Existing pipe rehabilitation method and pipe opening seal structure

Abstract

To seal both end opening parts in a gap between an existing pipe and a regeneration pipe in a good workability manner prior to filling a back-filling material into the gap.SOLUTION: A pipe opening seal structure 5U, 5D that, prior to filling a back-filling material into a gap 4 between an existing pipe 1 and a regeneration pipe 3, seals openings positioned at both ends in a pipe axial direction of the gap 4 includes a plurality of pieces having shapes corresponding to the openings of the gap 4, namely, a pair of lower pieces 20, a pair of intermediate pieces 30, and an apex piece 40.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for rehabilitating an existing pipe, in particular to a process for sealing both end openings of a gap between an existing pipe and a rehabilitated pipe in order to fill the gap with backfill material (pipe opening sealing process), and to a pipe opening sealing structure constructed at the openings. [Background technology]

[0002] It is well known that a plastic rehabilitation pipe is installed inside an existing pipe, such as an aging sewer pipe, to line and rehabilitate the existing pipe. After the rehabilitation pipe is installed along the entire length of the existing pipe, a backfill material is filled into the gap between the existing pipe and the rehabilitation pipe. However, to prevent the fluid backfill material from leaking from the openings at both ends of the gap, these openings must be sealed. This seal is called a pipe opening seal.

[0003] As disclosed in Patent Document 1, the pipe opening seal is constructed by sealing the entire periphery of the opening of the gap between the existing pipe and the rehabilitated pipe with clay cement. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-9649 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the construction of pipe opening seals using clay cement is difficult to do. That is, the clay cement must be mixed on-site, and typically requires two people: one to mix the clay cement and another to fill the gap between the existing pipe and the rehabilitated pipe. The larger the diameter of the existing pipe, the greater the amount of clay cement required, making the work even more difficult. Furthermore, when sealing the pipe opening while water is flowing through the existing pipe, the filled clay cement will be washed away, so it is necessary to fill it in as needed. There are also other inconveniences, such as the fact that backfilling work cannot begin until the clay cement in the pipe opening seal has hardened, and that cracks may appear in the hardened clay cement, causing the backfill material to leak. [Means for solving the problem]

[0006] In order to solve the above problem, the present invention provides a pipe opening sealing structure that seals openings located at both ends of the gap in the axial direction of the pipe before filling the gap between an existing pipe and a rehabilitation pipe installed within the existing pipe with backfill material, and is characterized by having a plurality of pieces having shapes corresponding to the openings of the gap, and these pieces block the openings. This configuration allows for the installation of multiple pieces in the opening of the gap between the existing pipe and the rehabilitated pipe, significantly improving workability compared to filling with clay cement. Furthermore, after the pieces are installed in the opening, the work of filling the backfill material can begin immediately. Furthermore, because cracks like those caused by clay cement do not occur, leakage of the backfill material can be suppressed.

[0007] Preferably, the plurality of pieces include at least a pair of side pieces that close the left and right sides of the opening of the gap, and a top piece that closes the top of the opening, and the external shapes of the at least a pair of side pieces are symmetrical when viewed from the tube axis direction. According to this configuration, the end of the rehabilitating pipe can be positioned at the center in the left-right direction of the end of the existing pipe.

[0008] Preferably, the at least one pair of side pieces includes a pair of left and right lower pieces that close the lower portion of the opening, and at least one pair of left and right intermediate pieces that are positioned between the lower piece and the top piece and close the middle portion of the opening. According to this configuration, the side pieces are divided into a lower piece and an intermediate piece, so that the installation work into the opening can be carried out smoothly.

[0009] Preferably, the top piece consists of a single piece, and the top piece that blocks the top of the opening at one end in the axial direction of the tube has a hole formed therein for injecting backfilling material, and the top piece that blocks the top of the opening at the other end in the axial direction of the tube has a hole formed therein for allowing the backfilling material to overflow. This configuration allows for the injection and overflow of backfill material using the holes in the top piece.

[0010] Preferably, a first engagement portion is formed on the outer periphery of the rehabilitation pipe, and a second engagement portion is formed on the inner periphery of the side piece, and engagement between the first engagement portion and the second engagement portion restricts movement of the side piece in the pipe axis direction relative to the rehabilitation pipe. This configuration allows the side pieces to be firmly held in place even when subjected to the filling pressure of the backfill material.

[0011] Preferably, the rehabilitation pipe is obtained by spirally winding a strip-shaped member and joining the side edges of adjacent wound portions, the strip-shaped member having a strip-shaped main portion and at least two protrusions protruding from the outer surface of the main portion, an engagement groove being formed between the protrusions as the first engagement portion, and an engagement protrusion that engages with the engagement groove being formed on the inner surface of the side piece as the second engagement portion. According to this configuration, the side pieces can be held by utilizing the protrusions of the band-shaped member.

[0012] Preferably, the plurality of pieces are arranged on a plane perpendicular to the pipe axis, and the engaging projections of the side pieces extend in a spiral having an angle equal to the spiral of the strip-shaped member of the rehabilitation pipe. This configuration allows the side pieces to be held more firmly in place. Also, by positioning the engagement protrusions of the side pieces and the engagement grooves of the rehabilitation pipe and dropping them from above, the side pieces can be accurately installed in the specified position by the guidance of the engagement protrusions and engagement grooves.

[0013] Preferably, the bearing further comprises connecting means for connecting the ends of the pieces adjacent in the circumferential direction to each other. According to this configuration, by connecting the pieces together, the strength of the pipe opening seal structure can be increased.

[0014] Preferably, the connecting means includes a mating recess formed at an end of one of the adjacent lower and intermediate pieces, and a mating protrusion formed at the end of the other piece that fits into the mating recess. According to this configuration, the intermediate piece can be easily connected by moving it downward in the circumferential direction toward the lower piece.

[0015] Preferably, the connecting means includes a pressure bolt threaded into the end of one of the adjacent top and intermediate pieces, and the top and intermediate pieces are connected so as to be immovable relative to each other by pressing the tip of the pressure bolt against the end face of the other piece. According to this configuration, the top piece and the intermediate piece can be connected by the pressure bolt, and therefore the connection strength of the entire plurality of pieces can be increased.

[0016] Preferably, the upper end of the side piece is formed with a bolt hole for threadably receiving a hook bolt. With this configuration, when removing the side pieces after the backfill material has been filled and hardened, even if the side pieces are fixed, they can be removed by pulling them upward in the circumferential direction via the hook bolts.

[0017] Another aspect of the present invention is a method for rehabilitating an existing pipe, comprising a rehabilitating pipe installation process for installing a rehabilitating pipe within an existing pipe, a pipe opening sealing process for sealing openings located at both ends in the axial direction of the gap between the existing pipe and the rehabilitating pipe, and a backfilling material filling process for filling the gap with backfilling material, wherein the pipe opening sealing process is characterized in that the opening is blocked using a plurality of pieces having shapes corresponding to the openings of the gap.

[0018] Preferably, the plurality of pieces include a pair of left and right lower pieces that close the bottom of the opening, one top piece that closes the top of the opening, and at least a pair of left and right intermediate pieces that are located between the lower and top pieces and close the middle of the opening, and the pipe opening sealing process sequentially involves inserting the lower piece into the opening from the tube axis direction and then moving it downward along the circumferential direction of the opening to close the bottom of the opening, inserting the intermediate piece into the opening from the tube axis direction and then moving it downward along the circumferential direction of the opening to close the middle of the opening, and inserting the top piece between the intermediate pieces from the tube axis direction to close the top of the opening. According to this method, the lower piece and the intermediate piece are tapered downwards, and by moving them downwards in the circumferential direction, the installation work of these pieces can be carried out smoothly.

[0019] Preferably, the method further comprises a piece removing step of removing the plurality of pieces from the opening after the back-filling material filling step is completed and the back-filling material has hardened. This method allows multiple pieces to be reused for other field pipe end seals.

[0020] Preferably, in the piece removing step, the middle piece and the lower piece are removed from the opening by pulling the upper end portions thereof upward. According to this method, the lower piece and the intermediate piece are tapered downwards, and by moving them upwards in the circumferential direction, the removal of these pieces can be carried out smoothly. [Effects of the Invention]

[0021] According to the present invention, pipe opening seals can be installed with good workability, and backfilling material filling work can be started without delay, thereby preventing leakage of backfilling material. [Brief explanation of the drawings]

[0022] [Figure 1] This is a schematic vertical cross-sectional view showing the state in which a pipe opening seal according to one embodiment of the present invention has been applied to the openings at both ends of the gap between the existing pipe and the rehabilitating pipe after the rehabilitating pipe has been installed inside the existing pipe. [Figure 2] This is a front view of the upstream pipe opening seal structure as seen from the manhole side. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] 5A and 5B are cross-sectional views showing the engagement state of the intermediate piece and the rehabilitating pipe of the pipe opening seal structure at different positions. [Figure 6] FIG. 2 is a view showing an upper end face of a main portion of the intermediate piece. [Figure 7] 4 is a view showing an upper end face of the lower piece of the pipe opening seal structure. FIG. [Figure 8] This is a front view of the downstream pipe opening seal structure as seen from the manhole side. DETAILED DESCRIPTION OF THE INVENTION

[0023] An embodiment of the present invention will be described below with reference to the drawings. An existing pipe 1 shown in Fig. 1 is, for example, a sewer pipe, and is installed between an upstream manhole 2A and a downstream manhole 2B. The deteriorated existing pipe 1 is rehabilitated by lining its inner periphery with a rehabilitation pipe 3. An outline of this rehabilitation method will be described below.

[0024] <Rehabilitation pipe installation process> In this embodiment, the rehabilitation pipe 3 is constructed by spirally winding a strip-shaped member 10 (profile) made of a synthetic resin such as polyvinyl chloride and joining the side edges of adjacent wound portions. As illustrated in FIG. 5, the strip-shaped member 10 has the same cross-sectional shape in the longitudinal direction and includes a strip-shaped main band portion 11, a female fitting portion 12 formed on one side edge of the main band portion 11, a male fitting portion 13 formed on the other side edge, and, for example, two reinforcing ribs 14. One surface of the main band portion 11 is smooth, and the female fitting portion 12, male fitting portion 13, and reinforcing rib 14 are formed so as to protrude from the other surface. The female fitting portion 12 and reinforcing rib 14 are ridges of the same height.

[0025] The strip-shaped member 10 is wound spirally, and the side edges of adjacent wound portions are overlapped and compressed radially, whereby the female fitting portion 12 and the male fitting portion 13 are fitted together to obtain the rehabilitating pipe 3. An engagement groove 15 (first engagement portion) having the function described below is formed between the female fitting portion 12 and one reinforcing rib 14.

[0026] As shown in Figure 1, the rehabilitation pipe 3 is installed over the entire length of the existing pipe 1, protruding a predetermined amount from both ends of the existing pipe 1. Because the outer diameter of the rehabilitation pipe 3 is smaller than the inner diameter of the existing pipe 1, a gap 4 is formed between the existing pipe 1 and the rehabilitation pipe 3. Because the rehabilitation pipe 3 rests on the bottom of the existing pipe 1 due to its own weight, the gap 4 is largest at the top and gradually becomes smaller towards the bottom.

[0027] <Pipe opening sealing process> After the installation process of the rehabilitation pipe 3, a pipe opening sealing process is carried out prior to the process of filling the gap 4 with backfill material (not shown). That is, as shown in Fig. 1, the opening at the upstream end of the gap 4 is sealed with a pipe opening seal structure 5U, and the opening at the downstream end of the gap 4 is sealed with a pipe opening seal structure 5D. As will be described later, these pipe opening seal structures 5U and 5D are composed of multiple pieces 20, 30, and 40 (see Fig. 4).

[0028] <Backfilling material filling process> Following the pipe mouth sealing process, the backfilling material filling process is carried out. First, an injection device 6 is connected to the top of the upstream pipe mouth sealing structure 5U, and an overflow device 7 is connected to the top of the downstream pipe mouth sealing structure 5D. These injection device 6 and overflow device 7 have pipes 6a and 7a, respectively, and valves 6b and 7b attached to the pipes 6a and 7a.

[0029] When backfill material (not shown) is injected from the injection tool 6, it fills the gap 4 between the existing pipe 1 and the rehabilitated pipe 3. The overflow tool 7 removes air from the gap 4 while the backfill material is being filled into the gap 4. When the backfill material has been completely filled into the gap 4, the backfill material overflows from the overflow tool 7, confirming that filling is complete. After confirming that the overflowed backfill material has the same properties as the injected backfill material, the valves 6a and 7b of the injection tool 6 and the overflow tool 7 are closed, completing the filling of the backfill material.

[0030] <Piece removal process> After the backfilling process is completed and the backfilling material has hardened, the pieces 20, 30, and 40 of the pipe opening seal structures 5U and 5D are removed. The removed pieces 20, 30, and 40 can be reused for pipe opening seals at other sites. Finishing mortar is applied to the space left after removal.

[0031] <Details of pipe opening seal structure> The pipe opening seal structure, which is a characteristic feature of the present invention, will be described in detail. The upstream pipe opening seal structure 5U and the downstream pipe opening seal structure 5D have almost the same configuration, so the same numbers will be used for each component. The following description will focus on the upstream pipe opening seal structure 5U.

[0032] 4, the pipe opening seal structure 5U of this embodiment is composed of a plurality of, for example, five arc-shaped pieces, namely, a pair of left and right lower pieces 20 (side pieces), a pair of left and right middle pieces 30 (side pieces), and one top piece 40. These pieces 20, 30, 40 are preferably made of metal, for example, steel, from the standpoint of workability and strength, but may also be made by carving out wood.

[0033] The pair of lower pieces 20, the pair of intermediate pieces 30, and the top piece 40 are designed based on the inner diameter of the existing pipe 1 and the outer diameter of the rehabilitating pipe 3 to correspond to the cross-sectional shape of the gap 4 when the rehabilitating pipe 3 is placed in the center of the existing pipe 1 in the left-right direction, and have an outer shape that can substantially close this gap 4. Therefore, the pair of lower pieces 20 have outer shapes that are symmetrical to each other when viewed from the pipe axis direction, and similarly, the pair of intermediate pieces 30 also have outer shapes that are symmetrical to each other. One top piece 40 has an outer shape that is symmetrical to each other. This will be described in detail below.

[0034] The pair of lower pieces 20 each have an angular range of approximately 90° and have a shape and dimensions corresponding to approximately the lower half of the opening of the gap 4, and are designed to close this lower half. The pair of middle pieces 30 have an angular range of approximately 60° and have a shape and dimensions corresponding to the left and right portions of approximately the upper half of the opening of the gap 4, excluding the top, and are designed to close these left and right portions. The top piece 40 has a shape and dimensions corresponding to the top of the opening of the gap 4, and is designed to close this top. These pieces 20, 30, and 40 are arc-shaped, and the lower piece 20 and middle piece 30 are tapered so that their thickness gradually decreases from the top to the bottom. It is preferable that the pieces 20, 30, and 40 be small enough to be carried by one person and to be able to be carried through a manhole with a diameter of 600 mm.

[0035] As shown in Fig. 4, the intermediate piece 30 has a main portion 30A curved in an arc shape and two engaging protrusions 30B (second engaging portions) provided on the inner peripheral side of the curved shape of the main portion 30A. As shown in Fig. 5, the main portion 30A has an inner peripheral wall 31 and an outer peripheral wall 32 that face each other in the radial direction, and a rear wall 33 located on the rear side in the pipe axial direction (opposite the manhole 2A), and has a U-shaped cross section.

[0036] Furthermore, the main portion 30A has end walls 34, 35 at both ends in the circumferential direction (longitudinal direction), i.e., at the upper and lower ends. Furthermore, the main portion 30A has front walls 36 (see FIG. 4) facing the manhole at two circumferentially spaced locations. Therefore, the main portion 30A has a rectangular (box-shaped) cross section at the location where the front walls 36 are located. These front walls 36 are used as grips when installing or removing the intermediate piece 30 in an opening, as will be described later.

[0037] The main portion 30A has a constant dimension (width) in the axial direction of the pipe, and is twice as wide as the strip-shaped member 10. The radial dimension (thickness) of the main portion 30A gradually decreases from the upper end to the lower end. As shown in FIG. 4, a fitting protrusion 37 (connecting means) is formed on the lower end wall 35. For example, two fitting protrusions 37 are formed, spaced apart in the axial direction of the pipe. As shown in FIG. 6, a bolt hole 38 is formed in the center of the axial direction of the pipe on the upper end wall 34.

[0038] As shown in Figures 5(A) and (B), the two engaging protrusions 30B are spaced apart in the pipe axial direction by the pitch of the spiral of the strip-shaped member 10. The engaging protrusions 30B extend over the entire length of the main portion 30A, tracing a spiral at an angle equal to the spiral of the strip-shaped member 10 of the rehabilitation pipe 3 described above, and are inclined with respect to the extension direction (longitudinal direction) of the main portion 30A. The engaging protrusions 30B have a constant height, which is approximately equal to the female fitting portion 12 and the reinforcing rib 14 of the strip-shaped member 10. The two engaging protrusions 30B are adapted to engage with the engaging grooves 15 of the two winding portions of the rehabilitation pipe 3, respectively.

[0039] As shown in Fig. 4, the lower piece 20 also has a main portion 20A curved in an arc shape and two engaging protrusions 20B (second engaging portions) provided on the inside of the curved shape of the main portion 20A. In this embodiment, the main portion 20A is hollow and rectangular in cross section, but it may also be solid. The main portion 20A has a constant dimension (width) in the axial direction of the pipe, which is equal to that of the main portion 30A of the intermediate piece 30. The radial dimension (thickness) of the main portion 20A gradually decreases from the upper end to the lower end.

[0040] The main portion 20A has an end wall 21 at its upper end. As shown in Fig. 7, a bolt hole 22 is formed in the center of the end wall 21 in the axial direction, and fitting recesses 23 (connecting means) are formed on both sides of the end wall 21 in the axial direction.

[0041] Like the engaging protrusions 30B of the intermediate piece 30, the two engaging protrusions 20B of the lower piece 20 are spaced apart in the pipe axis direction by the pitch of the spiral of the strip-shaped member 10. Like the engaging protrusions 30B of the intermediate piece 30, these engaging protrusions 20B also extend in a spiral at the same angle as the spiral of the strip-shaped member 10 and are inclined with respect to the extension direction (longitudinal direction) of the main portion 20A. The height of the engaging protrusions 20B is the same as that of the engaging protrusions 30B of the intermediate piece 30. As will be described later, when the intermediate piece 30 is joined to the lower piece 20, the position of the main portion 30A of the intermediate piece 30 in the pipe axis direction coincides with the main portion 20A of the lower piece 20, and the two engaging protrusions 30B of the intermediate piece 30 are substantially connected to the two engaging protrusions 20B of the lower piece 20 in a spiral.

[0042] As shown in FIG. 4 , the top piece 40 does not have an engaging protrusion like the intermediate piece 30 or the lower piece 20. Like the main portion 30A of the intermediate piece 30, the top piece 40 has an inner peripheral wall 41, an outer peripheral wall 42, and a rear wall 43, forming a U-shaped cross section. It has end walls 44 at both left and right ends, and front walls 46 at two locations spaced apart on the left and right. The top piece 40 has a constant axial dimension (width) equal to that of the main portion 30A of the intermediate piece 30, and its radial dimension (thickness) gradually decreases from the center to both ends. This radial dimension may vary slightly and may be constant. The left and right end walls 44 of the top piece 40 have bolt holes (not shown) formed at two locations spaced apart in the axial direction of the pipe, and pressure bolts 50 (connecting means) are threaded into these bolt holes.

[0043] As shown in an exaggerated manner in Figure 3, the circumferential length of the top piece 40 gradually decreases from the manhole side toward the back, and both circumferential end faces (end walls 44) are inclined with respect to the pipe axis direction so as to approach each other toward the back. In other words, when viewed from above, the top piece 40 has a wedge shape. Correspondingly, the end face of the intermediate piece 30 on the top piece 40 side is also inclined. As shown in Figure 4, a hole 48 (a hole for injecting backfill material) is formed in the circumferential center of the back wall 43 of the top piece 40.

[0044] As shown in Figure 8, the downstream pipe opening seal structure 5D has all the components of the upstream pipe opening seal structure 5U described above. A hole 48 formed in the top piece 40 of this pipe opening seal structure 5D is used to allow the backfill material to overflow. Furthermore, in the downstream pipe opening seal structure 5D, multiple holes 39 for allowing the backfill material to overflow are formed in the back wall 33 of the intermediate piece 30.

[0045] <Details of the pipe opening sealing process> As described above, the upstream and downstream openings of the gap 4 between the existing pipe 1 and the rehabilitating pipe 3 are sealed by constructing the pipe opening seal structures 5U and 5D. Specifically, the left and right lower pieces 20 are first fitted into the lower half of the opening of the gap 4 to seal the lower half. Specifically, the lower piece 20 is inserted into the opening of the gap 4 from the pipe axial direction above its final installation position and dropped in with the two engaging protrusions 20B aligned with the engaging grooves 15 in the two-turn portion of the rehabilitating pipe 3. As a result, with the engaging protrusions 20B engaged with the engaging grooves 15, the lower piece 20 moves downward along the circumferential direction and fits into the lower half of the opening. Because the lower piece 20 tapers downward and the engaging protrusions 20B are guided by the engaging grooves 15, the lower piece 20 can be smoothly fitted into the predetermined position in the lower half of the opening.

[0046] Next, the left and right intermediate pieces 30 are fitted into the left and right portions of the upper half of the opening of the gap 4, excluding the apex, to close the left and right portions. Specifically, the intermediate piece 30 is inserted axially above the final fitting position, i.e., into or near the apex of the opening of the gap 4, and then dropped in with the engaging protrusions 30B aligned with the engaging grooves 15 of the rehabilitating pipe 3. This causes the end wall 35 of the intermediate piece 30 to abut the end face of the lower piece 20, and the engaging protrusions 37 fit into the engaging recesses 23. The two engaging protrusions 30B engage with the engaging grooves 15 of the two winding portions of the rehabilitating pipe 3, respectively, and are spirally connected to the two engaging protrusions 20B of the lower piece 20. The intermediate piece 30 is also tapered downward, and the engaging protrusions 30B are guided by the engaging grooves 15, allowing it to be smoothly fitted into the predetermined position in the middle of the opening.

[0047] Next, the top piece 40 is pushed axially into the top of the opening of the gap 4, i.e., into the space between the left and right intermediate pieces 30. As mentioned above, the top piece has a wedge shape, so it can be pushed in smoothly, and its axial position can be aligned with the main portion 30A of the intermediate piece 30. In this way, the pair of lower pieces 20, the pair of intermediate pieces 30, and the top piece 40 are installed on a plane perpendicular to the pipe axis of the existing pipe 1 (rehabilitating pipe 3).

[0048] Next, the pressing bolt 50 threaded into the end wall 44 of the top piece 40 is screwed toward the intermediate piece 30, and its tip 51 (shown by the two-dot chain line in FIG. 6) is pressed firmly against the end wall 34 of the intermediate piece 30, thereby connecting the top piece 40 and the intermediate piece 30. The pressing force of this pressing bolt 50 also firmly joins the intermediate piece 30 to the bottom piece 20.

[0049] The outer peripheries of the pieces 20, 30, 40 have a radius equal to the inner periphery of the existing pipe 1, and are in surface contact with the inner periphery of this existing pipe 1. The inner periphery of the pieces 20, 30, 40 also has a radius equal to the outer periphery of the rehabilitating pipe 3 (the radial outer ends of the female fitting portion 12 and the reinforcing rib 14), and are in contact with the outer periphery of this rehabilitating pipe 3. In this way, the opening of the gap 4 is sealed.

[0050] If the deterioration of the existing pipe 1 causes unevenness on its inner surface, forming gaps between the outer peripheries of the pieces 20, 30, and 40, mortar is rubbed into these gaps. If gaps form between the pieces 20, 30, and 40, mortar is also filled into these gaps. In this way, the construction of the pipe opening seal structures 5U and 5D is completed.

[0051] As described above, the opening of the gap 4 is sealed with the pieces 20, 30, 40 without using a large amount of clay cement, so that workability can be greatly improved. Furthermore, even when installing the pipe opening seal while water is flowing through the existing pipe 1 and the rehabilitated pipe 3, once the lower piece 20 is fitted into the lower half of the opening of the gap 4, the work can be carried out without being washed away.The lower piece 20 can maintain a stable fit into the opening of the gap 4 due to the engagement between the engagement protrusion 20B and the engagement groove 15 of the rehabilitated pipe 3.

[0052] When water is flowing through an existing pipe, the water level should be kept below 30% of the inner diameter of the existing pipe as a rule, so it is preferable that the lower piece 20 blocks the existing pipe to a height of at least 30% of the inner diameter.More preferably, it is preferable to block the lower half of the opening, as in this embodiment.

[0053] <Effect of the pipe opening seal structure during the backfilling process> When filling the backfill material, the aforementioned injection tool 6 is inserted into the hole 48 formed in the top piece 40 of the upstream pipe mouth seal structure 5U, and the aforementioned overflow tool 7 is inserted into the hole 48 formed in the top piece 40 of the downstream pipe mouth seal structure 5D, and the backfill material is filled from the injection tool 6.

[0054] Because the engaging protrusions 20B, 30B of the lower pieces 20, 30 are engaged with the engaging grooves 15 of the rehabilitating pipe 3, the lower piece 20 and the intermediate piece 30 are prohibited from moving in the pipe axial direction relative to the rehabilitating pipe 3. Furthermore, the engaging recess 23 of the lower piece 20 and the engaging protrusion 37 of the intermediate piece 30 fit together, and the bolt 50 of the top piece 40 presses firmly against the end wall 34 of the intermediate piece 30, thereby firmly connecting the pieces 20, 30, 40. Therefore, even if the filling pressure of the backfill material is applied to the pipe opening seal structures 5U, 5D, the pipe opening seal structures 5U, 5D can reliably maintain their installed position and exhibit good sealing function.

[0055] The intermediate piece 30 of the downstream pipe opening seal structure 5D is formed with a hole 39 for the backfill material to overflow, so that during the filling process, the filling status of the backfill material can be confirmed by the backfill material overflowing from this hole 39. After confirming that the backfill material has overflowed, this hole 39 is closed with a cap or the like.

[0056] <Details of the piece removal process> After the backfilling material filling process is completed and the backfilling material has hardened, the pieces 20, 30, and 40 of the pipe opening seal structures 5U and 5D are removed, as will be described in detail below. First, loosen the bolts 50 on the top piece 40, then remove the top piece 40 by grasping the front wall 46 of the top piece 40 and pulling it axially toward the manhole. If the top piece 40 is stuck and cannot be easily removed by hand, attach a wire to the front wall 46 and pull it out with a lever lock (traction device).

[0057] Next, grasp the front wall 36 and pull the intermediate piece 30 upward in the circumferential direction. If the intermediate piece 30 is stuck and cannot be easily pulled out by hand, hit the front wall 36 from below with a hammer to loosen the fastening, then pull it out. If the intermediate piece 30 is more firmly stuck, thread a hook bolt (not shown) into a bolt hole 38 (see Figure 6) formed in the upper end wall 34 of the intermediate piece 30, attach a wire to the hook bolt, and pull it with a lever lock to pull the intermediate piece out.

[0058] Next, the lower piece 20 is pulled upward in the circumferential direction. Specifically, a hook bolt (not shown) is screwed into a bolt hole 22 (see FIG. 7) formed in the end face of the lower piece 20, and a wire is attached to the hook bolt and pulled with a lever lock to pull the lower piece out.

[0059] The intermediate piece 30 and the lower piece 20 are tapered downward, so they can be smoothly removed by pulling them upward.

[0060] <Other embodiments> The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention. 3 and 4, a plate-shaped stopper 100 protruding toward the top piece 40 may be fixed to the back surface of the main portion 30A of the intermediate piece 30 to restrict the top piece 40 from moving inward. In this case, the top piece 40 does not have to be wedge-shaped (i.e., both end faces of the top piece 40 and the end faces of the intermediate piece 30 may extend in the tube axis direction). The number of pieces in the pipe opening seal structure may be three. That is, it may be composed of a pair of left and right side pieces and one top piece. The pipe opening seal structure may also include multiple pairs of middle pieces.

[0061] The waterproofing properties can be improved by providing rubber on the surface of the piece that comes into contact with the existing pipe or by using rubber for the engaging protrusions. In this case, it is preferable to use a hard, slippery rubber.

[0062] A press bolt may be threaded into a bolt hole formed in the upper end of the intermediate piece and pressed against the end face of the top piece. In this case, the bolt hole in the intermediate piece is used for both the press bolt and the hook bolt, and no bolt hole is formed in the top piece. Alternatively, the lower piece may be formed with a mating projection, and the intermediate piece may be formed with a mating recess.

[0063] Instead of extending along the spiral, the engaging projections on the lower piece and intermediate piece may be formed as multiple projections spaced apart along the spiral, or may be formed locally in one location and engage with the engaging groove in the rehabilitating pipe.

[0064] bottom piece and intermediate piece and the top piece Instead of being installed on a plane perpendicular to the pipe axis, the engaging projections may be arranged spirally along the strip-shaped member of the rehabilitating pipe. piece and intermediate piece The extension direction of the main portion is formed parallel to the extension direction of the main portion. The rehabilitation pipe is not limited to a form in which a strip-shaped member is wound spirally, but various forms can be adopted, such as a form formed from plate-shaped segments. A structure in which a strip-shaped member 10 is joined to an adjacent strip-shaped member 10 via a separate connecting member may also be used. The existing pipe may be a water supply pipe, an agricultural water pipe, a hydroelectric power generation water pipe, a gas pipe, a tunnel, or the like. [Industrial Applicability]

[0065] The present invention can be applied to a technology for rehabilitating existing pipes such as aged sewer pipes. [Explanation of symbols]

[0066] 1 Existing pipes 3 Rehabilitation pipe 4. Gap 5U, 5D pipe opening seal structure 10. Belt-shaped member 11 Main belt section 12 Female fitting part (protrusion) 14 Reinforcing rib (protrusion) 15 Engagement groove (first engagement portion) 20 Lower piece (side piece) 20A Main section 20B Engagement protrusion (second engagement part) 22 bolt holes 23 Fitting recess (connection means) 30 Middle piece (side piece) 30A Main section 30B Engagement protrusion (second engagement part) 37 Fitting protrusion (connecting means) 38 bolt holes 40 Top piece 48 holes (holes for backfill injection; holes for backfill overflow) 50 Press bolt (connection means)

Claims

1. A pipe opening seal structure that seals openings located at both ends in the axial direction of a gap between an existing pipe and a rehabilitation pipe installed in the existing pipe before filling the gap with a backfill material, The rehabilitation pipe rests on the bottom of the existing pipe, and the gap is largest at the top and gradually becomes smaller toward the bottom. a plurality of pieces having shapes corresponding to the opening of the gap, and the opening is closed by inserting the plurality of pieces into the opening of the gap; The plurality of pieces include at least one pair of side pieces that close the left and right sides of the opening of the gap, and a top piece that closes the top of the opening, and the outer shapes of the at least one pair of side pieces, when viewed from the pipe axis direction, are symmetrical and have a tapered shape in which the radial thickness gradually decreases from the upper end to the lower end.

2. A pipe opening sealing structure as described in claim 1, characterized in that the outer periphery of each of the plurality of pieces has a radius equal to the inner periphery of the existing pipe and is in contact with the inner periphery of the existing pipe, and the inner periphery of each piece has a radius equal to the outer periphery of the rehabilitated pipe and is in contact with the outer periphery of the rehabilitated pipe.

3. A pipe opening sealing structure as described in claim 1, characterized in that the top piece consists of a single piece, and the at least one pair of side pieces include a pair of left and right lower pieces that block the lower part of the opening, and at least a pair of left and right intermediate pieces that are located between the lower piece and the top piece and block the middle part of the opening.

4. The pipe opening seal structure according to claim 3, characterized in that the top piece that blocks the top of the opening on one end side in the pipe axis direction has a hole for injecting backfill material, and the top piece that blocks the top of the opening on the other end side in the pipe axis direction has a hole for allowing the backfill material to overflow.

5. A pipe opening seal structure that seals openings located at both ends of the gap in the pipe axial direction before filling a gap between an existing pipe and a rehabilitation pipe installed within the existing pipe with backfill material, a plurality of pieces each having a shape corresponding to the opening of the gap, and the pieces close the opening; the plurality of pieces include at least a pair of side pieces that close left and right portions of the opening of the gap and a top piece that closes a top portion of the opening, and the outer shapes of the at least a pair of side pieces are symmetrical when viewed from the tube axis direction, a first engaging portion is formed on an outer periphery of the rehabilitating pipe, and a second engaging portion is formed on an inner periphery of the side piece, and engagement between the first engaging portion and the second engaging portion restricts movement of the side piece in the pipe axial direction relative to the rehabilitating pipe, The rehabilitation pipe is obtained by spirally winding a strip-shaped member and joining side edges of adjacent wound portions, and the strip-shaped member has a strip-shaped main portion and at least two protrusions protruding from the outer surface of the main portion, and an engagement groove is formed between the protrusions as the first engagement portion, A pipe opening seal structure characterized in that an engaging protrusion that engages with the engaging groove is formed on the inner peripheral surface of the side piece as the second engaging portion.

6. A pipe opening sealing structure as described in claim 5, wherein the plurality of pieces are arranged on a plane perpendicular to the pipe axis, and the engaging protrusion of the side piece extends in a spiral having an angle equal to the spiral of the strip-shaped member of the rehabilitation pipe.

7. 4. The pipe opening seal structure according to claim 3, further comprising connecting means for connecting the ends of the pieces adjacent in the circumferential direction.

8. The pipe opening seal structure according to claim 7, characterized in that the connecting means includes a mating recess formed at an end of one of the adjacent lower piece and intermediate piece, and a mating protrusion formed at the end of the other piece that fits into the mating recess.

9. 8. The pipe opening seal structure according to claim 7, wherein the connecting means includes a pressure bolt threaded into the end of one of the adjacent top and intermediate pieces, and the top and intermediate pieces are connected so as not to move relative to each other by pressing the tip of the pressure bolt against the end face of the other piece.

10. a rehabilitating pipe installation process for installing a rehabilitating pipe inside an existing pipe; a pipe opening sealing step of sealing openings located at both ends in the pipe axial direction of the gap between the existing pipe and the rehabilitating pipe; a backfilling material filling step of filling the gap with a backfilling material; In a method for rehabilitating an existing pipe, The rehabilitation pipe rests on the bottom of the existing pipe, and the gap is largest at the top and gradually becomes smaller toward the bottom. a plurality of pieces having shapes corresponding to the opening of the gap are prepared, the plurality of pieces comprising a pair of left and right lower pieces having shapes corresponding to the lower part of the opening, one top piece having a shape corresponding to the top of the opening, and a pair of left and right intermediate pieces having shapes corresponding to the middle part of the opening, the outer shapes of the lower piece and the intermediate piece as viewed in the tube axis direction being symmetrical and tapering in such a way that the radial thickness gradually decreases from the upper end to the lower end; In the pipe opening sealing step, a step of inserting the lower piece into the opening in the tube axial direction and then moving the lower piece downward along the circumferential direction of the opening to close a lower portion of the opening; a step of inserting the intermediate piece into the opening in the tube axial direction and then moving it downward along the circumferential direction of the opening to close the intermediate portion of the opening; a step of inserting the top piece between the intermediate pieces in the axial direction of the pipe to close the top of the opening, said step being carried out in sequence.

11. Further, a piece removing step is provided in which, after the back-filling material filling step is completed and the back-filling material has hardened, the plurality of pieces are removed from the opening, In the piece removing step, withdrawing the top piece axially from the top of the opening; removing the intermediate piece by moving it upward from the middle of the opening; removing the lower piece by moving it upward from the bottom of the opening; The method for rehabilitating an existing pipe according to claim 10, wherein the steps of:

12. The method for rehabilitating an existing pipe as described in claim 11, characterized in that bolt holes are formed in the upper ends of the intermediate piece and the lower piece, and in the piece removal process, hook bolts are screwed into the bolt holes and the intermediate piece and the lower piece are pulled upward via the hook bolts.

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