JP3790200B2 - Construction method of excavated underground structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an excavation underground structure construction method constructed when a road or a railroad is laid in the ground, and particularly proposes a construction method of a water stop portion of a joint portion.
[0002]
[Prior art]
FIG. 3 shows an example of a general excavated underground structure. In the figure, 1 is the ground surface, 2 is the excavation split constructed by excavating the ground surface, and 3 shows the excavated underground structure built inside the excavation split 2.
The excavated underground structure 3 is formed by pouring concrete into the formwork inside the excavation split 2. Since the construction method of constructing the open-cut underground structure 3 by repeating the construction of the formwork and the pouring of concrete is adopted, joints (joints) are formed at every required distance.
[0003]
A joint is unavoidably formed due to the construction method, but a joint having the following two functions has been practically used.
1. A joint for displacing the excavated underground structure 3 following the displacement of the ground when the ground is displaced by an earthquake, etc.
2. A joint to prevent cracking when concrete shrinks and deforms,
And exist.
The former is generally called a structural joint and is formed at intervals of about 20 to 30 m. The latter is called an induction joint and is formed at intervals of about 4 to 6 m. In FIG. 3, 4 is a structural joint, and 5 is an induction joint.
[0004]
FIG. 4 shows an example of the structure of the structural joint. The cross section shown in FIG. 4 is a cross sectional view of any of AA, BB, CC, and DD shown in FIG.
In the case of the structural joint 4, a joint material 6 such as elastite is filled between the structures 3-1 and 3-2, and a reaction force is generated between the structures 3-1 and 3-2. The main reinforcing bar 7-1 is stretched in the circumferential direction of the structures 3-1 and “3-2”, and the distribution bar 7-2 is stretched in the extending direction. The structures 3-1 and 3-2 are connected by a power distribution bar 7-3 stored in the sheath tube. Both ends of the power distribution bar 7-3 are fixed to the concrete constituting the structures 3-1 and 3-2, and are stored in the sheath tube at each joint portion of the structures 3-1 and 3-2. With this structure, when the compressive load and tensile load are applied to the structures 3-1 and 3-2, the end surfaces of the structures 3-1 and 3-2 are deformed by the stretching of the distribution bar 7-3. The structure prevents the extreme load from being applied to the portion, and prevents the end surface portion from being cracked due to the expansion and contraction of the distribution bar 7-3.
[0005]
8 shows the water stop board provided in the joint part. As shown in FIG. 6, this water stop plate is composed of a cavity portion 8-1 and fin portions 8-2 projecting on both sides of the cavity portion 8-1, and is made of an elastic material such as rubber. It is formed. The cavity portion 8-1 is arranged at the joint portion, and the fin portion 8-1 is inserted and fixed to the concrete constituting the structures 3-1 and 3-2.
FIG. 5 shows a cross-sectional structure of the induction joint 5. In the case of the induction joint 5, the joint is simply constituted by a concrete joint surface, and the water stop plate 8 is inserted across the joint surface.
[0006]
[Problems to be solved by the invention]
In the case of the joint structure using the conventional water stop plate 8, it is difficult to pour the concrete tightly in contact with the fin portion 8-2 of the water stop plate 8 when the concrete is driven in, and it is in contact with the fin portion 8-2. As a result, cavities are often formed in concrete. For this reason, there exists a fault with a bad water stop. In addition, when concrete is poured into the fin portion 8-2, there is a disadvantage that it takes time and workability is poor.
Furthermore, although the water stop plate 8 is made of an elastic material such as rubber, there is also a drawback that an accident that breaks at the time of an earthquake occurs due to insufficient elastic deformation for a large displacement.
[0007]
For this reason, water-stopping rubbers with Ω-shaped cross-sectional shapes have been proposed, but water-stopping rubbers with Ω-shaped cross-sectional shapes are expensive and economical to use in large quantities in long-distance excavated underground structures It is difficult to.
The object of the present invention is to propose a method for constructing an open-cut underground structure having high water-stopping performance and good workability during construction.
[0008]
[Means for Solving the Problems]
In this invention, a structure is cast in place for each unit length inside the cut groove, and a joint is provided every time the cast structure is hardened, and another structure is cast in place. In the excavation underground structure construction method to construct a thing,
[0009]
Cover the outer peripheral surface of the end that should be a joint with another structure of the cured structure with water-swelling water-stopping rubber in a band shape, and coat the peripheral surface of this water-swelling water-stopping rubber with a band-shaped protective steel plate At the same time, half of the band-shaped protective steel plate in the width direction protrudes in parallel with the surface to be the outer peripheral surface of the structure to be constructed next, and the structure of the structure to be constructed next to the projecting protective steel plate A water expansion waterproof rubber is held on a surface facing the outer peripheral surface, and another structure is cast in place in this state.
[0010]
Action According to the present invention, at least the outer periphery of the joint serving as a joint is provided with a structure that seals the outer periphery of the joint by applying water-expanding water-stopping rubber at substantially equal intervals from the joint and further expanding the water expansion. Since the outer periphery of the water-stopping rubber is covered with a protective steel plate, the sealing performance is high and high water-stopping performance can be obtained.
In particular, when a non-vulcanized rubber is used as the water-expandable water-stopping rubber, the non-vulcanized rubber has a high affinity for concrete and a strong adhesive force can be obtained. As a result, strong sealing performance can be obtained.
[0011]
Furthermore, since the unvulcanized rubber has a tensile elongation performance of 1000% or more, there is no possibility that a fracture accident will occur even if the joint is greatly deformed. As a result, a highly reliable water stop structure can be provided.
Furthermore, according to this invention, since it is not the structure inserted in the inside of concrete, the advantage that workability is good is also acquired.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of an excavated underground structure according to the present invention. The cross section shown in FIG. 1 also shows one of the cross sections AA, BB, CC, and DD shown in FIG. In the present invention, the joint structure according to the present invention is applied at intervals of 4 to 6 m without making a distinction between the structural joint 4 shown in FIG. 4 and the induction joint 5 shown in FIG. 5.
In the embodiment shown in FIG. 1, the structure 3-1 and 3-2 are provided with a force distribution bar 7-2, and the structures 3-1 and 3-2 are connected with the force distribution line 7-2. The water-expanding water-stopping rubber 11-1 is applied to the outer periphery of the joint across the joint, and the outer periphery of the water-expanding water-stopping rubber 11-1 is covered with a protective steel plate 12-1. is there.
[0013]
Non-vulcanized rubber is used as the water expansion water-stopping rubber 11-1. Non-vulcanized rubber has a property of hydrating with cement to concrete and strongly adhering to the concrete surface. Non-vulcanized butyl rubber straddles the joints and at approximately equal distances (extension direction of the structures 3-1 and 3-2), for example, the outer peripheral surfaces of the structures 3-1 and 3-2 over a width of about 70 to 80 mm from the joints. Adhere to both sides. The thickness is about 20 mm. In the embodiment shown in FIG. 1, the water expansion / stop rubber 11-2 is also applied to the inner peripheral surfaces of the structures 3-1 and 3-2, and the inner peripheral surface thereof is covered with a protective steel plate 12-2. Shows the case. The protective steel plates 12-1 and 12-2 can be strip-shaped zinc steel plates having a thickness of about 3 mm and a width w of about 200 mm.
[0014]
Furthermore, in this embodiment, a case is shown in which the joint portion is filled with a joint material 6 such as extite to give a reaction force between the adjacent structures 3-1 and 3-2. In this way, by filling the joint material 6 and giving a reaction force between the adjacent structures 3-1 and 3-2, the end surfaces of the structures 3-1 and 3-2 against the compressive load. Can prevent damage.
As a construction method for covering the water expansion waterproof rubber 11-1 and 11-2 and the protective steel plates 12-1 and 12-2, the water expansion waterproof rubber is applied to the end of the structure 3-1 on the side where the concrete is hardened, for example. 11-1 and 11-2 are deposited, and further, protective steel plates 12-1 and 12-2 are coated on the outer periphery. In this state, the water expansion waterproofing rubbers 11-1 and 11-2 to be attached to the structure where concrete is to be placed are held by the protective steel plates 12-1 and 12-2. And the concrete of the structure 3-2 to be constructed next is placed on the surfaces of the water-expanding water-stopping rubbers 11-1 and 11-2 held by 12-2, and the structure 3-2 is constructed. .
[0015]
As described above, according to the present invention, since the waterproof rubbers 11-1 and 11-2 are not inserted into the concrete, the concrete placing work can be performed simply and the workability is compared with the conventional case. Greatly improved.
FIG. 2 shows a modified embodiment of the present invention. In this embodiment, a case is shown in which the force distribution muscles connecting the structures 3-1 and 3-2 are force distribution muscles 7-3 stored in the sheath tube 13. That is, both ends of the distribution bar 7-3 are fixed to the concrete of the structures 3-1 and 3-2, and the distribution bar 7-3 is stored in the sheath tube 13 at the joint, and the distribution force is stored inside the sheath tube 13. A case where the muscle 7-3 can be freely expanded and contracted is shown.
[0016]
With this structure, as described with reference to FIG. 4, when a compressive load and a tensile load are applied to the structures 3-1 and 3-2, the structures 3-1 and 3- Accidents in which the end face of 2 is damaged can be prevented. As another structure, in this embodiment, an end face reinforcing bar 14 is provided, and the strength of each end face of the structures 13-1 and 13-2 is reinforced. Since the structure of other parts is the same as that of FIG. 1, further explanation is omitted here.
[0017]
【The invention's effect】
As described above, according to the present invention, the water stop performance is high, and even if the joints are greatly deformed, the water expansion water stop rubbers 11-1 and 11-2 are not broken, so that the reliability is high. Open-cut underground structures can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view for explaining an embodiment of the present invention.
FIG. 2 is a sectional view for explaining a modified embodiment of the present invention. FIG. 3 is a perspective view for explaining a general structure of an excavated underground structure.
FIG. 4 is a cross-sectional view for explaining a structural joint used in a conventional excavated underground structure.
FIG. 5 is a cross-sectional view for explaining the structure of a trigger joint used in a conventional excavated underground structure.
FIG. 6 is a perspective view for explaining the structure of a conventional water stop plate.
[Explanation of symbols]
3-1, 3-2 Structure 6 Joint material 7-1, 7-2 Strengthening force 7-3 Strengthening force 11-1, 11-2 stored in the sheath tube Water expansion waterproofing rubber 12-1, 12-2 Protection steel plate

Claims (1)

A structure is cast in place for each unit length inside the excavated groove, and each time the cast-in structure is cured, a joint is provided to place another structure in place, and the structure is built in the ground. In the excavation underground structure construction method to
Cover the outer peripheral surface of the end that should be a joint with another structure of the cured structure with water-swelling water-stopping rubber in a band shape, and coat the peripheral surface of this water-swelling water-stopping rubber with a band-shaped protective steel plate At the same time, half of the band-shaped protective steel plate in the width direction protrudes in parallel with the surface to be the outer peripheral surface of the structure to be constructed next, and the structure of the structure to be constructed next to the projecting protective steel plate A method for constructing an open-cut underground structure, characterized in that a water-expanding water-stopping rubber is held on a surface facing an outer peripheral surface, and another structure is cast in place in this state.

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