Rehabilitation methods for existing pipes

Abstract

To provide a pipe rehabilitation method that can prevent the rehabilitation pipe from floating even in small-diameter existing pipes where workers cannot enter and perform work inside. [Solution] A method for rehabilitating existing pipes, in which a rehabilitated pipe 40 is pushed into the existing pipe 30, granular material 51 is filled into the gap between the existing pipe 30 and the rehabilitated pipe 40 by blowing air, and a highly fluid grout material 52 is injected into the gap between the existing pipe 30 and the rehabilitated pipe 40 after the granular material has been filled.

Description

Technical Field

[0001] The present invention relates to a rehabilitation method for existing pipes such as aging sewer pipes.

Background Art

[0002] Conventionally, a rehabilitation pipe has been disposed inside an existing pipe such as an aging sewer pipe for repair. For example, in Patent Document 1, a belt-like member having joint portions at both side edges is spirally wound inside an existing pipe, and the joint portions of adjacent belt-like members are joined to form a rehabilitation pipe. Then, a backfill material is injected into the gap between the rehabilitation pipe and the existing pipe to integrate the existing pipe and the rehabilitation pipe. When the backfill material is injected into the gap between the existing pipe and the rehabilitation pipe in this way, buoyancy acts on the rehabilitation pipe according to its internal volume and the density of the backfill material, causing the rehabilitation pipe to float.

[0003] Therefore, in Patent Document 1, as a support member for a rehabilitation pipe that is disposed inside an existing pipe and rehabilitates the existing pipe, it has a circumference of at least half of the outer circumference of the rehabilitation pipe and an inner diameter corresponding to the outer diameter of the rehabilitation pipe, and is disposed along the outer surface of the rehabilitation pipe. It is provided with an arcuate support plate portion, and a plurality of spacing maintaining means provided on the outer surface of the support plate portion for maintaining the spacing between the inner surface of the existing pipe and the outer surface of the rehabilitation pipe. A large number of through holes are provided in the support plate portion, and the spacing maintaining means is provided with an elastic member that expands and contracts between the inner surface of the existing pipe and the outer surface of the rehabilitation pipe, and the amount of protrusion in the radial direction from the outer surface of the support plate portion can be changed. It is described that the amount of protrusion can be individually increased or decreased for each installation location inside the existing pipe.

[0004] Furthermore, Patent Document 2 describes a position adjustment spacer for adjusting the position of a rehabilitated pipe, which is a rehabilitated pipe whose outer diameter is smaller than the inner diameter of the existing pipe, and which is formed by sequentially connecting ring-shaped pipe units, each made of multiple segment members connected in the circumferential direction, in the longitudinal direction of the existing pipe. The position adjustment spacer comprises a first wedge-shaped member inclined at a predetermined angle such that the inner side in the insertion direction is higher, a second wedge-shaped member inclined at the same angle as the inclination angle of the first wedge-shaped member and superimposed on the first wedge-shaped member with its inclined angle surface aligned, and a locking means that allows the second wedge-shaped member to move in the insertion direction relative to the first wedge-shaped member, but locks it at multiple locking positions so that it cannot move in the opposite direction, and the height of the entire spacer is sequentially increased in stages by sequentially moving the second wedge-shaped member to the multiple locking positions in the insertion direction relative to the first wedge-shaped member. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 6622476 [Patent Document 2] Patent No. 4392275 [Overview of the project] [Problems that the invention aims to solve]

[0006] The rehabilitation pipes described in Patent Documents 1 and 2 above both form the rehabilitation pipe inside the existing pipe and are used in repair methods in which workers enter the inside of the existing pipe to perform repairs. In other words, the spacing member described in Patent Document 1 and the position adjustment spacer described in Patent Document 2 prevent the rehabilitation pipe from floating up by gradually forming the rehabilitation pipe inside the existing pipe and inserting them into the gaps of the formed rehabilitation pipe. Therefore, they cannot be applied to small existing pipes that workers cannot enter.

[0007] Therefore, the present invention aims to provide a method for rehabilitating existing pipes that can prevent the rehabilitated pipe from floating up, even in small-diameter existing pipes where workers cannot enter and perform work inside. [Means for solving the problem]

[0008] The pipe rehabilitation method of the present invention is characterized by including pushing a rehabilitation pipe into the interior of the existing pipe, filling the gap between the existing pipe and the rehabilitation pipe with granular material by blowing air, and injecting a highly fluid grout material into the gap between the existing pipe and the rehabilitation pipe after filling with granular material. According to the pipe rehabilitation method of the present invention, granular material is filled into the gap between the existing pipe and the rehabilitation pipe by blowing air, and a highly fluid grout material is injected into the gap between the existing pipe and the rehabilitation pipe after filling with granular material, so that the highly fluid grout material does not penetrate to the bottom of the gap between the existing pipe and the rehabilitation pipe. Therefore, it is possible to prevent the generation of buoyancy in the rehabilitation pipe by the highly fluid grout material.

[0009] The granular material should preferably consist of soil particles of medium size or smaller. Medium size refers to soil particles with a particle size of 4.75 mm to 19 mm. Soil particles of medium size or smaller also include fine gravel with a particle size of 2.0 mm to 4.75 mm, and sand with a particle size of 2.0 mm or less. In other words, soil particles of medium size or smaller are soil particles with a particle size of 19 mm or less. When the granular material consists of soil particles of medium size or smaller, it can be easily filled into the gap between the existing pipe and the rehabilitated pipe by blowing air. Furthermore, although the gap between the existing pipe and the rehabilitated pipe narrows as it approaches the bottom, the granular material can easily enter this narrow gap and fill it without any gaps. [Effects of the Invention]

[0010] (1) According to the existing pipe rehabilitation method, in which a rehabilitation pipe is pushed into the existing pipe, granular material is filled into the gap between the existing pipe and the rehabilitation pipe by blowing air, and a highly fluid grout material is injected into the gap between the existing pipe and the rehabilitation pipe after the granular material has been filled, it is possible to rehabilitate existing pipes with small diameters where workers cannot enter and work inside, by preventing the rehabilitation pipe from floating up. In addition, the amount of highly fluid grout material used can be reduced in proportion to the amount of granular material filled, thereby achieving cost reduction.

[0011] (2) Because the granular material consists of soil particles of medium gravel or smaller, it can be filled without gaps even in the narrow lower part between the existing pipe and the rehabilitation pipe, preventing the infiltration of highly fluid grout material and further preventing the rehabilitation pipe from floating up. [Brief explanation of the drawing]

[0012] [Figure 1] This is an explanatory diagram showing an overview of the rehabilitation method for existing pipes according to an embodiment of the present invention. [Figure 2] This is a cross-sectional view of a self-supporting pipe constructed using a rehabilitated pipe. [Modes for carrying out the invention]

[0013] Figure 1 is an explanatory diagram showing an overview of the rehabilitation method for existing pipes in an embodiment of the present invention, and Figure 2 is a cross-sectional view of a self-supporting pipe constructed with the rehabilitated pipe.

[0014] As shown in Figure 1, the rehabilitation method for existing pipes in the embodiment of the present invention involves pushing a rehabilitation pipe 40 into the existing pipe 30 buried underground between an insertion-side manhole 10 and a draw-side manhole 20, which are a type of shaft, and as shown in Figure 2, injecting granular material 51 as a primary filler and high-flowability grout material 52 as a secondary filler into the gap between the existing pipe 30 and the rehabilitation pipe 40 to construct a new self-supporting pipe 60.

[0015] Existing pipes 30 are mainly small-diameter (inner diameter D) circular pipes with a nominal diameter of 200 to 350, which workers cannot enter. Examples of existing pipes 30 include HP pipes (Hume pipes), TP pipes (stainless steel pipes for piping (JIS G 3459)), VU pipes (rigid polyvinyl chloride pipes (JIS K 6741)), and FRPM pipes (glass fiber reinforced plastic / resin mortar composite pipes)).

[0016] The rehabilitation pipe 40 is a small-diameter circular pipe with a nominal diameter of 150 to 300 that can be inserted inside the existing pipe 30. The outer diameter d of the rehabilitation pipe 40 is selected to be smaller than that of the existing pipe 30 according to the inner diameter D of the existing pipe 30. For example, for an existing pipe 30 with a nominal diameter of 200, a rehabilitation pipe 40 with a nominal diameter of 150 is used. For an existing pipe 30 with a nominal diameter of 350, a rehabilitation pipe 40 with a nominal diameter of 300 is used. Thereby, the gap h between the existing pipe 30 and the rehabilitation pipe 40 becomes 32 to 35 mm.

[0017] As the granular material 51 as the primary plugging material, soil particles with a particle size of 19 mm or less are used. The soil particles with a particle size of 19 mm or less are medium gravel (particle size 4.75 mm to 19 mm), fine gravel (particle size 2.0 mm to 4.75 mm), sand (particle size 2.0 mm or less), etc. Also, as the granular material 51, in addition to gravel and sand, plastics, styrofoam, etc. can also be used.

[0018] As the highly fluid grout material 52 as the secondary plugging material, a cement-based highly fluid grout material excellent in filling property, fluidity, and water separation property is used. For example, as the highly fluid grout material 52, blast furnace B-type cement, water, thickener, and defoaming agent are mixed and kneaded on-site for use.

[0019] Next, the construction procedure of the existing pipe rehabilitation method in the embodiment of the present invention will be described. <1> Pushing and pulling work of the rehabilitation pipe (1-1) Manually insert the rehabilitation pipe 40 into the insertion-side manhole 10. (1-2) In the insertion-side manhole 10, join the joint part of the inserted rehabilitation pipe 40. (1-3) Apply a pushing jig 70 to the rear part of the rehabilitation pipe 40 and push and pull it into the existing pipe 30 with the electric winch 80 on the pulling side. (1-4) Repeat the operations (1-1) to (1-3) above to push and pull the rehabilitation pipe 40 for the extended section.

[0020] <2> Injection work of the primary plugging material In the gap between the existing pipe 30 and the rehabilitation pipe 40 at the upstream nozzle of the (2-1) section, granular material 51 is filled as a primary plugging material by blowing air. Compressed air is blown from a compressor into the gap between the existing pipe 30 and the rehabilitation pipe 40 at the upstream nozzle of the section, and the granular material 51 is fed along with this blowing air. In the (2-2) step, the granular material 51 is gradually filled into the gap between the existing pipe 30 and the rehabilitation pipe 40. When the passage for blowing air becomes small and the granular material 51 cannot be fed in, it is considered that the filling is completed.

[0021] <2> Secondary plugging material injection process In the (2-1) step, an injection port and an overflow pipe are attached to the gap between the existing pipe 30 and the rehabilitation pipe 40 at the upstream nozzle of the section. Similarly, an air vent and an overflow pipe are attached to the downstream nozzle of the section to seal the nozzles at both ends. In the (2-2) step, an injection pipe from the injection equipment is connected to the injection port installed at the upstream nozzle of the section, and highly fluid grout material 52 is injected as a secondary plugging material by a grout pump. In the (2-3) step, when the highly fluid grout material 52 overflows from the overflow pipes installed at the upstream and downstream nozzles of the section, it is considered that the injection is completed.

[0022] As described above, according to the existing pipe rehabilitation method in this embodiment, even for a small-diameter existing pipe 30 where workers cannot enter inside for work, the rehabilitation pipe 40 is pushed into the inside of the existing pipe 30, and granular material 51 is filled as a primary plugging material into the gap between the existing pipe 30 and the rehabilitation pipe 40 by blowing air. After filling this granular material, highly fluid grout material 52 is injected as a secondary plugging material into the gap between the existing pipe 30 and the rehabilitation pipe 40. As a result, the highly fluid grout material 52 does not enter the lower part of the gap between the existing pipe 30 and the rehabilitation pipe 40, preventing the generation of buoyancy on the rehabilitation pipe 40 by the highly fluid grout material 52 and rehabilitating the existing pipe, and a self-supporting pipe 60 can be constructed.

[0023] Note that the amount of the highly fluid grout material 52 used can be reduced according to the filling amount of the granular material 51. Therefore, it is desirable to fill as much inexpensive granular material 51 as possible into the gap between the existing pipe 30 and the rehabilitation pipe 40. Thereby, the amount of the expensive highly fluid grout material 52 used can be reduced, and cost reduction can be achieved.

[0024] Furthermore, in this embodiment, since soil particles with a particle size of 19 mm or less are used as the granular material 51, it is possible to fill the narrow lower portion between the existing pipe 30 and the rehabilitated pipe 40 without any gaps, preventing the infiltration of the highly fluid grout material 52 and further preventing the rehabilitated pipe 40 from floating. It is also possible to use coarse gravel with a particle size of 19 mm to 75 mm as the granular material 51, but a large amount of wind force would be required to fill it by air. In addition, when using coarse gravel, gaps can be filled by including soil particles of medium gravel or smaller. [Industrial applicability]

[0025] The present invention is useful as a rehabilitation method for existing pipes such as aging sewer pipes, and is particularly suitable as a rehabilitation method for small-diameter existing pipes where workers cannot enter and perform work inside. [Explanation of Symbols]

[0026] 10 Insertion side manhole 20. Inlet manhole 30 Existing pipes 40 Rehabilitation pipe 51 Particulate matter 52 High-flow grout material

Claims

1. Pushing the rehabilitation pipe into the existing pipe, The gap between the existing pipe and the rehabilitated pipe is filled with granular material by blowing air into it. Inject a highly fluid grout material into the gap between the existing pipe and the rehabilitated pipe after filling it with the granular material. A rehabilitation method for existing pipes, including [specific components / materials].

2. The method for rehabilitating an existing pipe according to claim 1, wherein the granular material is soil particles of medium gravel size or smaller.

3. The method for rehabilitating an existing pipe according to claim 1, wherein the granular material is gravel, sand, plastic, or polystyrene foam.

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