JPH11141295A - Tunnel support structure - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a support body structure capable of firmly supporting an upper peripheral wall portion of a tunnel wall where rocks are easily collapsed. SOLUTION: When forming a ring-shaped support body S along a tunnel wall surface T by a plurality of support pieces 1 to 1B and one key piece 2, a key piece 2 which is weak against pressure from the tunnel wall surface T side is formed. The rock piece or skin that is locally formed on the tunnel wall T by the support piece 1 that is disposed on the lowermost peripheral wall side of the tunnel wall T where the rock is not collapsed and that is disposed on the upper peripheral side of the tunnel wall T It is assumed that the supporting body S supports a loose load due to dropping or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support structure for supporting a rock face 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. As shown in FIG. 9, a plurality of support pieces 71 curved in an arc shape are sequentially connected by bolts and nuts 72 to form a support body with a part on the upper peripheral part being separated, and then the separated part. The support body S 'which supports the tunnel wall surface T over the entire surface is formed by interposing the key piece 73 in the portion.

The key piece 73 is incorporated at the end when assembling the support S '. The spatial shape of the spaced portion is adjusted so that the support S' can be assembled efficiently and reliably. The opposing end faces of the support pieces 71, 71 facing each other via the spaced portion are formed on the inclined end face so as to have a trapezoidal shape that expands from the outer peripheral face toward the inner peripheral face of the key piece 73. Are formed on the inclined end surfaces inclined in the direction of expanding from the outer peripheral surface toward the inner peripheral surface of the support body S 'so as to join the two end surfaces to the inclined side end surfaces, and the both inclined end surfaces of the key piece 73 are formed. After slidingly contacting the inclined end surfaces on both sides of the support pieces 71, 71,
The joints are connected to each other by bolts and nuts 72.

[0004]

However, in the case of the above-mentioned conventional support body S ', the key piece 73 is attached to the support body S' in the same manner as the lining segment constructed in the tunnel when the excavated ground is earth and sand ground. It has a structure incorporated at the top. With such a structure, in the case of a tunnel excavated in the earth and sand ground, the earth pressure and water pressure act almost evenly on the entire peripheral surface of the support, and the entire support receives pressure in the diameter reducing direction. However, the joint surfaces connecting the pieces are in close contact with each other, and there is no problem in strength.However, in the case of a tunnel wall excavated on rocky ground, the rock is locally loosened, When this part is supported by the above-mentioned support body, a large pressing force is applied to the key piece 73 in the direction in which the key piece 73 falls out due to the collapse of the key piece and the loosening load of the rock on the skin dropping part. There was a problem that the body was weakened.

That is, since the joint surface between the key piece 73 and the support pieces 71, 71 on both sides thereof is inclined downward in the widening direction from the upper peripheral wall surface side of the tunnel, the joint surface becomes loose when the rock is loosened. The bolts and nuts 72 that connect the joint surfaces are subjected to a large tensile force and a shearing force, whereby the bolts and nuts 72 can withstand the loads. However, there is a problem that the rock piece collapses and is extremely dangerous, and the work cannot be performed smoothly, despite the construction of the support body because the key piece 73 comes out downward.

[0006] The present invention has been made in view of such problems, and an object of the present invention is to provide a support body for supporting a tunnel wall excavated on a rocky ground, which is locally generated. An object of the present invention is to provide a support body structure that can reliably support a loose ground where collapse or skin fall is likely to occur.

[0007]

According to a first aspect of the present invention, there is provided a support body in which a plurality of support pieces curved in an arc shape are connected to each other in a direction along a tunnel wall surface. Are formed in a state where the support is separated from the support, and a key piece is interposed in the separated portion of the support to completely support the tunnel wall surface. The structure is made.

In the above-mentioned support body, the invention according to claim 2 is a steel frame in which the support piece and the key piece are formed by fixing a joint plate between both ends of a front and rear main girder curved in an arc along a tunnel wall surface. And a rock fall prevention material is stretched over a support piece disposed at least on an upper peripheral side of the support body.

[0009]

[Function] A key piece is arranged on the lower peripheral side of the tunnel wall where collapse and skin fall do not occur to maintain the form of the support body, while the support piece is arranged on the upper peripheral side of the tunnel wall and localized. To support the parts of the rock that are likely to collapse or fall off. When a loose load due to rock collapse or the like acts on this support piece, the support piece tends to be pushed down into the tunnel due to the loose load, but the end faces of both sides of this support piece are wider on the inner circumferential side than on the outer circumferential side. Due to the inclination in the narrowing direction, the downward force due to the loose load of the rock is received by the side end faces of the adjacent support pieces joined to the both end faces via the both end faces of the support piece, and The pressing force applied to the inclined joint surface acts in a direction to expand the diameter of the adjacent support piece, and further presses the support piece to the tunnel wall surface, thereby forming a strong support body and securely supporting even if loose ground occurs.

[0010] The supporting piece and the key piece may be arranged in a second aspect.
As described in the above, the weight is reduced and the handling is easy by constructing from a steel frame in which the joint plate is fixed between both ends of the front and rear main girders curved in an arc shape in the direction along the tunnel wall surface. A support piece with a rock fall prevention material such as a wire mesh is installed only on the upper peripheral side of the tunnel wall where it can be constructed efficiently and rock collapse or surface fall may occur, By using a steel frame on which the rock fall prevention material is not stretched for other tunnel wall portions, material costs can be reduced and workability can be improved.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic longitudinal sectional front view of a support S, which is a preferred embodiment of the present invention. A plurality of support pieces 1, 1 curved in an arc along the circumferential direction of the tunnel wall T excavated by the excavator.
A, 1B and one key piece 2 are connected to each other by bolts and nuts 3 in a state where the key piece 2 is disposed on the lower peripheral side of the tunnel wall T. That is, in the support pieces 1 to 1B, the support pieces 1 and 1A are respectively disposed along the upper peripheral wall portion and both side peripheral wall portions of the tunnel wall T, and the support piece 1B is provided at the lower ends of the support pieces 1 and 1 on both sides. Are connected, these support pieces 1B,
A support member S having a circular cross section is formed by interposing the key piece 2 at a space between the opposing surfaces of 1B and having a trapezoidal inverted trapezoidal cross section.

As shown in FIG. 2, the support piece 1 disposed along the upper peripheral wall of the tunnel wall T has a longitudinal main girder 11, 12 curved in an arc shape along the tunnel wall T. A steel rectangular frame integrally fixed at both ends thereof by flat plate-shaped joint plates 13 and 14 and a fall prevention member 4 made of a wire mesh formed by combining bar-shaped metal wires in a lattice at the outer peripheral opening end of the rectangular frame. The support pieces 1A, 1A arranged along both side walls of the tunnel wall surface T are the steel rectangular frames which are not provided with the collapsible material 4 as shown in FIG. That is, the joint plates 13, 14 between the longitudinal ends of the front and rear main girders 21, 22 having the same shape and the same size as the main girders 11, 12.
It is formed of a steel rectangular frame in which joint plates 23 and 24 having the same shape and the same size as those described above are integrally fixed.

Further, as shown in FIG. 1, the joint plates forming both end surfaces of the support pieces 1 and 1A approach each other from the outer peripheral surface side of the support body S toward the inner peripheral surface side. The supporting surface of the joint plate 5 of the joint plate of the adjacent support pieces 1 and 1A connected by the bolts and nuts 3 is formed to have a shorter arc length on the inner peripheral surface side than the circular arc length on the outer peripheral surface side. It faces the center of the body S.

On the other hand, as shown in FIG. 4, the supporting pieces 1B disposed along both sides of the lower peripheral wall of the tunnel wall T are provided with front and rear main girders 31, each having a shorter arc length of the steel rectangular frame. 32
A joint plate 33, 34 having the same length as the above-mentioned joint plate is integrally fixed between both ends in the longitudinal direction of the steel plate, and the joint plate 33 disposed on the upper side is the both-side support pieces 1A, Like the lower joint plate 24 of 1A, it is directed toward the center of the support body S from the outer peripheral surface side toward the inner peripheral surface side, but the joint plate 34 disposed on the lower side is a support piece 1A on both sides. When the support pieces 1B and 1B are respectively connected to the lower ends of 1A and 1A, the key piece 2 is moved from the inside of the tunnel to the space formed by the space between the opposing surfaces of the joint plates 34 and 34 which are separated from each other. The direction in which the fitting can be easily performed, that is, the mutually facing surfaces are inclined in a direction in which the support body A expands from the outer peripheral portion toward the inner peripheral portion.

As shown in FIG. 5, the key piece 2 integrally includes joint plates 43, 44 having the same length as the joint plate between main beams 41, 42 shorter than the front and rear main beams 31, 32 of the support piece 1B. It is composed of a fixed steel rectangular frame, and its two-sided joint plates 43, 44 are inclined in such a direction that they can be fitted to the separated portions of the trapezoidal cross section formed between the opposing surfaces of the support pieces 1B, 1B. I have. That is,
The support S is inclined at the same angle as the lower joint plate 34 of the support piece 1B in a direction of expanding from the outer peripheral side to the inner peripheral part of the support body S. The main girder and the joint plate of the support pieces 1, 1A, 1B and the key piece 2 are provided with several bolt insertion holes 6, 7 for connecting adjacent pieces in the tunnel length direction and the circumferential direction. ing.

Then, as described above, the tunnel wall T
The support piece 1 is disposed on the uppermost peripheral side of the support piece 1 and the upper joint plates 23 of the support pieces 1A, 1A in contact with both side joint plates 13 and 14 of the support piece 1 on both side walls of the tunnel wall T. The bolt insertion holes 7, 7, which are connected to each other by joining 23, are integrally connected by bolts and nuts 3. Further, the supporting pieces 1A, 1A on both sides are connected to the lower joint plates 24, 24 by the supporting pieces. The upper joint plates 33 of 1B, 1B are joined 5a, and the bolt insertion holes 7, 7 communicating with each other are integrally connected by bolts and nuts 3, and the lower joint plates of the support pieces 1B, 1B are opposed to each other. The key piece 2 is fitted in a space between the trapezoidal portions formed in the space between the trapezoidal cross sections, and the joint plates 43, 44 on both sides thereof are connected to the lower joint plates 34, 34 of the support pieces 1B, 1B.
A circular ring-shaped support member which is integrally connected by bolts and nuts 3 between bolt insertion holes 7 and 7 which are joined to each other in a press-contact state by bolts and nuts 3 so as to entirely support the tunnel wall surface T. S.

This circular ring-shaped support body S is sequentially joined in the longitudinal direction of the tunnel to the front and rear main beams facing each other, and the bolt insertion holes 6, 6 are connected by bolts and nuts to form a tunnel support. Is what you do. In addition, the support bodies S adjacent in front and rear need not necessarily be connected to each other by bolts and nuts, but may be simply joined.

As described above, the support body S constructed as described above has the joint surfaces 5b, 5b between the key piece 2 and the support pieces 1B, 1B on both sides of the key piece 2 expanding toward the center of the tunnel (support center). The key piece 2 is disposed on the lowermost peripheral wall side of the tunnel wall T where the loose load such as collapse does not occur, although the strength against the pressure from the tunnel wall T is weak because of the inclination in the opening direction. Therefore, the support body S can always be maintained in a state of being stretched in the radially expanding direction. On the other hand, since the support piece 1 on which the fall prevention material 4 is stretched is disposed in contact with the uppermost peripheral wall surface of the tunnel wall T, when the bedrock falls or the skin falls, the fall prevention material 4 is used.
Thus, it is possible to prevent collapse in the tunnel.

Further, when the loose load B of the rock due to the collapse or the like acts on the support piece 1, the pressing force of the support piece 1 by the load B causes the joint with the support pieces 1A, 1A on both sides connected to the support piece 1. It acts on the joint surfaces 5, 5 formed by the plates, but since the joint surface 5 is inclined toward the center of the support body S, the support pieces 1A, 1A on both sides are pressed by the pressing force applied to the joint surface 5 to the tunnel wall surface T. Try to move to the side. However, since the outer peripheral surfaces of these support pieces 1A, 1A are in contact with the tunnel wall surface T, they do not move despite the above-described pressing force. Is suppressed, and the loose load B of the rock mass can be more firmly received by the support piece 1.

Next, a method of assembling the support body S will be described. The support body S shown in FIG.
As shown in the figure, after being assembled in the skin plate 51 of the tunnel excavator A, it is sequentially sent out to the tunnel wall T side according to the excavation of the tunnel excavator A, and the diameter is expanded by fitting the key piece 2 into the separated portion. To be sequentially pressed against the tunnel wall T.

The tunnel excavator A has a support member 52 disposed integrally with the skin plate 51 at the front end opening of a cylindrical skin plate 51, a rotatably supported by the support member 52, and A cutter plate 53 driven to rotate by a drive motor (not shown) mounted in the member 52
A beam 54 that extends horizontally horizontally from the rear end of the skin plate 51 through the central space of the skin plate 51 with the front end integrally fixed to the rear end of the support member 52; A radially expandable front gripper 55 integrally mounted on the upper, lower, left and right sides of the support member 52;
A rear support 56 protruding downward from the lower surface of the rear end and extending vertically up and down by a jack 56a; a rear gripper 57 slidably disposed along the lower surface of the beam body 54;
52 and a propulsion jack 58 connecting the rear gripper 57, a cylindrical sliding frame 59 is slidably fitted on the beam body 54, and a push-up jack 60 is fixed on the upper surface of the sliding frame 59. ing.

The erector ring 8 is rotatably disposed around the beam portion at the front side of the sliding frame 59 at a fixed distance from the inner peripheral surface of the skin plate 51. A rack 8a formed on the inner peripheral surface of the gear 8 is meshed with a pinion 9a fixed to a rotation shaft of a rotation drive motor 9 installed on the beam body 54, and the electric drive ring 9 is rotated by the rotation drive motor 9. As shown in FIG. 7, the erector ring 8 is provided with an erector head 10 which is detachably engaged with the support piece, and a support piece support bracket 8b is mounted on the outer peripheral surface. doing.

The skin plate 51 has a beam member 54.
The rear gripper 57 is integrally fixed and supported on the outer peripheral surface of the beam body via a connection frame member 61, and the rear gripper 57 is disposed on the rear side of the beam body 54 projecting rearward from the skin plate 51. A beam receiver 62 slidable relative to the body 54 projects horizontally from both lower surfaces of the beam receiver 62 toward both side surfaces of the tunnel wall T, and both rear grippers 57, 57 and the rear side portions of the support member 62. The spaces are connected by the propulsion jacks 58, 58, respectively. Further, the sliding frame 59 and the beam receiver 62 are connected via a connecting jack 63. The earth and sand excavated by the cutter plate 53 is discharged backward by a suitable carrying-out means such as a conveyor (not shown).

The supporting piece 1B disposed on one side of the key piece 2 is supplied onto the lower peripheral portion in the skin plate 51 of the tunnel excavator A thus configured as shown in FIG. After the support piece 1B is supported by the erector head 10, the rotating drive motor 9 rotates the erector ring 8 clockwise in the figure to move the support piece 1B upward along the inner peripheral surface of the skin plate 51. After moving by a certain circumference, it is held at that position. Next, the support piece
1A is carried onto the lower peripheral portion of the skin plate 51 and one of the joint plates 24 is joined to the joint plate 34 of the support piece 1B. Then, these joint plates 24 and 34 are connected by the bolts and nuts 3 and After the support piece 1A is supported by the support bracket 8b so as to be in sliding contact with the inner peripheral surface of the skin plate 51, the electoring ring 8 is further rotated clockwise as shown in FIG. The support piece 1A is moved upward along the inner peripheral surface of the skin plate 51 integrally with the piece 1B.

Similarly, as shown in FIGS. 8 (c) to 8 (e), the supporting pieces 1 and the supporting pieces 1A are sequentially connected to joint plates facing each other by bolts and nuts 3, and these supporting pieces are connected to each other. After being supported by the support bracket 8b, the erector ring 8 is rotated in the same direction to
By moving 10 along the skin plate 11 nearly one round, a downward-opening cross-section having an inverted equal-leg trapezoidal space C between the adjacent support pieces 1A, 1A on the lower circumferential side in the skin plate 51 Assemble the C-shaped support body S.

Thereafter, the sliding frame 59 is moved along the beam member 54.
Is moved forward by the connecting jack 63 to move the push-up jack 60 on the sliding frame 59 to the support S in the skin plate 51, and the push-up jack 60 supports the upper peripheral inner surface of the support S. Erecta head 10 and supporting bracket
Remove 8b from the support piece. Next, the sliding frame 59 is moved rearward from the skin plate 51 so that the rear end face of the support S supported by the push-up jack 60 abuts on the front end face of the existing support S supporting the tunnel wall surface T.

In this state, the key piece 2 is fitted into the separation portion C provided on the lower peripheral side of the support body S supported by the push-up jack 60. At this time, when the support body S is assembled by connecting the support pieces, since the cross-sectional shape of the separated portion C is formed to be shorter in circumference than the key piece 2, the cross-sectional shape is from the outer peripheral side toward the inner peripheral side. The two-sided inclined joint plates 43, 44 of the key piece 2 inclined in the expanding direction are slidably contacted with the inclined joint plates 34, 34 of the support pieces 1A, 1A facing each other with the separated portion C in the tunnel. When the support body S is pushed toward the wall surface T, the diameter of the support body S gradually increases, and the outer periphery of the support body S when the joint plates 43 and 44 of the key piece 2 are completely joined to the joint plates 34 and 34 of the support pieces 1A and 1A. The surface comes into contact with the tunnel wall surface T.

Thereafter, the joint plates 43, 44 of the key piece 2
Bolts and nuts 3 on the joint pieces 34, 34 of the support pieces 1A, 1A
And the main girder on the rear end side of the support S is connected to the main girder on the front end of the existing support S by bolts and nuts as necessary. Thus, the step of assembling the support body S whose lower peripheral side is separated in the skin plate 51 of the tunnel excavator A, sending this support body S to the tunnel wall surface T side, and fitting the key piece 2 into the separated section C. Thus, the step of expanding the diameter of the support body S and supporting the tunnel wall surface T is repeated to form a support structure for supporting the tunnel wall surface T.

In the excavation by the tunnel excavator 1, after the rear grippers 57, 57 are pressed against both side surfaces of the tunnel wall surface T, the rear support 56 is contracted and separated from the bottom surface of the tunnel wall surface T, and thereafter, the propulsion jack 58 The front gripper 55 is excavated on the wall surface T while the reaction force is supported on the tunnel wall surface T via the rear gripper 57 by extending the
It is excavated by the cutter plate 53 while being in sliding contact with. After excavating a tunnel of a certain length, the front gripper 55 is firmly pressed against the excavation wall T and the rear support 56
Is extended to be supported on the bottom surface of the excavation wall T, and after the rear gripper 57 is contracted, the propulsion jack 58 is contracted to advance the rear gripper 57 along the beam 54 to the next crimping position.

In the above embodiment, the joint plates 43 and 44 on both sides of the key piece 2 are separated from each other at the same inclination angle in the opposite directions from the outer peripheral surface side to the inner peripheral surface side of the key piece 2. One of the joint plates is inclined at the inclination angle, and the other joint plate is inclined at an angle toward the center of the support body S like the joint plate of the support pieces 1 and 1A. You may keep it. in this case,
Needless to say, the joint plates of the support pieces 1B, 1B on both sides joined to the joint plates on both sides of the key piece 2 are formed so as to have an inclination angle to be joined to the key piece 2, respectively.

Further, the fall prevention member 4 made of a wire mesh is stretched only on the support piece 1 on the uppermost peripheral side of the support body S, but one half of the upper peripheral side of the support pieces 1A, 1A on both sides, or The fall prevention material 4 may be stretched over the entire surface. Further, as described in the above embodiment, the support piece and the key piece are formed of the steel rectangular frame, but may be formed in a segment shape of a completely closed type. The support body S is assembled by assembling a small-diameter ring-shaped support body S whose lower peripheral portion is separated in the skin plate 51 of the tunnel excavator 1 and then sending the ring-shaped support body S to the tunnel wall surface T side. Although the diameter is enlarged by fitting the key piece 2 to the separated portion by pressing, the key piece 2 may be temporarily joined in advance in the skin plate 51 of the tunnel excavator 1.

[0032]

As described above, according to the structure of the tunnel support body of the present invention, a plurality of support pieces curved in an arc shape are connected in the direction along the tunnel wall to form a support body that is partially separated. However, in a support body in which a key piece is interposed in a separated portion of the support body to completely support the tunnel wall surface, a tunnel which does not generate a loose load such as collapse of a key piece having low strength against pressure from the tunnel wall side. Since the key piece is arranged on the lowermost peripheral wall side of the wall surface, there is no danger that the key piece will fall into the tunnel due to the collapse of the rock or the fall of the skin, and a stable support structure for the tunnel wall surface can be formed. is there.

Further, since the support pieces whose both end surfaces are inclined toward the center of the support body are arranged on the upper peripheral wall side of the tunnel wall, the support pieces strongly reduce loose loads such as rock collapse. A support structure suitable for supporting a tunnel wall surface that can be received and is likely to cause rock collapse and surface fall can be provided.

According to the second aspect of the present invention, the support piece and the key piece are made of a steel frame in which a joint plate is fixed between both ends of the front and rear main beams which are curved in an arc along the tunnel wall. So it is lightweight and easy to handle,
A support piece can be efficiently installed on the tunnel wall surface, and a rock piece such as a wire mesh can be installed only on the upper peripheral side of the tunnel wall where rock collapse or surface fall may occur. It is possible to reduce the material cost and improve the workability by arranging and using a steel frame on which the other tunnel wall portions are not covered with the rock fall prevention material.

[Brief description of the drawings]

FIG. 1 is a simplified longitudinal front view of a support body of the present invention,

FIG. 2 is a perspective view of a support piece on which a collapse prevention material is stretched;

FIG. 3 is a perspective view of a support piece consisting of only a rectangular frame;

FIG. 4 is a perspective view of a support piece disposed on both sides of a lower peripheral wall of a tunnel wall;

FIG. 5 is a perspective view of a key piece,

FIG. 6 is a simplified longitudinal side view of a tunnel excavator,

FIG. 7 is a simplified front view of a support formed on the electoring ring,

FIG. 8 is a simplified front view showing a support body assembling process;

FIG. 9 is a simplified vertical sectional front view of a conventional support body.

[Explanation of symbols]

 1, 1A, 1B Support piece 2 Key piece 3 Bolt / nut 4 Collapse prevention material 5 Joining surface S Support body B Loose load due to collapse, etc. C Separated part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junji Ono 2-2-2 Matsuzaki-cho, Abeno-ku, Osaka-shi Inside Okumura Gumi Co., Ltd. (72) Inventor Kazuo Nishikawa 2-2-2 Matsuzaki-cho, Abeno-ku, Osaka-shi Okumura Gumi Co., Ltd. (72) Inventor Shoji Inoue 2-2-2 Matsuzakicho, Abeno-ku, Osaka-shi Okumura Gumi Co., Ltd.

Claims (2)

[Claims] A plurality of support pieces curved in an arc shape are connected in a direction along a tunnel wall surface to form a support body which is partially separated, and a key piece is interposed in a separated portion of the support body. A structure of a tunnel supporting body, wherein the key piece is disposed on a lower peripheral side of the supporting body in a supporting body which entirely supports a tunnel wall surface. 2. The support piece and the key piece are each formed of a steel frame in which a joint plate is fixed between both ends of a front and rear main girder curved in an arc shape in a direction along a tunnel wall surface, and at least an upper peripheral portion of the support body. The structure of the tunnel support body according to claim 1, wherein a rock-fall prevention material is stretched on the support piece disposed on the side.