a rebound material of shotcrete or a shaping cutter. Cut pieces or rock pieces that have fallen down are dropped into the back space of the cutter plate through the opening between the adjacent rib plates on the upper peripheral side and stored between the adjacent rib plates on the lower peripheral side. It is possible to smoothly insert the cut pieces and the rock pieces that have fallen into the ribs plate along with the rotation of the cutter plate along with the excavated shears, throw them into the unloading start end of the unloading means, and unload them backward. it can.

[Brief description of the drawings]

FIG. 1 is a longitudinal side view of a tunnel excavator,

FIG. 2 is a front view of the cutter plate,

FIG. 3 is a longitudinal sectional front view of an outer peripheral wall portion of a cutter plate,

FIG. 4 is a simplified longitudinal side view for explaining a tunnel construction method,

FIG. 5 is a simplified longitudinal side view showing a state of shaping while spraying concrete,

FIG. 6 is a simplified vertical sectional side view showing a state in which the rear trunk portion has been drawn after spraying is completed;

FIG. 7 is a simplified longitudinal side view showing another embodiment of the tunnel construction method,

FIG. 8 is a simplified vertical sectional side view of a state in which a cutter plate is retracted.

FIG. 9 is a simplified vertical sectional side view showing a state in which a concrete lining layer is formed on a digging wall surface and is formed into a concrete lining layer having a constant thickness.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front trunk part 2 Rear trunk part 3 Cutter plate 3a Outer peripheral wall part 4 Thrust jack 5 Front gripper 6 Rear gripper 7 Spray nozzle 9 Rotation driving means 10 Opening 11 Shaping cutter 12 Belt conveyor 17 Tunneling digging blade 20 Rib plate C , C 'concrete lining

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-239000 (JP, A) JP-A-57-123397 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E21D 9/10 E21D 11/10

Claims (6)

(57) [Claims] An excavating section is moved forward with a propulsion section, which is connected to an excavating section having a rotary cutter plate provided at a front end thereof so as to extend and contract in a tunnel length direction, supported on a peripheral wall surface of the tunnel. A step of excavating a tunnel having a diameter larger than that of the excavation portion by the rotary cutter plate, and a radial direction provided on a rear outer peripheral wall portion of the cutter plate from the rear side of the cutter plate during the excavation step by the rotary cutter plate. Concrete is sprayed on the excavation wall surface through the opening to form a concrete lining layer, and the thick portion of the concrete lining layer is cut by a shaping cutter protruding from the rear end side of the opening. Shaping into a concrete lining layer with an inside diameter that allows the part to pass through, and after this step the excavated part is supported by the already hardened concrete lining layer, while the propulsion part from the tunnel peripheral wall surface And releasing the support to pull the propulsion section toward the excavation section. 2. The excavating section is moved forward with a propulsion section, which is connected to the excavating section having a rotary cutter plate provided at a front end thereof so as to be extendable and contractible in the tunnel length direction, supported on the peripheral wall surface of the tunnel. A step of excavating a tunnel having a larger diameter than the excavated portion by the rotary cutter plate, a step of retreating the excavated portion to the propulsion portion side after excavating a tunnel of a predetermined length, and A step of spraying concrete on the excavation wall surface from the rear side through a radial opening provided on the rear outer peripheral wall of the cutter plate to form a concrete lining layer and advance the excavation section; The step of unsupporting the propulsion section from the peripheral wall surface of the tunnel and pulling the propulsion section toward the excavation section while repeating the step of supporting the How to build a tunnel. 3. The excavating section is moved forward with a propulsion section, which is connected to the excavating section having a rotary cutter plate provided at the front end so as to be extendable and contractible in the tunnel length direction, supported on the peripheral wall surface of the tunnel. A step of excavating a tunnel having a larger diameter than the excavated portion by the rotary cutter plate, a step of retreating the excavated portion to the propulsion portion side after excavating a tunnel of a predetermined length, and A step of spraying concrete on the excavation wall surface from the back side through a radial opening provided in a rear outer peripheral wall portion of the cutter plate to form a concrete lining layer, and advancing the excavation portion while rotating the cutter plate Cutting the thick portion of the concrete lining layer with a shaping cutter protruding from the rear end side of the opening to shape the concrete lining layer having an inside diameter through which the excavated portion can pass, This A step of releasing the support of the propulsion section from the peripheral wall surface of the tunnel and pulling the propulsion section toward the excavation section while repeating the step of supporting the excavation section on the already hardened concrete lining layer after the step. Construction method. Blowing wherein concrete tunnel construction method according to claim 1, claim 2, or claim 3, characterized in that only the necessary places of the excavation walls in response to lithology. 5. A digging section having a front gripper radially extendable and retractable in a tunnel to be digged, and a tunnel radially connected to the rear of the digging section via a thrust jack so as to be extendable and contractible in a tunnel length direction. A propulsion unit having a rear gripper which is extendable and retractable in front of the excavation unit, and an excavation blade rotatably supported by the excavation unit via the opening and extending in a tunnel traveling direction and a tunnel radial direction excavation blade. A cutter plate, and a cutter plate rotating drive means and a cutting waste carry-out means provided in the excavation part, the tip of which faces the tunnel peripheral wall surface in the opening. The concrete spray nozzle is arranged so as to be pivotable in the circumferential direction and the rear of the above opening
To the spray nozzle
Cutting concrete lining layer sprayed on excavation wall
A tunnel excavator characterized by mounting a shaping cutter . 6. The tunnel excavator according to claim 5, wherein the shaping cutter is configured such that a protruding length from an outer peripheral wall portion of the cutter plate toward the excavation wall surface can be adjusted.