Existing pipe rehabilitation method

Abstract

To provide an existing pipe rehabilitation method capable of suppressing large local deformation of a peripheral edge of a communication port of a rehabilitation pipe due to injection of backfilling material even if a structure of a floating prevention work is simple.SOLUTION: A rehabilitation pipe 3 is lined on an inner surface of an existing pipe 1 having a connection port 2a with a branch pipe 2, and a communication port 3b with the connection port 2a is formed in the rehabilitation pipe 3. An elastic closing member 20 is installed in an inter-periphery annular gap 4c in an inter-pipe gap 4 to close the inter-periphery annular gap 4c. A floating prevention work 10 with a simple structure is installed, and a backfilling material 6 is injected into the inter-pipe gap 4. Thereafter, the closing member 20 is removed, and the inter-periphery annular gap 4c after removal is filled with a gap filler 8.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rehabilitation method for lining the inner surface of an existing pipe such as an aged sewer pipe with a rehabilitation pipe, and more particularly to a method for rehabilitating an existing pipe by filling a gap between the existing pipe and the rehabilitation pipe with a backfill material. [Background technology]

[0002] A widely known method for rehabilitating aging pipelines involves lining the inner periphery of the existing pipe with a rehabilitating pipe and filling the gap between the outer periphery of the rehabilitating pipe and the inner periphery of the existing pipe with a backfill material such as cement milk or mortar. Because buoyancy is applied to the rehabilitating pipe when filling the backfill material, anti-floating work is performed to prevent the pipe from floating up. For example, in the anti-floating work described in Patent Documents 1 to 3, a bottom wale extending in the axial direction of the rehabilitating pipe is provided at the bottom of the rehabilitating pipe. A plurality of columnar support members are erected on the bottom wale with intervals in the axial direction of the pipe. The upper ends of each support member penetrate the top of the rehabilitating pipe, abut against the top of the existing pipe, and are supported by a jack. This prevents the bottom of the rehabilitating pipe from floating up. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-183632 [Patent Document 2] Patent Publication No. 2021-067057 [Patent Document 3] Patent Publication No. 2021-188293 Summary of the Invention [Problem to be solved by the invention]

[0004] The anti-floating works disclosed in the above-mentioned Patent Documents 1 to 3 have a simple structure, can be easily installed and removed in a short time, and are easy to work with. However, because the structure is simplified, the portion of the rehabilitating pipe above the bottom may be deformed depending on the rigidity of the rehabilitating pipe and the way in which buoyancy is applied. In particular, if the rehabilitating pipe is structured to be tubular by connecting lining members, even if the lining members themselves are highly rigid, the connecting portions can stretch and deform, resulting in a large amount of displacement of the rehabilitating pipe. For this reason, if the rehabilitating pipe has a communication opening that connects to the attachment pipe opening (connection opening to the branch pipe) of the existing pipe, the shape of the communication opening and, ultimately, the aesthetic appearance of the rehabilitating pipe are likely to be damaged.

[0005] Specifically, a sealing material such as clay cement or quick-setting cement is provided in the annular gap between the periphery of the existing pipe's connecting pipe port (the port connecting to the branch pipe) and the periphery of the rehabilitating pipe's communication port to prevent backfill material from leaking into the rehabilitating pipe through the communication port during filling. When the backfill material is filled, the rehabilitating pipe as a whole is subjected to buoyancy and attempts to deform, but the periphery of the communication port in the rehabilitating pipe is restrained by the hardened sealing material and does not displace. This creates a difference in unevenness between the periphery of the communication port in the rehabilitating pipe and the surrounding area, causing the periphery of the communication port to deform so that it locally protrudes toward the inside of the rehabilitating pipe. In consideration of such circumstances, the present invention aims to prevent the peripheral portion of the communication port of the rehabilitation pipe from being locally deformed significantly by the injection of backfill material, even if the structure of the anti-floating work is simple. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides a method for rehabilitating an existing pipe, which comprises lining the inner surface of an existing pipe having a connection port with a branch pipe, forming a communication port with the connection port in the rehabilitating pipe, installing anti-floating works including a bottom wale and a bracing member, and injecting backfill material into the gap between the rehabilitating pipe and the existing pipe, a step of placing an elastic blocking member in a peripheral annular gap between a peripheral portion of the connection port and a peripheral portion of the communication port in the inter-pipe gap before injecting the backfilling material, thereby blocking the peripheral annular gap; removing the blocking member after injecting the backfilling material; filling the removed peripheral annular gap with a gap filler; The present invention is characterized by the following features.

[0007] By closing the peripheral annular gap with the blocking member, the backfill material is prevented from leaking from the communication opening into the rehabilitating pipe. The blocking member is elastically deformable and does not restrict the peripheral edge of the communication port, allowing it to displace. Therefore, if the rehabilitating pipe is deformed by the buoyancy of the backfill material injected, the elastic deformation of the blocking member will also displace the peripheral edge of the communication port along with its surrounding area. This prevents unevenness from occurring between the peripheral edge of the communication port and its surrounding area in the rehabilitating pipe, and prevents large localized deformation of the peripheral edge of the communication port. As a result, damage to the shape of the communication port can be avoided, and the aesthetic appearance of the rehabilitating pipe can be maintained. After the backfill material hardens, the blocking member is removed and the gap between the periphery is filled with gap filler to complete the work, allowing fluids such as sewage to flow smoothly from the branch pipe to the rehabilitated pipe. By removing the blocking member, it will not affect the performance of the rehabilitated pipe after construction. The anti-floating work has a simple structure consisting of a bottom wale and bracing members, which allows it to be installed and removed in a short time, making it easy to work with.

[0008] Preferably, the blocking member is made of a low-water-absorbent elastic material. This prevents moisture from the backfill material, such as mortar, from seeping into the blocking member, and thus prevents the backfill material and the blocking member from becoming integrated. Therefore, the blocking member can be easily removed after the backfill material has hardened. Preferably, the blocking member is made of a closed-cell soft foam resin material, which makes the blocking member less water-absorbent and also ensures impermeability to the backfill material.

[0009] Preferably, the blocking member is a long elastic member with a rectangular cross section whose length is equal to or greater than the circumferential length of the annular gap, and the long elastic member is wrapped around the annular gap at least once during installation. This ensures that the entire periphery of the annular gap is blocked, preventing leakage of backfill material. By making the cross section of the long elastic member rectangular, the contact area of ​​the long elastic member with the existing pipe or rehabilitated pipe can be increased, allowing the long elastic member to be stably installed in the annular gap. Preferably, both ends of the elongated elastic member are tapered, and the both ends of the elongated elastic member that has been wound around the periphery of the annular gap are overlapped with each other. Preferably, both end faces of the long elastic member are inclined relative to the longitudinal direction, and these end faces are overlapped with each other.

[0010] If the outer periphery of the rehabilitation pipe is uneven, it is preferable to fill the recessed portion of the periphery of the communication port with a flattening filler before installing the blocking member. Therefore, the periphery of the communication port can be flattened, and then the blocking member can be placed on the flattened periphery of the communication port. This prevents gaps from forming between the blocking member and the periphery of the communication port, thereby reducing the risk of backfill material leaking. The planarizing filler may be a cement-based material or the like. As an example of the uneven structure on the outer periphery of the rehabilitation pipe, the lining material constituting the rehabilitation pipe is formed with an irregular cross section having multiple ribs protruding to the outer periphery, each rib constituting a convex portion of the unevenness, and the grooves between adjacent ribs constituting a concave portion of the unevenness.

[0011] Preferably, when injecting the backfill material, a second tension member is placed within the rehabilitating pipe, and a pressing member at the tip of the second tension member is placed against the periphery of the communication port from inside the rehabilitating pipe. The second tension member presses the blocking member outward in the pipe diameter direction via the periphery of the communication port of the rehabilitating pipe, thereby sandwiching the blocking member between the periphery of the connection port of the existing pipe and the periphery of the communication port of the rehabilitating pipe. This prevents the blocking member from slipping out of the peripheral annular gap even when pressure is applied to the blocking member during filling with backfill material, thereby reducing the risk of backfill material leaking.

[0012] Preferably, when injecting the backfilling material, a hollow annular packer is provided along the inner periphery of the annular gap. This allows the blocking member installed in the annular gap to be pressed down from the inside by the packer, and even if pressure is applied to the blocking member when filling the backfilling material, the blocking member can be prevented from slipping out of the annular gap, thereby reducing the risk of backfilling material leaking. [Effects of the Invention]

[0013] According to the present invention, even if the structure of the anti-floating work is simple, it is possible to prevent the peripheral portion of the communication port of the rehabilitation pipe from being significantly deformed locally due to the injection of backfill material. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a side view of an existing pipe and a pipe to be rehabilitated during rehabilitation work according to a first embodiment of the present invention, viewed from the side directly facing the communication opening. [Figure 2] FIG. 2 is a front cross-sectional view showing the existing pipe undergoing rehabilitation work and the rehabilitating pipe in a state before the backfilling process. [Figure 3] Fig. 3(a) is a cross-sectional view showing the cross section of the rehabilitating pipe and the existing pipe along line III-III in Fig. 1 in a flattening process, Fig. 3(b) is a cross-sectional view showing the cross section in a closing process, and Fig. 3(c) is a cross-sectional view showing the cross section in a backfilling process. [Figure 4]Fig. 4(a) is an enlarged cross-sectional view of the circled portion IVa in Fig. 2. Fig. 4(b) is a cross-sectional view showing a state in which the upper portion of the rehabilitation pipe in the portion of Fig. 4(a) has been displaced by backfilling. [Figure 5] FIG. 5 is a perspective view showing the elongated elastic member constituting the closure member shown in FIG. 1 in an initial state. [Figure 6] Figure 6(a) is a cross-sectional view showing the part shown in Figure 4(a) in a removal step, and Figure 6(b) is a cross-sectional view showing the part shown in Figure 4(a) in a finishing step. [Figure 7] FIG. 7 shows a second embodiment of the present invention and is a perspective view of a long elastic member. [Figure 8] Fig. 8(a) is a side view of the rehabilitating pipe during the closing process with the long elastic member of the second embodiment, as viewed from the side facing the communication opening. Fig. 8(b) is a side view of the rehabilitating pipe after the closing process of the second embodiment, as viewed from the side facing the communication opening. [Figure 9] FIG. 9 shows a third embodiment of the present invention and is a front cross-sectional view of an existing pipe and a pipe to be rehabilitated during rehabilitation work. [Figure 10] FIG. 10 shows a fourth embodiment of the present invention and is a front cross-sectional view of an existing pipe and a pipe to be rehabilitated during rehabilitation work. [Figure 11] FIG. 11 is a side view of the rehabilitating pipe in the fourth embodiment, seen from the side directly facing the communication opening. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. <First embodiment (FIGS. 1 to 4)> As shown in FIG. 1, the existing pipe 1 to be rehabilitated in the first embodiment of the present invention is an aging sewer pipe, particularly a main pipe. The rehabilitation target is not limited to sewer pipes, but may also be a water supply pipe, an agricultural water pipe, a hydroelectric power generation water pipe, a gas pipe, etc. As shown in FIG. 2, an attachment pipe 2 (branch pipe) is connected to the upper half of the existing pipe 1, which is a sewer main pipe. As shown in FIG. 4(a), an attachment pipe opening 2a (connection opening with the branch pipe) at the end of the attachment pipe 2 is connected to the interior of the existing pipe 1. An end face 2e (periphery of the connection opening) of the attachment pipe 2 is flush with the inner surface of the existing pipe 1.

[0016] The existing pipe 1 is rehabilitated as follows. <Lining process> 1 and 2, a rehabilitation pipe 3 made of synthetic resin is lined along the inner surface of an existing pipe 1. An annular inter-pipe gap 4 is formed between the existing pipe 1 and the rehabilitation pipe 3.

[0017] As shown in FIG. 1, the rehabilitating pipe 3 is composed of a strip-shaped lining member 30 (profile) made of synthetic resin. As shown in FIG. 3(a), the lining member 30 is formed into a modified cross-sectional shape having a strip portion 31, multiple ribs 32 protruding from the strip portion 31 toward the outer periphery (upward in FIG. 3(a)), and male and female mating portions 33, 34 on both edges of the strip portion 31. As shown in FIGS. 1 and 3(a), the lining member 30 is wound spirally around the inner surface of the existing pipe 1, and adjacent mating portions 33, 34 that are offset from each other are connected by a concave-convex mating, thereby producing a helical rehabilitating pipe 3. The outer periphery of the rehabilitating pipe 3 is formed with a spiral concave-convex pattern. The ribs 32 and the connecting portions 36 between the mating portions 33, 34 form the convex portions of the concave-convex pattern. The grooves 35 between adjacent ribs 32 or between ribs and connecting portions 36 form the concave portions of the unevenness. In the drawings other than FIG. 3, the ribs 32 and the irregularities are omitted.

[0018] <Communication port formation process> As shown in Figures 1 and 2, a communication opening 3b is formed by drilling in the location of the rehabilitating pipe 3 facing the attachment pipe opening 2a. This allows the attachment pipe opening 2a to communicate with the interior of the rehabilitating pipe 3 via the communication opening 3b. The annular portion of the inter-pipe gap 4 that surrounds the communication opening 3b constitutes a periphery-to-periphery annular gap 4c. The periphery-to-periphery annular gap 4c is defined between the end face 2e of the attachment pipe 2 (the periphery of the connection opening) and the periphery 3c of the communication opening 3b in the rehabilitating pipe 3. The size of the periphery-to-periphery annular gap 4c (the distance between the attachment pipe end face 2e and the communication opening periphery 3c) is, for example, approximately 10 mm to 100 mm, although the present invention is not limited to this.

[0019] <Flattening process> 3(a), a flattening filler 38 is filled into the groove 35 (recessed portion) in the peripheral portion 3c of the communication opening of the rehabilitation pipe 3. This flattens the outer periphery of the peripheral portion 3c of the communication opening. As the flattening filler 38, for example, a cement-based material or the like is used.

[0020] <Closure process> 3(b) and 4(a), a blocking member 20 is installed in the annular gap 4c. The annular blocking member 20 is inserted from the communication opening 3b into the entire area of ​​the annular gap 4c, thereby blocking the annular gap 4c. Even if the outer surface of the rehabilitation pipe 3 is uneven, a flattening process performed in advance can prevent a large gap from forming between the blocking member 20 and the peripheral edge of the communication opening 3c.

[0021] Preferably, as shown in Figure 4(a), the inner peripheral portion 22 of the closing member 20 is made to slightly protrude from the inner periphery of the communication opening 3b. The amount of protrusion of the inner peripheral portion 22 from the inner periphery of the communication opening 3b is preferably about several mm to about 10 mm, and more preferably about 10 mm.

[0022] The blocking member 20 is made of an elastic material that is impermeable to the backfilling material 6 (FIG. 3(c)) described below or an elastic material with low water absorption. Preferably, the blocking member 20 is made of a closed-cell soft foam resin material such as EPDM (ethylene propylene diene rubber) sponge. The hardness of the blocking member 20 is preferably about 20±5.

[0023] 5, the blocking member 20 is made of a long elastic member 21 having, for example, a rectangular cross section. The rectangular cross section increases the contact area between the upper surface of the blocking member 20 and the existing pipe 1 and the contact area between the lower surface of the blocking member 20 and the rehabilitating pipe 3. Therefore, the blocking member 20 can be stably installed in the peripheral annular gap 4c.

[0024] The length of the elongated elastic member 21 is equal to or greater than the circumferential length of the annular gap 4c. As shown in FIG. 1, the elongated elastic member 21 is wound around the annular gap 4c at least once in the circumferential direction. This ensures that the entire annular gap 4c is completely filled. The thickness (height) of the elongated elastic member 21 is, for example, approximately 30 mm to 50 mm. If the annular gap 4c is larger than the thickness of the elongated elastic member 21, it is preferable to fill the annular gap 4c by winding the elongated elastic member 21 two or more times. By making the length of one elongated elastic member 21 several times the circumferential length of the annular gap 4c, two or more windings may be made, or multiple elongated elastic members 21 may be wound around each other. When installed (before backfilling, as described below), the blocking member 20 is preferably in a state that allows for some compressive deformation, i.e., in an uncompressed state, a weakly compressed state, or a state where it is not compressed to its limit.

[0025] <Floating prevention process> Next, as shown in FIG. 2, anti-floating works 10 are installed in the rehabilitation pipe 3. The anti-floating structure 10 includes a bottom wale 11 and multiple tension members 12. The bottom wale 11 is installed at the bottom of the rehabilitating pipe 3. The longitudinal direction of the bottom wale 11 is oriented in the axial direction of the rehabilitating pipe 3. Multiple columnar tension members 12 are erected vertically on top of the bottom wale 11, spaced apart from one another in the axial direction. Jacks 13 at the bottom of each tension member 12 are engaged with the bottom wale 11. The upper end of each tension member 12 is passed through the top of the rehabilitating pipe 3 and abutted against the top of the existing pipe 1. The tension members 12 are then tensioned by the jacks 13. The anti-floating structure 10 has a simple structure, can be easily installed in a short time, and is easy to work with.

[0026] <Backfilling process> As shown in FIG. 3(c) and FIG. 4(b), thereafter, a backfilling material 6 is injected into the gaps 4 between the pipes and filled therein. At this time, the rehabilitating pipe 3 is subjected to buoyancy from the backfill material 6. In response to this, the resistance of the anti-floating work 10 prevents at least the bottom of the rehabilitating pipe 3 from floating up. However, because the anti-floating work 10 has a simple structure, deformation of the portion 3a above the bottom of the rehabilitating pipe 3 may occur depending on the rigidity of the rehabilitating pipe 3 and the way in which the buoyancy is applied. In the rehabilitating pipe 3, even if the rigidity of the lining member 30 itself is high, the connecting portion 36 is capable of elongation and deformation, so the amount of deformation due to buoyancy from the backfill material 6 is large. As a result, the portion 3a above the bottom of the rehabilitating pipe 3 tends to be displaced upward as a whole, as shown by the two-dot chain line in Figure 2.

[0027] 2 and 4(b), the rehabilitating pipe upper portion 3a includes a communication port peripheral edge portion 3c and further includes a peripheral portion 3d thereof. The peripheral portion 3d is located outside the blocking member 20 and is not directly restrained by the blocking member 20, so it can be displaced upward together with the other portions of the rehabilitating pipe upper portion 3a.

[0028] Although the blocking member 20 covers the communication port peripheral portion 3c, the blocking member 20 is capable of elastic deformation (especially compressive deformation). Therefore, the blocking member 20 does not restrict the communication port peripheral portion 3c from deforming. As a result, the communication port peripheral portion 3c is also allowed to displace upward together with its surrounding area 3d. This prevents unevenness from occurring between the communication port peripheral portion 3c and its surrounding area 3d in the rehabilitation pipe 3, and prevents large localized deformation of the communication port peripheral portion 3c.

[0029] As a result, it is possible to avoid impairing the shape of the communication opening 3b, and the aesthetic appearance of the rehabilitating pipe 3 can be ensured. If the blocking member were not elastically deformable, as shown by the imaginary line (two-dot chain line) in Figure 4(b), the upward displacement of the rehabilitating pipe upper portion 3a would relatively deform the peripheral edge portion 3c of the communication opening so as to protrude radially inward of the rehabilitating pipe 3, damaging the shape of the communication opening 3b and ultimately damaging the aesthetic appearance of the rehabilitating pipe 3. As shown in FIG. 3(c) and FIG. 4(b), the blocking member 20 is compressed as the communication port peripheral edge portion 3c is displaced.

[0030] As shown in Figure 4(b), by closing the peripheral annular gap 4c with the blocking member 20, the backfilling material 6 is prevented from leaking from the communication port 3b into the rehabilitation pipe 3. In particular, by flattening the outer periphery of the communication port peripheral portion 3c by the flattening process, the risk of the backfilling material 6 leaking from between the blocking member 20 and the communication port peripheral portion 3c can be reduced.

[0031] By using an elastic material that is impermeable to the backfilling material 6 as the blocking member 20, leakage of the backfilling material 6 can be reliably prevented. By using an elastic material with low water absorption as the blocking member 20, it is possible to prevent moisture in the backfilling material 6 from seeping into the blocking member 20. By using a closed-cell foam resin material as the blocking member 20, it is possible to ensure low water absorption and therefore impermeability to the backfilling material 6.

[0032] <Removal process> After the backfill material 6 has cured and hardened, the anti-floating structure 10 and the blocking member 20 are removed, as shown in Figure 6(a). During the blocking step (Figure 4(a)), by leaving the inner circumferential portion 22 of the blocking member 20 protruding from the inner periphery of the communication opening 3b, the blocking member 20 can be easily pulled out of the peripheral annular gap 4c by pinching and pulling out the inner circumferential portion 22. The anti-floating structure 10 has a simple structure and can be easily removed in a short time, making it easy to work with. The blocking member 20 has low water absorption and hardly absorbs the moisture of the backfilling material 6, so the blocking member 20 can be prevented from being integrated with the hardened backfilling material 6. Therefore, the blocking member 20 can be easily removed.

[0033] <Finishing process> As shown in Figure 6(b), the removed peripheral annular gap 4c is finished by filling it with a gap filler 8 (finishing material) such as mortar. This allows fluids such as sewage from the lateral pipe 2 to flow smoothly into the rehabilitated pipe 3. Because the blocking member 20 has been removed, the blocking member 20 does not affect the performance of the rehabilitated pipe 3 after construction.

[0034] Next, another embodiment of the present invention will be described. In the following embodiments, the same components as those already described will be denoted by the same reference numerals in the drawings and the description thereof will be omitted. <Second embodiment (FIGS. 7 and 8)> 7, in the second embodiment of the present invention, both end faces 21e, 21f of a long elastic member 21B constituting a blocking member 20 are inclined with respect to the longitudinal direction. Therefore, both end portions of the long elastic member 21B are tapered.

[0035] As shown in Figure 8(a), in the closing process of the second embodiment, one end face 21e of the long elastic member 21B is accommodated in the peripheral annular gap 4c facing the communication opening 3b, and the long elastic member 21B is inserted into the peripheral annular gap 4c sequentially along the longitudinal direction.

[0036] After the elongated elastic member 21B is wound around the peripheral annular gap 4c, the opposite end face 21f is pressed toward the one end face 21e, thereby overlapping the end faces 21e, 21f. This allows the two ends of the elongated elastic member 21B to be tightly overlapped, preventing the backfilling material 6 from leaking between the two ends.

[0037] <Third embodiment (FIG. 9)> As shown in Figure 9, in the third embodiment of the present invention, a second tension member 40 is prepared when injecting backfilling material 6. The second tension member 40 includes a tension rod 41, a jack 42, and a pressing member 43. The pressing member 43 is attached to the tip of the single-tube tension rod 41 via the jack 42. The pressing member 43 is formed in a curved plate shape so as to fit along the inner periphery of the rehabilitation pipe 3. The area of ​​the pressing member 43 is larger than the area of ​​the communication opening 3b.

[0038] A second tension member 40 is placed within the rehabilitating pipe 3, and a pressure member 43 is placed against the communication opening periphery 3c from inside the rehabilitating pipe 3. The base end of the tension rod 41 abuts against a portion of the rehabilitating pipe 3 180 degrees opposite the communication opening 3b, or penetrates that portion and abuts against the existing pipe 1. Furthermore, a jack 42 presses the blocking member 20 radially outward through the communication opening periphery 3c. This clamps the blocking member 20 between the end face 2e (periphery of the connection opening) of the attachment pipe 2 and the communication opening periphery 5c of the rehabilitating pipe 3. This prevents the blocking member 20 from slipping out of the peripheral annular gap 4c even when pressure is applied to the blocking member 20 during filling with the backfill material 6. This reduces the risk of backfill material 6 leaking. When the upper part 3a of the rehabilitation pipe 3 is displaced upward due to the buoyancy from the backfill material 6, it is preferable to extend the jack 42 accordingly so that the pressing member 43 always presses against the peripheral edge 3c of the communication port with an appropriate pressing force.

[0039] <Fourth embodiment (FIGS. 10 and 11)> As shown in Figures 10 and 11, in the fourth embodiment of the present invention, when injecting the backfilling material 6, a packer 50 is provided along the inner periphery of the peripheral annular gap 4c. The packer 50 is formed in a hollow ring shape with a center hole 51. The outer circumferential surface of the packer 50 is pressed against the inner circumferential surface of the annular blocking member 20. This allows the blocking member 20 to be pressed from the radially inside. Therefore, even if pressure is applied to the blocking member 20 when the backfilling material 6 is filled, the blocking member 20 can be prevented from slipping out of the peripheral annular gap 4c. This reduces the risk of the backfilling material 6 leaking. Even when the sewer system is in service, fluids such as sewage from the lateral pipe 2 can flow into the rehabilitation pipe 3 through the central hole 51 of the packer 50.

[0040] 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. For example, the rehabilitation pipe 3 is not limited to being made of a strip-shaped lining member 30 with an irregular cross section, but may be made of a tubular member with smooth outer and inner peripheral surfaces. In this case, the flattening step can be omitted. The step of installing the anti-floating structure 10 may be carried out before the step of forming the communication opening 3b, or may be carried out in parallel with the step of forming the communication opening 3b. The installation process of the blocking member 20 may be carried out after the formation of the communication opening 3b and before the backfilling process, and may be carried out in parallel with the installation process of the anti-floating structure 10, or may be carried out after the installation process of the anti-floating structure 10. Instead of the long elastic member, a seamless closed loop elastic member may be used as the blocking member. [Industrial Applicability]

[0041] The present invention can be applied to repairing, for example, deteriorated sewer pipes. [Explanation of symbols]

[0042] 1. Sewer main (existing pipe) 2. Attachment pipe (branch pipe) 2a Installation pipe port (connection port) 2e End face (periphery of connection port) 3 Rehabilitation pipe 3a Upper part from the bottom 3b Communication port 3c Periphery of communication port 3d and surrounding areas 4 Pipe gap 4c Circumferential gap 6 Backfill material 8 Gap filling material (finishing material) 10 Floating prevention works 11 Bottom wale 12 Bracing member 13 Jack 20 Closure member 21, 21B Long elastic member 30 Lining material 31 Band part 32 Rib (convex part) 33 Female mating part 34 Male mating part 35 Groove (concave part) 36 Connecting part 38 Flattening filler 40 Second bracing member 41 Tension rod 42 Jack 43 Pressing member 50 Packer 51 Center hole

Claims

1. In a method for rehabilitating an existing pipe, the inner surface of an existing pipe having a connection port with a branch pipe is lined with a rehabilitation pipe, a communication port with the connection port is formed in the rehabilitation pipe, and anti-floating works including a bottom wale and a bracing member are installed, and backfill material is injected into the gap between the rehabilitation pipe and the existing pipe. a step of placing an elastic blocking member in a peripheral annular gap between a peripheral portion of the connection port and a peripheral portion of the communication port in the inter-pipe gap before injecting the backfilling material, thereby blocking the peripheral annular gap; removing the blocking member after injecting the backfilling material; filling the removed peripheral annular gap with a gap filler; An existing pipe rehabilitation method comprising:

2. 2. The method for rehabilitating an existing pipe according to claim 1, wherein the blocking member is a closed-cell soft foamed resin material.

3. 3. A method for rehabilitating an existing pipe as described in claim 1 or 2, characterized in that the blocking member is a long elastic member with a rectangular cross section whose length is equal to or greater than the circumferential length of the peripheral annular gap, and that during installation, the long elastic member is wrapped around the peripheral annular gap at least once.

4. A method for rehabilitating an existing pipe as described in claim 3, characterized in that both ends of the long elastic member are tapered, and both ends of the long elastic member that has been wrapped around the circumferential annular gap are overlapped with each other.

5. 5. The method for rehabilitating an existing pipe according to claim 4, wherein both end faces of the long elastic member are inclined relative to the longitudinal direction, and these end faces are overlapped with each other.

6. A method for rehabilitating an existing pipe as described in claim 1 or 2, characterized in that the outer periphery of the rehabilitation pipe is formed with unevenness, and the concave portion at the periphery of the communication port is filled with a flattening filler material, and then the blocking member is installed.

7. A method for rehabilitating an existing pipe as described in claim 1 or 2, characterized in that when injecting the backfill material, a second tension member is placed within the rehabilitation pipe, and a pressure member at the tip of the second tension member is placed against the peripheral portion of the communication opening from the inside of the rehabilitation pipe.

8. 3. The method for rehabilitating an existing pipe according to claim 1, wherein a hollow annular packer is provided along the inner periphery of the peripheral annular gap when the backfilling material is injected.

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