JP2003138587A - Remaking method for manhole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a remaking method capable of remaking an existing manhole in a short construction term with satisfactory construction property. SOLUTION: A bottomed thermoplastic resin pipe (PET pipe) 1 constituted in such a way that a cylindrical side wall 11 having an outside diameter smaller than an inside diameter of the existing manhole 101 and a bottom wall 12 are integrally formed and an inlet A for heating and pressurizing medium is provided in an upper part is used to introduce heating medium (for example, hot water) into the thermoplastic resin pipe 1 while the thermoplastic resin pipe 1 is inserted and arranged in the existing manhole 101 in order to heat the side wall 11 and the bottom wall 12. Next, the inside of the thermoplastic resin pipe 1 is pressurized to expand the side wall 11 and the bottom wall 12 so as to perform lining on an inner side face 111 and a bottom face 112 of the existing manhole 101 by thermoplastic resin.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for rehabilitating an existing manhole in a sewer. 2. Description of the Related Art Manholes in sewage systems usually have a concrete structure and are subject to corrosion due to long periods of time, external pressure from around the manholes, or reaction with alkali by hydrogen sulfide contained in sewage. The concrete wall may be cracked or the concrete wall may be damaged. [0003] When such cracks or breakage occur, there is a problem that groundwater infiltrates into the manhole, and the infiltrated water flows out downstream along with sewage. In particular, when a large amount of groundwater infiltrates the manhole during heavy rain, etc., the amount of sewage exceeding the treatment capacity of the downstream sewage treatment plant may flow out to the downstream. [0004] Therefore, when an existing manhole is deteriorated, it is necessary to rebuild it. However, rebuilding a manhole requires operations such as excavation around the manhole, removal of the existing manhole, formwork assembly, concrete placement and curing, and backfilling, which greatly increases the construction period. Moreover, it is necessary to cut off the road for a long time during the construction period for rebuilding the manhole. In addition, it is necessary to temporarily install a bypass pipe. As one method of solving such a problem, a belt-like profile formed of polyethylene, polypropylene, polyvinyl chloride, or the like is used, and this profile is spirally formed along the inner peripheral surface of the existing manhole. There is a rehabilitation method for lining the inner surface of an existing manhole by winding. [0006] By the way, in a sewer manhole, it is particularly apt to be deteriorated at the bottom of the manhole. However, according to the lining method based on the above-described profile, the bottom of the existing manhole is removed. It cannot be lined and the bottom needs to be rehabilitated in another way. [0007] In the lining method based on the profile, it is difficult to spirally wind the profile, and much time is required. Further, there is a problem that the cost is high because it is necessary to use a profile having a complicated sectional shape. The present invention has been made to solve such a problem, and an object of the present invention is to provide a method for rehabilitating an existing manhole, which has good workability and can rehabilitate an existing manhole in a short construction period. A rehabilitation method according to the present invention is a method for rehabilitating an existing manhole installed in a sewerage system, wherein a tubular side wall and a bottom have an outer diameter smaller than an inner diameter of the existing manhole. While the wall is integrally molded, using a bottomed thermoplastic resin pipe provided with an inlet for the heating and pressurizing medium at the top, with this thermoplastic resin pipe inserted and arranged in the existing manhole, A heating medium is introduced into the inside of the thermoplastic resin pipe to heat the side wall and the bottom wall, and then the inside of the thermoplastic resin pipe is pressurized to expand the side wall and the bottom wall. Is lined with a thermoplastic resin. According to the rehabilitation method of the present invention, with the bottomed thermoplastic resin tube inserted and arranged in the existing manhole, the bottom surface of the existing manhole can be simply operated by heating and pressurizing the thermoplastic resin tube. Can be lined, and the rehabilitation work can be completed in a short time. The thermoplastic resin tube used in the rehabilitation method of the present invention is preferably made of PET, PP, PE or PBT. Specific examples of the heating medium used in the rehabilitation method of the present invention include hot water or steam. As the pressurizing medium, hot water or steam used for heating may be used under pressure, or compressed air may be used instead of hot water or steam. Embodiments of the present invention will be described below with reference to the drawings. The manhole targeted by this embodiment is:
As shown in FIG. 1, an existing manhole 10 made of concrete is used.
1, the upstream sewer pipe 102 and the downstream sewer pipe 103
Is connected to the bottom. Next, a PET tube (thermoplastic resin tube) 1 used in this embodiment will be described with reference to FIG. 1 and FIG. The PET tube 1 is a bottomed tube 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 an upper portion. The outside diameter (before expansion) of the side wall 11 of the PET tube 1 is formed to be smaller than the inside diameter of the existing manhole 101. The height of the PET tube 1 is larger than the depth of the existing manhole 101, and as shown in FIG.
The cap 2 is located above the upper end of the existing manhole 101 in a state where the cap 2 is placed on the bottom surface 112 of the first manhole 101. 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 expands, which will be described later. A sealed state can be maintained. The cap 2 is provided with an inlet pipe 3 and an outlet pipe 4. The upper end of the introduction pipe 3 is an inlet 3A for warm water. The lower end of the introduction tube 3 extends to near 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 above the PET pipe 1 (near the cap 2). The introduction pipe 3 and the discharge pipe 4
Is made of, for example, stainless steel or aluminum. A hot water supply system (not shown) provided with a pressurizing pump and the like is connected to the introduction pipe 3 so that hot water can be introduced into the bottom of the PET pipe 1. The introduced hot water is
It 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 (neither is shown).
As the hot water introduced into the PET tube 1, either one of a low pressure state and a pressurized state by a pressurizing pump can be selected. It is to be noted that cooling water can flow through the PET pipe 1 through a hot water supply system (or a cooling water supply system) and an introduction pipe 3. Next, an embodiment of the rehabilitation method of the present invention is shown in FIG.
This will be described with reference to FIG. Incidentally, FIG.
It is the arrow view and the Y arrow view. First, as shown in FIGS. 1 and 3, butyl rubber 5 for stopping water is adhered to the peripheral portion of each of the sewer pipes 102 and 103 of the existing manhole 101. Next, the PET pipe 1 is inserted into the existing manhole 101 to be positioned at a substantially central position in the manhole, and the bottom wall 12 of the PET pipe 1 is placed in the existing manhole 1.
01 on the bottom surface 112. At this time, PET tube 1
May be temporarily fixed to the existing manhole 101 using an appropriate jig. After the setting of the PET tube 1 is completed (the state of FIG. 1), warm water (for example, 90 ° C.) is flowed at a low pressure into the inside of the PET tube 1 to heat the side wall 11 and the bottom wall 12, and then pressurize. The side wall 11 and the bottom wall 12 of the PET tube 1 are expanded by pressurizing hot water (for example, 0.5 MPa) with a pump. 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 with the side wall 11 and the bottom wall 12 of the PET tube 1. In addition, the butyl rubber 5 attached to the peripheral portion of each of the sewer pipes 102 and 103 adheres tightly to the side wall 11 of the PET pipe 1, and water is stopped between the respective sewer pipes 102 and 103 and the side wall 11 of the PET pipe 1. Is done. After the above lining step is completed, PE
Cooling is performed by flowing cooling water inside the T tube 1. During this cooling, if the internal pressure of the PET tube 1 decreases, the expanded side wall 11 and the bottom wall 12 try to return to their original state, so that it is necessary to flow cooling water in a pressurized state. Finally, an unnecessary portion of the side wall 11 of the PET tube 1 (an upper portion of the existing manhole 101) is removed together with the cap 2. Furthermore, each sewer pipe 102, 10
The rehabilitation work is completed by removing the side wall 11 existing in the opening into the existing manhole 101 of No. 3. As described above, in the embodiment of the present invention, the heating and pressurizing of the PET tube 1 in a state where the PET tube 1 is inserted and arranged in the existing manhole 101 can be performed with a simple operation. The side surface 111 and the bottom surface 112 in the existing manhole 101 can be lined with PET. Also, with respect to the water stoppage of the sewer pipes 102 and 103, sufficient water stoppage can be ensured by a simple operation of pasting the butyl rubber 5 to the periphery of the sewer pipes 102 and 103 in advance. Here, specific numerical values are not shown for the outer diameter of the PET tube 1 before inflation (the state shown in FIG. 1) and for the dimensions of each part such as the wall thickness of the side wall 11 and the bottom wall 12; May be determined based on the size of the existing manhole 101 to be rehabilitated, the thickness of the lining layer, and conditions such as heating temperature and pressure during heating and expansion. In the above embodiment, hot water is used for both heating and pressurization of the PET tube 1. However, the present invention is not limited to this, and the PET tube 1 is heated with hot water and heated. A method in which the subsequent pressurization is performed by compressed air may be adopted. For cooling after heating and expansion, compressed air may be used instead of cooling water. 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 handleability and safety. In the above embodiment, a bottomed PET tube is used, but the present invention can be implemented by using a bottomed PP tube, PE tube, or PBT tube instead. As described above, according to the present invention,
Heat and pressurize the thermoplastic resin pipe while inserting the bottomed thermoplastic resin pipe in which the cylindrical side wall and bottom wall whose outer diameter is smaller than the inner diameter of the existing manhole are integrally formed into the existing manhole. Since the inner surface including the bottom surface of the existing manhole can be lined by only a simple operation, the rehabilitation operation can be completed in a short time. In addition, since it is not necessary to use a lining material having a complicated shape, it is possible to achieve cost reduction of rehabilitation.

[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 an explanatory diagram of the embodiment. FIG. 3 is a view as seen from the arrow X and the arrow Y in FIG. 1; [Explanation of symbols] 1 PET tube (thermoplastic resin tube) 11 PET tube side walls 12 Bottom wall of PET tube 2 caps 3 introduction pipe 3A Hot water inlet 4 Discharge pipe 4A Hot water outlet 5 Butyl rubber 101 Existing manhole 111 Side of existing manhole 112 Bottom of existing manhole 102,103 sewer pipe

Claims (1)

Claims 1. 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. At the same time, using a bottomed thermoplastic resin tube with an inlet for the heating and pressurizing medium provided at the top, this thermoplastic resin tube is inserted inside the existing manhole and heated inside the thermoplastic resin tube. By introducing the medium to heat the side wall and the bottom wall, and then pressurizing the inside of the thermoplastic resin tube to expand the side wall and the bottom wall, the inside side surface and the bottom surface of the existing manhole are lined with the thermoplastic resin. A method for rehabilitating a manhole, comprising: