JP3318093B2 - Tunnel structure with precast concrete slab - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an underground tunnel having an arched tunnel wall, and more particularly to a tunnel structure in which the tunnel wall is formed of a precast concrete slab.

[0002]

2. Description of the Related Art When an arched tunnel is to be constructed by an excavation method, a bottom slab extending in the length direction of the tunnel is constructed by casting concrete on site at the bottom of the excavated ground, and concrete is spread across both ends in the width direction of the bottom slab. In general, a method in which a tunnel wall is formed by casting in the shape of an arch and then embankment is applied to cover the tunnel wall. In other words, both the bottom slab and the tunnel wall are constructed by casting concrete in place.

[0003]

In the case of the above-mentioned conventional tunnel structure, particularly when forming an arch-shaped tunnel wall, a self-propelled formwork called a support or a center is arranged on the inner peripheral side, and A fixed formwork is installed on the side and concrete is poured between these forms, but this work is complicated and costly, and the problem is particularly noticeable when constructing a large tunnel with a large cross section. Becomes Also, since the bottom slab and the tunnel wall have a structure that simply relies on the connection between concrete, the thickness of the tunnel wall must be set large to ensure sufficient resistance to earth pressure of the embankment. This leads to an increase in material costs.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a tunnel structure using a precast concrete slab capable of facilitating construction and reducing costs.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and comprises a pair of left and right arc-shaped precast concrete plates between both ends in the width direction of a bottom plate extending in the tunnel length direction. Are connected in the direction of the length of the tunnel while being bridged in an arch shape, and at both ends in the width direction of the bottom slab, the tunnel swells upward at an appropriate distance from the outer surface of the leg outside the leg of each precast concrete slab. A side band extending in the length direction is provided integrally, a pressure receiving member is interposed between the side band and the leg, and the leg is fastened to the side band with a fastening member such as a bolt, and the embankment covers the concrete plate. Is provided.

[0006]

According to the present invention, since an arch-shaped tunnel wall is constructed by assembling a plurality of concrete slabs, the operation is less time-consuming and does not require a formwork as compared with conventional on-site casting. . In addition, since the inward or outward horizontal force generated by the earth pressure of the embankment is received by the fastening member or the pressure receiving member, respectively, the resistance against the earth pressure of the embankment is sufficiently exerted. The thickness can be set thinner than in the case of conventional casting in place.

[0007]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a tunnel 1 to which the present embodiment is applied. The tunnel 1 has a pair of left and right sides disposed between two widthwise ends of a bottom plate 2 extending in the length direction (the front and back directions in FIG. 1). The arc-shaped precast concrete slabs 3 are bridged in an arch shape and are connected in a plurality in the longitudinal direction of the tunnel 1, and the plurality of concrete slabs 3 constitute an arch-shaped tunnel wall 1A.

The tunnel 1 is constructed by an excavation method. First, the bottom slab 2 having a configuration in which the bottom slab 2 having a shape curved downward with respect to the length direction and both ends in the width direction rises is provided at the bottom of the ground G which has been excavated. It is formed by casting. The bottom embankment G1 is back-filled on the bottom slab 2 so that the bottom of the inner space is horizontal, and a road surface or the like is paved here. At both ends in the width direction of the bottom plate 2, side bands 4 bulging upward and extending in the length direction are provided integrally with the bottom plate 2.

A precast concrete slab (hereinafter abbreviated as concrete slab) 3 has a top 3a at one end and a leg 3 at the other end.
b, a reinforced concrete slab formed with a predetermined curvature and a predetermined width. The leg 3b is placed on the bottom slab 2 inside the side band 4, and the tops 3a are abutted against each other and installed in an arch shape. . The arrangement state of the left and right concrete slabs 3 may be equal in width as shown in FIG.
Further, as shown in FIG. 3B, a staggered set shifted by half a width may be used.

As shown in FIG. 2, there is an appropriate gap 5 between the outer surface of the leg 3b of the concrete slab 3 and the side band 4. A bolt (fastening member) 7 is passed through a bolt insertion hole 6 formed through the inside counterbore 6a of the leg 3b, and the bolt 7 is a collar made of a required rigid body disposed at the interval 5. (Pressure receiving member) 8 is screwed into an insert fitting 9 embedded in the side band 4, whereby the leg 3 b is fastened to the side band 4. In this state, the collar 8 is in contact with the opposing surfaces of the side band 4 and the leg 3b. The bolt insertion holes 6 are formed at two locations per concrete slab 3, and are set so that a plurality of concrete slabs 3 are connected at equal intervals as a whole. Then, all the concrete slabs 3 and the side zones 4 are covered, and the cut portion is buried back to fill the embankment G2, thereby forming the tunnel 1.
In addition, the said interval 5 is grouted and water-stop processing is carried out.

According to the tunnel 1 having the above structure, the arch-shaped tunnel wall 1A is constructed by assembling a plurality of concrete slabs 3, so that the work of transporting and assembling the concrete slabs 3 is required, but the conventional technique is required. Compared to on-site casting, the work is less time-consuming and requires no formwork.

In order to backfill the embankment G2, a method of distributing it to left and right cut portions of the concrete slab 3 and backfilling it in a repeated order is generally adopted. It leans inward from the side. As a result, while the embankment G2 is being backfilled, the concrete slab 3 receives a horizontal force inward, but the load is received by the bolt 7 and the concrete slab 3 does not move or deform. When the backfill of the embankment G2 is completed, the earth pressure acts downward, and this time receives a horizontal force outward, but the load is received by the collar 8 and the concrete slab 3 moves or deforms. Absent.
That is, the horizontal force inward and outward is received by the bolt 7 and the collar 8, respectively, so that the resistance against the earth pressure of the embankment G2 is sufficiently exhibited, and thus the tunnel wall 1A is provided.
, That is, the thickness of the concrete slab 3 can be set smaller than in the case of the conventional casting in place.

Due to the above factors, the tunnel 1 of the present structure
Can facilitate construction and reduce costs.

[0014]

As described above, according to the tunnel structure using the precast concrete slab of the present invention, a pair of left and right arc-shaped precast concrete slabs are provided between the both ends in the width direction of the bottom slab extending in the tunnel length direction. And are connected in the length direction of the tunnel, and at both ends in the width direction of the bottom slab, bulge upward at an appropriate distance from the outer surface of the foot outside the foot of each precast concrete slab, and A side band extending in the direction is integrally provided, a pressure receiving member is interposed between the side band and the leg, and the leg is fastened to the side band with a fastening member such as a bolt, and embankment is applied to cover the concrete plate. It is constructed by assembling an arch-shaped tunnel wall with multiple concrete slabs. And the work is not troublesome, the formwork is not required, and the inward or outward horizontal force generated by the earth pressure of the embankment is received by the fastening member or the pressure receiving member, respectively. Sufficiently exhibited, therefore, the thickness of the tunnel wall body, that is, the thickness can be set thinner than in the case of the conventional casting in place, and as a result, simplification of construction and reduction in cost can be achieved. This has the effect.

[Brief description of the drawings]

FIG. 1 is a front sectional view of one embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part.

FIG. 3 is a plan view showing an arrangement state of concrete slabs constituting a tunnel wall, in which (a) is an example and (b) is another example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Tunnel, 1A ... Tunnel wall, 2 ... Bottom plate, 3 ... Precast concrete plate, 3a ... Top part, 3b ... Leg part,
4 ... side band, 5 ... interval, 7 ... bolt (fastening member), 8 ... collar (pressure receiving member), G ... ground, G2 ... embankment.

Continuation of the front page (56) References JP-A-3-137398 (JP, A) JP-A-6-128913 (JP, A) JP-A-5-171895 (JP, A) JP-A-3-191200 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) E02D 29/05 E21D 11/08

Claims (1)

(57) [Claims] 1. A pair of left and right arc-shaped precast concrete slabs are laid in an arch shape and connected in the tunnel length direction between both ends in the width direction of a bottom slab extending in the length direction of the tunnel, and both ends in the width direction of the bottom slab. In the outside of the legs of each precast concrete slab, a side band that bulges upward at an appropriate distance from the outer surface of the legs and extends in the tunnel length direction is integrally provided, and between the side bands and the legs. A tunnel structure using a precast concrete slab, wherein a pressure receiving member is interposed, a leg is fastened to a side band by a fastening member such as a bolt, and the concrete slab is filled with embankment.