JP7707480B2 - Rehabilitation structure of existing culvert - Google Patents

Description

The present invention relates to a rehabilitation structure for an existing culvert where water can seep in from the surrounding ground through walls made of masonry, concrete, etc.

2. Description of the Related Art Conventionally, for example, in urban areas, culverts (waterways) constructed of stone masonry, concrete, or the like have been used for a long time.
Some of these culverts were originally open, but due to urban development etc., the tops of the culverts have been covered to make them into underground conduits, and they are now used as roads, etc.
However, deterioration has progressed due to collapse and cracks in the stonework and concrete, and the functionality and strength of the culvert can no longer be guaranteed.

Countermeasures to this problem include updating and rehabilitating existing culverts.
The method of updating existing culverts requires the temporary removal of the existing culverts, which requires a huge amount of labor and cost, and has the disadvantage of affecting citizens' lives through large-scale road closures, etc.
For this reason, there has been a demand for a method for rehabilitating existing culverts while keeping them in their original state, which does not involve the above-mentioned problems.

Incidentally, as a method for rehabilitating existing culverts or culverts, a method using a rehabilitation pipe made of a thermoplastic resin or a thermosetting resin has been proposed (see, for example, Patent Documents 1 and 2).
Although the methods disclosed in Patent Documents 1 and 2 can achieve the purpose of rehabilitating existing culverts, it is difficult to ensure the strength of existing culverts whose strength has been reduced due to the ground surface being used as a road or the like, since the rehabilitation pipe itself cannot be expected to significantly improve the strength of the culvert.
Furthermore, in the case of existing culverts, there may be places where water seeps in from the surrounding ground through walls made of masonry, concrete, etc., and with the methods disclosed in Patent Documents 1 and 2, there is a risk that water that has seeped in will accumulate around the rehabilitation pipe, causing the rehabilitation pipe to float up due to buoyancy or that the surrounding ground (soil) will flow out, resulting in a sinkhole accident.

JP 2002-294679 A JP 2012-219985 A Patent No. 5746443 JP 2017-198305 A

In consideration of the problems with conventional methods for rehabilitating existing culverts while they are still in their original state, the first objective of the present invention is to provide a rehabilitation structure for an existing culvert that does not allow water to seep in from the surrounding ground through walls made of masonry, concrete, etc., and accumulate around the rehabilitation pipe, causing the rehabilitation pipe to float up due to buoyancy, or to prevent the surrounding ground from washing away and causing a collapse.

A second object of the present invention is to provide a rehabilitation structure for an existing culvert that can ensure the strength of an existing culvert whose strength has been reduced due to the ground surface being used as a road or the like by using a rehabilitation pipe.

In order to achieve the first object, the rehabilitation structure of an existing culvert of the present invention comprises:
A rehabilitating pipe that forms a waterway inside;
A filler material filled and hardened between the rehabilitation pipe and the existing culvert;
The rehabilitating pipe is provided at the boundary between the filling material and the existing culvert in the axial direction of the rehabilitating pipe, and is provided with a water conveyance pipe through which water that has seeped in from the surrounding ground through the wall of the existing culvert is introduced.

In addition, a planar member can be provided at the boundary between the filling material and at least the side wall of the existing culvert, so that water that seeps in from the surrounding ground along the planar member can be introduced into the water pipe.

Furthermore, in order to achieve the second object, the rehabilitation pipe can be provided with an annular fixing member that also serves as a first reinforcing member and is installed at intervals in the axial direction of the rehabilitation pipe along the inner peripheral surface of the existing culvert, a connecting member disposed on the fixing member, and a band-shaped inner surface material that is stretched across the connecting member and the connecting member disposed on the fixing member adjacent to the axial direction of the rehabilitation pipe.

The rehabilitation pipe may also be provided with a second reinforcing member arranged in an annular shape on the outer periphery of the fixing member.

According to the rehabilitation structure of the present invention for an existing culvert, a water conduit is provided at the boundary between the filler and the existing culvert in the axial direction of the rehabilitation pipe, through which water that has seeped in from the surrounding ground through the wall of the existing culvert is introduced. By discharging water that has seeped in around the rehabilitation pipe of the existing culvert, where there are areas where water seeps in from the surrounding ground through walls made of masonry or concrete, through the water conduit, water that has seeped in around the rehabilitation pipe does not accumulate around the rehabilitation pipe, and it is possible to prevent the rehabilitation pipe from floating up due to buoyancy or the surrounding ground from washing away and causing a collapse.

In addition, by providing a planar member at the boundary between the filler and at least the side wall of the existing culvert, and allowing water that seeps in from the surrounding ground along the planar member to be introduced into the water conduit, water that seeps in from the surrounding ground can be more reliably discharged through the water conduit.

In addition, by making the rehabilitation pipe comprise an annular fixing member that also serves as a first reinforcing member and that is installed at intervals in the axial direction of the rehabilitation pipe along the inner circumferential surface of the existing culvert, a connecting member disposed on the fixing member, and a band-shaped inner surface material that is stretched across the connecting member and the connecting member disposed on the fixing member adjacent to the axial direction of the rehabilitation pipe, the strength of the existing culvert, whose strength has been reduced due to the ground surface being used as a road or the like, can be ensured by the rehabilitation pipe with the annular fixing member that also serves as the first reinforcing member and the filling material.

In addition, by providing the rehabilitation pipe with a second reinforcing member arranged in an annular shape on the outer periphery of the fixing member, the strength of the existing culvert, whose strength has been reduced, can be more reliably guaranteed.

1A and 1B show an embodiment of a rehabilitation structure for an existing culvert according to the present invention, in which FIG. 1A is a cross-sectional view, and FIG. 1B is an enlarged cross-sectional view of the surface layer of a rehabilitation pipe. FIG. 11 is a cross-sectional view showing a modified embodiment of the rehabilitation structure for the existing culvert. 1A and 1B show examples of conventional rehabilitation structures for existing pipes, where FIG. 1A is an explanatory diagram showing the rehabilitation structure for an existing pipe with a circular cross section, and FIG. 1B is an explanatory diagram showing the rehabilitation structure for an existing pipe with a rectangular cross section.

Below, an embodiment of the present invention's rehabilitation structure for an existing culvert will be explained with reference to the drawings.

FIG. 1 shows an embodiment of a rehabilitation structure for an existing culvert according to the present invention.
This rehabilitation structure for an existing culvert is intended to rehabilitate an existing culvert 1 having a location where water seeps in from the surrounding ground through a wall made of masonry, concrete or the like, and comprises a rehabilitation pipe 2 forming a waterway inside, a filling material 3 filled and hardened between the rehabilitation pipe 2 and the existing culvert 1, a planar member 4 provided at the boundary between the filling material 3 and a side wall 11 of the existing culvert 1, and a water conveyance pipe 5 provided in the axial direction of the rehabilitation pipe 2 at the boundary between the filling material 3 (or the planar member 4, if provided) and the existing culvert 1, for introducing water that has seeped in from the surrounding ground through the side wall 11 of the existing culvert 1.

The existing culvert 1 that is the subject of this embodiment is constructed with side walls 11 made of masonry, a bottom 12 made of concrete, and a top surface 13 made of concrete floor panels supported by PC girders, but the rehabilitation structure of an existing culvert of the present invention is not limited to this, and is intended to cover a wide range of existing culverts that have areas where water can seep in from the surrounding ground through walls made of masonry, concrete, etc.

The rehabilitation pipe 2 can be a publicly known rehabilitation pipe used to rehabilitate existing pipes such as aged sewer pipes, but in this embodiment, the rehabilitation pipe shown in Figure 3 (the FFT Construction Method Association's "String Construction Method" (registered trademark)) (see Patent Documents 3 and 4) is used.

Specifically, the rehabilitation pipe 2 comprises an annular fixing member 21 which also serves as a first reinforcing member made of deformed steel bars installed at intervals in the axial direction of the rehabilitation pipe 2 along the inner surface of the existing culvert 1, a connecting member 22 arranged on the fixing member 21, a band-shaped inner surface material 23 made of a synthetic resin such as high-density polyethylene which is stretched across the connecting member 22 arranged on the fixing members 21 adjacent to each other in the axial direction of the rehabilitation pipe 2 via a spacer which determines the spacing, and a fastener 24 made of a synthetic resin such as high-density polyethylene/thermoplastic elastomer which connects adjacent inner surface materials 23 together and covers the gaps therebetween. Furthermore, in this embodiment, a second reinforcing member 25 made of deformed steel bars arranged in an annular shape on the outer periphery of the fixing member 21 is also provided.
Here, reinforcing bars 26a, 26b are arranged, as necessary, between adjacent fixing members 21, between adjacent second reinforcing members 25, and between the fixing members 21 and the second reinforcing members 25 arranged in a ring shape on their outer periphery.
The size (diameter) and arrangement of the fixing member 21, which also serves as the first reinforcing member, the second reinforcing member 25, and the reinforcing bars 26a, 26b, and the thickness of the filling material 3, etc., are designed to ensure the strength of the weakened existing culvert 1. In particular, since it is not (or is difficult to) consider the strength of the existing culvert 1 made of masonry, the structural design is performed using the rehabilitation pipe 2 and the filling material 3.
As a result, the rehabilitation pipe 2 and filling material 3, which are equipped with the annular fixing member 21 that also serves as the first reinforcing member and the second reinforcing member 25, make it possible to ensure the strength of the existing culvert 1 whose strength has been reduced due to the ground surface being used as a road or the like.

High-flow, high-strength mortar is suitable for use as the filler 3.

In this embodiment, the planar member 4 guides and introduces water that seeps in from the surrounding ground through the side wall 11 of the existing culvert 1, which is made of stone masonry, into the water conveyance pipe 5, and prevents the poured filler material 3, which has fluidity, from leaking into the existing culvert 1. In this embodiment, the planar member 4 is provided only at the boundary between the filler material 3 and the side wall 11 of the existing culvert 1 (in the modified embodiment shown in FIG. 2, only at the boundary between the filler material 3 and the side wall 11 of the existing culvert 1, which is made of stone masonry). However, depending on the structure of the existing culvert 1, the planar member 4 can also be provided on the bottom 12 or the top surface 13.

For the planar member 4, water-proof sheets made of synthetic resins such as polyethylene and polyvinyl chloride (e.g., "Vinon" (registered trademark) manufactured by Takiron C.I. Co., Ltd.), as well as planar members with water-proof and water-conductive properties such as embossed drainage and protection mats (e.g., "Geoflow" (registered trademark) manufactured by Takiron C.I. Co., Ltd.), planar drainage materials (e.g., "Glysheet" (product name) manufactured by Takiron C.I. Co., Ltd.), etc., that have the function of achieving the above-mentioned objectives can be used.

The water conveyance pipe 5 is used to introduce water that has seeped in from the surrounding ground through the side wall 11 of the existing culvert 1 and to drain the introduced water to the outside, for example, to a waterway formed inside the rehabilitated pipe 2 at an appropriate location. It is installed at the lowest position of the side wall 11 of the existing culvert 1, which is made of masonry (or at the lowest, upper, or intermediate positions of the side wall 11 of the existing culvert 1, if multiple pipes are installed), at the boundary between the filler 3 (or the planar member 4, if a planar member 4 is installed) and the existing culvert 1, in a location that does not affect the strength of the rehabilitated pipe 2 and the filler 3.

The water conduit 5 can be a perforated pipe or mesh pipe made of synthetic resin such as polyethylene that has the function of achieving the above-mentioned purpose (for example, the external pressure collection and drainage pipe "Super Pipe W Type" (product name) manufactured by Takilon C.I. Civil Corporation, or the culvert drainage pipe "Double Drain" (product name) manufactured by the same company).

According to this rehabilitation structure for an existing culvert, a water conduit 5 is provided at the boundary between the filling material 3 (or the planar member 4, if a planar member 4 is provided) and the existing culvert 1, in the pipe axial direction of the rehabilitation pipe 2, into which water that has infiltrated from the surrounding ground through the side wall 11 of the existing culvert 1 is introduced. By discharging water that has infiltrated around the rehabilitation pipe 2 of the existing culvert 1, where there are locations where water can infiltrate from the surrounding ground through walls made of masonry, concrete, or the like, through the water conduit 5, the water that has infiltrated around the rehabilitation pipe 2 does not stagnate, and it is possible to prevent the rehabilitation pipe 2 from floating up due to buoyancy or the surrounding ground from washing away and causing a collapse.
Furthermore, this rehabilitation structure for an existing culvert can be constructed without excavating the existing culvert 1, which reduces costs and shortens the construction period, while minimizing the impact on the surrounding area.

The rehabilitation structure for an existing culvert of the present invention has been described above based on its embodiment, but the present invention is not limited to the configuration described in the above embodiment, and the configuration can be changed as appropriate within the scope of the spirit of the invention.

The rehabilitation structure of the present invention for an existing culvert has a wall made of masonry, concrete, etc., where water seeps in from the surrounding ground and accumulates around the rehabilitation pipe, preventing the rehabilitation pipe from floating up due to buoyancy and preventing the surrounding ground from washing away and causing a collapse. In addition, the rehabilitation pipe can ensure the strength of an existing culvert whose strength has been reduced due to the ground surface being used as a road, etc., so it can be suitably used for the rehabilitation of an existing culvert where water seeps in from the surrounding ground through a wall made of masonry, concrete, etc.

Reference Signs List 1: Existing culvert 11: Side wall portion 12: Bottom portion 13: Top surface portion 2: Rehabilitation pipe 21: Fixing member (first reinforcing member)
22 Connecting member 23 Inner surface material 24 Fastener 25 Second reinforcing member 26a Reinforcing bar 26b Reinforcing bar 3 Filling material 4 Planar member 5 Water guide pipe

Claims (3)

This is a rehabilitation structure for an existing culvert.
A rehabilitating pipe that forms a waterway inside;
A filler material filled and hardened between the rehabilitation pipe and the existing culvert;
A planar member provided at the boundary between the filler and at least the side wall of the existing culvert, the planar member having a water impermeability to prevent the poured filler from leaking into the existing culvert and a water conductivity to guide water that has infiltrated from the surrounding ground;
a water conveyance pipe provided at the boundary between the planar member and the existing culvert in the axial direction of the rehabilitation pipe, through which water that has seeped in from the surrounding ground through the wall of the existing culvert is introduced along the planar member . 2. The rehabilitation structure for an existing culvert according to claim 1, characterized in that the rehabilitation pipe comprises: an annular fixing member which also serves as a first reinforcing member made of deformed steel bars installed at intervals in the axial direction of the rehabilitation pipe along the inner peripheral surface of the existing culvert; a connecting member disposed on the fixing member; and a band-shaped inner surface material which is installed between the connecting member and a connecting member disposed on a fixing member adjacent to the fixing member in the axial direction of the rehabilitation pipe. The rehabilitation structure for an existing culvert according to claim 2, characterized in that the rehabilitation pipe comprises a second reinforcing member made of a deformed steel bar arranged in a ring shape on the outer periphery of the fixing member, and a reinforcing bar arranged between the fixing member and the second reinforcing member .