JP6820726B2 - Manhole rehabilitation structure and manhole rehabilitation method - Google Patents

Description

The present invention relates to a structure and a method for rehabilitating an existing manhole.

Sewerage pipelines are formed over 450,000 km throughout Japan, and there are more than 10 million manholes installed at intervals in these pipelines. Recently, the problem of aging of these manholes is becoming apparent. Excavating and removing these dilapidated manholes and re-installing new manholes can be difficult in highly urbanized areas. In addition, the cost increases.

Therefore, various structures and methods have been proposed for rehabilitation while leaving the existing manhole as much as possible in order to minimize excavation.
In Patent Document 1, the corroded surface layer portion of the inner wall of the manhole is cut and then lined. However, this method does not reinforce the bottom of the manhole and cannot solve the problem of water entering from the bottom.

Patent Document 2 discloses a rehabilitation structure of an existing manhole in which the upstream side pipeline and the downstream side pipeline are arranged so as to form a straight line. This rehabilitation structure includes a plastic manhole rehabilitation member and a vertically formed φ300 plastic rising pipe. The manhole rehabilitation member has a straight pipe and a rising port portion formed in the center of the straight pipe, and the rising pipe is connected to the rising port portion. The upstream side pipeline of the existing manhole is connected to the inflow portion of the straight pipe portion via the inflow pipe, and the downstream side pipeline of the existing manhole is connected to the outflow portion of the straight pipe portion via the outflow pipe. ..

JP-A-1999-140894 Japanese Unexamined Patent Publication No. 2002-106051

The manhole rehabilitation structure of Patent Document 2 replaces an existing manhole that can be inspected by a person with a small inspection hole that cannot be inspected by a person, and has a problem of poor inspectionability. Further, it can be applied only to the rehabilitation of an existing manhole in which the upstream side pipeline and the downstream side pipeline are in a straight line, and the existing manhole in which the upstream side pipeline and the downstream side pipeline intersect at 90 °, for example, can be rehabilitated. The development of the structure was awaited.

In order to solve the above problems, the present invention has a structure for rehabilitating an existing manhole arranged so that the upstream side pipe and the downstream side pipe intersect, and the bottom of the manhole is made of plastic. A manhole rehabilitation member is installed, and this manhole rehabilitation member has a curved pipe having a circular cross section and whose pipe axis is bent according to the intersection angle of the upstream side pipe and the downstream side pipe, and this curved pipe. It has an integral rising port that projects vertically upward from the pipe, the inflow part of the curved pipe is watertightly connected to the upstream side pipe, and the outflow part of the curved pipe is watertight to the downstream side pipe. A plastic rising pipe that is vertically connected and allows a person to enter is connected to the rising port of the manhole rehabilitation member in an integrated manner or as a separate body.
According to this configuration, since a manhole rehabilitation member having a curved pipe is used, even an existing manhole where the pipe axes of the upstream side pipe and the downstream side pipe intersect can be rehabilitated at low cost by simple construction. ..

Preferably, the manhole rehabilitation member is made of a plastic composite material.
According to this configuration, the strength and durability of the manhole rehabilitation member can be improved, and the manhole used for a flow path having a larger diameter can be rehabilitated. In addition, it is possible to secure a large mounting strength of the step for a person to move up and down.

Preferably, the rising pipe portion is divided into an upper rising pipe portion and a lower rising pipe portion, and the upper rising pipe portion and the lower rising pipe portion are connected via a rubber ring.
According to this configuration, the rubber ring connection can increase the resistance to the impact of an earthquake.

Preferably, an upper manhole made of concrete is further provided, and an upper end portion of the rising pipe is inserted into the lower end portion of the upper manhole, and a filler is inserted between the lower end portion of the upper manhole and the upper end portion of the rising pipe. Is filled.
According to this configuration, since the concrete upper manhole is connected to the plastic rising pipe, the strength of the upper part of the rehabilitated manhole can be increased. In addition, concrete manhole members are cheaper than plastic manholes of the same size, and the overall manhole rehabilitation cost can be reduced.

More preferably, sand is fixed to the outer periphery of the upper end of the rising pipe.
According to this configuration, it is possible to improve the adhesion and water stoppage between the upper end of the rising pipe and the lower end of the upper manhole.

In another aspect of the present invention, in the manhole rehabilitation method using the manhole rehabilitation structure, a bent installation recess is formed by partially hanging the bent flow path of the invert of the existing manhole, and the manhole is used for this installation. It is characterized in that the lower half of the curved pipe of the manhole rehabilitation member is installed in the recess.
According to this method, it is possible to simplify the chipping work of the invert and the installation work of the manhole rehabilitation member.

According to the present invention, an existing manhole that has deteriorated can be rehabilitated as a manhole that can be inspected for entry, including the bottom. In addition, the existing manhole where the pipe axes of the upstream side pipeline and the downstream side pipeline intersect can be rehabilitated at low cost.

In order to rehabilitate the existing manhole, the superstructure is removed while leaving the substructure, and the ground around the superstructure is excavated. (A) is a vertical sectional view, and (B) is a plan sectional view. is there. A state in which the invert flow path of the substructure is squeezed is shown, (A) is a vertical sectional view, and (B) is a plan sectional view. A state in which a manhole rehabilitation member having a rehabilitation structure according to the first embodiment of the present invention is installed in the invert and the manhole rehabilitation member is connected to an upstream side pipeline and a downstream side pipeline, (A) shows a vertical cross section. FIG. 3B is a plan sectional view. It is a vertical cross-sectional view which shows the state which fixed the manhole rehabilitation member by placing the backing material in the lower structure, and connected the rising pipe of the rehabilitation structure to the manhole rehabilitation member. It is an enlarged sectional view of the connection part of the said manhole rehabilitation member and the said riser pipe. It is a perspective view which shows by disassembling the said rehabilitation structure. It is a perspective view which shows by disassembling the rehabilitation structure which concerns on 2nd Embodiment of this invention. (A) is an exploded perspective view showing a rehabilitated structure according to a third embodiment of the present invention in an exploded manner, and (B) is an exploded perspective view showing a modified example thereof. (A) is an exploded perspective view showing a rehabilitated structure according to a fourth embodiment of the present invention in an exploded manner, and (B) is an exploded perspective view showing a modified example thereof.

Hereinafter, the first embodiment of the present invention will be described with reference to FIGS. 1 to 6. As shown in FIG. 1, the existing manhole includes a lower structure 1 and an upper structure (not shown). The lower structure 1 is composed of a manhole body 10 made of concrete. The manhole body 10 has a peripheral wall 11 and a bottom slab 12 that closes the lower end of the peripheral wall 11. In the present embodiment, the cross section of the peripheral wall 11 is square, but it may be circular.

An upstream side pipeline 2 and a downstream side pipeline 3 having a circular cross section are connected to the lower end portion of the peripheral wall 11, and the outlet portion 2a of the upstream side pipeline 2 and the inlet portion 3a of the downstream side pipeline 3 are the manhole main body 10. Facing the internal space 19 of. The pipe axes of the upstream side pipe 2 and the downstream side pipe 3 intersect at an angle of, for example, 90 °.

The upper portion of the bottom plate 12 of the manhole body 10 is provided as an invert 13, and a flow path 14 is formed on the upper surface of the invert 13. The flow path 14 has a semicircular cross section and has a planar shape bent at 90 °, which is the same as the intersection angle of the upstream side pipeline 2 and the downstream side pipeline 3. One end of the flow path 14 is aligned with the lower half of the outlet 2a of the upstream pipeline 2, and the other end of the flow path 14 is aligned with the lower half of the inlet 3a of the downstream pipeline 3. ..

The superstructure of the existing manhole is composed of, for example, a concrete top plate covering the upper end of the peripheral wall 11 of the manhole main body 10, an iron manhole member installed on the top plate, metal fittings for height adjustment, an iron lid, and the like. Has been done.

Prior to the rehabilitation work of the existing manhole, a plastic manhole rehabilitation member 20 (see FIG. 6) suitable for the existing manhole to be rehabilitated is manufactured. The plastic material of the manhole rehabilitation member 20 is not particularly limited, but polyolefins such as polyethylene and polypropylene, thermoplastics such as vinyl chloride, polystyrene and urethane may be used, and unsaturated polyesters, epoxy acrylates, epoxys and the like may be used. Thermosetting plastic may be used.

Preferably, as the plastic material, a plastic composite material whose strength is increased by a filler made of an organic or inorganic material, fibers, or the like is used in order to prevent deformation due to live load or earth pressure of the upper part.
Examples of the filler include sand, crushed stone, slag aggregate, silica sand, calcium carbonate, aluminum hydroxide, fly ash, steel slag and the like.
Examples of the fiber include glass fiber, carbon fiber, metal fiber and the like.

The plastic material is more preferably FRP, which is a plastic composite material of unsaturated polyester or epoxy acrylate base material and glass fiber, resin mortar, which is a plastic composite material of filler, or a multi-layer of FRP and resin mortar. The configuration and the like can be mentioned. These have the flexibility and corrosion resistance of plastics, as well as the required rigidity and high economic efficiency.

As shown in FIG. 6, the manhole rehabilitation member 20 integrally has a curved pipe 21 and a rising port portion 22. The curved pipe 21 has a flow path having a circular cross section, and has a planar shape bent at the same angle as the intersection angle of the upstream side pipe 2 and the downstream side pipe 3, that is, 90 °. More specifically, it has two short straight pipe portions and a 90 ° bent portion connecting these straight pipe portions. The rising port portion 22 projects vertically upward from the bent portion at the center of the curved pipe 21.
In this embodiment, the lower rising pipe portion 32 of the rising pipe 30, which will be described later, is integrally connected to the rising opening portion 22.

A method for manufacturing the manhole rehabilitation member 20 will be briefly described.
First, the curved pipe 21 is formed. Based on the measured data of the intersection angle between the upstream side pipeline 2 and the downstream side pipeline 3, a plurality of molds are combined to construct one mold, and a curved pipe 21 is formed by laminating a plastic material on this mold. .. This lamination may be performed manually or by rotating the mold and winding a continuous plastic material.
Other methods for forming the curved pipe 21 include a method of joining and integrating a large number of parts created by cutting a straight pipe, and a method of softening the straight pipe with heat or an organic solvent to deform it.

The bending angle of the curved pipe 21 allows an error of ± 5 ° with respect to the actual intersection angle of the upstream side pipe 2 and the downstream side pipe 3, but is preferably ± 3 °, more preferably ±. Set to 1 °.

The rising port portion 22 (in this embodiment, the rising port portion 22 and the lower rising pipe portion 32) is integrated by joining a short straight pipe to the communication port formed in the curved pipe 21. This communication port is preferably formed in the curved tube 21 in advance at the time of molding, but the communication port 21x may be formed after the curved tube 21 is formed.
The diameter of the rising port 22 and the rising tube 30 described later is 600 mm or more, and people can enter and exit.

Hereinafter, the rehabilitation work of the existing manhole will be described in the order of processes.
First, as shown in FIG. 1, the superstructure of the existing manhole is removed and the ground around it is excavated.

Next, as shown in FIG. 2, the flow path 14 of the invert 13 is hung substantially evenly to form an installation recess 15 having a cross-sectional shape slightly larger than the flow path 14. The installation recess 15 also has a planar shape bent at 90 °.

Next, as shown in FIG. 3, the curved pipe 21 of the manhole rehabilitation member 20 is installed in the installation recess 15, and the inflow portion 21a of the curved pipe 21 is made to match the outlet portion 2a of the upstream side pipeline 2. , The outflow portion 21b is matched with the inlet portion 3a of the downstream side pipeline 3.
The amount of chipping of the flow path 14 of the invert 13 required for the installation of the manhole rehabilitation member 20 is small, but it is necessary for the installation of the manhole rehabilitation member 20 when the invert 13 is severely corroded or deteriorated. The flow path 14 may be pierced in an amount larger than the above amount, or the entire invert 13 may be pierced and removed to flatten the bottom plate 12.

Next, in the installed state of the manhole rehabilitation member 20 shown in FIG. 3, the inflow portion 21a of the curved pipe 21 is watertightly connected to the outlet portion 2a of the upstream side pipeline 2, and the outflow portion 21b of the curved pipe 21 is connected to the downstream side. It is watertightly connected to the inlet portion 3a of the pipeline 3. This connection structure is not particularly limited, but for example, the space between the inflow portion 21a of the curved pipe 21 and the outlet portion 2a of the upstream side pipeline 2 is filled with a filler such as mortar or epoxy, and / or the inner circumference of both. An annular connecting band 25 made of rubber is arranged in the. The rubber connecting band 25 is pressed in the radial and outward directions by an annular metal band arranged on the inner peripheral side thereof. Instead of the connection band 25, FRP lamination may be carried out on the inner circumferences of both, or the FRP lamination and the connection band 25 may be used in combination. The same applies to the connection between the outflow portion 21b of the curved pipe 21 and the inlet portion 3a of the downstream side pipeline 3.
The connection structure may be an insertion structure, an adhesive structure, or a welding structure.

Next, as shown in FIG. 4, the backing material 40 is injected between the manhole rehabilitation member 20 and the manhole body 10. As the backing material 40, mortar, air mortar, fluidized soil and the like can be used. In some cases, a part of the backing material may be used, and the rest may be earth and sand, crushed stone, or improved soil to which a cement-based improving agent is added. The backing material 40 or the backing material + improved soil is filled up to the rising port 22.

Next, as shown in FIG. 4, the upper rising pipe portion 31 of the plastic rising pipe 30 that is separate from the manhole rehabilitation member 20 is attached to the lower rising pipe portion 32 that is integrated with the manhole rehabilitation member 20 with rubber. It is vertically connected via a connecting pipe 35 with a ring.

As shown in FIG. 5, a rubber ring 35a for a stopper having an L-shaped cross section is attached to the inner circumference of the middle portion of the connecting pipe 35, and rubber rings 35b and 35c for sealing are attached to the inner circumference of the upper and lower end portions thereof. ing. In a state where the connecting pipe 35 is covered with the upper end portion of the lower rising pipe portion 32 and the lower end portion of the upper rising pipe portion 31, between the upper end of the lower rising pipe portion 32 and the lower end of the upper rising pipe portion 31. A rubber ring 35a for a stopper is interposed, and rubber rings 35b and 35c for sealing are in close contact with the outer periphery of the lower end portion of the upper rising pipe portion 31 and the outer periphery of the upper end portion of the lower rising pipe portion 32, respectively. These rubber rings 35a, 35b, 35c also play a role of absorbing the impact at the time of an earthquake.

As the plastic material of the upper rising pipe portion 31, the same material as the manhole rehabilitation member 20 can be used.
As shown in FIG. 6, handrails 34 are attached to the inner circumferences of the upper rising pipe portion 31 and the lower rising pipe portion 32 of the rising pipe 30, respectively. These handrails 34 are basically necessary for entry inspection, but may not be necessary when using a removable ladder.

Next, a backing material (not shown) is injected between the rising pipe 30 and the concrete body 10.
Next, the lid means 50 (shown only in FIG. 6) is installed in the upper end opening of the rising pipe 30. The lid means 50 includes, for example, a height adjusting metal fitting 51 and an iron lid 52.
Finally, the excavated ground is backfilled and the manhole rehabilitation work is completed.

Next, other embodiments of the present invention will be described with reference to the drawings. In these embodiments, the components corresponding to the preceding embodiments are designated by the same number or similar numbers, and detailed description thereof will be omitted.

In the second embodiment shown in FIG. 7, the rising pipe 30A is not divided into upper and lower parts and is composed of one straight pipe portion, and is integrated with the rising opening portion 22 of the manhole rehabilitation member 20.
In addition, one rising pipe 30A may be formed separately from a manhole rehabilitation member 20. In this case, it is preferable to increase the diameter of the lower end of the rising pipe 30A and connect using the rubber rings 35 and 36.

In the third embodiment shown in FIG. 8A, the rising pipe 30A is integrated with the rising opening 22 of the manhole rehabilitation member 20 as in the second embodiment, but the upper end of the rising pipe 30A is made of concrete. Manhole assembly 60 is connected. The manhole assembly 60 is an assembly of a vertically straight pipe-shaped upper manhole 61 and a slanted wall 62 installed on the upper manhole 61.

The upper manhole 61 is installed on the upper surface of the backing material described above with the upper end portion of the rising pipe 30A inserted into the lower end portion thereof. Fillers such as mortar, adhesive, and caulking material are filled between the lower end of the upper manhole 61 and the upper end of the rising pipe 30A.
In this embodiment, since the general-purpose concrete manhole assembly 60 is used, it is excellent in economy and the strength against live load can be increased.

FIG. 8B shows a modified example of the third embodiment. In this modified example, the outer periphery of the upper end of the rising pipe 30A is sanded and sand 39 is fixed. In this structure, by filling a filler such as mortar between the upper end portion of the rising pipe 30A and the lower end portion of the manhole pipe 51, the adhesion and water stopping property are excellent.

In the fourth embodiment shown in FIG. 9A, the rising pipe 30 is separate from the lower rising pipe portion 32 that is integrated with the rising portion 22 of the manhole rehabilitation member 20, as in the first embodiment. It is divided into an upper rising pipe portion 31. The connection of the upper and lower rising pipe portions 31 and 32 is the same as in the first embodiment. The concrete assembly 60 is connected to the upper portion of the upper rising pipe portion 31 (the upper end portion of the rising pipe 31) in the same manner as in the third embodiment.
FIG. 9A shows a modified example of the fourth embodiment. In this modified example, the outer periphery of the upper portion of the upper rising pipe portion 31 is sanded, and the sand 39 is fixed.

The present invention is not limited to the above-described embodiment, and various modifications can be made as long as it does not contradict the gist thereof.

The present invention can be applied to the rehabilitation of an existing manhole.

1 Substructure of existing manhole 2 Upstream side pipeline 3 Downstream side pipeline 13 Invert 14 Flow path 15 Recess for installation 20 Manhole rehabilitation member 21 Curved pipe 21a Inflow part 21b Outflow part 22 Rise opening part 30, 30A Rise pipe 31 Upper rise Pipe 32 Lower rising pipe 35a, 35b, 35c Rubber ring 39 Sand 50 Lid means 61 Concrete upper manhole

Claims (4)

It is a structure for rehabilitating an existing manhole arranged so that the upstream side pipeline and the downstream side pipeline intersect.
Plastic manhole rehabilitation member is installed at the bottom of the manhole, the manhole rehabilitation member is provided with a bend to have a circular cross-section of the flow path, the curved pipe has two straight tube portions and the two Tsunojika and a bent portion contiguous with the tube portion together, the bent portion is tube axis is bent at an intersection angle of the upstream conduit and the downstream conduit, the bent portion of the bent tube is The above-mentioned rising port portion that protrudes vertically upward is integrally formed.
The inflow portion consisting of the end of one straight pipe portion of the curved pipe is watertightly connected to the upstream pipeline, and the outflow portion consisting of the end of the other straight pipe of the curved pipe is the downstream pipeline. Connected to the watertight
A manhole rehabilitation structure characterized in that, at the rising port portion of the manhole rehabilitation member, plastic rising pipes that are vertical and allow the human body to enter and exit are connected in an integrated manner or separately. .. The rising pipe is divided into an upper rising pipe portion and a lower rising pipe portion, and the lower rising pipe portion is integrally connected with the rising opening portion, and the lower end portion of the upper rising pipe portion and the lower portion are connected. A connecting pipe is attached to the upper end of the side rising pipe,
One side of a rubber ring for a stopper having an L-shaped cross section is attached to the inner circumference of the middle portion of the connecting pipe, and a rubber ring for sealing is attached to the inner circumference of the upper and lower ends of the connecting pipe.
The other side portion of the stopper rubber ring is interposed between the lower end of the upper rising pipe portion and the upper end of the lower rising pipe portion, and the upper and lower sealing rubber rings are formed on the upper rising pipe portion. The manhole rehabilitation structure according to claim 1 , wherein the outer periphery of the lower end portion and the outer periphery of the upper end portion of the lower rising pipe portion are in close contact with each other . Furthermore, it is equipped with a concrete upper manhole that is separate from the existing manhole structure, and the upper end of the rising pipe is inserted into the lower end of this upper manhole and directly connected, and the lower end of these upper manholes and the rising The manhole rehabilitation structure according to claim 1 or 2 , wherein the gap between the pipe and the upper end thereof is filled with a filler. In manhole rehabilitation method using a manhole rehabilitating structure according to any one of claims 1 to 3, by Hatsuru a bent flow path forming invert the semicircular section of the existing manhole partially forms a semicircular section A manhole rehabilitation method characterized in that a bent installation recess is formed and the lower half of the curved pipe of the manhole rehabilitation member is installed in the installation recess.

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