JP2878267B1 - Concrete box for underground structures - Google Patents

Abstract

[Problem] To prevent the occurrence of cracks even when receiving a load for pushing out by a propulsion jack or the like, and to be able to efficiently pass this load backward, and to ensure sufficient waterproofness. As a result, highly reliable underground structures can be constructed. SOLUTION: In a concrete box 4 for an underground structure having left and right side plates 4a, 4b and upper and lower floor plates 4c, 4d so as to have openings 15 at front and rear end faces, the concrete box 4 for an underground structure is placed underground. Of the end surfaces of the left and right side plates 4a, 4b and the upper and lower floor plates 4c, 4d located at the front end surface or the rear end surface, which are the joint surfaces when buried sequentially in a tandem state, the ends of the left and right side plates 4a, 4b and their vertical extensions A relatively hard cushioning material 16a and a relatively soft cushioning material 16b having the same thickness are attached to the ends of the upper and lower floor plates 4c and 4d therebetween.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground structure used in an open shield method for constructing an underground structure such as a laid underpass such as water and sewage, a common ditch, a telegraph and a telephone in an urban area and other propulsion methods. It relates to a reinforced concrete box.

[0002]

2. Description of the Related Art The open shield method is a rational method utilizing the advantages of the open cutting method (open cut method) and the shield method. FIGS. 4 to 7 schematically show an open shield machine 1 having a front, rear, and upper surface opened with left and right side walls 1a and a bottom plate 1b connected to these side walls 1a. Machine. In the open shield machine 1, the front ends of the side wall plate 1a and the bottom plate 1b are formed as blades 2, and the propulsion jacks 3 are arranged vertically rearward near the center or near the rear end of the side wall plate 1a.

As shown in FIG. 4, this open shield machine 1 is installed in a starting pit 8, and a propulsion jack 3 of the shield machine 1 is extended to take a reaction force against a reaction wall 9 in the starting pit to shield the shield. The machine 1 is advanced, and the first concrete box 4 forming the underground structure is suspended from above, and is set behind the contracted propulsion jack 3 in the tail portion of the shield machine 1. In the figure, reference numeral 10 denotes a strut, which is disposed between the propulsion jack 3 and the reaction wall 9 for adjusting the distance therebetween. The starting pit 8 is formed of a retaining wall, and the retaining wall is partially mirror-cut to start the open shield machine 1. However, if necessary, a ground improvement 11 May be given.

Next, earth and sand are excavated from the front surface or the upper surface of the open shield machine 1 by an excavator 6 such as a shovel and the earth is discharged. Simultaneously with or after this earth removal step, the propulsion jack 3 is extended to advance the shield machine 1. In the case of this advancing process, a pressing angle 7 composed of a frame using a box steel material or a mold steel is disposed in front of the concrete box 4. Then, the second concrete box 4 is suspended in the tail part of the shield machine 1 before the first concrete box 4. Hereinafter, the same earth removal process, advance process, and setting process of the concrete box 4 are appropriately repeated, and the concrete box 4 is sequentially left in the ground as the open shield machine 1 advances, and the concrete box 4 is further removed. A backfill 5 is applied to the upper surface of 4 and a pavement 12 is applied to the surface.

In this way, when the open shield machine 1 reaches the reaching pit 13, it is removed and the construction is completed. The concrete box 4 is made of reinforced concrete with reinforcing bars, and as shown in FIG.
a, the front and rear surfaces of a right side plate 4b, an upper floor plate 4c, and a lower floor plate 4d have openings 15, and a haunch which is a joint between the left side plate 4a, the right side plate 4b, the upper floor plate 4c, and the lower floor plate 4d. The portion 17 is a corner.

[0006]

In such an open shield method, as described above, the concrete box 4
It is suspended in the tail part of the shield machine 1, leaves the tail part as the open shield machine 1 advances, and remains in the ground. The concrete box 4 receives a reaction force when the propulsion jack 3 is extended in order to advance the shield machine 1. However, although the push angle 7 is arranged at the front part, a considerable load is applied to the front end thereof. This part is split and fractured, and cracks are easily generated.

[0007] Since such cracks have irregularities on the surface of the concrete box 4, the cracks are caused by the fact that the joint surface with the push angle 7 and the joint surface with the concrete box 4 do not overlap uniformly and densely.

In particular, when performing a curve construction, the stroke of the propulsion jacks 3 arranged on the left and right inside the shield machine 1 is made different so that the shield machine 1 is bent and moved forward. Since an uneven load is applied on the left and right sides, cracks are more likely to occur.

As a method of preventing the occurrence of such cracks, a band-shaped cushioning material made of a veneer plate or a rubber plate is widely attached to the joint surface of the concrete box 4, as disclosed in Japanese Utility Model Laid-Open No. 63-194988. There is also.

However, the band-shaped cushioning material disclosed in Japanese Utility Model Laid-Open Publication No. 63-194988 has a uniform thickness and hardness, and when a pressing load of a jack or the like is received, the band-shaped cushioning material is removed. A material that is too soft to transmit the load to a wide rear cylinder through the intermediary is not suitable. On the other hand, a hard cushioning material may impair the waterproofness as a joint.

Further, the pressing load of the jacks and the like is not evenly applied to the left and right side plate ends and the upper and lower floor plates due to the arrangement of the jacks and the like. As a result, the upper and lower floor plates bridged between these left and right side plates are curved. Cracks tend to occur at the ends of the levers.

An object of the present invention is to eliminate the disadvantages of the prior art, to prevent the occurrence of cracks even when receiving a load for pushing by a propulsion jack or the like, and to efficiently pass this load backward. Another object of the present invention is to provide a concrete box for an underground structure capable of constructing an underground structure with high reliability because the water can be sufficiently secured and the waterproof property can be sufficiently secured.

[0013]

In order to achieve the above object, the present invention firstly provides a concrete box for an underground structure having left and right side plates and upper and lower floor plates having openings at front and rear end faces. When the concrete boxes for structures are buried sequentially in the ground in the vertical state, the end faces of the left and right side plates and the upper and lower floor plates located on the front end face or the rear end face, which are the joint faces, A relatively hard cushioning material, and a relatively soft cushioning material with the same thickness attached to the upper and lower floor plate ends in between. Second, the cushioning material is
Third, the cushioning material is such that a relatively hard cushioning material and a relatively soft cushioning material are integrally formed with each other. Fourthly, the relatively hard cushioning material is formed of left and right side plate ends and The gist of the invention is that it is attached to the haunch portion as an extension of the vertical direction.

According to the first aspect of the present invention, even if the concrete box for an underground structure receives a biased pressing load from a propulsion jack or the like, the joint surface of the concrete box for an underground structure is buffered. Since the cushioning material is occupied by the material, the relatively hard cushioning material of this cushioning material does not undergo large compression deformation, and the cushioning material plays the role of efficiently transmitting thrust to the concrete box for the underground structure behind it . Further, the cushioning material has an effect of absorbing unevenness (unevenness) on the end face of the concrete cylinder to prevent cracks.

[0015] The pressing load from the propulsion jack or the like is directly received by the left and right side plates, and when these are pressed, the upper and lower floor plates bridged therebetween are slightly bent to bend.
Since a relatively soft cushioning material is stuck on the joint surface between the upper and lower floor plate ends, even the above-described bending and distortion can be absorbed by a large deformation of the cushioning material, and the occurrence of cracks can be prevented at the center of the upper and lower floor plate ends. It can be prevented from easily occurring in the part. In addition, since a relatively hard cushioning material and a relatively soft cushioning material are attached with the same thickness, uniform joints can be secured at the beginning of the installation of the concrete box for underground structures, and there is no danger of damaging water stoppage etc. Absent.

According to the second aspect of the present invention, in addition to the above functions, the buffer material is a rubber plate, for example, to change the degree of vulcanization, or to add a foaming substance or a water-swelling substance. By changing the content and ratio of the object, a relatively hard cushioning material and a relatively soft cushioning material can be easily produced.

According to the third aspect of the present invention, the cushioning material is a relatively hard cushioning material and a relatively soft cushioning material are integrated with each other, so that the labor for attaching the concrete box for underground structures is reduced. However, there is little risk of position rubbing, etc. once.

According to the fourth aspect of the present invention, a relatively hard cushioning material is attached to the haunch portion where cracks are less likely to be formed, so that a relatively large bonding area of the relatively hard cushioning material is secured. It can be firmly fixed and can be made less likely to rub. Note that a relatively soft cushioning material is interposed at the center of the upper and lower floor plates at which cracks easily occur, so that the occurrence of the cracks can be effectively prevented.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view showing a first embodiment of a concrete box for an underground structure of the present invention, and FIG. 2 is a perspective view showing a second embodiment of the same.

The concrete box 4 is made of reinforced concrete with reinforcing bars as in the conventional example shown in FIG. 3, and includes a left side plate 4a, a right side plate 4b, an upper floor plate 4c, and a lower floor plate 4.
d, and has openings 15 in the front and rear surfaces, and a haunch portion 17 which is a joint between the left side plate 4a, the right side plate 4b, the upper floor plate 4c, and the lower floor plate 4d is defined as a corner.

The present invention is directed to such a concrete box 4
The buffer material 16 is stuck in a wide band on the front end face or the rear end face, which is the joining surface when they are sequentially buried in the ground in a vertical state, but this buffer material 16 is relatively soft with a relatively hard buffer material 16a. It consisted of two types, the cushioning material 16b, and was attached with the same thickness.

Among them, the relatively hard cushioning material 16a is attached so as to cover the end surfaces of the left side plate 4a and the right side plate 4b located on the front end surface or the rear end surface, and the haunch portion 17 which is an extension of the left and right plates.

On the other hand, a relatively soft cushioning material 16b is attached to the end surfaces of the upper floor plate 4c and the lower floor plate 4d located between the haunch portions 17.

Each of the relatively hard cushioning material 16a and the relatively soft cushioning material 16b is a natural or synthetic rubber plate, and the degree of vulcanization depends on whether the material is relatively hard or relatively soft. Alternatively, it is formed by vulcanization or unvulcanization.

In still another embodiment, the rubber plate serving as the cushioning material 16 may be a mixture of a synthetic resin foam material and a water-swellable material. By adjusting the ratio, it is possible to make the material relatively hard or relatively soft.

The relatively hard cushioning material 16a and the relatively soft cushioning material 16b may be formed separately and bonded together to cover the joint surface of the concrete box 4, but as a second embodiment, As shown in FIG. 2, the relatively hard cushioning material 16a and the relatively soft cushioning material 16b may be integrated.

If the cushioning material 16 is attached only to one end joining surface of the concrete cylinder 4, the joining surface of the other concrete cylinder 4 where the cushioning material 16 does not have the cushioning material 16 when arranged in tandem. You will be in contact with this. Also, as another embodiment,
The cushioning material 16 is provided on the joint surface of both ends of the concrete cylinder 4,
It is also possible to alternately arrange the concrete cylinders 4 with the cushioning material 16 and the concrete cylinders 4 without the cushioning material 16 at all.

The general outline of the open shield method using the concrete box 4 of the present invention is as shown in FIGS. 4 to 7 and detailed description is omitted. By repeating the setting process of the box 4, the concrete box 4 is sequentially left underground as the open shield machine 1 advances, and the upper surface of the concrete box 4 is backfilled 5.

In this case, the concrete box 4 receives a reaction force when the propulsion jack 3 is extended to move the shield machine 1 forward. Since it is arranged on the joint surface of the body 4, there is no possibility of cracking due to split fracture. This is the same in the case of performing a curve construction. The stroke of the propulsion jacks 3 arranged on the left and right inside the shield machine 1 is made different and the shield machine 1 is bent and advanced, and the concrete box 4 is also moved left and right. Unequal load, but can prevent the occurrence of cracks.

Further, even in the case of using a propulsion method other than the open shield method and a method in which the load of the propulsion jack is similarly applied, cracks can be similarly prevented.

[0031]

As described above, the concrete box for underground structures according to the present invention can prevent the occurrence of cracks even under the load for pushing out by the propulsion jack or the like. This load can be efficiently dissipated to the rear by properly using a hard cushioning material and a relatively soft cushioning material, and the waterproof property can be sufficiently secured, so that a highly reliable underground structure can be constructed. .

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a concrete box for an underground structure according to the present invention.

FIG. 2 is a perspective view showing a first embodiment of a concrete box for an underground structure according to the present invention.

FIG. 3 is an external perspective view of a concrete box for an underground structure.

FIG. 4 is a vertical sectional side view of a first step showing an outline of an open shield method.

FIG. 5 is a vertical side view of a second step showing an outline of the open shield method.

FIG. 6 is a vertical sectional side view of a third step showing an outline of the open shield method.

FIG. 7 is a vertical side view of a fourth step showing an outline of the open shield method.

FIG. 8 is a plan view showing a state of occurrence of cracks in a concrete box for an underground structure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Open shield machine 1a ... Side wall plate 1b ... Bottom plate 2 ... Blade hole 2a ... Slide earthing plate 3 ... Propulsion jack 4 ... Concrete box 4a ... Left side plate 4b ... Right side plate 4c ... Upper floor plate 4d ... Lower floor plate 5 ... Backfill 6 ... excavator 7 ... push angle 8 ... starting pit 9 ... reaction wall 10 ... strut 11 ... ground improvement 12 ... pavement 13 ... arrival pit 15 ... opening 16 ... cushioning material 16a ... relatively hard cushioning material 16b ... relatively soft cushioning Material 17 ... Haunch part

Claims (4)

(57) [Claims] 1. A concrete case for an underground structure comprising left and right side plates and upper and lower floor plates having openings at front and rear end faces, wherein the concrete case for an underground structure is sequentially buried in the ground in a vertical state. Of the end surfaces of the left and right side plates and the upper and lower floor plates located at the front end surface or the rear end surface, which are the joining surfaces of the left and right floor plates, relatively hard cushioning material is provided on the left and right side plate ends and their vertical extension, and the upper and lower floor plate ends between them are compared. A concrete cylinder for underground burying, characterized in that soft cushioning material is stuck with the same thickness. 2. The underground concrete cylinder according to claim 1, wherein the cushioning member is a rubber plate. 3. The concrete cylinder for underground burying according to claim 1, wherein the cushioning material is a relatively hard cushioning material and a relatively soft cushioning material integrated with each other. 4. A relatively hard cushioning material is attached to the left and right side plate ends and the vertical extension thereof to the haunch portion.
A concrete tubular body for underground burial according to any one of claims 3 to 3.