JP4449875B2 - Large-section tunnel structure and its construction method - Google Patents

Description

The present invention is mainly used for a tunnel formed by a cutting method, and particularly relates to a tunnel structure having a large cross section and a method for constructing the tunnel structure.

Conventionally, this type of large-section tunnel is generally constructed by assembling a formwork on the ground and placing concrete in the formwork on-site. However, the construction of a tunnel using cast-in-place concrete has the problem that the number of work steps increases and costs increase. For such a problem, a pair of left and right arc plate-shaped precast concrete plates are arched between both ends in the width direction of the bottom plate extending in the tunnel length direction and connected in the tunnel length direction. At both ends in the width direction, side bands that bulge upward at an appropriate distance from the outer surface of the leg part and extend in the tunnel length direction on the outside of the leg part of each precast concrete plate are integrally provided. A pressure receiving member is interposed therebetween, and a leg portion is fastened to a side band by a fastening member such as a bolt, and a bank is applied to cover the concrete plate (for example, Patent Document 1). ).
JP 7-21617 A

However, in the tunnel structure described above, although the arc plate can be constituted by a precast concrete plate and the cost can be reduced, it is necessary to form the bottom plate extending in the length direction of the tunnel with the cast-in-place concrete, and this work is complicated. There was a limit to the cost that could be reduced.

In view of the above-described problems, an object of the present invention is to provide a tunnel structure having a large cross section that can reduce the cost by reducing the number of man-hours for field work and a construction method thereof.

In order to achieve the above-mentioned object, the invention according to claim 1 is directed to a pair of left and right precast concrete L-shaped members extending in the tunnel height direction from the bottom side of the tunnel, and a precast horizontally mounted between the L-shaped members. The L-shaped member includes a bottom portion and a side wall portion extending vertically from one end of the bottom portion, and the side wall portion is curved inward at the upper side, and the side wall portion A connection joint projects from the upper end surface of the arch member, and the connection joint is inserted into a joint receiving portion provided in the arch member .

The invention according to claim 2 is characterized in that, in claim 1, the arch member is divided into left and right at the top.

The invention according to claim 3, Oite to claim 1 or 2, wherein the arch member is characterized in that it comprises an embedded member.

The invention according to claim 4 is characterized in that, in any one of claims 1 to 3 , a central bottom plate portion is provided between the L-shaped members.

The invention according to claim 5 is characterized in that, in any one of claims 1 to 3 , a back bottom plate portion is provided on the back surface of the L-shaped member.

Further, the invention according to claim 6 is provided by installing a pair of left and right precast tunnel L-shaped members extending in the tunnel height direction from the tunnel bottom side, and connecting the pair of L-shaped members with a spacing member. An arch member is horizontally mounted, and after the L-shaped member and the arch member are connected , the spacing member is removed.

According to the tunnel structure having a large cross section according to claim 1 of the present invention, the construction of the member made of precast concrete divided into a plurality of parts reduces the man-hours for on-site work even with a large cross section, and reduces the cost. Can be reduced. Further, since the side wall is made of an L-shaped member, the side wall can stand on its own, so that it can be easily installed and the number of work steps can be reduced.

Further, according to the tunnel structure with a large cross section according to claim 2 , the arch member is divided and configured to facilitate transportation, and even a tunnel having a large cross section is constructed with a precast concrete member. Cost can be further reduced.

According to the tunnel structure having a large cross section according to claim 3 , by embedding the embedded body, the arch member can be reduced in weight, and the material cost and the transportation cost can be reduced, and the work on the site can be easily performed. Therefore, the cost can be further reduced.

Moreover, according to the tunnel structure of the large cross section of Claim 4 , it can construct | assemble reliably in a soft ground by providing a center bottom slab part.

Further, according to the tunnel structure having a large cross section according to the fifth aspect , by providing the back bottom plate portion, the construction can be made with a small amount of material, so that the cost can be reduced.

Moreover, according to the tunnel construction method of the large cross section of Claim 6 , since a pair of left and right L-shaped members are connected by the holding member, the L-shaped member can be prevented from falling during the construction. In addition, since the L-shaped members can be held at a predetermined interval, a tunnel with a large cross section can be constructed safely and easily, so that the cost can be reduced.

A first embodiment of the present invention will be described below with reference to the drawings.

A tunnel structure 1 shown in FIG. 1 includes a pair of left and right precast concrete L-shaped members 2 extending in the tunnel height direction from a tunnel bottom side, and a precast concrete arch that is horizontally mounted above the L-shaped members 2. And the member 3. Further, between the L-shaped members 2, a central bottom slab portion 4 which is a bottom slab portion is formed of cast-in-place concrete.

The L-shaped member 2 includes a bottom portion 5 that contacts the ground G and a side wall portion 6 that extends perpendicularly from one end of the bottom portion 5 and is formed in advance at a factory. The side wall portion 6 is gently curved upward on the inner side, that is, toward the other end side of the bottom portion 5, and is formed at a height approximately in the middle of the height of the tunnel. Further, the L-shaped member 2 is provided with a vertical fastening insertion hole 7 for performing vertical fastening in the length direction of the tunnel.

The arch member 3 is a rectangular plate member having substantially the same thickness as the side wall portion 6 which is curved in the width direction of the tunnel so as to protrude upward, and is formed in advance at a factory. is there. The arch member 3 includes a joint portion 8 provided at one end in the circumferential direction and a top portion 9 provided at the other end. Further, the arch member 3 is provided with a vertical fastening insertion hole 7 on the outer peripheral surface for vertical fastening in the length direction of the tunnel.

An embedded body 17 is embedded in the L-shaped member 2 and the arch member 3, whereby the L-shaped member 2 and the arch member 3 can be reduced in weight. Various types of the embedded body 17 are conceivable. For example, a tube or a cylinder may be formed of paper, cardboard, polystyrene foam, or the like, or a polyvinyl chloride tube may be used. Moreover, it is good also as replacing with the reinforcing bar arranged by the L-shaped member 2 and the arch member 3 by comprising the embedded body 17 with a steel pipe. A plurality of the embedded bodies 17 embedded in the arch member 3 can be embedded over substantially the entire curved circumferential direction by providing a plurality of embedded bodies 17 in the circumferential direction.

As shown in FIG. 2, a connection joint 10 and a guide member 11 are provided at the upper end of the side wall portion 6. The connection joint 10 protrudes perpendicularly to the upper end surface 6 a of the side wall portion 6. The guide member 11 is a steel plate member, is fixed to the inside of the side wall portion 6, and protrudes in a direction perpendicular to the upper end surface 6a. A joint receiving portion 12 with which a joint 10 provided on the upper end surface 6a of the side wall portion 6 of the L-shaped member 2 engages with a joint surface 8a of the joint portion 8 provided at one end in the circumferential direction of the arch member 3. Is installed.

As shown in FIG. 3, an insertion hole 15 penetrating perpendicularly to the top end face 9a is formed in the top 9 provided at the other end in the circumferential direction of the arch member 3. A seat surface 16 is provided in an opening formed on the surface side of the arch member 3 by the insertion hole 15. The arch members 3 are configured as a pair of left and right, and are arranged to face each other at the top end face 9a and are arranged on the ceiling portion of the tunnel.

Next, a method for constructing the tunnel structure 1 will be described with reference to the drawings.

First, the case where the L-shaped member 2 and the arch member 3 made of precast concrete are installed will be described. As shown in FIG. 4 (A), a foundation 20 is laid on the ground G that has been cut by using leveled concrete. Next, after constructing a mortar (not shown) on the foundation 20, the L-shaped member 2 is installed as a pair of left and right. Since the L-shaped member 2 is integrated with the bottom portion 5, it can stand on its own and workability can be improved.

In this way, the same operation is repeated in the length direction of the tunnel, and the pair of left and right L-shaped members 2 are connected by the spacing member 27. The spacing member 27 is composed of a pair of horizontal rods 28a having male screws formed at both ends. One end of each horizontal rod 28a is inserted into a through-hole formed in advance in the side wall of the L-shaped member, and fixed to the nut 26b via the plate 29. The other ends of the spacing members 27 are connected to each other by a connecting means 28b, for example, a turnbuckle, at the approximate center of the pair of L-shaped members 2. As a result, the L-shaped member 2 can be prevented from falling down during the construction, and can be held at a predetermined interval. In addition, the space | interval holding member 27 horizontally mounted as mentioned above is removed after fastening the L-shaped member 2 and the arch member 3 by the method mentioned later.

Next, as shown in FIG. 4 (B), a movable base 21 is installed approximately in the middle of the pair of L-shaped members 2. A jack 22 is provided at the upper end of the gantry 21. Although not shown, a frame for preventing overturning is provided on the back side of the L-shaped member 2, and a scaffold for constructing the arch member 3 is provided on the inner side of the L-shaped member 2.

Next, one arch member 3 is horizontally mounted on the side wall portion 6 of the L-shaped member 2. In order to horizontally mount the arch member 3 on the side wall portion 6 of the L-shaped member 2, the wires 23 are locked in the vicinity of both ends of the arch member 3 as shown in FIG. 5. A chain block 24 is connected in advance to the top side wire 23a locked to the top 9 side of the arch member 3. The wire 23 is connected to a crane (not shown), and the arch member 3 is pulled up by the crane. Next, the top wire 23a is wound up by the chain block 24, and the top 9 of the arch member 3 is lifted. By lifting the top portion 9 of the arch member 3, the angle of the joint surface 8a of the arch member 3 provided with the joint receiving portion 12 is matched with the angle of the upper end surface 6a of the side wall portion 6 as shown in FIG. After matching the angle between the joint surface 8a of the arch member 3 provided with the joint receiving portion 12 and the upper end surface 6a of the side wall portion 6, the connecting joint 10 is inserted into the joint receiving portion 12, and the arch member 3 is attached to the base 21. Install in. At this time, since the guide member 11 is provided at the upper end of the side wall portion 6, the connection joint 10 can be easily inserted. The joint receiving portion 12 is filled with mortar, and the arch member 3 and the side wall portion 6 are fixed at the joint portion 8. Similarly, the joint portion 8 of the other arch member 3 is connected to the upper end 6a of the side wall portion 6 of the L-shaped member 2 and installed on the mount 21 (FIG. 4C).

Next, a case where the pair of left and right arch members 3 are joined at the top 9 will be described. First, the jack 22 provided on the gantry 21 is moved up and down to adjust the height of the top portion 9 of one arch member 3, and is adjusted to the height of the top portion 9 of the other arch member 3. When the heights of the top portions 9 of both arch members 3 can be positioned, the PC steel rod 25 is inserted into the insertion hole 15 penetrating perpendicularly to the top end surface 9a, as shown in FIG. A nut 26 a is screwed to both ends of the PC steel rod 25 inserted through the insertion hole 15, the nut 26 a is tightened, and a tension force is introduced into the PC steel rod 25. Thereby, prestress which is tension in the left-right direction is introduced into the top portions 9 of the left and right arch members 3. This prestress reaction force is absorbed by the seating surface 16 formed on the outer surface of the arch member 3.

Further, the same operation is repeated in the length direction of the tunnel, and when a predetermined number, for example, 10 sets of the arch members 3 are installed, they are vertically tightened in the length direction of the tunnel and integrated. Although the vertical tightening is not shown, a PC steel rod is inserted into the vertical tightening insertion hole 7 formed on the outer peripheral surface of the arch member 3 and the L-shaped member 2, and nuts are screwed into both ends of the PC steel rod. This is done by introducing tension to the PC steel bar.

Next, the case where the center bottom slab part 4 is driven in the said tunnel member installed in the field is demonstrated. The center bottom plate portion 4 is composed of a reinforcing bar (not shown) arranged between the bottom portions 5 of the L-shaped member 2 and a cast-in-place concrete, and the reinforcing bars and the reinforcing bars formed in advance on the bottom portion 5 are formed. They are connected by a mechanical joint (not shown). Various mechanical joints are conceivable. For example, although not shown in the drawings, the embedding sleeve is fixed to the reinforcing bar provided on the bottom 5 of the L-shaped member 2, and the connecting sleeve is fixed to the reinforcing bar at the end constituting the central bottom plate portion 4. Either a right female screw or a left female screw is formed so as to be paired with the sleeve, and the connection can be established by fixing with a connection bolt having a right screw at one end and a left screw at the other end. In this way, the concrete is cast between the bottom portions 5 of the L-shaped member 2 to which the reinforcing bars are joined to form the central bottom plate portion 4 (FIG. 4D). After the above work is completed, the framework and scaffolding are dismantled and removed.

As described above, the tunnel structure 1 according to the present embodiment is constituted by a plurality of divided precast concrete members, so that installation and dismantling of the formwork are unnecessary as compared with a case where the tunnel structure 1 is constructed by on-site concrete. The work man-hours can be greatly reduced and the cost can be greatly reduced. In addition, since the tunnel structure 1 is constituted by four parts, it can be easily formed in a factory and can be easily transported.

In addition, when the ground G is soft, it is necessary to provide the center bottom plate | board part 4 between the bottom parts 5 of the L-shaped member 2 as mentioned above, but for the strong ground G, it shows in FIG. The back bottom plate portion 30 can be applied as such a bottom plate portion. The back bottom plate portion 30 is formed on the back surface of the L-shaped member 2 by cast-in-place concrete. Thereby, since the amount of members to be used can be reduced as compared with the central bottom plate portion 4, the cost can be reduced while maintaining a sufficient strength.

The tunnel structure 1 having a large cross section constructed as described above absorbs the arch member 3 and the side wall 6 with a PC steel rod 25 into which prestress is introduced when a moment due to earth pressure or the like is generated. Further, in the tunnel structure 1 according to the present embodiment, stress concentrates on a location where the side wall portion 6 and the bottom portion 5 of the L-shaped member 2 are connected. As described above, the L-shaped member 2 has the side wall portion 6 and the bottom portion 5. Can be ensured sufficient strength against stress. As described above, the tunnel structure 1 has a structure capable of absorbing each stress. Therefore, the tunnel structure 1 has a large cross section and is made of a plurality of precast concrete members, but ensures sufficient strength. Can do.

As described above, in the present embodiment, a pair of left and right precast concrete L-shaped members 2 extending in the tunnel height direction from the bottom side of the tunnel, and a precast concrete arch horizontally mounted between the L-shaped members 2 By forming with the member 3, even if it is a large cross section, cost can be reduced by reducing the man-hour of field work. Further, since the side wall is made of the L-shaped member 2, the side wall can stand on its own, so that it can be easily installed and the number of work steps can be reduced.

Further, since the arch member 3 is divided into left and right at the top portion 9, it is easy to transport and can be constructed with a precast concrete member even if it is a tunnel having a large cross section. Can be reduced.

Further, since the arch member 3 includes the embedded body 17, the arch member 3 can be reduced in weight to reduce the material cost and the transportation cost, and the field work can be easily performed, so that the cost can be further reduced. be able to.

In addition, by providing the central bottom plate portion 4 between the L-shaped members 2, the soft ground G can be reliably constructed.

Moreover, since the back bottom plate portion 30 is provided on the back surface of the L-shaped member 2, it can be constructed with a small amount of material, so that the cost can be reduced.

Also, a pair of left and right precast concrete L-shaped members 2 extending in the tunnel height direction from the tunnel bottom side are installed, and an arch member 3 divided into left and right at the top is horizontally mounted, and the L-shaped member 2 and the arch member 3 and the arch members 3 are fastened to each other with a PC steel rod introduced with a tension force at the top portion 9, so that even a tunnel having a larger inner space can be made of a precast concrete member. Therefore, the cost can be reduced.

Also, a pair of left and right precast concrete L-shaped members 2 extending from the tunnel bottom side in the tunnel height direction are installed, the pair of L-shaped members 2 are connected by a spacing member 27, and divided into left and right at the top. The arch member 3 constructed as above is horizontally mounted, the L-shaped member 2 and the arch member 3 are fastened, and the arch members 3 are fastened to each other by a PC steel rod introduced with a tension force at the top portion 9. By removing the spacing member 27, the pair of left and right L-shaped members 2 are connected to each other by the spacing member 27, so that the L-shaped member 2 can be prevented from falling during the construction. Further, since the L-shaped member 2 can be held at a predetermined interval, and a tunnel with a large cross section can be constructed safely and easily, the cost can be reduced.

Further, in the present embodiment, the case where the ceiling of the tunnel is closed with the arch member 3 has been described. However, the present invention is not limited to this, and the arch member 32 provided with the oblique cuts 31 as shown in FIG. 2 may be connected. By doing so, it is also possible to form a light source at the tunnel exit.

Next, a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected about the structure similar to the structure which concerns on the above-mentioned 1st Example, and description is abbreviate | omitted for simplicity.

The tunnel structure 35 according to this embodiment shown in FIG. 8 is different from the tunnel structure 1 according to the first embodiment only in the arch member 3, and is horizontally mounted between a pair of L-shaped members 2 and the L-shaped members 2. And the integrated arch member 36. That is, the integrated arch member 36 according to the present embodiment is a rectangular plate member having substantially the same thickness as the side wall portion 6 that is curved in the width direction of the tunnel so as to protrude upward. , Previously formed at the factory. In the contact portion 37 between the integral arch member 36 and the L-shaped member 2, an insertion hole (not shown) penetrating perpendicularly to the contact surface is formed.

Next, a method for constructing the tunnel structure 1 will be described with reference to FIG. First, as shown in FIG. 9 (A), a foundation 20 is laid on the ground G that has been cut by using leveled concrete. Next, after laying mortar (not shown) on the foundation 20, the L-shaped member 2 is installed as a pair of left and right (FIG. 9B).

Next, as shown in FIG. 9 (C), a movable base 21 is installed approximately in the middle of the pair of L-shaped members 2. Although not shown, a frame for preventing overturning is provided on the back side of the L-shaped member 2, and a scaffold for constructing the arch member 3 is provided on the inner side of the L-shaped member 2. Moreover, the center bottom plate | version | printing part 4 is driven in the said tunnel member installed in the field. The center bottom plate portion 4 is composed of a reinforcing bar (not shown) arranged between the bottom portions 5 of the L-shaped member 2 and a cast-in-place concrete, and the reinforcing bars and the reinforcing bars formed in advance on the bottom portion 5 are formed. They are connected by a mechanical joint (not shown).

Next, the integral arch member 36 is horizontally mounted on the side wall portion 6 of the L-shaped member 2. That is, as shown in FIG. 9D, the wire 23 is locked in the vicinity of both ends of the integrated arch member 36. A chain block 24 is connected to the wire 23 in advance. The wire 23 is connected to a crane (not shown), and the integrated arch member 36 is pulled up by the crane. Next, the position of the integrated arch member 36 is finely adjusted by adjusting the length of the wire 23 by the chain block 24, and the integrated arch member 36 is formed into an L-shaped member by the fastening PC steel rod inserted through the insertion hole. Connect to 2. Each time one set of the integrated arch member 36 is installed, the joint portion is filled with mortar, and the integrated arch member 36 and the side wall portion 6 are fixed.

In this way, the same operation is repeated in the tunnel length direction, and when a predetermined number, for example, two sets of the integrated arch members 36 are installed, they are vertically tightened in the tunnel length direction and integrated. After completion of the above work, dismantle and remove the framework and scaffolding.

Needless to say, the L-shaped member 2 may be connected by the spacing member 27.

As described above, since the tunnel structure according to the present embodiment is constructed with the integrated arch member 3, the number of members can be reduced, so that the number of work steps can be reduced and the cost can be reduced.

The present invention is not limited to this embodiment, and various modifications can be made within the scope of the gist of the present invention. For example, in the present embodiment, the tunnel structure in the open-cut method has been described, but the present invention is not limited to this and can be applied as an arch bridge.

It is a longitudinal cross-sectional view which shows the tunnel structure of the large cross section based on this embodiment. It is a longitudinal cross-sectional view which shows the junction part of a side wall part and an arch member same as the above. It is a longitudinal cross-sectional view of the top part as above. It is a figure which shows the construction method of the tunnel of a large section concerning this embodiment in steps. It is a figure which shows the state which installs an arch member same as the above. It is a longitudinal cross-sectional view which shows the modification of this embodiment. It is an external view which shows another modification of this embodiment. It is a longitudinal cross-sectional view which shows the tunnel structure based on 2nd Example of this invention. It is a figure which shows the construction method of a tunnel step by step same as the above.

DESCRIPTION OF SYMBOLS 1 Tunnel structure 2 L-shaped member 3 Arch member 4 Center bottom plate part 9 Top part
17 Embedded

Claims (6)

A pair of left and right precast concrete L-shaped members extending in the tunnel height direction from the bottom side of the tunnel, and an arch member made of precast concrete horizontally placed between the L-shaped members, the L-shaped member, A bottom portion and a side wall portion extending perpendicularly from one end of the bottom portion, the side wall portion being curved inward on the upper side, a connection joint projecting from the upper end surface of the side wall portion, A tunnel structure having a large cross section, which is inserted into a joint receiving portion provided on an arch member . The arch member is large section of the tunnel structure according to claim 1 Symbol mounting, characterized in that it is constituted by being divided into right and left at the top. The arch member is large section of the tunnel structure according to claim 1 or 2 Symbol mounting, characterized in that it comprises an embedded member. The tunnel structure with a large cross section according to any one of claims 1 to 3, wherein a central bottom plate portion is provided between the L-shaped members. The large-section tunnel structure according to any one of claims 1 to 3, wherein a back bottom plate portion is provided on a back surface of the L-shaped member. A pair of left and right precast concrete L-shaped members extending in the tunnel height direction from the tunnel bottom side are installed, the pair of L-shaped members are connected to each other by a spacing member, an arch member is horizontally mounted, and the L-shaped After connecting a member and the said arch member, the said space holding member is removed, The construction method of the tunnel of a large cross section characterized by the above-mentioned.

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