JP2013079543A - Cutoff rubber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutoff rubber 1 for a pipe body joint, capable of surely preventing swell due to constant water pressure load, coping with displacement of a pipe body in an earthquake, and reducing manufacturing cost.SOLUTION: A cutoff rubber 1 is arranged on the inner side of a joint part 4 between two subsurface pipe bodies 2, 3 facing each other. The cutoff rubber 1 is corrugated and is made of a rubber having a fiber base fabric 23 inside. Both ends 6, 7 of the cutoff rubber 1 are fixed to the pipe bodies 2, 3 by anchor bolts 10, 11, respectively. Holding plates 16, 17 joined to the anchor bolts 10, 11 of the pipe bodies 2, 3 respectively, extending toward a central part of the cutoff rubber 1, and for suppressing swell due to pressure generated in the cutoff rubber 1 are arranged. The tips of the holding plates 16, 17 face each other at an interval Δ equal to or larger than the width L of the joint part 4. A thin steel plate 18 having a width W equal to or larger than the interval Δ is installed between the cutoff rubber 1 and the holding plates 16, 17.

Description

  The present invention relates to a waterproof rubber for a pipe joint.

The waterstop rubber is used to cover a joint portion between concrete tubular bodies constituting an underground structure such as a tunnel from the inside of the tubular body.
As an anti-seismic measure, the water-stopping rubber has functions of water-stopping (preventing leakage of water to the inside of the tunnel due to groundwater pressure) and displaceability (absorbing displacement of the tubular body due to earthquakes).
In order to absorb the displacement between the tubular bodies at the time of an earthquake, the shape of the water stop rubber has various shapes in which a surplus length is given to a U-shape, a corrugation, and the like. On the other hand, when the external water pressure is applied to the water stop rubber, the extra length of the water stop rubber tends to swell inside the tunnel.

In particular, in the case of "waterproof rubber for retrofitting joints" to be installed on existing structures, the water pressure is always applied for reasons such as securing the empty space in the tunnel or preventing it from hitting existing obstacles. In some cases, it may be disliked that the waterproof rubber bulges inward.
There is a technique shown in FIG. 3 or FIG. 4 as a technique for preventing the swelling of the still water rubber against a constant water pressure load.

In the water stop rubber shown in FIG. 3, the inside of the water stop rubber 101 having a corrugated cross section is covered with a cylindrical cover rubber 102 (referred to as a cover rubber system; for example, see Non-Patent Document 1). The displacement of the tube during an earthquake follows the deformation of the waterstop rubber and the deformation of the cover rubber.
Further, the water-stopping rubber shown in FIG. 4 includes a cover rubber 112 that covers the water-stopping rubber 111 and is formed by providing a folded portion 112a on a nylon base fabric. The folded portion 112a is adhered and stopped by a topping rubber 113. (Referred to as the folding method). Although the water stop rubber does not bulge against a constant water pressure load, when a large external force is applied during an earthquake or the like, the folded portion 112a is detached, and the water stop rubber can be deformed.

Japanese Patent No. 30223362

Nihon Bivic Co., Ltd. Catalog “Square type repair joints Seismic joint expansion / contraction flexible joints Square type flexible joints” (Seismic joint expansion / contraction flexible joint VKRH type)

However, in the water-stopping rubber shown in FIG. 3, the water-stopping rubber 101 always swells due to a water pressure load, so that the cover rubber 102 also expands due to water pressure. It will be higher than the initial height.
Further, in the waterproof rubber shown in FIG. 4, as a method for manufacturing the cover rubber 112, the nylon base fabric is folded and vulcanized, and the topping rubber 113 is bonded / added as a batch application rubber portion so that the folded portion is not opened again. Sulfur bonding is required. As a result, a lot of manufacturing steps are required and the manufacturing method is complicated. Therefore, the manufacturing cost is increased.

Therefore, a structure for preventing the swelling of the water stop rubber shown in FIG. 5 is conceivable. That is, a pair of steel pressing plates 121 are projected from the base of the water-stopping rubber 122 toward the center. The base of each presser plate 121 is fixed to the anchor bolt of the corresponding tubular body, and the tip ends of the pair of presser plates are opposed to each other with a gap Δ. The presser plate 121 can prevent swelling of the water stop rubber.
However, in FIG. 5, if the interval Δ between the pair of pressing plates 121 is narrower than the width of the joint portion 125 of the tubular body in order to prevent the waterproof rubber from sticking out, the pair of pressing plates 121 are mutually connected during an earthquake. It will interfere. On the other hand, as shown in FIG. 6, when the distance Δ between the pair of pressing plates 121 is made wider than the width of the joint portion 125 of the tubular body, the waterproof rubber 122 (shown by the broken line 122) that is always expanded due to a hydraulic load It protrudes from the gap between the pressing plates 121.

  The present invention has been made in view of such a conventional technique, and its purpose is to reliably prevent bulging due to a constant hydraulic load and to cope with displacement of a tubular body during an earthquake, thereby reducing manufacturing costs. It is to provide a waterproof rubber that can be used.

  The invention according to claim 1 is a waterproof rubber disposed inside the joint portions of two opposing underground pipes, and the waterproof rubber has a corrugated shape and has a fiber base fabric inside. Made of rubber, both ends of the waterstop rubber are fixed to the pipe body with anchor bolts, joined to the anchor bolt of one pipe body, extended toward the center of the waterstop rubber, and pressure generated in the waterstop rubber There is a holding plate for suppressing expansion due to pressure, and a pressing plate that is joined to the anchor bolt of the other tubular body, extends toward the center of the waterproof rubber, and suppresses expansion due to pressure generated in the waterproof rubber. Provided, the tips of both pressing plates face each other with a gap Δ greater than the width of the joint, and a thin steel plate with a width equal to or larger than the gap Δ is installed between the water stop rubber and the pressing plate. It is a water-stopping rubber for pipe joints.

According to a second aspect of the present invention, there is a portion where the thin steel plates overlap on the distal end side of the pressing plate, and the dimension from the base portion of one pressing plate to the distal end direction, to the portion where the thin steel plates overlap. Is the dimension from the base of the other pressing plate to the tip direction, and the length to the portion where the thin steel plates overlap is Δ2, the width W of the thin steel plate is:
Δ <W <Δ1 + Δ2
The water-stopping rubber for pipe joints according to claim 1, wherein the relationship is satisfied.

  According to the first aspect of the present invention, the water stop rubber can be covered by the both pressing plates and the thin steel plate, so that it is possible to reliably prevent the water stop rubber from bulging due to a constant hydraulic load. Since the distance Δ between the tips of both pressing plates is set to be equal to or greater than the width of the joint, interference between the tips of both pressing plates can be prevented when the joint is narrowed and deformed due to an earthquake or the like. Therefore, the deformation of the waterproof rubber is not hindered during an earthquake. Further, since a pair of pressing plates and a thin steel plate, which can be usually manufactured at low cost, are used for preventing the swelling of the water stop rubber, the manufacturing cost can be reduced.

  According to the invention of claim 2, the thin steel plate is not stretched between the base portions of the two pressing plates at the time of shrinkage deformation in which the joint portion becomes narrow due to an earthquake or the like. The deformation of the water rubber is prevented from being hindered.

FIG. 1 is a partial cross-sectional view of a water blocking rubber for a pipe joint according to an embodiment of the present invention. FIG. 2 is a partial cross-sectional view of a waterproof rubber according to an embodiment of the present invention. FIG. 3 is a partial cross-sectional view of a conventional waterproof rubber. FIG. 4 is a partial cross-sectional view of another conventional waterproof rubber. FIG. 5 is a partial cross-sectional view of water-stopping rubber as a related technique, and shows a state where the interval between the pressing plates is narrow. FIG. 6 is a partial cross-sectional view of water-stopping rubber as a related technique, and shows a state where the interval between the pressing plates is wide.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a partial cross-sectional view of a waterproof rubber 1 for a pipe joint according to an embodiment of the present invention.
The water blocking rubber 1 is disposed inside the joint portion 4 of two opposing underground pipes 2 and 3 (only a part is shown). In FIG. 1, the inner space surrounded by the tubular bodies 2 and 3 is shown. The pair of tube bodies 2 and 3 are adjacent to each other and buried in the basement in a state where the insides thereof communicate with each other, and constitute at least a part of an underground structure such as a tunnel. The joint portion 4 that is a joint between the tubular bodies 2 and 3 is configured by, for example, an annular elastic joint disposed along the end surfaces of the tubular bodies 2 and 3. Both end portions 6 and 7 of the waterproof rubber 1 are fixed to the inner surfaces 8 and 9 of the tubular bodies 2 and 3 by anchor bolts 10 and 11 and nuts 12 and 13 so as to cover the inside of the joint portion 4.

One end of the anchor bolts 10 and 11 is fixed by being embedded in the corresponding tube bodies 2 and 3. A male screw is formed at the other end of the anchor bolts 10 and 11, and nuts 12 and 13 are screwed into the male screw.
In addition, a pair of pressing plates 16 and 17 and a thin steel plate 18 are provided so as to cover the intermediate portion 14 of the water blocking rubber 1 from the inside to suppress expansion due to pressure generated in the water blocking rubber 1. A base portion 25 to be described later of each pressing plate 16, 17 is joined to the corresponding tube body 2, 3 in a state of being fastened together with the corresponding end portion 6, 7 of the water blocking rubber 1. The thin steel plate 18 is sandwiched between an extension portion 26 (described later) of the one pressing plate 16 and the waterstop rubber 1, and together with the extension portion 26 of the other pressing plate 17, It is sandwiched between the still water rubber 1 in a displaceable state.

The waterstop rubber 1 is made of rubber having a fiber base fabric 23 therein. For example, the waterproof rubber 1 is formed with a total thickness of the base fabric 23 and the rubber of 5 to 20 mm. As the rubber, for example, natural rubber, chloroprene, or EPDM rubber can be used. As the fiber base fabric 23, for example, a nylon base fabric can be used.
The waterstop rubber 1 has a plate shape having a corrugated cross section, and extends in a direction perpendicular to the paper surface. The waterstop rubber 1 has a pair of end portions 6 and 7 and an intermediate portion 14 in the axial direction X along the axis of the tubular bodies 2 and 3. The intermediate portion 14 has a cross-sectional corrugated shape and can be expanded and contracted in the axial direction X. The end portions 6 and 7 have a flat plate shape, have insertion holes for inserting the anchor bolts 10 and 11, and function as fixing portions.

The pair of pressing plates 16 and 17 are configured similarly. About the structure which has the same function of each holding | suppressing board 16 and 17, the same name and the same code | symbol are attached | subjected.
The holding plates 16 and 17 include a base portion 25 having an L-shaped cross section and a plate-like extension portion 26 extending in a predetermined length from the base portion 25 toward the central portion 1c of the waterproof rubber 1 in the axial direction X. Have. The base portion 25 and the extending portion 26 are made of steel and are integrally formed by a welding structure.

  The base portions 25 of the pair of pressing plates 16 and 17 are disposed on both sides of the intermediate portion 14 of the water blocking rubber 1. The extending portions 26 of the pressing plates 16 and 17 extend in the opposite directions from the base portion 25, and the ends of the extending portions 26 have an interval Δ (Δ ≧ L) greater than the width L of the joint portion 4. Are facing each other. The extended portion 26 is supported by the base 25 at a distance commensurate with the corrugated height of the intermediate portion 14 of the waterstop rubber 1 and away from the inner surfaces 8 and 9 of the tubular bodies 2 and 3.

The thin steel plate 18 has a flat plate shape, and is formed of a steel plate such as stainless steel, for example. Since the thin steel plate 18 is not fixed to any of the pressing plates 16 and 17 and the waterproof rubber 1, it can be freely displaced in the extending direction of the extending portion 26 of the pressing plates 16 and 17.
Further, with respect to the width direction of the thin steel plate 18 (corresponding to the above-described axial direction X), one end as a part of the thin steel plate 18 and a part on the front end side of the extending portion 26 of the one pressing plate 16. Are overlapping each other. At the same time, the other end as a part of the thin steel plate 18 and a part on the distal end side of the extending portion 26 of the other pressing plate 17 are overlapped with each other.

The central portion 14 of the water-stopping rubber 1 is always deformed by a hydraulic load (a part of the contour of the deformed central portion 14 is shown by a broken line in FIG. 1), but is partitioned by the pressing plates 16 and 17 and the thin steel plate 18. Housed inside.
Since the distance Δ between the tips of the extending portions 26 of the pressing plates 16 and 17 is set to be equal to or greater than the width L of the joint portion 4, both the pressing plates 16 and 17 can be deformed when the joint portion 4 becomes narrow due to an earthquake or the like. Interference between the ends of the extended portion 26 is prevented. Further, the thin steel plate 18 closes the gap 27 while being displaced with respect to the pressing plates 16 and 17.

Therefore, since the pair of pressing plates 16 and 17 and the thin steel plate 18 are used to prevent the waterproof rubber 1 from bulging, the manufacturing cost can be reduced.
Note that the width W of the thin steel plate 18 may be set to a value equal to or greater than the interval Δ between the tips of the extending portions 26 of the pressing plates 16 and 17 described above. Thereby, the gap 27 between the pressing plates 16 and 17 can be closed. Further, from the viewpoint of reliably and easily closing the gap 27, the width W of the thin steel plate 18 is preferably set to a dimension longer than the interval Δ by a predetermined length.

Furthermore, in this embodiment, the length of the portion that does not overlap the thin steel plate 18 in the extended portion 26 of one pressing plate 16 is Δ1, and the portion that does not overlap the thin steel plate 18 in the extended portion 26 of the other pressing plate 17. The width W of the thin steel plate 18 is
Δ <W <Δ1 + Δ2
It is set to satisfy the relationship.

  As a result, the thin steel plate 18 is not stretched between the base portions 25 of the presser plates 16 and 17 at the time of contraction deformation in which the joint portion 4 becomes narrow due to an earthquake or the like, so that the thin steel plate 18 is displaced with respect to the presser plates 16 and 17. This is possible, and as a result, the deformation of the waterproof rubber 1 is prevented from being hindered.

FIG. 2 is a partial cross-sectional view of the still water rubber 51 of the embodiment of the present invention.
The water-stopping rubber 51 of the embodiment differs from the water-stopping rubber 1 shown in FIG. 1 with respect to the number of corrugated heads of the intermediate portion 14 of the water-stopping rubber 1, 51, but is the same in other respects, Corresponding components are given the same reference numerals. The water stop rubber 51 of the example was formed with the dimensions shown in FIG. 2 and the following tests were performed.

Moreover, the water-stopping rubber (not shown) of a comparative example was manufactured, and the same test was implemented. The water-stopping rubber of the comparative example is different from the water-stopping rubber 51 of the embodiment in that it is not covered with a thin steel plate, but the other points are the same as the water-stopping rubber 51 of the embodiment.
[Test and results]
The water stop rubber 51 of the embodiment is fixed to a test jig corresponding to the pipe bodies 2 and 3, and a water pressure is applied between the pipe bodies 2 and 3 and the water stop rubber 51.

Specifically, the water-stopping rubber 51 was formed with a length of 1030 mm in the vertical direction on the paper surface, and the test was performed in a state where both ends in the vertical direction on the paper surface were sealed with a jig. The tightening torque of the anchor bolts 10 and 11 was 80 N · m.
The water pressure is increased to a predetermined pressure (0.1 MPa) and held in this state for a predetermined time (1 hour), and it is visually confirmed whether or not the water stop rubber 51 has bulged. Here, the predetermined pressure (0.1 MPa) described above is a normally assumed value (design value).

Next, the water pressure is increased to 0.15 MPa, and this state is maintained for a predetermined time (one month), and the presence or absence of bulging is similarly confirmed.
In the water stop rubber 51 of the example, it was confirmed that no swelling occurred even after 1 month at 0.15 MPa, which is severer than the normally assumed water pressure. It was also confirmed that no water leak occurred.

On the other hand, the same test was tried for the water-stopping rubber of the comparative example, but swelling occurred at a low pressure (0.01 to 0.02 MPa) until the above-described predetermined pressure was reached.
The present invention is not limited to the above description, and various design changes can be made within the scope of the matters described in the claims.

1, 51 Water-stop rubber 1c Center part 2, 3 Tube body 4 Joint part 6, 7 End part 10, 11 Anchor bolt 16, 17 Holding plate 18 Steel sheet 23 Base cloth 25 Base part L Width of joint part W Width of steel sheet Δ interval

Claims (2)

A waterproof rubber placed inside the joints of two opposing underground pipes,
The water-stopping rubber is made of rubber that has a corrugated shape and has a fiber base fabric inside.
Both ends of the still water rubber are fixed to the tube with anchor bolts,
A holding plate that is joined to the anchor bolt of one pipe body, extends toward the center of the waterstop rubber, and suppresses expansion due to pressure generated in the waterstop rubber,
It is joined to the anchor bolt of the other pipe, extends toward the center of the water-stopping rubber, and is provided with a pressing plate for suppressing expansion due to pressure generated in the water-stopping rubber,
The tips of both holding plates face each other with an interval Δ greater than the width of the joint,
Further, a waterproof rubber for tubular joints, characterized in that a thin steel plate having a width equal to or greater than the distance Δ is installed between the waterproof rubber and the pressing plate. On the tip side of the pressing plate, there is a portion where the thin steel plates overlap,
The length from the base of one holding plate to the tip direction, the length from the base of the other holding plate to the tip direction is Δ1, and the length from the base of the other holding plate to the tip direction. When the length to the overlapping part is Δ2,
The width W of the thin steel plate is
Δ <W <Δ1 + Δ2
The water-stopping rubber for pipe joints according to claim 1, wherein the relationship is satisfied.

Images