JPH08170486A - Tunnel excavated muck carry-out gantry - Google Patents

Abstract

PURPOSE: To shorten a construction period by carrying out the excavated muck of upper and lower benches efficiently in tunnel work by a two-stage bench cutting construction method so as to enable the execution of primary lining to the excavated wall surface, an invert concrete forming process, and the like abreast with one another. CONSTITUTION: A transporter 3 formed of a belt conveyor with the front half part tiltable downward is suspension-supported in the longitudinally movable state from a gantry body 1 of long horizontal frame shape formed by installing a front side stud 11 on an upper stage bench A in a two-stage bench and rear side studs 12 on the existing invert concrete C in such a way as to be travelable. The excavated muck of the working face ground of the upper and lower stage benches A, B is carried out backward by the transporter 3, and after carrying out, primary lining timbering, wire-netting, and the like are conveyed to the respective benches A, B by a traveling trolley disposed at the gantry body 1 so as to perform primary lining D on the excavated wall surface of the upper and lower stage benches A, B at the same time. Further in the lower space part of the gantry body 1, placing work of inverted concrete C is performed abreast with the work process of this primary lining D.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gantry for carrying out the excavation shear of upper and lower benches to the rear side in the tunnel construction in which the tunnel face is divided into an upper bench and a lower bench and the face ground of each bench is excavated. It is about.

[0002]

2. Description of the Related Art Conventionally, in a tunnel construction in which a tunnel section is divided into an upper half side bench and a lower half side bench and the face of each bench is excavated by a so-called two-stage bench cut method, After excavating the ground face of the upper bench with an appropriate excavating device and carrying out the excavation shear to the rear of the tunnel, assembling the support for the excavated wall surface of the bench part, tensioning the wire mesh, and concrete spraying work in sequence. Then, the face ground of the lower bench is excavated by an appropriate excavating device, this excavation shear is discharged to the rear of the tunnel, and as with the upper bench, the support work is assembled to the excavated wall surface and the wire mesh is stretched. , The concrete spraying work is done in sequence and temporary lining is performed. In addition, excavating the invert on the bottom of the tunnel behind the lower bench,
A concrete is cast into the invert and a secondary lining concrete is cast in the rear to construct a tunnel.

[0003]

However, according to the tunnel excavation by the two-stage bench cutting method as described above, a series of work from the excavation work of the face to the concrete spraying work on the excavation wall surface is performed in the upper bench. After the operation, the excavation work on the lower bench shifts to the concrete spraying work on the excavation wall surface, so the workability of tunnel excavation is poor and a long construction period is required.

Such a problem can be solved by excavating the face ground of the upper bench and the lower bench at the same time and carrying out the excavation slips of each by a sediment carrier such as a dump truck. If a sand carrier is driven near the excavation site in a tunnel with a narrow space, it will be dangerous because the sand carrier will be overwhelmed, and it will also hinder the invert excavation work and concrete placing work on the rear side. As a matter of fact, simultaneous drilling is difficult.

The present invention has been made in view of the above problems, and an object of the present invention is to carry out the excavation shear of the ground face of the upper bench and the lower bench to the rear side of the already placed invert concrete. In this way, the primary lining work on the excavated wall surface on both bench sides can be performed in parallel, and the concrete excavation work on the invert can be performed concurrently in the lower part of the excavation shear conveyance. It is to provide a sled-out gantry.

[0006]

In order to achieve the above object, a tunnel excavation shearing gantry of the present invention is a tunnel for excavating a ground face of both benches by dividing a tunnel face into an upper bench and a lower bench. It is a sled-out gantry used for construction, and the gantry body can run freely on the upper bench above and the rear invert on both the front end and both ends of the horizontal frame that is long in the length direction of the tunnel. The front pedestal and the rear pedestal to be supported are fixed to each other to form a front gate shape. A rail is fixed to the horizontal frame of the gantry body for almost the entire length, and the rail is slid out via rollers. It has a structure in which the device is suspended so that it can travel.

In the gantry, the shearing device may be a belt conveyor as described in claim 2, and in this case, as described in claim 3, the front half of the belt conveyor can be bent vertically. It is desirable to configure it. Further, instead of such a belt conveyor, as described in claim 4, a bucket whose bottom portion can be opened and closed may be used. As described in claim 5, the gantry body can travel in the tunnel length direction by the infinite track attached to the lower end of the front pedestal of the gantry body and the wheel attached to the lower end of the rear pedestal. The infinite crawler belt is vertically adjustable with respect to the front pedestal, while the wheels are movably supported by rails already laid on invert concrete.

Further, in the invention described in claim 6, while the laser oscillator is mounted on both end portions on the rear side of the gantry body, the light receiver is mounted on both end portions on the front side so as to face the laser oscillator. Is characterized by points, and
The invention described in claim 7 is characterized in that a trolley for transportation such as support work is disposed on the gantry body so as to be movable in the longitudinal direction.

[0009]

[Operation] A gantry is installed between the upper bench and the invert conveyor so that the gantry can travel freely, and the skid excavated by the excavator on both benches is provided by a conveyor such as a belt conveyor or a bucket provided on the gantry. The gantry is unloaded to the rear end, loaded into a waiting earth and sand carrier, and loaded. At that time, when the carrying device is composed of a belt conveyor and the front half of the belt conveyor is configured to be bendable up and down, the whole front of the belt conveyor is railed by making the front half horizontal in the extension direction of the rear half. After moving forward, the front end of the first half part is located on the upper bench and the excavation shear on the upper bench side is carried out by this belt conveyor, then the belt conveyor is retracted and the first half part is bent downwards so that the upper bench is on the lower bench. It is possible to carry out the excavation shear on the lower bench side by placing it on the lower bench side, and hold the bent front half on the lower bench to drop the excavated shear on the upper bench side into the lower bench, It can also be carried out backwards along with the excavation slide.

After the excavation of the upper and lower benches is carried out, the primary lining from the construction of the support work to the concrete spraying is performed in parallel on the excavated wall surface of each bench. At this time, by disposing the trolley in the gantry body so that the trolley can travel freely, the trolley can transport the primary lining member such as support and wire netting from the rear of the gantry body to the upper and lower benches. On the other hand, since the excavated sediment is carried out along the gantry body from the upper and lower bench side over the existing invert concrete on the rear side, there is an invert to be placed next below the gantry body in the meantime, Accordingly, the work of assembling the formwork and the work of placing concrete in the invert can be performed in parallel in the space below the gantry without being disturbed by the slip-out operation.

When the primary lining on the excavated wall surface of the predetermined tunnel length and the placing and hardening of the invert concrete are completed, the gantry is advanced and the work of carrying out the above-mentioned shear is performed again. It is to be noted that, as described in claim 5, the front pedestal is adjustable in vertical movement with respect to the infinite crawler belt at the lower end thereof, while as described in claim 6, at both end portions on the rear side of the gantry body. If the laser oscillator is equipped with light receivers at both ends on the front side, the height and posture of the gantry body can be kept constant at all times by allowing the laser light to be received by the light receiver. Is possible.

[0012]

Embodiments of the present invention will now be described with reference to the drawings.
1 to 3, reference numeral 1 denotes a gantry body composed of a horizontal frame that is long in the length direction of the tunnel T. The face part of the tunnel T is divided into an upper bench A and a lower bench B, respectively. The gantry body 1 has a length reaching from the upper bench A to a space above the invert concrete C on the rear side, and the pedestals 1 of the same length are provided on both sides of the front end thereof.
1, 1 and 11 are integrally fixed in a hanging state, and pedestals 12 and 12 longer than the front pedestals 11 and 11 are integrally fixed to both sides of the rear portion to form a front gate shape. is there. The horizontal frame body that constitutes the gantry body 1 is composed of a pair of upper and lower horizontal girder members 13, which are horizontally arranged on both upper sides of the tunnel T.
14 are integrally connected by longitudinal girders 15 at appropriate intervals in the length direction, and upper girder members 13, 13 are integrally connected by a lateral girder 16, and the space below is connected to a cutter loader described later. It is formed in a work space where people can freely go in and out and can easily perform work such as invert excavation and formwork assembly.

As shown in FIG. 2, the short pedestal 11 on the front end side that supports the front end portion of the gantry body 1 is, as shown in FIG.
The endless tracks (caterpillars) 17 running on the horizontal bottom surface of the upper bench A are attached to the lower ends of the pedestals 11 and 11 on both sides. This endless track 17 is driven by a motor 17a
It is attached to the lower ends of 11 and 11 via an elevating jack 18, and by extending and contracting the elevating jack 18, the pedestal
11 and 11 are moved in the vertical direction so that the height of the front end side of the gantry body 1 is adjusted to the height of the rear end side.

On the other hand, the rear pedestal 12 supporting the rear side of the gantry body 1 is, as shown in FIGS. 1 and 3, both side ends of the cross beam 16 at a position behind the center of the gantry body 1. The pedestal with the upper end fixed to the and the crossbeam near the rear end
Wheels running on rails 2 laid on already-inverted concrete C at the lower ends of these four pillars 12, which are composed of pillars each having upper ends fixed to both side ends of 16. 19 is rotatably supported. In addition, this wheel
Reference numeral 19 is configured to be positively driven to rotate by a drive motor (not shown) installed at a proper position of the gantry body 1.

Reference numeral 3 denotes a carrying device composed of a belt conveyor suspended from the gantry body 1 so as to be movable in the front-rear direction. As shown in FIG. 1 and FIG. , The suspension support rails 31, 31 are fixed over substantially the entire length of the gantry body 1, and a plurality of gate-shaped support frames 32 are attached to the suspension support rails 31, 31.
The lower ends of these gate-shaped support frames 32, 32 ... 32, which are suspended so as to be able to travel via bearing members 34 that axially support wheels 33 running above, and are arranged in parallel at appropriate intervals, are belt conveyor bodies. Rear horizontal conveyor frame 35 that houses the latter half of 3a
Are integrally fixed to both sides of the.

Further, at the front end of the rear horizontal conveyor frame 35, the rear end of the front tilting conveyor frame 36, which houses the front half of the belt conveyor main body 3a, is rotatably pivoted 37 in the vertical direction.
Then, the lower end of the chain block 38 is fixed to the frame body 32a fixed to the tilting conveyor frame 36, and the upper end of the chain block 38 is connected to the bearing member 34 running along the suspension rails 31 and 31. I am trying. Reference numeral 39 is a hopper attached to the front end of the tilting conveyor frame 36.

Therefore, by rotating the wheels 33 through an appropriate drive mechanism (not shown), the belt conveyor main body is rotated.
Rails for suspending the front and rear conveyor frames 35 and 36 that incorporate 3a
It is configured to be movable in the longitudinal direction of the gantry body 1 along 31, 31, and the tilting conveyor frame 36 is moved horizontally from the downward tilting state with respect to the rear horizontal conveyor frame 35 by operating the chain block 38. It is configured to undulate to the state. The belt conveyor main body 3a is endlessly driven by a driving means (not shown) such as a motor arranged at the rear end of the rear horizontal conveyor frame 35. The length of the carrying device 3 composed of this belt conveyor is formed to reach from the upper bench A above the front end of the existing invert concrete C.

The gantry body 1 is provided with trolleys 4 and 4 which run in the lengthwise direction of the gantry body 1 on both sides of the carrying device 3. This trolley 4 is attached to the lower surface of the gantry body 1 on both sides of the central portion of the cross beam 16 in the gantry body 1.
The trolley suspension support rail 5 is fixed over substantially the entire length of the trolley, and the trolley suspension support rail 5 is moved in the front-rear direction along the rail 5 by an appropriate drive mechanism (not shown) to transport the support work, the wire mesh, or the formwork, It is used to suspend. Further, an upper rail 6 is laid on the gantry body 1 over the entire length, and a concrete spraying machine 7 is arranged on the front side of the rail 6 and a ventilation axial fan 8 is arranged on the rear side thereof so as to run freely. In addition, work cages 9 are provided on both sides of the upper front end of the gantry body 1 as shown in FIG. Reference numeral 10 is a ventilation duct connected to and communicating with the ventilation axial fan 8.

Reference numeral 20 denotes both pedestals 12 and 12 on the rear side of the gantry body 1.
, 21 is a laser oscillator mounted on the front surface of the upper end of the gantry body 1, and is a light receiver mounted on the rear surface of the upper ends of the pedestals 11, 11 on the front side of the gantry body 1 so as to face the laser oscillator 20. Then, the front pedestal 11 is moved up and down and adjusted, and the laser beam from the laser oscillator 20 is received.
By making 21 receive the light, the posture of the gantry body 1 such as height and levelness is always kept constant.

A method of excavating the tunnel T using the gantry thus constructed will be described. The upper half of the face of the tunnel T is divided into the upper bench A and the lower half is divided into the lower bench B. The face of the upper and lower benches A and B is excavated in the tunnel T for a certain length after excavation. ,
The excavation shear is removed by the gantry body 1, and after the displacement is removed, the primary lining D from the construction of the support work to the concrete spraying is performed in parallel on the excavated wall surfaces of the upper and lower benches A and B, while At the bottom of the tunnel behind the lower bench B, the excavation of Invert E to the concrete C
The placing work is performed in parallel with the construction work of the primary lining D from the removal of the excavation shear.

A fixed length of the face of the face for the upper and lower benches A and B (the distance between the support works is about 1 m).
The work process from the excavation of No. 1 to the primary lining D is defined as one cycle, and 5 to 10 cycles are performed, and the work process from the excavation of Invert E to the concrete placement, which is carried out during this cycle, is sequentially carried out as the construction length of one span. The tunnel is excavated by repeating the above-mentioned work steps during the span.

The excavation of the face ground of the upper bench A is carried out by a cutter loader 40 which is provided with an arm 42 having a cutter 41 at its tip so as to be vertically rotatable and a belt conveyor 43 at the rear end of the arm 42. The arm 42 is provided with a chain conveyor (not shown) for scraping up the earth and sand excavated by the cutter 41 and conveying it to the belt conveyor 43. On the other hand, excavation of the face ground of the lower bench B is performed by the excavator / loader 50 composed of a backhoe. Next, the tunnel excavation work sequence will be described based on FIG. 8 in which the work steps of the gantry, upper bench A, lower bench B, and invert E are divided.

First, when the curing of the invert concrete E for one span is completed, the invert concrete E
The gantry body 1 is moved upward by the supporting and supporting interval (about 1 m). Hereinafter, by repeating this forward movement as one cycle for 5 to 10 cycles, the wheel 19 of the rear pedestal 12 of the gantry body 1 travels on the existing invert concrete E, while the front pedestal 11 of the gantry body 1 travels. Infinite Track 17
Is driven on the horizontal bottom surface of the upper bench A by the drive motor 17a, and the gantry body 1 moves forward for the next cycle.

On the other hand, when the carrier device 3 standing by on the rear side of the gantry body 1 is advanced along the rails 31 and the tilt conveyor frame 36 on the front side reaches the rear end of the lower bench B, the tilt conveyor is moved. The frame 36 is rotated downward so that its front end is set on the rear end of the lower bench B. In the upper and lower benches A and B, the face ground is simultaneously excavated by the cutter loader 40 and the excavator / loader 50, and the excavation shear of the upper bench A is conveyed from the rear to the lower bench B by the belt conveyor 43 of the cutter loader 40. Drop and deposit on top.

The hopper mounted with the excavation slide on the upper bench A side together with the excavation slide on the lower bench B side by the excavator / loader 50 at the front end of the tilting conveyor frame 36 of the carrier device 3.
The gantry main body 1 from the tilting conveyor frame 36 through the horizontal conveyor frame 35 by placing it on the conveyance start end of the belt conveyor main body 3a of the conveying device 3 which is placed in the hopper 39 and facing the opening lower end of the hopper 39. Then, the gantry body 1 is transferred to a carrier 60 such as a dump truck waiting at the rear end of the gantry body 1 and carried out behind the tunnel.

In this way, when the face ground of the upper and lower benches A and B is excavated and removed by the tunnel length corresponding to the support interval, the primary lining D is formed on the excavated wall surface of these upper and lower benches A and B. I do. The divided support and wire mesh for the primary lining are conveyed from the rear of the gantry body 1 to the upper and lower benches A and B by the trolleys 4 and 4 arranged in the gantry body 1, and the work cage 9 After the worker performs the wire netting work between the construction of the support work on the excavated wall surface and the existing support work on the top surface of the support work, the gantry body 1
The primary lining work is completed by spraying concrete up to the thickness of the supporting work with the spraying machine 7 arranged on the upper surface of the front end of the.

On the lower bench B side, before performing the primary lining D, the tilting conveyor frame 36 of the carrying device 3 is hung up by the chain block 38 to be in the same horizontal state as the horizontal conveyor frame 35 on the rear side. , The entire carrier device 3 is moved to the rear side of the gantry body 1 and kept on standby so as not to interfere with the primary lining work. Further, since dust is generated by the spraying machine 7 when the concrete is sprayed, after the spraying work on the upper bench A side, the lower bench B is continuously blown.
It is desirable to perform spraying work on the side.

When the one-step working process from the excavation of the face ground to the upper and lower benches A and B to the primary lining is completed in this way, the forward movement of the gantry body 1 and the face ground for the support interval are performed again in the same manner as above. Perform one cycle of work from excavation to primary lining, and perform this work process for 5-10
Repeat the cycle.

On the other hand, in the invert section, the above 5
In parallel with the 10-cycle work process, the concrete is placed into the invert E, which has been continuously excavated for one span on the front end side of the existing invert concrete C before the first cycle. In this work, the form 70 removed from the invert concrete C that was placed last time after being hardened is suspended by the trolley 4 arranged in the gantry main body 1 and conveyed to a position above the invert E. , Lower it and install it.

As shown in FIG. 1, FIG. 4 and FIG. 5, this form 70 is composed of a plurality of horizontal girders 71, which are long in the tunnel length direction, and are arranged side by side at appropriate intervals in the length direction. A girder 71 is integrally connected to the girders 71, 71 on the lower surface of the front end of the girders 71, and a gable form 73 is integrally hung, and the girder 71 projecting forward from the gable form 73 is expanded and contracted by a jack. Free leg
In addition to mounting 74, leg 76 with roller 75 is also mounted on the rear end of girder 71 by means of a jack. Further, side wall forms 77, 77 are attached to both side ends of the juxtaposed beam 72, and a groove forming passage forming form 78 is provided at a proper position between the girders 71, 71 from the gable form 73 rearward. It is arranged toward.

The form 70 having the above-described structure is inverted E
Align the front leg 74 with the lower bench B according to the predetermined position of
While installing on the bottom of the front end of the invert E in the vicinity, install the rear leg 76 on the front end of the existing invert concrete C, and adjust the height with both legs 74, 76 to excavate the wife form 73 etc. It is brought into close contact with a predetermined part of the surface. Then, concrete C is placed in the invert E from the rear side of the gantry body 1 by a concrete mixer truck or the like.

During the curing of the cast concrete C and before hardening, after forming the primary lining D for one span for the upper and lower benches 1 and 2, the bottom portion of the lower bench B is excavated and piled. The invert 50 is excavated into a curved shape in a tunnel shape and the next one span of invert is excavated. This excavation slide may be carried out rearward by the carrying device 3 while excavating, but since the amount of excavation is relatively small, it is once deposited on the lower bench B and the excavation of the face ground of the lower bench B is carried out. It can be carried out by the carrier device 3 together with the earth and sand. In addition, as shown in FIG. 5, a secondary lining is applied to the thickness portion F between the primary lining D and the side wall forms 77, 77 at the rear of the tunnel.

As described above, the work steps from excavation of the face ground to the upper and lower benches A and B to the primary lining D are sequentially performed for several cycles to advance the tunnel for one span, and at the same time, 1 The work from the invert excavation to the concrete placing on the lower bench B side is performed continuously with the existing invert concrete E in the length part of the span, and the tunnel formation of this unit span and the invert concrete E
The construction of the tunnel is repeated in sequence to build the tunnel. After the concrete is hardened, the running rails 2 of the gantry body 1 are laid on the invert where the concrete is placed.

FIG. 9 shows a work process diagram of another excavation method for the upper and lower benches A and B. In the above embodiment, the excavation of the face ground of the upper and lower benches A and B was performed at the same time. In the above, after excavating the face ground of the upper bench A for the support interval and carrying out the excavation shear to the rear by the carrying device 3, the face ground of the lower bench B is excavated for the support interval and carrying the excavated shear. It is characterized in that it is carried out rearward by the device 3.

That is, the tilting conveyor frame 36 of the carrying device 3 is lifted up to a horizontal state by the chain block 38, and in this state, the carrying device 3 is advanced along the rails 31 to move the front end of the conveyor frame 36 to the upper bench A. The slide excavated by the cutter loader 40 is placed in the hopper 39 so as to face the rear end portion, and is carried out rearward by the belt conveyor main body 3a. Then, the carrier device 3 is retracted, the tilting conveyor frame 36 is tilted downward by the chain block 38, and its lower tilted end is positioned on the rear end of the lower bench B, and the excavator / loader 50 excavates. The earth and sand of the face of the lower bench B is carried out rearward by the belt conveyor body 3a of the carrying device 3.

After the removal of the sand from the upper and lower benches A and B is completed, transportation of support work, construction, wire mesh installation, and primary lining by concrete spraying are performed on the respective excavated wall surfaces in the same manner as in the above embodiment. As described in the above embodiment, this process is regarded as one cycle, and the primary lining work for one span and the placing of the invert concrete C are performed. Other work processes and the like are similar to the work process of FIG. According to this method, it is suitable when the amount of excavation of the face ground of the lower bench B is large, and it is possible to avoid the problem that a long working time is required if it is removed together with the excavated soil on the upper bench A side. Further, when excavating the upper bench A side, since the tilting conveyor frame 36 is lifted in the horizontal state, the working space on the lower bench B is widened, and the movement of the invert form 70, the assembly, and the concrete placing work are performed on the upper stage. It can be easily and safely performed when excavating the bench A. In the above embodiment, the excavation of the upper and lower benches A and B is carried out by the single carrier device 3. However, the two carrier devices are arranged on the gantry body 1 so that they can run in parallel. The excavation shear of the upper bench A may be carried out by one carrying device, and the excavation shear of the lower bench B may be carried out by the other carrying device at the same time.

FIGS. 6 and 7 show another example of the carrying device 3. In the above embodiment, the carrying device 3 is constituted by a belt conveyor, and the conveyor frames 35, 36 are suspended on the gantry body 1 so as to be freely movable. In this example, the electric chain block 82 is attached to the suspension support rails 81, 81 fixed to both sides of the upper and lower surfaces of the gantry body 1 over the entire length of the gantry body 1.
A transporting device 3'comprising buckets whose bottoms are freely opened and closed by suspending trolleys 83 equipped with
Is suspended. As described above, when the transporting device 3'comprising a bucket is adopted instead of the transporting device 3 including the belt conveyor, it becomes possible to transport the excavated earth and sand containing water, which is difficult to carry out by the belt conveyor. Other structures and operations are the same as those of the gantry shown in FIG.

[0038]

As described above, according to the tunnel excavation shearing gantry of the present invention, the slit unloading used for tunnel construction for dividing the tunnel face into an upper bench and a lower bench and excavating the face ground of both benches. In the gantry, the gantry body has front pedestals that are movably supported on the upper bench and the rear invert at both front and rear ends of a horizontal frame that is long in the tunnel length direction. It is formed in the shape of a front gate that is fixed to the rear pedestal, and the rail is fixed to the horizontal frame of the gantry body for almost the entire length, and the slide carry-out device is hung on the rail so that it can travel. Since it is installed, the excavation of the ground face of the upper and lower benches is carried out by the transportation device installed on the gantry that is installed in the erected state from the upper bench to the existing invert concrete. It is possible to smoothly and smoothly carry out each rear of the tunnel to the rear side of the tunnel, and it is possible to carry out the primary lining from the construction of the support work to the excavated wall surface of the upper and lower benches to the spraying of the kuncrete in parallel. The tunnel excavation work can be performed efficiently and the construction period can be significantly shortened.

Furthermore, since the gantry has its front end side pedestal movably supported on the upper bench and the rear pedestal movably supported on the invert concrete behind the face of the face, the upper and lower benches are The excavation slide can be carried out efficiently while advancing according to the length of the primary lining process for the excavated wall surface, and the invert excavation work and the assembly of the formwork for the invert in the space below the gantry. , Concrete pouring work,
Inverted concrete can be created in parallel with the primary lining work on the upper and lower bench sides without hindering the excavation work carried out, and the work efficiency of tunnel excavation can be further improved.

Further, by disposing a transportation trolley such as a supporting structure on the gantry so that the trolley can travel freely, the members necessary for the primary lining can be easily provided from the rear side of the tunnel to the upper and lower bench side through the gantry. It can be efficiently transported, and moreover, it can be used for suspending and assembling a concrete placing formwork for an invert, and the workability is improved. Furthermore, if a laser oscillator is attached to both rear columns of the gantry and a light receiver is attached to both front columns, the height and posture of the gantry can be kept constant by allowing the laser beam to be received by the light receiver. It is possible to excavate tunnels with high accuracy.

[Brief description of drawings]

FIG. 1 is a simplified side view of a gantry used for tunnel excavation,

FIG. 2 is an enlarged vertical front view of the front end side thereof,

FIG. 3 is an enlarged vertical front view of an intermediate portion thereof,

FIG. 4 is a vertical sectional side view showing a formwork installation state with respect to an invert;

FIG. 5 is a partially cutaway vertical front view thereof,

FIG. 6 is a simplified side view of a gantry using a bucket as a transport device,

FIG. 7 is an enlarged vertical front view thereof,

FIG. 8 is a block diagram showing a work process of tunnel excavation,

FIG. 9 is a block diagram showing another work process of tunnel excavation.

[Explanation of symbols]

 T tunnel A upper bench B lower bench 1 gantry body 11 front leg Note 12 rear pedestal 2 rail 20 laser oscillator 21 light receiver 3 carrier device 31 suspension rail 33 wheel 35 rear horizontal conveyor frame 36 front tilt conveyor frame

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasutoshi Hagiwara 2-2-2 Matsuzaki-cho, Abeno-ku, Osaka City Okumura-gumi Co., Ltd. Stock company Okumura Gumi

Claims (7)

[Claims] 1. A sled-out gantry used for tunnel construction in which a tunnel face is divided into an upper bench and a lower bench to excavate the face ground of both benches, and the gantry body has a long horizontal length in the tunnel length direction. It is formed in a front gate shape in which front and rear pedestals are fixed to each other so that they can run freely on the upper bench and on the rear invert at both front and rear ends of the frame. A tunnel excavating shear unloading gantry characterized in that a rail is fixed to a horizontal frame of the gantry main body over substantially the entire length, and a shear unloading device is movably suspended on the rail via rollers so as to be able to travel. 2. The tunnel excavation shear unloading gantry according to claim 1, wherein the shear unloading device is a belt conveyor. 3. The tunnel excavation shear carrying-out gantry according to claim 2, wherein the front half of the belt conveyor is vertically bendable. 4. The tunnel excavation shear unloading gantry according to claim 1, wherein the shear unloading device is a bucket whose bottom portion can be opened and closed. 5. The gantry body can travel in the tunnel length direction by an infinite track attached to the lower end of the front pedestal and a wheel attached to the lower end of the rear pedestal. 2. The tunnel excavation shear unloading gantry according to claim 1, wherein the wheels are vertically adjustable with respect to each other, while the wheels are movably supported by rails on the laid concrete. 6. The laser oscillator is mounted on both end portions on the rear side of the gantry body, while the light receiver is mounted on both end portions on the front side so as to face the laser oscillator. The tunnel excavation slide-out gantry described. 7. The tunnel excavation shearing / unloading gantry according to claim 1, wherein a trolley for transportation such as support work is disposed on the gantry body so as to be movable in the length direction.