JP3865616B2 - Rehabilitation method of manhole - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for rehabilitating an existing manhole in a sewer.
[0002]
[Prior art]
Manholes in sewers usually have a concrete structure, and cracks may occur in the concrete wall due to corrosion due to long years, external pressure from around the manhole, or reaction with alkali from hydrogen sulfide contained in sewage. The concrete wall may be damaged.
[0003]
When such a crack or breakage occurs, there is a problem that groundwater enters into the manhole, and the intruded water flows out downstream with the sewage. In particular, when a large amount of groundwater enters the manhole during heavy rain, there is a risk that sewage exceeding the capacity of the downstream sewage treatment plant will flow downstream.
[0004]
Therefore, when the existing manhole is obsolete, it needs to be rebuilt. However, manhole reconstruction requires excavation around the manhole, removal of existing manholes, formwork assembly, concrete placement / curing, and backfilling, which greatly increases the construction period. Moreover, it is necessary to block the road for a long period during the construction period for reconstructing the manhole. It is also necessary to temporarily install a bypass line.
[0005]
As one method for solving such a problem, a belt-like profile formed of polyethylene, polypropylene, polyvinyl chloride or the like is used, and this profile is spirally wound along the inner peripheral surface of an existing manhole. Therefore, there is a rehabilitation method for lining the inner surface of an existing manhole.
[0006]
[Problems to be solved by the invention]
By the way, in sewer manholes, aging is particularly likely to occur at the bottom of the manhole, but with the lining method based on the profile as described above, the bottom surface of the existing manhole cannot be lined, and the bottom surface can be changed by another method. Need to be rehabilitated.
[0007]
Further, in the lining method using a profile, it is difficult to perform a spiral winding of the profile, and a lot of time is required. Furthermore, since it is necessary to use a profile having a complicated cross-sectional shape, there is a problem that the cost is high.
[0008]
The present invention has been made to solve such problems, and an object of the present invention is to provide a manhole rehabilitation method capable of rehabilitating existing manholes with good workability and a short construction period.
[0009]
[Means for Solving the Problems]
The rehabilitation method of the present invention is a method for rehabilitating an existing manhole installed in a sewer, wherein a cylindrical side wall and a bottom wall whose outer diameter is smaller than the inner diameter of the existing manhole are integrally formed, and at the top Using a bottomed thermoplastic resin tube provided with a heating / pressurizing medium inlet, with the thermoplastic resin tube inserted and arranged in an existing manhole, the heating medium is introduced into the thermoplastic resin tube. Characterize by lining the inner side and bottom of an existing manhole with a thermoplastic resin by heating the side wall and bottom wall and then pressurizing inside the thermoplastic tube to expand the side wall and bottom wall It is done.
[0010]
According to the rehabilitation method of the present invention, the inner surface including the bottom surface of the existing manhole can be obtained by a simple operation of heating and pressurizing the thermoplastic resin tube with the bottomed thermoplastic resin tube inserted and arranged in the existing manhole. The rehabilitation work can be completed in a short time.
[0011]
As a material of the thermoplastic resin tube used in the retreading method of the present invention, PET, PP, PE, PBT, or the like is preferable.
[0012]
Specific examples of the heating medium used in the rehabilitation method of the present invention include hot water or steam. Further, as the pressurizing medium, hot water or steam used for heating may be pressurized and used, or compressed air may be used instead of hot water or steam.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
The manhole targeted by this embodiment is an existing manhole 101 made of concrete as shown in FIG. 1, and an upstream sewage pipe 102 and a downstream sewage pipe 103 are connected to the bottom.
[0015]
Next, a PET pipe (thermoplastic resin pipe) 1 used in this embodiment will be described with reference to FIGS.
[0016]
The PET tube 1 is a bottomed tube body in which a cylindrical side wall 11 and a bottom wall 12 are integrally formed, and a cap 2 (for example, made of stainless steel or aluminum) is provided on the top.
[0017]
The outer diameter (before expansion) of the side wall 11 of the PET tube 1 is formed to be smaller than the inner diameter of the existing manhole 101. The height of the PET tube 1 is larger than the depth of the existing manhole 101, and the bottom wall 12 of the PET tube 1 is placed on the bottom surface 112 of the existing manhole 101 as shown in FIG. Thus, the cap 2 is positioned above the upper end of the existing manhole 101.
[0018]
The cap 2 is firmly fixed to the upper end of the side wall 11 of the PET tube 1, and does not come off from the upper end of the side wall 11 even when the PET tube 1 to be described later is expanded. Can be maintained.
[0019]
The cap 2 is provided with an introduction pipe 3 and a discharge pipe 4. The upper end of the introduction pipe 3 is an inlet 3A for hot water. The lower end of the introduction tube 3 extends to the vicinity of the bottom of the PET tube 1. The upper end of the discharge pipe 4 is a hot water outlet 4A. The lower end of the discharge pipe 4 is located on the upper part of the PET pipe 1 (near the cap 2). The introduction pipe 3 and the discharge pipe 4 are made of, for example, stainless steel or aluminum.
[0020]
A hot water supply system (not shown) provided with a pressurizing pump or the like is connected to the introduction pipe 3, and hot water can be introduced into the bottom of the PET pipe 1. The introduced hot water is discharged to the outside of the PET pipe 1 through the discharge pipe 4 and guided to a drainage system or a hot water circulation system (both not shown). The hot water introduced into the PET pipe 1 can be selected from either a low pressure state or a pressurized state by a pressure pump.
[0021]
Note that cooling water can also flow inside the PET pipe 1 via the hot water supply system (or cooling water supply system) and the introduction pipe 3.
[0022]
Next, an embodiment of the rehabilitation method of the present invention will be described with reference to FIGS. FIG. 3 is a view taken in the direction of arrows X and Y in FIG.
[0023]
First, as shown in FIG.1 and FIG.3, the butyl rubber 5 for water stop is affixed on the peripheral part of each sewer pipe 102,103 of the existing manhole 101. FIG.
[0024]
Next, the PET tube 1 is inserted into the existing manhole 101 and positioned at a substantially central position in the manhole, and the bottom wall 12 of the PET tube 1 is disposed on the bottom surface 112 of the existing manhole 101. At this time, the PET tube 1 may be temporarily fixed to the existing manhole 101 using an appropriate jig.
[0025]
After the setting of the PET pipe 1 is completed (state shown in FIG. 1), hot water (for example, 90 ° C.) is allowed to flow through the PET pipe 1 at a low pressure to heat the side wall 11 and the bottom wall 12, and then hot water is supplied by a pressure pump. The side wall 11 and the bottom wall 12 of the PET tube 1 are expanded by pressurizing (for example, 0.5 MPa).
[0026]
By such heating and expansion, as shown in FIG. 2, the side surface 111 and the bottom surface 112 in the existing manhole 101 are lined by the side wall 11 and the bottom wall 12 of the PET tube 1. In addition, the butyl rubber 5 adhered to the peripheral portions of the sewage pipes 102 and 103 is brought into close contact with the side wall 11 of the PET pipe 1 to ensure water stoppage between the sewage pipes 102 and 103 and the side wall 11 of the PET pipe 1. Is done.
[0027]
After the above lining process is completed, cooling is performed by flowing cooling water into the PET pipe 1. When the internal pressure of the PET pipe 1 decreases during this cooling, the expanded side wall 11 and bottom wall 12 tend to return to the original state, so it is necessary to flow cooling water in a pressurized state.
[0028]
Finally, an unnecessary portion of the side wall 11 of the PET tube 1 (upper portion of the existing manhole 101) is removed together with the cap 2. Furthermore, the rehabilitation work is completed by removing the side wall 11 present at the opening into the existing manhole 101 of each of the sewer pipes 102 and 103.
[0029]
As described above, according to the embodiment of the present invention, the existing manhole can be obtained simply by heating and pressurizing the PET tube 1 with the PET tube 1 inserted and disposed in the existing manhole 101. The side surface 111 and the bottom surface 112 in 101 can be lined with PET. In addition, with respect to the water stoppage of each of the sewage pipes 102 and 103, sufficient waterstop can be ensured by a simple operation of simply sticking the butyl rubber 5 to the peripheral edge of the sewage pipes 102 and 103 in advance.
[0030]
Here, the outer diameter of the PET tube 1 before expansion (state of FIG. 1) and the dimensions of each part such as the thickness of each of the side wall 11 and the bottom wall 12 do not show specific numerical values. May be determined based on conditions such as the size of the existing manhole 101 for rehabilitation, the thickness of the lining layer, and the heating temperature and pressure during heating and expansion.
[0031]
In the above embodiment, hot water is used for both heating and pressurization of the PET tube 1, but the present invention is not limited to this, and the PET tube 1 is heated with warm water and heated after heating. You may employ | adopt the method of performing a pressure with compressed air. Further, for cooling after heating and expansion, compressed air may be used instead of the cooling water.
[0032]
In the above embodiment, hot water is used as the heating medium, but steam may be used instead. However, since steam has a high temperature and a high pressure, it is preferable to use hot water as a heating medium in consideration of handling and safety.
[0033]
In the above embodiment, a bottomed PET tube is used, but the present invention can also be implemented by using a bottomed PP tube, PE tube, or PBT tube instead.
[0034]
【The invention's effect】
As described above, according to the present invention, the bottomed thermoplastic resin tube in which the cylindrical side wall and the bottom wall having an outer diameter smaller than the inner diameter of the existing manhole is integrally formed is inserted into the existing manhole. In this state, the inner surface including the bottom surface of the existing manhole can be lined by a simple operation of simply heating and pressurizing the thermoplastic resin tube, so that the rehabilitation operation can be completed in a short time. In addition, since it is not necessary to use a complicatedly shaped lining material, the cost of rehabilitation can be reduced.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an embodiment of a rehabilitation method of the present invention.
FIG. 2 is also an explanatory diagram of the embodiment.
FIGS. 3A and 3B are a view as viewed from an arrow X and a view as viewed from an arrow Y in FIG.
[Explanation of symbols]
1 PET pipe (thermoplastic resin pipe)
DESCRIPTION OF SYMBOLS 11 PET pipe side wall 12 PET pipe bottom wall 2 Cap 3 Inlet pipe 3A Hot water inlet 4 Drain pipe 4A Hot water outlet 5 Butyl rubber 101 Existing manhole 111 Side surface of existing manhole 112 Bottom surface 102, 103 of existing manhole

Claims (1)

A method of rehabilitating an existing manhole installed in a sewer, in which a cylindrical side wall and a bottom wall whose outer diameter is smaller than the inner diameter of the existing manhole are integrally formed, and an inlet for a heating / pressurizing medium is formed at the top A bottomed thermoplastic resin tube is used, and with the thermoplastic resin tube inserted and placed in an existing manhole, a heating medium is introduced into the thermoplastic resin tube to heat the side wall and the bottom wall. Then, the inner side surface and the bottom surface of the existing manhole are lined with thermoplastic resin by pressurizing the inside of the thermoplastic resin tube to expand the side wall and the bottom wall, thereby rehabilitating the manhole.

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