Rehabilitation method for existing pipe, and floating prevention member for rehabilitation pipe used in the same

Abstract

To provide a rehabilitation method for an existing pipe having a small diameter that does not allow a worker to enter the inside of the pipe for work, and a floating prevention member for a rehabilitation pipe used in the method.SOLUTION: A rehabilitation method for an existing pipe pushes a rehabilitation pipe 40 into an existing pipe 30, and injects a filler material 50 into a gap between the existing pipe 30 and the rehabilitation pipe 40. In the rehabilitation method, a support member 42 is made of an elastic material and is interposed in the gap between an inner top end of the existing pipe 30 and an outer top end of the rehabilitation pipe 40, the support member bends when the rehabilitation pipe 40 is pushed into the existing pipe 30, and while the support member 42 pressing the rehabilitation pipe 40 against buoyancy generated in the rehabilitation pipe 40 when the filler material 50 is injected into the gap between the existing pipe 30 and the rehabilitation pipe 40 is being held by the outer top end of the rehabilitation pipe 40, the rehabilitation pipe 40 is pushed into the existing pipe 30.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for rehabilitating existing pipes such as aged sewer pipes, and to a member for preventing the rehabilitated pipes from floating up, which is used in the method. [Background technology]

[0002] Conventionally, repairs have been performed by placing a rehabilitation pipe inside an existing pipe, such as an aging sewer pipe. For example, Patent Document 1 describes a rehabilitation method for an existing pipe in which a strip-shaped member having joints on both edges is spirally wound inside the existing pipe, the joints of adjacent strip-shaped members are joined to form a rehabilitation pipe, and 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. Furthermore, when backfill material is injected into the gap between the existing pipe and the rehabilitation pipe in this way, buoyancy acts on the rehabilitation pipe depending on its internal volume and the density of the backfill material, causing the rehabilitation pipe to float up. Therefore, Patent Document 1 describes a support member for a rehabilitation pipe that is placed within an existing pipe to rehabilitate the existing pipe, which comprises an arc-shaped support plate portion that has a circumference that is at least half the outer circumference of the rehabilitation pipe and an inner diameter that corresponds to the outer diameter of the rehabilitation pipe, and is placed along the outer surface of the rehabilitation pipe, and a plurality of spacing maintaining means that are provided on the outer surface of the support plate portion and maintain the distance between the inner surface of the existing pipe and the outer surface of the rehabilitation pipe, with a number of through holes in the support plate portion, and the spacing maintaining means that are provided with elastic members that expand and contract between the inner surface of the existing pipe and the outer surface of the rehabilitation pipe, so that the amount of radial protrusion from the outer surface of the support plate portion can be changed, and the configuration is such that the amount of protrusion can be increased or decreased individually for each installation location within the existing pipe.

[0003] Patent Document 2 also describes a position-adjusting spacer for adjusting the position of a rehabilitating pipe whose outer diameter is smaller than the inner diameter of the existing pipe. The rehabilitating pipe is formed by sequentially connecting ring-shaped pipe units, each consisting of a plurality of segments connected circumferentially, along the length of the existing pipe. The position-adjusting spacer includes a first wedge-shaped member inclined at a predetermined angle so that the rear end is higher in the insertion direction, a second wedge-shaped member inclined at the same angle as the first wedge-shaped member and overlapping the first wedge-shaped member with its inclined surface aligned, and a locking means for locking the second wedge-shaped member at multiple locking positions so that it can move relative to the first wedge-shaped member in the insertion direction but cannot move in the reverse direction. The height of the entire spacer is 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]

[0004] [Patent Document 1] Patent No. 6622476 [Patent Document 2] Patent No. 4392275 Summary of the Invention [Problem to be solved by the invention]

[0005] The rehabilitation pipes described in Patent Documents 1 and 2 are both formed inside an existing pipe and are used in a construction method in which workers enter the existing pipe to perform repairs. That is, the spacing member described in Patent Document 1 and the position adjustment spacer described in Patent Document 2 prevent the rehabilitating pipe from floating up by inserting them into the gaps in the rehabilitating pipe as the rehabilitating pipe is formed little by little inside the existing pipe. For this reason, they cannot be applied to existing pipes that are too small for workers to enter.

[0006] Therefore, an object of the present invention is to provide a method for rehabilitating existing small-diameter pipes that does not allow workers to enter the interior of the pipes to perform work, and a member for preventing the rehabilitated pipes from floating up to be used in this method. [Means for solving the problem]

[0007] The method for rehabilitating an existing pipe of the present invention is a method for rehabilitating an existing pipe by pushing a rehabilitated pipe into the inside of the existing pipe and injecting filler material into the gap between the existing pipe and the rehabilitated pipe, and includes pushing the rehabilitated pipe into the inside of the existing pipe while holding the support member, which is made of an elastic material and is interposed in the gap between the inner top end of the existing pipe and the outer top end of the rehabilitated pipe, in a bent state when the rehabilitated pipe is pushed into the inside of the existing pipe, against the buoyancy generated in the rehabilitated pipe when filler material is injected into the gap between the existing pipe and the rehabilitated pipe, on the outer top end of the rehabilitated pipe.

[0008] According to the method for rehabilitating an existing pipe of the present invention, when the rehabilitating pipe is pushed into the existing pipe while the support member made of an elastic material is held on the outer top end of the rehabilitating pipe, the support member bends and the rehabilitating pipe is inserted into the existing pipe, and the rehabilitating pipe is installed inside the existing pipe with the support member interposed in the gap between the inner top end of the existing pipe and the outer top end of the rehabilitating pipe. After the rehabilitating pipe is installed inside the existing pipe in this way, when filler material is injected into the gap between the existing pipe and the rehabilitating pipe, the support member holds the rehabilitating pipe down against the buoyancy generated in the rehabilitating pipe, preventing it from floating up and resulting in the construction of a free-standing pipe of stable quality.

[0009] Before injecting the filler into the gap between the existing pipe and the rehabilitated pipe, it is desirable to pull back the rehabilitated pipe to bring the bent support member into an upright position. This allows the rehabilitated pipe to be stably held down because the buoyancy generated in the rehabilitated pipe is received in the direction of compression of the upright support member.

[0010] The support members are preferably held in a receiving frame provided on the top end of the outer surface of the rehabilitating pipe. This simplifies installation, as the support members only need to be held in the receiving frame provided on the top end of the outer surface of the rehabilitating pipe, and the support members held in the receiving frame are always maintained on the top end of the outer surface of the rehabilitating pipe, allowing the rehabilitating pipe to be stably held down.

[0011] The frame is preferably fixed to a band wrapped around the outer periphery of the rehabilitating pipe, so that the support member can be held within the frame simply by wrapping the band with the frame fixed around the outer periphery of the rehabilitating pipe.

[0012] The anti-floating member for a rehabilitated pipe of the present invention is a member for preventing the rehabilitated pipe from floating up, used in a method of rehabilitating an existing pipe, in which the rehabilitated pipe is pushed into the inside of the existing pipe and filler material is injected into the gap between the existing pipe and the rehabilitated pipe.The member is made of an elastic material and is a support member that is placed in the gap between the top end of the inner surface of the existing pipe and the top end of the outer surface of the rehabilitated pipe.When the rehabilitated pipe is pushed into the inside of the existing pipe, it becomes bent, and includes a support member that holds down the rehabilitated pipe against the buoyancy that occurs in the rehabilitated pipe when filler material is injected into the gap between the existing pipe and the rehabilitated pipe.

[0013] According to the anti-floating member for a rehabilitating pipe of the present invention, when the rehabilitating pipe is pushed into the existing pipe while the support member, made of an elastic material and interposed in the gap between the inner top end of the existing pipe and the outer top end of the rehabilitating pipe, is held by the outer top end of the rehabilitating pipe, the support member bends and the rehabilitating pipe is inserted into the existing pipe. After the rehabilitating pipe is installed inside the existing pipe, when filler material is injected into the gap between the existing pipe and the rehabilitating pipe, the support member holds the rehabilitating pipe down against the buoyancy generated in the rehabilitating pipe, preventing the rehabilitating pipe from floating up and resulting in the construction of a self-supporting pipe of stable quality. [Effects of the Invention]

[0014] (1) According to the present invention, even in the case of an existing pipe with a small diameter that workers cannot enter and work inside, the rehabilitated pipe can be inserted into the existing pipe with the support member made of an elastic material simply being held at the top end of the outer surface of the rehabilitated pipe and the rehabilitated pipe with the support member bent can be inserted into the existing pipe.When the filler material is injected, the support member holds down the rehabilitated pipe against the buoyancy generated in the rehabilitated pipe, preventing it from floating up, making it possible to construct a free-standing pipe of stable quality.

[0015] (2) Before injecting the filler material into the gap between the existing pipe and the rehabilitated pipe, the rehabilitated pipe is pulled back to bring the bent elastic body into an upright position. This allows the rehabilitated pipe to receive the buoyancy generated in the compression direction of the support member in the upright position, thereby enabling the rehabilitated pipe to be held down stably, making it possible to construct a free-standing pipe of more stable quality.

[0016] (3) By holding the support member in a receiving frame provided on the outer top surface of the rehabilitated pipe, the support member can be easily installed, and the support member held in the receiving frame is always maintained on the outer top surface of the rehabilitated pipe, allowing the rehabilitated pipe to be held down stably, making it possible to construct a free-standing pipe of more stable quality.

[0017] (4) Since the receiving frame is fixed onto a band wrapped around the outer periphery of the rehabilitation pipe, the support member can be easily held within the receiving frame by simply wrapping the band to which the receiving frame is fixed around the outer periphery of the rehabilitation pipe. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is an explanatory diagram showing an overview of an existing pipe rehabilitation method according to an embodiment of the present invention; [Figure 2] This is a cross-sectional view of a freestanding pipe constructed using rehabilitated pipes. [Figure 3] FIG. 4 is an enlarged cross-sectional view of the support member as seen from the axial direction of the rehabilitating pipe. [Figure 4] 4 is a cross-sectional view taken along the line AA in FIG. 3. [Figure 5] 4 is a view corresponding to the cross section AA in FIG. 3 when the rehabilitation pipe is being pushed in. FIG. [Figure 6] 6 is a diagram showing the rehabilitating pipe pulled back from the state shown in FIG. 5 to bring the support member into an upright state. [Figure 7] FIG. 10 is a schematic diagram showing buoyancy when filling material is injected. DETAILED DESCRIPTION OF THE INVENTION

[0019] Figure 1 is an explanatory diagram showing an overview of the existing pipe rehabilitation method in an embodiment of the present invention, Figure 2 is a cross-sectional view of a self-supporting pipe constructed using a rehabilitation pipe, Figure 3 is an enlarged cross-sectional view of the support member viewed from the axial direction of the rehabilitation pipe, Figure 4 is a cross-sectional view AA of Figure 3, Figure 5 is a view corresponding to the cross-sectional view AA of Figure 3 when the rehabilitation pipe is pushed in, and Figure 6 is a view of the rehabilitation pipe being pulled back from the state shown in Figure 5 to bring the support member into an upright position.

[0020] As shown in Fig. 1, the existing pipe rehabilitation method in this embodiment of the present invention involves pushing a rehabilitation pipe 40 into the interior of an existing pipe 30 buried underground between an insertion manhole 10 (a type of vertical shaft) and an inlet manhole 20, and then, as shown in Fig. 2, injecting filler material 50 into the gap between the existing pipe 30 and the rehabilitation pipe 40 to construct a new self-supporting pipe 60. Note that this existing pipe rehabilitation method in this embodiment can be carried out while the sewer system is in service. In this case, the insertion manhole 10 is located on the upstream side of the construction section, and the inlet manhole 20 is located on the downstream side of the section.

[0021] The existing pipe 30 is mainly a small-diameter (inner diameter D) circular pipe with a nominal diameter of 200 to 350 that workers cannot enter. Examples of existing pipes 30 that are used 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 and resin mortar composite pipes).

[0022] 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 depending on the inner diameter D of the existing pipe 30. For example, a rehabilitation pipe 40 with a nominal diameter of 150 is used for an existing pipe 30 with a nominal diameter of 200. A rehabilitation pipe 40 with a nominal diameter of 300 is used for an existing pipe 30 with a nominal diameter of 350. As a result, the gap h between the existing pipe 30 and the rehabilitation pipe 40 is 32 to 35 mm.

[0023] 3 and 4, a floating prevention member 41 is attached to the rehabilitation pipe 40. The floating prevention member 41 includes a support member 42 that is placed in the gap between the inner top end of the existing pipe 30 and the outer top end of the rehabilitation pipe 40. The support member 42 is made of an elastic body. It is desirable to use a material (e.g., ethylene propylene (EDPM)) that complies with Class IA of waterworks rubber (JIS K 6353) for the support member 42.

[0024] The support member 42 is held in a receiving frame 43 provided on the outer top end of the rehabilitation pipe 40. The receiving frame 43 is box-shaped. The receiving frame 43 is fixed onto a band 44 that is wrapped around the outer periphery of the rehabilitation pipe 40. The band 44 may be, for example, a steel band.

[0025] The support member 42 has a generally rectangular parallelepiped shape so that it can be held within the box-shaped receiving frame 43. The upper portion of the support member 42 (the side that comes into contact with the inner top end of the existing pipe 30) is formed in a pleated shape with multiple flat plate-like portions 42A standing upright at predetermined intervals in the insertion direction X of the rehabilitation pipe 40 into the existing pipe 30. When the rehabilitation pipe 40 is pushed into the existing pipe 30, the support member 42 bends by a deflection amount ε as shown in FIG. 5 , and fills the gap between the rehabilitation pipe 40 and the existing pipe 30.

[0026] It is desirable to use a cement-based, highly fluid grout material that has excellent filling properties, fluidity, and underwater segregation properties as the filler 50. For example, the filler 50 is made by mixing and kneading on-site blast furnace type B cement, water, a thickener, and an antifoaming agent.

[0027] Next, a construction procedure for the existing pipe rehabilitation method according to the embodiment of the present invention will be described. <1> Pushing and towing of rehabilitation pipes (1-1) The anti-floating member 41 is attached to the rehabilitation pipe 40, the support member 42 is attached to the receiving frame 43, and the pipe is manually inserted into the insertion side manhole 10. (1-2) The joint portion of the inserted rehabilitation pipe 40 is joined inside the insertion side manhole 10. (1-3) A pushing jig 70 is placed on the rear of the rehabilitating pipe 40, and the rehabilitating pipe 40 is pushed and pulled into the existing pipe 30 by the electric winch 80 on the pulling side. At this time, the support member 42 is bent as shown in FIG. 5, and the rehabilitating pipe 40 moves inside the existing pipe 30. (1-4) The above steps (1-1) to (1-3) are repeated to push and pull the rehabilitating pipe 40 for the extended section. (1-5) The rehabilitation pipe 40 is pulled back slightly to bring the support member 42, which is in a bent state as shown in FIG. 5, into an upright state as shown in FIG.

[0028] <2> Filling material injection machine (2-1) An injection port and an overflow pipe are installed in the gap between the existing pipe 30 and the rehabilitated pipe 40 at the pipe opening on the upstream side of the section, and an air vent and an overflow pipe are similarly installed at the pipe opening on the downstream side of the section, and the pipe openings on both ends are sealed off. (2-2) An injection pipe from the injection equipment is connected to the injection port installed at the pipe mouth on the upstream side of the section, and the filler material 50 is injected using a grout pump. (2-3) When the filling material 50 overflows from the overflow pipes installed at the pipe openings on the upstream and downstream sides of the section, the injection is complete.

[0029] As described above, according to the method for rehabilitating an existing pipe in this embodiment, even if the existing pipe 30 has a small diameter that prevents workers from entering and working inside, when the rehabilitation pipe 40 is pushed into the existing pipe 30 while the support member 42 made of an elastic material is held at the top end of the outer surface of the rehabilitation pipe 40, the support member 42 bends by an amount of deflection ε and the rehabilitation pipe 40 is inserted into the existing pipe 30, and the rehabilitation pipe 40 is installed inside the existing pipe 30 with the support member 42 interposed in the gap h between the top end of the inner surface of the existing pipe 30 and the top end of the outer surface of the rehabilitation pipe 40. After the rehabilitation pipe 40 has been installed inside the existing pipe 30 in this manner, when filling material 50 is injected into the gap h between the existing pipe 30 with an inner diameter D and the rehabilitation pipe 40 with an outer diameter d, as shown in Figure 7, the support member 42 presses down on the rehabilitation pipe 40 against the buoyancy u generated in the rehabilitation pipe 40 with a restoring force equivalent to the deflection ε, thereby preventing the rehabilitation pipe 40 from floating up and constructing a self-supporting pipe 60 with stable quality.

[0030] Furthermore, in the existing pipe rehabilitation method of this embodiment, before injecting the filler material 50 into the gap between the existing pipe 30 and the rehabilitating pipe 40, the rehabilitating pipe 40 is pulled back to bring the bent support member 42 into an upright position as shown in Fig. 6. This allows the rehabilitating pipe 40 to be stably held down because it receives buoyancy generated in the compression direction of the upright support member 42. It is also possible to inject the filler material 50 into the gap between the existing pipe 30 and the rehabilitating pipe 40 in the position shown in Fig. 5 without pulling back the rehabilitating pipe 40.

[0031] Furthermore, in the existing pipe rehabilitation method of this embodiment, the support member 42 is simply held in a receiving frame 43 provided on the outer top end of the rehabilitation pipe 40, making installation simple, and the support member 42 held in the receiving frame 43 is always maintained at the outer top end of the rehabilitation pipe 40, making it possible to stably hold down the rehabilitation pipe 40. Note that the receiving frame 43 may be omitted and the support member 42 may be fixed directly onto the rehabilitation pipe 40.

[0032] Furthermore, since the receiving frame 43 in this embodiment is fixed onto the band 44 wrapped around the outer periphery of the rehabilitating pipe 40, it is possible to hold the support member 42 within the receiving frame 43 simply by wrapping the band 44 to which the receiving frame 43 is fixed around the outer periphery of the rehabilitating pipe 40. It is also possible to omit the band 44 and fix the receiving frame 43 directly onto the rehabilitating pipe 40. [Industrial Applicability]

[0033] The present invention is useful as a rehabilitation method for existing pipes such as aging sewer pipes, and as a member for preventing the rehabilitated pipes from floating up used in this method, and is particularly suitable as a rehabilitation method for existing small-diameter pipes that do not allow workers to enter the interior to work, and as a member for preventing the rehabilitated pipes from floating up used in this method. [Explanation of symbols]

[0034] 10 Insertion side manhole 20 Inlet manhole 30 Existing pipes 40 Rehabilitation pipe 41 Anti-floating member 42 Support member 42A Flat plate part 43 slots 44 bands 50 Filling material 60 Freestanding pipe 70 Push-in jig 80 Electric winch

Claims

1. A method for rehabilitating an existing pipe by pushing a rehabilitation pipe into the inside of the existing pipe and injecting filler into the gap between the existing pipe and the rehabilitation pipe, A method for rehabilitating an existing pipe, comprising: a support member made of an elastic material and interposed in the gap between the inner top end of the existing pipe and the outer top end of the rehabilitating pipe; the support member bends when the rehabilitating pipe is pushed into the existing pipe; the support member holds the rehabilitating pipe against the buoyancy generated in the rehabilitating pipe when filling material is injected into the gap between the existing pipe and the rehabilitating pipe; and the rehabilitating pipe is pushed into the existing pipe while the support member is held on the outer top end of the rehabilitating pipe.

2. 2. A method for rehabilitating an existing pipe as described in claim 1, characterized in that before injecting filler material into the gap between the existing pipe and the rehabilitating pipe, the rehabilitating pipe is pulled back to bring the bent support member into an upright position.

3. 3. The method for rehabilitating an existing pipe according to claim 1, wherein the support member is held in a receiving frame provided on the top end of the outer surface of the rehabilitating pipe.

4. 4. The method for rehabilitating an existing pipe according to claim 3, wherein the receiving frame is fixed onto a band wrapped around the outer periphery of the rehabilitating pipe.

5. A rehabilitating pipe floatation prevention member used in a rehabilitating method for an existing pipe in which a rehabilitating pipe is pushed into the inside of the existing pipe and a filler material is injected into the gap between the existing pipe and the rehabilitating pipe, A support member made of an elastic material that is placed in the gap between the inner top end of the existing pipe and the outer top end of the rehabilitated pipe, and that becomes bent when the rehabilitated pipe is pushed into the existing pipe, and that holds down the rehabilitated pipe against the buoyancy that occurs in the rehabilitated pipe when filler material is injected into the gap between the existing pipe and the rehabilitated pipe.

6. 6. The anti-floating member for a rehabilitating pipe according to claim 5, further comprising a receiving frame for holding the support member on the outer top end of the rehabilitating pipe.

7. 7. The anti-floating member for a rehabilitating pipe according to claim 6, further comprising a band that is wound around the outer periphery of the rehabilitating pipe and to which the receiving frame is fixed.

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