JP7780385B2 - Existing pipe rehabilitation method - Google Patents

Description

The present invention relates to a rehabilitation method for lining the inner surface of an existing pipe, such as an aging sewer pipe, with a rehabilitation pipe, and in particular to a method for rehabilitating an existing pipe by filling the gap between the existing pipe and the rehabilitation pipe with a backfill material.

A widely known method for rehabilitating aging pipelines involves lining the inside of the existing pipe with a rehabilitating pipe and filling the gap between the outer surface of the rehabilitating pipe and the inner surface of the existing pipe with backfill material such as cement milk or mortar. Because buoyancy is applied to the rehabilitating pipe when filling with backfill material, anti-floating measures are taken to prevent the pipe from floating up. For example, in the anti-floating measures described in Patent Documents 1 to 3, a bottom wale extending in the axial direction is installed at the bottom of the rehabilitating pipe. Multiple columnar support members are erected on the bottom wale, spaced apart from one another in the axial direction. The upper end of each support member penetrates the top of the rehabilitating pipe, abuts against the top of the existing pipe, and is braced with a jack. This prevents the bottom of the rehabilitating pipe from floating up.

Japanese Patent Application Laid-Open No. 2019-183632 Japanese Patent Application Laid-Open No. 2021-067057 Japanese Patent Application Laid-Open No. 2021-188293

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

Specifically, a sealing material such as clay cement or quick-setting cement is provided in the peripheral annular gap between the peripheral edge of the existing pipe's attachment pipe port (the port connecting to the branch pipe) and the peripheral edge 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 peripheral edge 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 peripheral edge of the communication port in the rehabilitating pipe and the surrounding area, causing the peripheral edge 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.

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;
and filling the peripheral annular gap with a gap filler after the removal.

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.

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.

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.

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.

Preferably, when injecting the backfill material, a second tension member is placed within the rehabilitation pipe, and a retaining member at the tip of the second tension member is placed against the periphery of the communication port from inside the rehabilitation pipe. The second tension member presses the blocking member radially outward via the periphery of the rehabilitation pipe's communication port, thereby clamping the blocking member between the periphery of the connection port of the existing pipe and the periphery of the rehabilitation pipe's communication port. This prevents the blocking member from slipping out of the annular gap between the peripheries, even if pressure is applied to the blocking member when filling the backfill material, thereby reducing the risk of backfill material leaking.

Preferably, a hollow annular packer is provided along the inner circumference of the annular gap when the backfill material is injected. This allows the packer to press down on the blocking member placed in the annular gap from the inside, preventing the blocking member from slipping out of the annular gap even if pressure is applied to the blocking member when the backfill material is filled, thereby reducing the risk of backfill material leaking.

According to the present invention, even if the structure of the anti-floating work is simple, it is possible to prevent large localized deformation of the peripheral edge of the communication opening of the rehabilitation pipe due to the injection of backfill material.

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. FIG. 2 is a front cross-sectional view showing the existing pipe undergoing rehabilitation and the rehabilitating pipe in a state before the backfilling process. Figure 3(a) is a cross-sectional view showing the cross section of the rehabilitating pipe and the existing pipe along line III-III in Figure 1 in a flattening process, Figure 3(b) is a cross-sectional view showing the cross section in a closing process, and Figure 3(c) is a cross-sectional view showing the cross section in a backfilling process. 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. FIG. 5 is a perspective view showing the elongated elastic member constituting the closure member shown in FIG. 1 in an initial state. Fig. 6(a) is a cross-sectional view showing the part shown in Fig. 4(a) in a removal step, and Fig. 6(b) is a cross-sectional view showing the part shown in Fig. 4(a) in a finishing step. FIG. 7 shows a second embodiment of the present invention and is a perspective view of a long elastic member. 8(a) is a side view of the rehabilitating pipe during the closing process using the long elastic member according to 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 according to the second embodiment, as viewed from the side facing the communication opening. 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. 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. FIG. 11 is a side view of the rehabilitating pipe according to the fourth embodiment, as viewed from the side directly opposite the communication opening.

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 accordance with 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 (a 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 (a peripheral portion of the connection opening) of the attachment pipe 2 is flush with the inner surface of the existing pipe 1.

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.

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 spirally wound around the inner surface of the existing pipe 1, and adjacent mating portions 33, 34, which are offset from each other, are connected by a concave-convex mating, thereby producing the helical rehabilitating pipe 3. The outer periphery of the rehabilitating pipe 3 has a spirally formed concave-convex shape. The ribs 32 and the connecting portions 36 between the mating portions 33, 34 form the convex portions of the concave-convex shape. 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.

<Communication port formation process>
1 and 2, a communication port 3b is formed by drilling at a location of the rehabilitating pipe 3 facing the attachment pipe port 2a. This places the attachment pipe port 2a in communication with the interior of the rehabilitating pipe 3 via the communication port 3b. The annular portion of the inter-pipe gap 4 surrounding the communication port 3b constitutes a peripheral annular gap 4c. The peripheral annular gap 4c is defined between the end face 2e of the attachment pipe 2 (the peripheral portion of the connection port) and the peripheral portion 3c of the communication port 3b in the rehabilitating pipe 3. The size of the peripheral annular gap 4c (the distance between the attachment pipe end face 2e and the peripheral portion 3c of the communication port) is, for example, approximately 10 mm to 100 mm, although the present invention is not limited to this.

<Flattening process>
3A, 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. The flattening filler 38 may be, for example, a cement-based material.

<Closing process>
3(b) and 4(a), a blocking member 20 is installed in the circumferential annular gap 4c. The annular blocking member 20 is inserted from the communication opening 3b into the entire circumferential annular gap 4c, thereby blocking the circumferential 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 circumferential edge of the communication opening 3c.

Preferably, as shown in Figure 4(a), the inner peripheral portion 22 of the blocking member 20 protrudes slightly beyond 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 several to several dozen mm, and more preferably approximately 10 mm.

The blocking member 20 is made of an elastic material that is impermeable to the backfill material 6 (see Figure 3(c)), which will be described later, or a low-water-absorbent elastic material. 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 approximately 20±5.

As shown in Figure 5, the blocking member 20 is made of a long elastic member 21 with a rectangular cross section, for example. 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.

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 wrapped around the annular gap 4c at least once. This ensures that the entire annular gap 4c is completely sealed. 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 wrapping the elongated elastic member 21 two or more times. By making the length of a single elongated elastic member 21 several times the circumferential length of the annular gap 4c, two or more wraps may be wrapped around the gap, or multiple elongated elastic members 21 may be wrapped around each other. When installed (before backfilling, as described below), the blocking member 20 is preferably in a state that allows for some degree of compressive deformation, i.e., in an uncompressed, weakly compressed, or fully compressed state.

<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 abuts 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.

<Backfilling process>
As shown in FIG. 3( c ) and FIG. 4( b ), the backfilling material 6 is then injected and filled into the gaps 4 between the pipes.
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 can prevent at least the bottom of the rehabilitating pipe 3 from floating up. On the other hand, 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 manner 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 becomes large. As a result, as shown by the two-dot chain line in Figure 2, the portion 3a above the bottom of the rehabilitating pipe 3 tends to be displaced upward as a whole.

As shown in Figures 2 and 4(b), the rehabilitating pipe upper portion 3a includes the communication port peripheral portion 3c and further includes the surrounding portion 3d. The surrounding 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 rest of the rehabilitating pipe upper portion 3a.

Although the blocking member 20 covers the communication port peripheral edge 3c, the blocking member 20 is capable of elastic deformation (particularly compressive deformation). Therefore, the blocking member 20 does not restrict the communication port peripheral edge 3c from deforming. This allows the communication port peripheral edge 3c, along with its surrounding area 3d, to displace upward. This prevents unevenness between the communication port peripheral edge 3c and its surrounding area 3d in the rehabilitation pipe 3, and prevents large localized deformation of the communication port peripheral edge 3c.

As a result, it is possible to avoid damaging the shape of the communication opening 3b, and the aesthetic appearance of the rehabilitation 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 3c of the communication opening so that it protrudes 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 FIGS. 3(c) and 4(b), the blocking member 20 is compressed in accordance with the displacement of the communication port peripheral edge portion 3c.

As shown in Figure 4(b), by blocking the peripheral annular gap 4c with the blocking member 20, the backfill 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 through the flattening process, the risk of backfill material 6 leaking between the blocking member 20 and the communication port peripheral portion 3c can be reduced.

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

<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 Fig. 6(a). During the blocking step (Fig. 4(a)), the inner peripheral portion 22 of the blocking member 20 is left protruding from the inner periphery of the communication opening 3b, so that the blocking member 20 can be easily pulled out of the peripheral annular gap 4c by pinching and pulling out the inner peripheral 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 that 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.

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

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 surfaces 21e, 21f of the elongated elastic member 21B constituting the blocking member 20 are inclined with respect to the longitudinal direction, so that both end portions of the elongated elastic member 21B are tapered.

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

After the elongated elastic member 21B has been wound around the peripheral annular gap 4c, the opposite end face 21f is pressed toward the one end face 21e, overlapping these end faces 21e and 21f. This allows both ends of the elongated elastic member 21B to fit snugly together, preventing the backfill material 6 from leaking between these ends.

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 the backfill 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.

A second tension member 40 is placed within the rehabilitating pipe 3, and a pressure member 43 is placed against the communication port 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 port 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 port periphery 3c. This clamps the blocking member 20 between the end face 2e (periphery of the connection port) of the attachment pipe 2 and the communication port 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.

<Fourth embodiment (FIGS. 10 and 11)>
As shown in Figures 10 and 11, in the fourth embodiment of the present invention, a packer 50 is provided along the inner periphery of the peripheral annular gap 4c when injecting the backfilling material 6. 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 inner side. 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 leakage of the backfilling material 6.
Even when the sewer system is in service, fluids such as sewage from the bay pipe 2 can flow into the rehabilitation pipe 3 through the central hole 51 of the packer 50.

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 work 10, or may be carried out after the installation process of the anti-floating work 10.
Instead of the long elastic member, a seamless closed loop elastic member may be used as the blocking member.

The present invention can be applied, for example, to repairing aging sewer pipes.

1. Sewer main (existing pipe)
2. Attachment pipe (branch pipe)
2a Mounting pipe port (connection port)
2e End face (periphery of connection port)
3 Rehabilitation pipe 3a Bottom upper portion 3b Communication port 3c Communication port peripheral portion 3d Further surrounding portion 4 Pipe gap 4c Peripheral annular gap 6 Backfill material 8 Gap filling material (finishing material)
10 Floating prevention structure 11 Bottom wale 12 Brace member 13 Jack 20 Closure member 21, 21B Long elastic member 30 Lining member 31 Band plate portion 32 Rib (convex portion)
33 Female fitting portion 34 Male fitting portion 35 Groove (recessed portion)
36 Connecting portion 38 Flattening filler 40 Second tension member 41 Tension rod 42 Jack 43 Pressing member 50 Packer 51 Center hole

Claims (8)

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;
and filling the peripheral annular gap with a gap filler after the removal. The existing pipe rehabilitation method described in claim 1, characterized in that the blocking member is made of a closed-cell soft foam resin material. The existing pipe rehabilitation method 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. The existing pipe rehabilitation method described in claim 3, characterized in that both ends of the elongated elastic member are tapered, and the both ends of the elongated elastic member that has been wrapped around the peripheral annular gap are overlapped. The existing pipe rehabilitation method described in claim 4, characterized in that both end faces of the long elastic member are inclined relative to the longitudinal direction, and these end faces are overlapped. The method for rehabilitating an existing pipe described in claim 1 or 2, characterized in that the outer periphery of the rehabilitation pipe is uneven, and the recessed portion around the periphery of the communication opening is filled with a flattening filler before the blocking member is installed. The existing pipe rehabilitation method 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 retaining member at the tip of the second tension member is placed against the periphery of the communication opening from the inside of the rehabilitation pipe. The existing pipe rehabilitation method described in claim 1 or 2, characterized in that a hollow annular packer is provided along the inner circumference of the peripheral annular gap when injecting the backfill material.