JP2000186331A - Large-section tunnel and method for constructing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily construct a large-section tunnel without increasing cost. SOLUTION: A plurality of precast walls 21 of a wall portion 22 forming an internal surface of a tunnel main body 1 are erected on the upper portion of each of bases 13 of an invert 12. Each of the precast walls 21 has a rib portion 23 formed thereon along the peripheral direction of a tunnel. The precast walls 21 are connected to each other in the tunnel shaft direction. Further, a cage type reinforcement is arranged in a depression 24 between the rib portions 23, and a form plate 33 is installed on the external periphery of the precast wall 21. Further, concrete C is placed between the precast wall 21 and the form plate 33, to thereby construct a side wall portion 15. Then, a precast slab 41 is mounted on the upper portion of each side wall portion 15 to complete an arch tunnel 11, and thereafter back-filling is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large-section tunnel constructed by an open-cutting method and a method of constructing the tunnel.

[0002]

2. Description of the Related Art As one method of constructing a tunnel, a ground is cut and a two-part precast arch plate 1 formed by a forming die is formed on the cut portion at a site as shown in FIG. There is known an open-cutting method or the like in which an arched tunnel 2 is assembled by assembling the tunnels with each other and then backfilled.

[0003]

The construction method of the tunnel by the open-cutting method using the precast arch plate 1 has an advantage that the construction is easy. However, when the tunnel 2 to be constructed has a large cross section, However, the size of the arch plate 1 has been increased, and the following problems have been encountered. . The mold for molding the large arch plate 1 also becomes large, and the equipment cost increases. In addition, it is difficult to manufacture a reinforcing bar disposed inside, and furthermore, a large overhead crane for moving the formed arch plate 1 is required.
Equipment costs increase. . The transport truck has limitations on the size of the load and the load weight, and therefore, it is difficult to transport the large arch plate 1. . A large stock yard is needed to store the large arch version 1 at factories and sites. . A heavy machine such as a large crane for lifting the large arch plate 1 is required at the site, and various restrictions occur at the site by using such a heavy machine.

[0004] That is, it was extremely difficult to construct a large-section tunnel using a large arch version 1. here,
What is necessary is just to divide this arch version 1 into a plurality and make it smaller,
When the arch plate 1 is divided into a plurality of portions, joint portions between the arch plates are formed at a plurality of positions in the circumferential direction, and the tunnel 2 becomes unstable.

The present invention has been made in view of the above circumstances, and has as its object to provide a large-section tunnel which can be easily constructed without increasing the cost, and a method of constructing the tunnel.

[0006]

In order to achieve the above object, a large-section tunnel according to claim 1 is a large-section tunnel constructed by an open-cutting method that is assembled on an open-cut ground and then backfilled. And a bottom plate portion and an arched tunnel body provided on the bottom plate portion,
The tunnel body has side walls forming side portions of the tunnel body, and a ceiling portion connected to upper ends of the side wall portions to form an upper portion of the tunnel body. The side walls are provided with reinforcing bars on the outer peripheral side of the precast walls joined to each other in the tunnel axial direction, and concrete is cast to bury the reinforcing bars. It is characterized by becoming.

Thus, the arch-shaped tunnel body is
It is composed of a side wall part forming both sides thereof and a ceiling part connected to the upper ends of these side wall parts to form an upper part of the tunnel main body, and this ceiling part is formed of a precast plate which is abutted and joined to each other. As a result, the size of the precast plate can be significantly reduced as compared with a case where the entire tunnel main body is formed of precast plates joined to each other by butting. This makes it possible to reduce the size of the forming frame for the precast plate and the reinforcing bars disposed inside, and also eliminates the need for a large overhead crane, thereby reducing equipment and manufacturing costs. . In addition, with the miniaturization of the precast plate, the precast plate can be easily transported on trucks with restrictions on the size of the load and the loading weight.
A large stock yard at the site can be dispensed with, and heavy equipment such as a large crane at the site is also unnecessary, so that restrictions at the site can be eased. Further, since the precast wall is also used for the side wall part constituting the tunnel main body, the work of constructing the side wall part can be facilitated.

According to a second aspect of the present invention, there is provided a tunnel having a large cross section, wherein the precast wall has a wall portion forming an inner surface of a tunnel body and an outer peripheral side of the wall portion, which is arranged in a tunnel circumferential direction. When the precast walls are joined to each other in the tunnel axis direction, the reinforcing bars are arranged in concave portions formed between the rib portions. It is characterized by being established.

That is, the precast wall used for the side wall portion is formed on the outer peripheral side of the wall portion forming the inner surface of the tunnel body.
Since the rib portion is formed in a T-shaped cross section along the circumferential direction of the tunnel, the strength of the precast wall can be greatly increased. In addition, since the reinforcing bars are arranged in the recesses between the rib portions formed by joining these precast walls in the tunnel axis direction, the work of arranging the reinforcing bars at the time of construction can be easily performed. In addition, the construction work of the side wall portion can be facilitated.

According to a third aspect of the present invention, there is provided a method for constructing a large-section tunnel, wherein the ground is cut and a bottom slab is formed on the cut ground.
A method of constructing a large-section tunnel consisting of an arch-shaped tunnel body provided on the bottom slab, and then constructing a large-section tunnel by an open-cutting method that refills the tunnel, and is constructed on open-cut ground A side wall is constructed by supporting a precast wall on the upper side of both sides of the bottom slab, arranging a reinforcing bar on the outer periphery thereof and casting concrete, and an upper end of the side wall is provided with a tunnel periphery. The feature is that the ceiling is constructed by assembling precast plates that face each other.

As described above, the side walls constituting both sides of the tunnel main body are constructed on the upper portions on both sides of the bottom slab,
Since the ceiling is constructed by assembling a precast plate that is abutted in the tunnel circumferential direction on the upper end of these side walls,
Compared to a case where the entire tunnel main body is formed of precast plates that are abutted and joined to each other, a smaller precast plate can be used as the precast plate that forms the ceiling. As a result, the workability of assembling the precast plate at the site can be greatly improved, and a small-sized heavy machine such as a crane for assembling the precast plate can be used, greatly reducing work restrictions at the site. Is done. Furthermore, since the precast wall is joined in the axial direction of the tunnel, a reinforcing bar is arranged on the outside, a formwork plate is installed, and concrete is filled, eliminating the need for a formwork on the inner surface side when constructing the side wall. And the construction work can be simplified.

According to a fourth aspect of the present invention, there is provided a method of constructing a large-section tunnel, wherein the precast wall constituting the side wall portion is provided as the pre-cast wall.
A precast wall having a T-shaped cross section having a wall portion forming the inner surface of the tunnel body and a rib portion formed along the tunnel circumferential direction on the outer peripheral side of the wall portion is used. Direction, and a reinforcing bar is arranged between the ribs of these precast walls, and a formwork plate is provided on the outer peripheral side, and concrete is cast between the wall portion and the formwork plate. It is characterized by.

As described above, the precast wall is formed on the outer peripheral side of the wall constituting the inner surface of the tunnel main body by forming the rib portion along the tunnel circumferential direction to enhance the strength of the precast wall having a T-shaped cross section. Since it is used, a side wall having sufficient strength can be constructed. In addition, since the reinforcing bars are provided in the concave portions between the rib portions formed by joining these precast walls in the tunnel axial direction, the work of arranging the reinforcing bars can be easily performed, and the work of constructing the side wall portion can be performed. Can be facilitated.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a large section tunnel according to the present invention and a method of constructing the tunnel. In FIG. 1, reference numeral 11 denotes a large-section tunnel. The tunnel 11 includes an invert (bottom plate portion) 12 constructed by on-site construction, and an arch-shaped tunnel main body 14 constructed to bridge over a base portion 13 on both sides of the invert 12. . Tunnel body 14
Has side walls 15 on both sides and a ceiling 1 on the middle.
6.

As shown in FIG. 2 to FIG.
A plurality of precast walls 21 joined in the axial direction of the tunnel
And concrete C cast on the outer peripheral side of the precast wall 21. The precast wall 21
As shown in FIGS. 5 and 6, a wall portion 22 forming an inner peripheral surface of the side wall portion 15 and a rib portion 23 formed along the tunnel circumferential direction are formed in a T-shaped cross section. so,
The wall portion 22 is provided with a joint portion 22a that is joined to each other in the tunnel axial direction by bolts and nuts.

When these precast walls 21 are joined to each other in the tunnel axial direction, the respective precast walls 21
A cage-type reinforcing bar (rebar) 25 is provided in a concave portion 24 formed between the rib portions 23. In the precast wall 21, a plurality of insertion holes 26 are formed in the rib portion 23, and force distribution bars 27 are inserted through the insertion holes 26 along the tunnel axis direction.

The precast wall 21 has a rib 23
A flange portion 29 having an insertion hole 28 formed therein is provided at the lower end thereof. An anchor frame 30 erected on the base portion 13 of the invert 12 is inserted through the insertion hole 28 of the flange portion 29. I have. Further, a plurality of anchor bars 31 are erected on the base portion 13, and the anchor bars 31 are attached to the cage type reinforcing bars 2 provided in the recess 24.
Wrapped with 5. Also, on the outer peripheral side of the concave portion 24,
Form plates 33 are provided respectively, and these form plates 3
3 is screwed and fixed to an insert nut (not shown) provided on the rib portion 23 of the precast wall 21.

The ceiling 16 is provided with a pair of precast plates 41.
One end of each precast plate 41 is a joint end 41a to be joined to each other, and is fastened and fixed with, for example, bolts and nuts. The precast plate 41 is formed from high-strength concrete and has a reduced thickness.

The other end of the precast plate 41 forming both ends of the ceiling portion 16 is a connection end 41b with the upper end of the side wall portion 15. The connecting end 41b has a flange portion 42 protruding in the outer peripheral direction and the thickness thereof is substantially the same as the thickness of the side wall portion 15. The flange portion 42 of the connecting end 41b has a thickness in the axial direction of the tunnel. A plurality of communication holes 43 are formed at intervals.

The communication hole 43 is provided in the side wall portion 15.
The connecting bar 44 erected at the upper end of the is inserted. The connecting bar 44 has an upper end protruding above the flange portion 42 of the precast plate 41, and a nut 40 is screwed and fastened to the protruding portion.

Next, a case where the tunnel 11 having the above structure is constructed will be described. (1) First, the invert 12 is constructed by cast-in-place concrete. (2) Next, the anchor frame 30 of the base part 13 is inserted into the insertion hole 28 of the flange part 29 on the upper part of the base part 13 of the invert 12 while the precast wall 21 is inserted.
And a nut 32 is screwed into the anchor frame 30 and fastened and fixed.

(3) The precast walls 21 erected on the base portion 13 as described above are joined and fixed together with bolts and nuts at the joint portions 22a of the wall portions 22. By doing so, a concave portion 24 is formed between the rib portions 23 of the precast wall 21. (4) Then, a cage type reinforcing bar 25 is provided in the concave portion 24. (5) Further, the force distribution bars 27 are inserted into the insertion holes 26 formed in the respective rib portions 23 of the precast walls 21. (6) Next, by fixing the form plate 33 to the rib portion 23 of the precast wall 21 by screwing, the concave portion 24 formed between the rib portions 23 is covered with the form plate 33.

(7) In this state, concrete C is poured into each of the concave portions 24 closed by the form plate 33, and the side wall portion 15 is completed. In addition, the mold plate 33 used when constructing the side wall portion 15 may be removed after the concrete C is hardened, or may be used as a discard mold to be buried and killed. (8) Next, the precast plate 41 is set on the upper end of the side wall 15 constructed as described above. That is, the flange portion 42 constituting the connection end 41b of the precast plate 41
The connecting end 41b is placed on the side wall portion 15 while the connecting bar 44 provided at the upper end of the side wall portion 15 is inserted into the communication hole 43 formed in the precast plate 41.
Butts are joined together and joined by bolts and nuts. Further, the nut 40 is screwed into the connecting bar 44,
The flange 11 of the precast plate 41 is fastened and fixed to the upper end of the side wall 15 to complete the tunnel 11, and thereafter,
This tunnel 11 is backfilled.

As described above, according to the above-described large-section tunnel and the method of constructing the same, the arch-shaped tunnel body 14 is
Side walls 15 forming both sides thereof;
And the ceiling 16 which is connected to the upper end of the tunnel main body 14 and constitutes the upper part of the tunnel main body 14. Since the ceiling 16 is formed of a precast plate 41 which is abutted and joined to each other, the entire tunnel main body 14 is The precast plate 41 can be significantly reduced in size as compared with the case where the precast plate 41 is formed by abutting and joining with each other.

As a result, it is possible to reduce the size of the mold for forming the precast plate 41 and the reinforcing bars disposed inside the precast plate 41, and it is also unnecessary to use a large overhead crane, thereby reducing equipment costs and manufacturing costs. Can be planned. Also,
With the miniaturization of the precast plate 41, the size of the cargo,
Pre-cast version 4 on trucks with limited loading capacity
1 can be easily transported. In addition, a large stock yard can be eliminated in factories and sites, and heavy machinery such as a large crane in the site is not required, so that restrictions on the site can be reduced.

Further, since the precast wall 21 is also used for the side wall portion 15 constituting the tunnel main body 14,
The construction work of the side wall portion 15 can be facilitated. Also, since the precast wall 21 is joined in the tunnel axial direction, the cage type reinforcing bar 25 is disposed outside the form plate 33 and the concrete C is filled, so that the concrete C is filled. Can be eliminated, and the construction work can be simplified.

The precast wall 21 used for the side wall 15 is formed by the wall 2 forming the inner surface of the tunnel body 14.
2 has a T-shaped cross section in which a rib portion 23 is formed along the circumferential direction of the tunnel, so that the strength of the precast wall 21 can be greatly increased, and the side wall portion having sufficient strength 15 can be set. Further, since the cage type reinforcing bar 25 is disposed in the concave portion 24 between the rib portions 23 formed by joining these precast walls 21 in the tunnel axis direction, the cage type reinforcing bar 25 is arranged at the time of construction. The installation work can be easily performed, and the construction work of the side wall portion 15 can be facilitated.

[0028]

As described above, according to the large-section tunnel and the method of constructing the same according to the present invention, the following effects can be obtained. According to the large-section tunnel according to the first aspect, the arch-shaped tunnel main body is composed of the side walls forming the both sides thereof, and the ceiling connected to the upper ends of these side walls to form the upper part of the tunnel main body. Since this ceiling is composed of precast plates that are joined and joined to each other, the precast plate is greatly reduced in comparison with the case where the entire tunnel body is composed of precast plates that are joined and joined to each other. It can be downsized. This makes it possible to reduce the size of the forming frame for the precast plate and the reinforcing bars disposed inside, and also eliminates the need for a large overhead crane, thereby reducing equipment and manufacturing costs. . In addition, with the miniaturization of precast plates, precast plates can be easily transported on trucks with limited cargo size and loading weight, and there is no need for large stockyards at factories and sites. In addition, heavy equipment such as a large crane at the site becomes unnecessary, and the restrictions at the site can be reduced. Further, since the precast wall is also used for the side wall part constituting the tunnel main body, the work of constructing the side wall part can be facilitated.

According to the large-section tunnel according to the second aspect,
Since the precast wall used for the side wall portion has a T-shaped cross section in which a rib portion is formed along the tunnel circumferential direction on the outer peripheral side of the wall portion constituting the inner surface of the tunnel main body, the strength of the precast wall is Can be greatly increased.
In addition, since the reinforcing bars are arranged in the recesses between the rib portions formed by joining these precast walls in the tunnel axis direction, the work of arranging the reinforcing bars at the time of construction can be easily performed. In addition, the construction work of the side wall portion can be facilitated.

According to the method for constructing a large-section tunnel according to the third aspect, side walls constituting both sides of the tunnel main body are constructed on both sides of the bottom slab, and the upper ends of these side walls are arranged in the tunnel circumferential direction. Since the ceiling is constructed by assembling the precast plate to be abutted against, compared to the case where the entire tunnel body is composed of the precast plate to be joined and joined to each other, a small precast plate constituting the ceiling is used. be able to. As a result, the workability of assembling the precast plate at the site can be greatly improved, and a small-sized heavy machine such as a crane for assembling the precast plate can be used, greatly reducing work restrictions at the site. Is done. Furthermore, since the precast wall is joined in the axial direction of the tunnel, a reinforcing bar is arranged on the outside, a formwork plate is installed, and concrete is filled, eliminating the need for a formwork on the inner surface side when constructing the side wall. And the construction work can be simplified.

According to the method for constructing a tunnel having a large cross section according to the fourth aspect, the precast wall has a rib portion formed on the outer peripheral side of the wall portion forming the inner surface of the tunnel body along the circumferential direction of the tunnel, thereby achieving high strength. Since the precast wall having a T-shaped cross section is used, a side wall having sufficient strength can be constructed. In addition, since the reinforcing bars are provided in the concave portions between the rib portions formed by joining these precast walls in the tunnel axial direction, the work of arranging the reinforcing bars can be easily performed, and the work of constructing the side wall portion can be performed. Can be facilitated.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a large-section tunnel illustrating an embodiment of the present invention and a method of constructing the tunnel.

FIG. 2 is a cross-sectional view of a part of the large-section tunnel illustrating a large-section tunnel and a method of constructing the same according to an embodiment of the present invention.

FIG. 3 is an exploded side view of the large-section tunnel illustrating an embodiment of the present invention and a method of constructing the tunnel;

FIG. 4 is a cross-sectional view of a side wall portion of the large-section tunnel for explaining the large-section tunnel and the method of constructing the same according to the embodiment of the present invention.

FIG. 5 is a side view of a precast wall used for a side wall of the large-section tunnel for explaining the large-section tunnel and the method of constructing the same according to the embodiment of the present invention.

FIG. 6 is a front view of a precast wall used for a side wall of the large-section tunnel for describing the large-section tunnel and the method of constructing the same according to the embodiment of the present invention.

FIG. 7 is a schematic perspective view of a tunnel showing an example of a tunnel using a precast plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Large section tunnel 12 Invert (bottom plate part) 14 Tunnel main body 15 Side wall part 16 Ceiling part 21 Precast wall 22 Wall part 23 Rib part 24 Concave part 25 Reinforcing bar 33 Form plate 41 Precast plate C concrete

Claims (4)

[Claims] 1. A large-section tunnel constructed by an open-cutting method that is rebuilt after being assembled on an excavated ground, comprising: a bottom plate portion; and an arched tunnel main body provided on the bottom plate portion. The tunnel body has side walls forming side portions of the tunnel body, and a ceiling portion connected to upper ends of the side wall portions to form an upper portion of the tunnel body. The side wall is provided with a reinforcing bar on the outer peripheral side of the precast wall joined to each other in the axial direction of the tunnel, and concrete is struck so as to bury the reinforcing bar. A large section tunnel characterized by being installed. 2. The precast wall is formed to have a T-shaped cross section having a wall portion forming an inner surface of a tunnel main body and a rib portion formed on an outer peripheral side of the wall portion along a tunnel circumferential direction. The rebar is arranged in a recess formed between the rib portions when the precast walls are joined in the tunnel axial direction.
The large section tunnel described. [3] The ground is cut out, and on the cut ground,
A method of constructing a large-section tunnel composed of a bottom slab portion and an arch-shaped tunnel body provided on the bottom slab portion, and thereafter constructing a large-section tunnel by an open-cutting method of backfilling the tunnel. A side wall is constructed by supporting a precast wall on both sides of the bottom slab constructed on the ground, arranging a reinforcing bar on the outer peripheral side and pouring concrete, and an upper end of the side wall. A method of constructing a large-section tunnel, comprising: assembling a precast plate that abuts in a circumferential direction of the tunnel to construct a ceiling. 4. A cross section having, as the precast wall forming the side wall portion, a wall portion forming an inner surface of a tunnel body and a rib portion formed on an outer peripheral side of the wall portion along a tunnel circumferential direction. Using a T-shaped precast wall, the precast walls are joined to each other in the tunnel axial direction, a reinforcing bar is provided between the ribs of these precast walls, and a form plate is provided on the outer peripheral side, The method for constructing a large-section tunnel according to claim 3, wherein concrete is cast between the portion and the formwork plate.