JP3236564B2 - Tunnel support unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a support unit for supporting a rock excavation wall surface excavated by a tunnel excavator.

[0002]

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

[0003]

However, according to the above-mentioned prior art, the assembling work of the ring-shaped support body and the work of stretching the lining member require time and effort, which not only reduces the working efficiency, but also reduces the work efficiency. There is a problem that skill is required for the work, and furthermore, there is a possibility that the rock may collapse during the work of stretching the lining member, which is extremely dangerous. For this reason, a rectangular frame is formed by integrally connecting both ends of a pair of front and rear steel materials curved in an arc shape in the tunnel circumferential direction with a straight steel material, and a fall prevention member such as a wire mesh is formed on the frame. Stretched support units have been developed.

According to this support unit, a ring-shaped support liner can be easily assembled by sequentially connecting a plurality of support units with the front and rear steel materials curved in a circular arc shape in the tunnel circumferential direction. However, tunnel excavators that excavate rock usually use a rear gripper pressed against the tunnel excavation wall to receive the excavation reaction force and extend the propulsion jack to excavate the tunnel. When the reaction force is applied to the tunnel excavation wall, the straight steel material forming the steel frame of the support unit prevents the rear gripper from crimping to the tunnel excavation wall, and the tunnel excavator may not be able to excavate There is a point.

When a reaction force is applied to the wall surface of the tunnel excavation, the rear gripper is pressed against the wall surface of the tunnel excavation through a fall prevention member such as a wire mesh stretched over the support unit. When the rock is a loosely collapsed rocky ground, the pressing force of the rear gripper against the rock is weakened, and the propulsion reaction force required to propel the tunnel excavator cannot be obtained.

For this reason, it is only necessary to increase the pressing force of the rear gripper to swell and deform the collapsible member to the rock side, thereby consolidating the loose rock ground and increasing the locking force with the rear gripper. Since the support unit is formed in a rectangular frame by a straight steel material between both ends of the front and rear arc-shaped steel materials, and the four-sided peripheral portion of the collapsible member is fixed to this frame, the pushing of the rear gripper is performed. When the collapse preventing member is swelled and deformed by the pressure, the front and rear arc-shaped steel materials are curved and deformed in a direction approaching each other, so that there is a problem that the function as a support for the tunnel excavation wall surface cannot be exhibited.

Further, when excavating a curved tunnel portion, it is necessary to use a tapered support unit in which the interval between the front and rear arc-shaped steel materials becomes narrower or wider as going from one end side to the other end side in the tunnel circumferential direction. However, the rectangular frame-shaped support unit as described above cannot be adapted to support the curved tunnel portion, and the cost increases because a new taper support unit must be manufactured. Further, there is a problem that a rectangular frame formed by connecting both ends of a front and rear arc-shaped steel material with a straight steel material has a large weight and is inferior in handleability and transportability.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and its purpose is to facilitate the handling and to perform the construction easily and accurately. It is an object of the present invention to provide a tunnel support unit which can be surely performed and can be easily constructed on an excavation wall surface of a curved tunnel portion at a site in accordance with the curvature of the tunnel.

[0009]

In order to achieve the above object, a tunnel support unit according to a first aspect of the present invention comprises a pair of arc-shaped steel members arranged at an interval in front and rear, and a pair of arc-shaped steel members. It consists of a collapse preventing member that is extended between the arcuate steel, before these together have between opposite ends of the arc-shaped steel longitudinal is opened in the circumferential direction without connected by straight steel
A spacing member is detachably connected between the rear arc-shaped steel materials.
Of the front and rear edges of the collapse prevention member.
The edge of any one of the arc-shaped steel material corresponding to the edge
It is structured to be movable .

[0010] The invention according to claim 2 of the present invention includes a pair of arcuate steel which is arranged at intervals in the front-rear, and collapse prevention member which is bridged between these front and rear arcuate steel Tona
Connecting the opposite ends of the front and rear arc-shaped steel materials with straight steel materials
And open in the circumferential direction without
A spacing member is detachably connected between the rear arc-shaped steel materials.
In addition, the collapsing prevention member is
Divided into semi-collapse prevention member and front edge of front half collapse prevention member
Part is fixed to the outer peripheral surface of the front arc-shaped steel material,
Secure the rear edge of the fall prevention member to the outer peripheral surface of the rear arc-shaped steel material.
And the opposite ends of the front-rear collapse prevention members are attached to each other.
And have a structure in which they are overlapped by an appropriate width .

[0011]

A ring-shaped support liner is assembled by sequentially connecting a plurality of support units having front and rear steel materials curved in an arc shape in the tunnel circumferential direction between opposing end surfaces of the opposed arcuate steel materials. The excavator is supported with the outer peripheral surface in contact with the wall excavated by the excavator.

When assembling such a support liner,
At least as a support unit arranged on the tunnel excavation wall surface corresponding to the rear gripper of the tunnel excavator, only the fall prevention member is stretched between the front and rear arc-shaped steel materials, and between the ends of these front and rear arc-shaped steel materials. Uses a support unit not provided with a straight steel material, and the connection between the support unit and the support unit adjacent to the support unit in the tunnel circumferential direction is performed by a joint plate fixed to the end face of the front and rear arc-shaped steel material. This is performed by joining the pieces in a butt shape and connecting them by connecting means such as bolts and nuts.

The support unit is not connected between the opposite ends of the front and rear arc-shaped steel members by the straight steel members.
Since the structure is such that the collapse preventing member is merely stretched between the front and rear arc-shaped steel materials, there is a possibility that the space between the front and rear arc-shaped steel materials may be contracted and deformed during construction. Therefore, it is desirable to connect the facing surfaces of the front and rear arc-shaped steel materials in advance with a spacing member, and the spacing member keeps the width of the supporting unit constant in the tunnel length direction and thereby connects the supporting units with each other. The connection by the joint plate can be easily and smoothly performed. In the case where the distance holding member becomes an obstacle during the operation of the rear gripper, it may be removed after connecting the support units.

As described above, as the support unit constructed to correspond to the tunnel excavation wall surface to which the rear gripper is crimped, a straight steel material is provided between the ends of the front and rear arc-shaped steel materials so as not to hinder the crimping of the rear gripper. In this case, when one end between the front and rear arc-shaped steel materials in the tunnel circumferential direction in the support unit does not interfere with the crimping of the rear gripper, a straight steel material is used between the ends. A support unit that is integrally connected may be used.

Further, a fall prevention member such as a wire mesh may be provided on all the support units constituting the support liner. However, the loose rocks and the fall of the surface of the rock may occur on the upper peripheral side of the tunnel. For this reason, a fall prevention member is stretched only on the support unit that constitutes the upper half of the support liner, and the lower half is formed by a support unit made of a front and rear arc-shaped steel material without a fall prevention member. This configuration can reduce material costs and improve workability.

The ring-shaped support liner is installed every time the tunnel excavator excavates for a certain length. When the tunnel excavator excavates, the support liners are provided on both sides of the existing support liner supporting the tunnel excavation wall surface. The rear gripper is pressed between the front and rear arc-shaped steel materials by a collapsing prevention member stretched between the front and rear arc-shaped steel materials, and the collapsing prevention member is pressed against the excavation wall surface to support the propulsion reaction force on the excavation wall surface, In this state, the propulsion jack is extended while excavating while rotating the cutter head.

In this case, since the straight steel material long in the length direction of the tunnel is not provided between the ends of the front and rear arc-shaped steel materials of the support unit as described above, the extension direction of the rear gripper is changed to the front and rear arc-shaped steel materials. The rear gripper can be surely pressed against the tunnel excavation wall via the fall prevention member only by making the gap between them. In addition, since the rear gripper can be moved in the length direction of the tunnel by the expansion and contraction of the propulsion jack, the direction of extension between the front and rear arc-shaped steel materials of the support unit can be easily matched.

When the tunnel excavation wall surface is hard rock, the rear gripper is pressed against the hard rock through the collapse prevention member without substantially bulging and deforming the collapse prevention member of the support unit, thereby propelling the tunnel excavator. Since the reaction force can be reliably taken, the front and rear edges of the fall prevention member may be fixed to the front and rear arc-shaped steel material, but if the rock on the tunnel excavation wall surface is loose, the rear gripper should be soft. Unless the rock is densified into a compact rock, the tunnel excavator cannot take a certain propulsion reaction force. For this reason, the collapsing prevention member of the support unit is swelled and deformed by the rear gripper and presses against soft rock.
It is configured as follows .

At this time, as a fall prevention member of the support unit pressed by the rear gripper, a structure in which the center of the fall prevention member is divided in the circumferential direction of the tunnel and the divided ends overlap each other, that is, two sheets The front end of one of the collapsible members is fixed to the arcuate steel material on the front side, and the rear end of the other collapsible member is fixed to the arcuate steel material on the rear side. If the opposite ends of the prevention member are overlapped with each other, the overlapped portion swells and deforms while sliding against each other due to the pressing force of the rear gripper, and the tensile force during the deformation almost acts on the front and rear arc-shaped steel materials Therefore, it is possible to provide an accurate and strong support structure without a risk that the front and rear arc-shaped steel materials are bent and deformed in a direction in which they are attracted to each other.

Further, stretched the collapse prevention members one was between the front and rear arcuate steel, when are fixed, among the front and rear edges of the collapse prevention members, said one of the edge portions If it is attached so as to be relatively movable in the front-rear direction with respect to the arc-shaped steel material corresponding to the edge, the edge of the collapsible preventing member bulges and deforms while being pulled inward according to the pressing force of the rear gripper. However, transmission of the pulling force to the front and rear arc-shaped steel materials can be blocked.

Further, in the support unit , as described in claim 2, the fall prevention member is simply stretched in a state of being erected without connecting the both ends of the front and rear arc-shaped steel members with a straight steel material. And the tapered support unit that gradually narrows or widens the space between these front and rear arc-shaped steel materials from one end side to the other end side, that is, in the tunnel circumferential direction. Since the width and the angle can be easily changed, the support liner along the excavation wall surface of the curved tunnel can be easily and accurately constructed.

[0022]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to FIG. 3 show a support unit A according to a first embodiment of the present invention . A steel material 1 made of an arc-shaped curved U-shaped channel steel,
A rock-fall prevention member 3 in which rod-shaped metal wires are combined in a grid between outer circumferential surfaces of the front and rear arc-shaped steel materials 1 and 2 which are curved in a convex arc.
Is stretched in an erected state, and the front and rear circular arc-shaped steel materials 1,
Openings 4 and 5 are formed in the circumferential direction between the two opposed ends without being connected by a straight steel material. Further, a rectangular joint plate 6 having a bolt hole 7 formed in the center is fixed to both longitudinal end surfaces of the front and rear arc-shaped steel materials 1 and 2, and the front and rear arc-shaped steel materials 1 and 2 are fixed to each other. Bolt holes 8 are formed in the facing surface at regular intervals in the length direction.

A cylindrical locking member 10 is fixed to the opposed surfaces of the front and rear arc-shaped steel materials 1 and 2 at appropriate intervals in the circumferential direction of the tunnel, and the locking metal members 10 and 10 opposed to each other in the front and rear direction. The front and rear arc-shaped steel materials 1 and 2 are configured to be maintained at a constant interval by engaging the bent portions 9a and 9a at both ends of the interval holding member 9 formed of a steel rod. In addition, as the fall prevention member 3 stretched between the front and rear arc-shaped steel materials 1 and 2, in addition to the above-described structure in which the metal wires are combined in a lattice shape, the strength of a wire mesh, a metal plate-like material, a canvas, and the like is provided. Cloth material may be used.

The fall prevention member 3 is made of the above-mentioned front and rear arc-shaped steel material 1,
2 is formed in a flat rectangular shape having a length equal to the length of the circular arc and a fixed width, and the longer side is defined as a front and rear edge .
As shown in FIG. 3 , one of the front and rear edges is fixed to the outer peripheral surface of one arc-shaped steel material, and the other edge is relatively movable in the front-rear direction with respect to the outer peripheral surface of the other arc-shaped steel material. mounted
I have. As means for attaching the edge of the fall prevention member 3 so as to be relatively movable in the front-rear direction with respect to the outer peripheral surface of the arc-shaped steel material, the edge may be simply placed on the outer peripheral surface of the arc-shaped steel material. The mounted portion may be covered with a band (not shown) or the like, and may be slidably held between the band and the outer peripheral surface of the arc-shaped steel material. In any case, the front and rear arc-shaped steel materials 1 and 2 are, as described above, attached to the locking metal fittings 10 and 10 fixed to the opposing surfaces thereof at both end bent portions 9 of the spacing member 9.
By engaging a and 9a, they can be connected in a juxtaposed state with a certain interval. The support unit shown in FIG.
As A _1, it may have been stretched in a bridged state collapse prevention members 3 only half of the tunnel circumferential direction of the front and rear arcuate steel 1,2.

FIG. 5 shows the support unit A shown in FIGS.
Shows a modification of, in this支保unit A _2, has a structure obtained by dividing the collapse prevention members 3 in the first half of collapse prevention members 3A and late collapse preventing member 3B. That is,
The front edge of the first half fall prevention member 3A is fixed to the outer peripheral surface of the front circular arc-shaped steel material 1 by welding or the like, while the rear end edge of the second half collapse prevention member 3B is welded to the outer peripheral surface of the rear circular arc steel material 2. Therefore, the front arc-shaped steel material 1 to which the first half fall prevention member 3A is fixed and the rear arc-shaped steel material 2 to which the rear half fall prevention member 3B is fixed have a structure separated from each other. The front and rear arc-shaped steel materials 1 and 2 can be connected in a state where a predetermined width interval exists between the front and rear arc-shaped steel materials 1 and 2 by making the opposite end portions of the front and rear collapse prevention members 3A and 3B overlap each other by an appropriate width. ing.

Other structures such as a rectangular joint plate 6 having a bolt hole 7 formed therein and a locking fitting 10 for engaging and disengaging both end bent portions 9a, 9a of the spacing member 9 are provided. Are the same as those in the above-described embodiment, and therefore, the same portions are denoted by the same reference numerals and description thereof will be omitted.

FIG. 6 shows the top of the wall T of the tunnel excavation .
The support unit A ′ shown in FIGS. 1 to 3 , wherein the front and rear arc-shaped steel material 1 made of a U-shaped cross-section steel channel curved in an arc shape along the tunnel excavation wall surface T. 2, one end in the longitudinal direction is integrally connected by a straight steel material 11, and the other end is opened in the circumferential direction without being connected by the straight steel material.

In this support unit A ', the collapsible member 3 stretched in a state of being bridged between the convexly curved outer peripheral surfaces of the front and rear circular arc-shaped steel materials 1 and 2 has front and rear end edges which are long sides thereof. May be fixed to the outer peripheral surfaces of the front and rear arc-shaped steel materials 1 and 2 by welding or the like, but one of the front and rear edges is fixed to the outer peripheral surface of one of the arc-shaped steel materials as in the above-described embodiment. ,
The other end portion may be attached so as to be relatively movable in the front-rear direction with respect to the outer peripheral surface of the other arc-shaped steel material. Further, the above-mentioned fall prevention member 3 may be used as a front half fall prevention member and a rear half fall prevention member. While dividing, the front edge of the first half fall prevention member is fixed to the outer peripheral surface of the front circular arc-shaped steel material 1, and the rear end edge of the second half fall prevention member is fixed to the outer peripheral surface of the rear circular steel material 2. The opposite end portions of the front / rear fall prevention members may be overlapped by an appropriate width without being connected to each other. Further, the fall prevention member 3 is connected to the front and rear arc-shaped steel materials 1,
Alternatively, it may be stretched only in a half portion where no straight steel material is provided in the circumferential direction of the tunnel.

In this support unit A ', bolt holes 7a, 7a are formed at both ends in the longitudinal direction of the straight steel material 11, and the other longitudinal direction arc-shaped steel materials 1, 2 are provided. The bolt holes 7a, 7a are formed in the rectangular joint plates 6, 6, which are fixed to the end faces.
The bolt holes 7 and 7 are formed so as to face. Bolt holes 8 are formed at regular intervals in the length direction on the facing surfaces of the front and rear arc-shaped steel materials 1 and 2.
Since the interval between the two is maintained at a constant interval by the straight steel material 11, there is no need to provide the interval holding member 9 or the locking metal fitting 10.

FIG. 7 shows a tunnel excavator 20. A support member 22 is provided integrally with the skin plate 21 at an opening at the front end of a cylindrical skin plate 21.
A cutter plate 23 rotatably supported by the support member 22 and rotationally driven by a drive motor (not shown) mounted in the support member 22; and a front end integrally fixed to a rear end of the support member 22 A beam 24 extending horizontally rearward from the rear end of the skin plate 21 through the center space of the skin plate 21; and a telescopic front mounted integrally on the upper, lower, left and right sides of the support member 22. A gripper 25, a rear support 26 protruding downward from the lower surface of the rear end of the beam body 24 and being vertically expandable and contractable by a jack 26a, and a rear gripper 27 slidably disposed along the lower surface of the beam body 24. , And a propulsion jack 28 connecting the support member 22 and the rear gripper 27.

The skin plate 21 has a beam member 24.
Are fixed and supported integrally on the outer peripheral surface of the skin plate 21 via a connecting frame member 21a, and the rear gripper 27 is
As is well known, both sides of the lower surface of the beam receiver 29 slidable relative to the beam body 24 are provided on both sides of the tunnel excavation wall T. , And both rear grippers 27, 27 are connected to both sides of the rear surface of the support member 22 by the propulsion jacks 28, 28, respectively. The earth and sand excavated by the cutter plate 23 is discharged backward by an appropriate carrying-out means such as a conveyor (not shown).

Further, in the tunnel excavator 20 constructed as described above, the lower rear part of the skin plate 21 is cut off 30 and a plurality of support units are sequentially arranged in the skin plate 21 in the circumferential direction. A swivel-type liner assembling erection 31 for connecting and assembling the ring-shaped support liner S is provided, and a plurality of liner pushing jacks 32 are provided on the inner peripheral surface of the skin plate 21 at appropriate intervals in the circumferential direction. Is installed.

In the rear end of the skin plate 21 of the tunnel excavator 20 constructed as described above, first, a plurality of support units having a constant arc length curved in an arc shape are connected in the circumferential direction to form a tunnel excavation wall T. A ring-shaped support body having a circular shape when viewed from the front and having a diameter smaller than the diameter and having the fall prevention member 3 stretched on the outer peripheral surface of the upper half portion, that is, a support liner S is formed.

The formation of the support liner S is first performed by referring to FIGS.
After the fall prevention member 3 is stretched between the front and rear arc-shaped steel materials 1 and 2 as shown in FIGS. 3 and 5, and the support unit A whose opposite surface is connected by the spacing member 9 is supported by the erector 31. By rotating the erector 31 in the circumferential direction to move the support unit A upward along the inner peripheral surface of the skin plate 21 by a predetermined circumferential length, and then holding the support unit A at that position,
Next, one end of the next support unit is connected to the other end of the support unit A in the tunnel circumferential direction. At this time, as shown in FIG. 8 and FIG. 9, when the support liner S is composed of three support units in which the upper half thereof is provided with the collapsible member 3, A support unit A 'shown in FIG. 6 is used as a support unit for supporting the upper portion. Instead of the support unit A ', a normal support unit in which a fall prevention member is stretched on a rectangular frame formed by fixing a straight steel material between both ends of the front and rear arc-shaped steel materials may be used.

Then, the joint plate 6 or the straight steel member 11 provided at one end of the support unit A 'in the circumferential direction of the tunnel is connected to the front and rear arc-shaped steel members 1, 2 of the support unit A supported by the erector 31. Joint plate 6 fixed to the end face,
6, and the supporting units A and A 'are integrally connected by fixing the bolt holes which coincide with each other with bolts and nuts 12. After a while, Elekta
The support unit A 'is further rotated in the circumferential direction to position the support unit A' on the uppermost peripheral side of the skin plate 21, and then the straight steel member 11 or the joint plate provided at the other end of the support unit A ' 6, a joint plate 6 fixed to one end surface of the front and rear arc-shaped steel materials 1 and 2 of the support unit A having the same structure as the support unit A assembled first is butt-joined, and a gap between the matched bolt holes is formed. The support units A ′ and A are integrally connected by being fixed by the bolts and nuts 12.

The support unit A 'formed by connecting one end of the front and rear arc-shaped steel members 1 and 2 with the fall prevention member 3 as described above by the straight steel member 11 is connected to the uppermost peripheral side of the skin plate 21. The support units A, A, in which the fall prevention member 3 is stretched between the front and rear arc-shaped steel materials 1 and 2 having no straight steel material at both ends of the support unit A ', are connected and supported. After forming the upper half of the liner S, the front and rear arc-shaped steel materials 1, 2 of the support units A, A arranged on both sides are formed.
Collapsible member 3 attached to joint plates 6, 6 fixed to the lower end surface of
The joint plates 6, 6 fixed to the upper end surfaces of the front and rear arc-shaped steel materials 1, 2 which are not stretched are joined to each other in abutting manner, and the matched bolt holes are connected by bolts and nuts 12. In addition,
At the lower ends of the support units A, A arranged on both sides, FIG.
As shown in ( ₁₎ , the support units A ₁ and A ₁ having the fall prevention member 3 stretched in the upper half may be connected.

Further, the front and rear arc-shaped steel materials 1 and 2 are placed on the bottom surface of the tunnel excavation wall T exposed to the cutout portion 30 in the lower rear part of the skin plate 21, and the front and rear arc-shaped steel materials 1 and 2 are installed. The front and rear arc-shaped steel members 1 and 2 connecting the joint plates 6 fixed to both end surfaces to the support units A and A, respectively.
The joints 6 are butt-joined to a joint plate 6 fixed to the lower end surface of the front end, and the expansion jacks 33, 33 are provided between the inner peripheral surfaces of the front end arc-shaped steel members 1, 1 and the rear arc-shaped steel members 2, 2 at the joints. The support liner S is constituted by being connected by the. As shown in FIGS. 8 and 9, bridge members 13, 13 made of I-shaped steel are fixed between opposed surfaces of the front and rear circular arc-shaped steel members 1, 2 installed on the bottom surface of the tunnel excavation wall surface T. .
The front and rear arc-shaped steel materials 1 and 2 are fixed by driving an anchor bolt 14 into the bottom surface of the tunnel excavation wall surface T.

The support unit A incorporated in the upper half of the support liner S and the front and rear arc-shaped steel materials 1 and 2 without the collapsing prevention member 3 are fixed to the opposing surfaces in advance. The spacing member 9 is disposed between the locking metal fittings 10, 10 and the bent ends 9a, 9a thereof are engaged with the locking metal fittings 10, 10 so that the front and rear arc-shaped steel materials 1, 2 can be interposed. With the front-rear width kept at a constant interval, they are sequentially connected in the circumferential direction as described above. Further, the front and rear arc-shaped steel materials 1 disposed on the lowermost peripheral side of the support liner S,
In the assembly work of 2, the support unit is attached to the skin plate 21
, May be sent to the tunnel excavation wall surface T side, and then performed on the bottom surface of the tunnel excavation wall surface T.

The support liner S (hereinafter, referred to as a new support liner) assembled in the skin plate 21 of the tunnel excavator 20 is first assembled by extending the liner pushing jack 32 {on the tunnel excavation wall T side. The new support liner S is moved to the side of the already-assembled support liner S that is being sent out, and the rear end surface of the newly installed support liner S is brought into contact with the front end surface of the newly-assembled support liner S. The holes 8, 8 are loosely connected by bolts and nuts, and the skin plate 21
It is relatively moved from inside to the tunnel excavation wall T side and sent out.

When the rear half of the newly installed support liner S is sent out from the skin plate 21 to the tunnel excavation wall T side, the rear arc-shaped steel members 2 on the lower half side of the newly installed support liner S are moved. Expansion jack 33 connecting
Is extended to expand the diameter of the rear half of the support liner S, and the outer peripheral surface of the rear half is brought into contact with the entire periphery of the tunnel excavation wall T to prevent the rock from collapsing. While the rear end of the new support liner S is sent out from the skin plate 21 to the tunnel excavation wall T side, the next support liner is assembled in the skin plate 21 in the same operation procedure as described above, and the rear end is separated from the skin plate 21. The rear end face is brought into contact with and connected to the front end face of the newly installed support liner S as described above.

Further, the support liner S moves relatively to the tunnel excavation wall T side by the excavation of the tunnel excavator 20, and the front end of the support liner S whose diameter in the rear half is enlarged is separated from the rear end of the skin plate 21. When the whole of the support liner S is sent out to the tunnel excavation wall surface T side, the expansion jack 33 connecting between the front circular arc-shaped steel materials 1 and 1 on the lower half side of the support liner S is extended to thereby extend the support liner S. Is enlarged, and the outer peripheral surface thereof is brought into close contact with the tunnel excavation wall surface T entirely. In this state, the joint plates 6, 6 and the like joined together are firmly connected by bolts and nuts, and a key piece (not shown) or the like is interposed between opposing portions connected by the expansion jack 33, or After the bolts are fixed at a fixed interval with bolts, the expansion jack 33 is removed.

As described above, the support liner S assembled in the skin plate 21 is connected to the already-assembled support liner S in the skin plate 21, and the support liner S is sequentially sent out from the rear end of the skin plate 21 according to the excavation of the tunnel excavator 20. The step of supporting the tunnel excavation wall T by sequentially increasing the diameter of the rear end and the front end of the support liner is repeated to form a series of supports that support the tunnel excavation wall T over the entire length. Things.

When the tunnel excavator 1 excavates the tunnel, the rear grippers 27, 27 are provided on both sides of the tunnel excavation wall T via the collapsible member 3 extending between the front and rear arc-shaped steel materials 1, 2 of the support liner S. After the propulsion reaction force is obtained by crimping to the surface, the rear support 26 is contracted and separated from the bottom surface of the tunnel excavation wall T, and then the propulsion jack 28 is extended to thereby extend the tunnel excavation wall T via the rear gripper 27. The front gripper 25 is excavated by the cutter plate 23 while sliding the front gripper 25 against the excavation wall surface T while supporting the reaction force. After excavating a tunnel of a certain length, the front gripper 25 is firmly pressed against the excavation wall T, and the rear support 26 is extended to be supported on the bottom surface of the excavation wall T, and the rear gripper 27 is contracted. The rear gripper 27 is advanced to the next crimping position along the beam member 24 by contracting 28.

The compression position of the propulsion jack 28 is set so that the pressure position of the rear gripper 27 is between the front and rear arc-shaped steel materials 1 and 2 on both sides of the support liner S. When the crimping is performed on the side wall portion of the tunnel excavation wall surface T through the gap between the front and rear arc-shaped steel materials 1 and 2, a straight steel material such as the conventional support unit is not provided between the opposed ends of the front and rear arc-shaped steel materials 1 and 2 and the adjacent support is not provided. Since the openings 4, 5 formed between the front and rear joint plates 6, 6 joined and connected to each other in the unit are in a state of communicating with each other in the circumferential direction, the rear gripper 27 can be securely pressed. . If the spacing member 9 connecting the front and rear arc-shaped steel materials 1 and 2 interferes with the pressing of the rear gripper 27, the spacing member 9 may be removed. You may keep it.

In the case where the side wall of the tunnel excavation wall T to which the rear grippers 27, 27 are crimped via the fall prevention member 3 is a loose rock part where cracks or collapses occur, the amount of extension of the rear grippers 27 is increased. Therefore, it is necessary to firmly press against the excavation wall T to consolidate the bedrock portion so as to obtain a reliable propulsion reaction force. At this time, the fall prevention member 3 is moved to the rear gripper 27.
Due to the pressing force of the slab, it swells and deforms so as to bite into the rock.

The swelling and deformation of the collapse prevention member 3 are shown in FIG.
As shown in FIG. 3, one of the front and rear edges of the fall prevention member 3 is fixed to the outer peripheral surface of one arc-shaped steel material, and the other edge is fixed to the outer peripheral surface of the other arc-shaped steel material. By installing the support unit A having a structure arranged to be relatively movable in the front-rear direction without being attached to both sides of the support liner S corresponding to the rear gripper 27, the collapsing prevention member 3 can be broken or the front-rear arc-shaped steel material 1 can be broken. And 2 can be smoothly and reliably performed without being bent. That is, if the rear gripper 27 is pressed against the collapsible member 3 to extend it, the collapsible member 3 is provided with the edge fixed to one arc-shaped steel member as a fulcrum and the other edge portion from above the other arc-shaped steel material. Rear gripper
It swells and deforms while being drawn to the 27 side.

In order to reliably expand and deform by the pressing force of the rear gripper 27 without breaking the fall prevention member 3 and causing unreasonable deformation of the front and rear arc-shaped steel materials 1 and 2 as described above, A support unit A ₂ as shown in FIG. 5, that is, a front half-fall prevention member 3A having its front edge fixed to the front arc-shaped steel material 1 and a rear end edge fixed to the rear arc-shaped steel material 2 Support unit A ₂ having a structure in which opposing ends with the latter half fall prevention member 3B are overlapped with each other
May be incorporated into both sides of the support liner S corresponding to the gripper 27. In this case, the rear gripper 27 can expand and deform by pushing and expanding while overlapping the overlapping portions of the front and rear fall prevention members 3A and 3B with each other.

The fall prevention member 3 is stretched to support a collapsed soft rock portion, and the front and rear arc-shaped steel material 1 is used for a rock mass which is not likely to collapse or fall. 2 may be simply provided as a ring-shaped support body connected in the circumferential direction of the tunnel. Further, when the rear gripper 27 is crimped to both sides of the tunnel excavation wall surface T, a member such as a straight steel material may not be provided at the crimping position of the rear gripper 27, so that the support liner is supported by a plurality of support units. When assembling S, as shown in FIG. 6 described above, one end in the longitudinal direction of the arc-shaped steel materials 1 and 2 is integrally connected by a straight steel material 11 and the other end is connected by a straight steel material. Alternatively, a support structure in which the support unit A ′ having the opening 5 in the circumferential direction may be incorporated into both sides of the support liner S may be used. In this case, the straight steel material 11 is positioned on the upper peripheral side of the support liner S where the rear gripper 27 does not abut, and the straight steel material 11 is assembled in a state where the opening 5 side where the straight steel material 11 is not provided faces the lower peripheral side. It is something to keep.

Further, as shown in FIG. 3 and FIG. 5, according to the support unit in which the front and rear arc-shaped steel materials 1 and 2 are separated from each other without being integrally connected by the straight steel material or the collapse prevention member,
Since the width interval between the front and rear arc-shaped steel materials 1 and 2 can be freely changed, the support liner S for the tunnel excavation wall surface T is provided.
Can be set freely according to the properties of the rock, and when excavating a curved tunnel portion, the interval between these front and rear circular arc-shaped steel materials 1 and 2 is increased from one end to the other end. That is, it can be incorporated as a tapered support unit gradually narrowed or widened in the circumferential direction of the tunnel, and the support liner along the excavation wall surface of the curved tunnel can be easily and accurately constructed.

[0050]

As described above, according to the tunnel support unit of the present invention, a pair of arc-shaped steel members arranged at an interval in front and rear, and a fall prevention member erected between these front and rear arc-shaped steel members. It consists of a straight between opposite ends of the arc-shaped steel longitudinal
Since the support unit is opened in the circumferential direction without being connected by the steel material , this support unit is installed on both sides of the support liner to which the rear gripper of the tunnel excavator is crimped, thereby preventing the rear gripper from being stretched to the support unit. It is possible to easily and surely press the inner wall of the tunnel through the member, and the tunnel excavation operation can be performed smoothly.

Further, in a support unit having a structure in which the front and rear arc-shaped steel materials are simply arranged side by side without connecting the both ends of the front and rear arc-shaped steel materials with a straight steel material, a straight line is formed between both ends of the front and rear arc-shaped steel materials. Compared with a normal support unit integrally connected by steel materials, the structure is extremely simple, the material cost can be reduced, and the weight and the handling are easy, so that the construction work can be improved. Also,
Can be removed between the front and rear arc-shaped steel materials of the support unit
Since the support units are connected by a functional space holding member, the width of the support units in the tunnel length direction can be kept constant, and the connection between the support units adjacent in the circumferential direction of the tunnel can be easily and smoothly performed. Can be.

Also, of the front and rear edge portions of the fall prevention member ,
Either edge shall be movably attached to the arc-shaped steel material corresponding to the edge, or
As described in claim 2, the front end edge of one of the collapsing prevention members is formed into a front arc-shaped steel material using two collapsing prevention members, and the rear end edge of the other collapsing prevention member is formed on the rear side. Each of the collapsible members is fixed to the arc-shaped steel material and the opposite ends of the collapsible members are overlapped, so that the collapsible members can easily bulge into the tunnel excavation wall according to the pressing force of the rear gripper. , And the tensile force due to the deformation hardly acts on the front and rear arc-shaped steel materials. Therefore, there is no possibility that the front and rear arc-shaped steel materials are curved and deformed in a direction in which they are attracted to each other. The structure can be constructed.

Further, as described above, the support unit is configured in such a manner that the collapsible member is simply stretched in a state of being bridged without connecting both ends of the front and rear arc-shaped steel members with the straight steel members. Therefore, the interval between these front and rear arc-shaped steel materials can be a tapered support unit that gradually narrows or widens from one end to the other end, that is, in the tunnel circumferential direction. Since the angle can be easily changed, the support liner along the excavation wall surface of the curved tunnel can be easily and accurately constructed.

[Brief description of the drawings]

FIG. 1 is a perspective view of a support unit viewed from an inner peripheral surface side;

FIG. 2 is a perspective view of the support unit viewed from an outer peripheral surface side;

FIG. 3 is an exploded perspective view thereof ,

FIG. 4 is a perspective view of a support unit in which a fall prevention member is stretched in an upper half part;

FIG. 5 is a perspective view showing another embodiment of the support unit.

FIG. 6 is a perspective view of a support unit for supporting an uppermost portion of a tunnel excavation wall surface ;

FIG. 7 is a simplified vertical sectional side view of a tunnel excavator on which a support body is being constructed;

FIG. 8 is a simplified perspective view of a support liner,

FIG. 9 is a front view thereof.

[Explanation of symbols]

 1, 2 front and rear arc-shaped steel material 3 collapsing prevention member 4, 5 opening 6 joint plate 7, 8 bolt hole 9 interval holding member 10 locking bracket 11 straight steel material 20 tunnel excavator 27 rear gripper A support unit S support liner T tunnel Excavated wall

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-77798 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) E21D 11/14

Claims (2)

(57) [Claims] A pair of arc-shaped steel materials arranged at an interval in front and rear, and a fall prevention member spanned between these front and rear arc-shaped steel materials, and a gap between opposed ends of the front and rear arc-shaped steel materials is provided. Opened in the circumferential direction without connecting with straight steel
At the same time, a space holding member is
It is detachably connected and furthermore, before and after the collapsing prevention member
One of the edges corresponds to the edge
A tunnel support unit which is movably attached to an arc-shaped steel material . 2. A pair of arc-shaped steel materials arranged at an interval in front and rear, and a fall prevention member erected between these front and rear arc-shaped steel materials. Opened in the circumferential direction without connecting with straight steel
At the same time, a space holding member is
It is detachably connected, and furthermore, the fall prevention member is
Divided into fall prevention member and second half fall prevention member and collapsed in the first half
The front edge of the prevention member is fixed to the outer peripheral surface of the front arc-shaped steel material.
On the other hand, the rear edge of the fall prevention member
A member that is fixed to the outer peripheral surface of the steel material and that prevents them from collapsing
Characterized in that the opposing ends of the tunnel support units are overlapped with each other by an appropriate width .