JP7750786B2 - Existing pipe rehabilitation method - Google Patents

Description

The present invention relates to a method for rehabilitating existing pipes by installing a spiral rehabilitation pipe along the inner circumference of the existing pipe, and a tensioning jig used in this method. In particular, the present invention relates to an existing pipe rehabilitation method and tensioning jig suitable for existing pipes that have non-straight sections, such as bends or steps.

A known method for rehabilitating aging existing pipes, such as sewer pipes, is to use a self-propelled pipe-making machine to spirally wrap a strip-shaped member around the inner circumference of the existing pipe to create a rehabilitated pipe (see Patent Documents 1 and 2, etc.). This type of pipe-making machine generally has an inner circumference restrictor, such as a link roller, that adheres the rehabilitated pipe to the pipe and restricts the shape of the rehabilitated pipe from the inner circumference (see Patent Document 1, etc.). Meanwhile, inner circumference restrictor-less pipe-making machines that manufacture pipes without an inner circumference restrictor are also known (see Patent Document 2, etc.). In inner circumference restrictor-less pipe-making machines, the drive unit and the fitting unit that engages the opposing edges of the spirally wound strip-shaped member, which are offset from each other, are separated.

Existing pipes are not always straight, and may have bends or steps. To address these issues, for example, Patent Document 1 installs a conical roller on the side of the pipe making machine so that the conical roller comes into contact with the bends or steps, preventing the pipe making machine from directly coming into contact with the bends or steps. Patent Document 2 installs a leading roller on the pipe making machine, adjusting the orientation and height of the pipe making machine to match the bends and steps in the existing pipe.

Japanese Patent Application Laid-Open No. 2019-188679 International Publication WO2018/043619 (Figure 22)

When producing a rehabilitation pipe using a pipe production machine with a general inner circumference restrictor, it is complicated to adjust the inner circumference restrictor to fit the bent or stepped portions of the existing pipe.
On the other hand, such adjustments are not necessary with a pipe making machine without an inner circumference restrictor. Furthermore, because the drive unit and the mating unit are separated, it is easy to match the cross section of the existing pipe. However, according to the inventor's knowledge, the rehabilitated pipe tends to deviate toward the outer circumference over time at bent sections, which can lead to cross section distortion. Such deviations and distortions are also transmitted from the bent section to the straight pipe section. If a wale extending in the pipe axial direction is pressed against the inner surface of the rehabilitated pipe to correct the deviations and distortions, at least two wale supports must be used to support both ends of the wale. Therefore, the strip-shaped member introduced into the pipe making machine through the rehabilitated pipe is likely to get caught on the wale supports, resulting in reduced yield. Pressing a single short end locally against the inner surface of the rehabilitated pipe may cause a dent in only that area.

Furthermore, the conical rollers and leading rollers of the above-mentioned Patent Documents 1 and 2 are difficult to handle when there is a large step.
In view of the above circumstances, the present invention aims to make it possible to produce a rehabilitated pipe that is adapted to the non-straight pipe section, preferably using a pipe making machine without an inner circumference restrictor, when an existing pipe has a non-straight pipe section such as a bend or a step.

In order to solve the above problems, the present invention provides a method for rehabilitating an existing pipe, which involves constructing a spiral-shaped rehabilitating pipe by spirally winding a strip-shaped member around the inner periphery of an existing pipe having a non-straight pipe portion including a bent portion or a stepped portion, and
A tension member of a tension jig is spanned in the pipe diameter direction inside the non-straight pipe portion or the vicinity thereof, and the width direction of the tension member is oriented in the pipe circumferential direction;
The base end of the tension member is abutted against the rehabilitating pipe or passed through the rehabilitating pipe and abutted against the existing pipe,
The rehabilitating pipe is pressed radially outward by a pressing member provided at the tip of the tension member so as to extend in the width direction.
Preferably, the rehabilitating pipe is produced by a pipe producing machine without an inner circumferential restrictor.

By using a tensioning jig to tension the rehabilitated pipe in the radial direction according to the condition of the non-straight pipe section, it is possible to correct or prevent deviations and distortions of the cross section of the rehabilitated pipe at bent sections, and to deform the cross section at stepped sections. This makes it possible to produce a rehabilitated pipe that is suitable for the non-straight pipe section.
Since the pressing member extends in the width direction, it is possible to prevent the pressing force from being localized, and it is possible to prevent the rehabilitating pipe from being locally dented.
The number of the tensioning jigs per non-linear section is preferably one (single), which prevents the tensioning jig from getting caught on the strip-shaped member being introduced into the pipe making machine through the rehabilitating pipe, and even if it does get caught, it can be easily released, preventing a decrease in yield.

the non-straight pipe portion is a bent portion,
The tip of the tension member is directed toward the upper quarter portion of the inner circumference of the bent portion or its vicinity,
The base end of the tension member is directed toward the lower quarter portion on the outer periphery of the bent portion or its vicinity,
It is preferable that the pressing member presses the upper quarter portion of the inner circumference of the bent portion of the rehabilitating pipe or the vicinity thereof outward in the pipe radial direction.
At bent sections, the rehabilitated pipe tends to be biased toward the outer periphery or have a distorted cross section. By using a tensioning jig to push the upper quarter of the inner periphery of the rehabilitated pipe outward in the radial direction, the bias and distortion can be corrected or prevented. This improves the shape of the rehabilitated pipe.

the non-straight pipe portion is a stepped portion,
The tension member is bridged in the height direction of the step portion, and the base end portion is passed through the rehabilitation pipe and abutted against the existing pipe,
It is preferable that the pressing member presses the rehabilitating pipe obliquely toward the tip side of the tension member and on both sides in the width direction so that the cross-sectional shape of the rehabilitating pipe becomes an ellipse with the height direction as the minor axis direction.
By deforming the rehabilitating pipe into the elliptical cross section, the rehabilitating pipe can be manufactured so that it can reliably overcome the step portion.

It is preferable that a spacer be provided at the top of the existing pipe so as to be interposed between the existing pipe and the rehabilitating pipe.
At the bent portion, the rehabilitated pipe tends to enter the outer space defined by the spacer, but this can be prevented by tensioning with the tensioning jig.
When filling the space between the rehabilitated pipe and the existing pipe with backfill material after pipe manufacturing, the spacer can prevent the rehabilitated pipe from floating up.

The tension jig used in the existing pipe rehabilitation method includes a tension member including a main tension rod and a plurality of branch tension rods branched from the main tension rod,
It is preferable that the pressing members are provided at the tip ends of these branch tension rods, or at the tip ends of the main tension rod and branch tension rods, respectively.
This allows the rehabilitating pipe to be pressed over a wide area by a plurality of pressing members spaced apart from one another, thereby preventing the rehabilitating pipe from being locally dented by applying strong pressure to a localized area.

It is preferable that the length of each pressing member along the axial direction of the rehabilitating pipe is shorter than the distance between adjacent pressing members.
By shortening the length of each pressure member, only one tension member is required to support each pressure member, which reduces the risk of the belt-shaped member being caught on the tension member as it passes through the rehabilitating pipe and is introduced into the pipe making machine.Even if it does get caught, it can be easily released, preventing a decrease in yield.

The tensioning jig used in the existing pipe rehabilitation method may have a clamping member that extends in the width direction of the tensioning member, and the surface of the clamping member that faces outward in the pipe diameter direction may be formed in an arc shape.
This allows the entire area of the rehabilitating pipe to be pressed evenly, maintaining the desired curvature. The surface of the pressing member of the tensioning jig facing outward in the pipe diameter direction may be an arc-shaped surface that is convex outward, and the surface facing inward in the pipe diameter direction may be a flat surface, etc.

This invention makes it possible to effectively manufacture rehabilitating pipes that are adapted to the non-straight sections of existing pipes, such as bends or steps.

FIG. 1 is a plan cross-sectional view of an existing pipe having a bent portion that is being rehabilitated using a tensioning jig according to a first embodiment of the present invention. FIG. 2 is a side cross-sectional view of the top of the existing pipe during the rehabilitation work, taken along line II-II in FIG. FIG. 3 is a front cross-sectional view of the existing pipe during the rehabilitation work, taken along line III-III in FIG. FIG. 4 is a perspective view of the pressing member shown in FIG. 5(a) to 5(c) are plan cross-sectional views of the vicinity of a bent portion of an existing pipe, showing modified examples of the installation location of a tensioning jig. FIG. 6 is a front cross-sectional view of an existing pipe being rehabilitated using a tensioning jig according to a second embodiment of the present invention. FIG. 7 is a front cross-sectional view of an existing pipe being rehabilitated using a tensioning jig according to a third embodiment of the present invention. FIG. 8 is a front cross-sectional view of an existing pipe being rehabilitated using a tensioning jig according to a fourth embodiment of the present invention. FIG. 9 shows a fifth embodiment of the present invention and is a side cross-sectional view of an existing pipe having a step portion during rehabilitation work using a tensioning jig. FIG. 10 is a front cross-sectional view of the existing pipe during the rehabilitation work, taken along line XX in FIG. FIG. 11 shows a sixth embodiment of the present invention and is a front cross-sectional view of an existing pipe having a step portion that is being rehabilitated using a tensioning jig.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First Embodiment (FIGS. 1 to 4)
1 and 2 show how an aged existing pipe 1 is rehabilitated. In this embodiment, the existing pipe 1 to be rehabilitated is an aged sewer pipe. As shown in FIG. 1, the existing pipe 1 has a bent portion 10 (non-linear portion) where the pipe axis is bent or curved. Note that the existing pipe to be rehabilitated is not limited to a sewer pipe, but may also be a water supply pipe, an agricultural water pipe, a hydroelectric power generation water pipe, a gas pipe, a tunnel, etc.

A rehabilitation pipe 9 is constructed along the inner circumference of the existing pipe 1. The rehabilitation pipe 9 is bent at a bend 10 in imitation of the existing pipe 1. Here, unless otherwise specified, the bend 10 is considered to include the bends of both the existing pipe 1 and the rehabilitation pipe 9.

The rehabilitation pipe 9 is a helical pipe made of a strip-shaped member 8 (profile). The main material of the strip-shaped member 8 is a synthetic resin such as polyvinyl chloride. The strip-shaped member 8 is wound helically around the inner circumference of the existing pipe 1, and adjacent edges are joined together, offset from each other, to form the helical rehabilitation pipe 9 (see Patent Document 1, etc.).

As shown in Figures 1 and 3, the production of a rehabilitated pipe 9 from a strip-shaped member 8 is performed by a pipe production machine 20 without an inner circumferential restrictor (see Patent Documents 2 and 3, etc.). The pipe production machine 20 has a drive unit 21 and a fitting unit 22, and is located at the front end in the extension direction of the rehabilitated pipe 9 being produced. The drive unit 21 and the fitting unit 22 are located away from each other.

As shown in Figures 1 and 3, the trailing band portion 8b of the unprocessed pipe in the band-shaped member 8 is introduced, with a curled curl, from the rear end (pipe production start end, left end of the page in Figure 1) in the extension direction of the rehabilitating pipe 9 through the inside of the rehabilitating pipe 9 into between a pair of drive rollers 21a, 21b of the drive unit 21 of the pipe production machine 20. The trailing band portion 8b is sent out from the drive unit 21, and in the fitting unit 22, which includes a fitting roller 22a and a receiving member 22b, the opposing edges of the leading end of the rehabilitating pipe 9 in the extension direction and the trailing band portion 8b, which are offset from each other, are fitted together. This incorporates the trailing band portion 8b into the rehabilitating pipe 9, and the rehabilitating pipe 9 is produced. As the pipe is produced, the pipe production machine 20 is propelled (self-propelled) in the spiral winding direction around the inner circumference of the existing pipe 1.

An outer peripheral wire 23 is wound around the front end of the rehabilitating pipe 9 in the extension direction during pipe production. Both ends 23a, 23b of the outer peripheral wire 23 are attached to the pipe production machine 20. The outer peripheral wire 23 allows the circumferential length and therefore the pipe diameter of the rehabilitating pipe 9 to be adjusted.

As shown in Figure 2, a spacer 60 is provided at the top of the existing pipe 1. The spacer 60 is formed in the shape of a long rod with a rectangular cross section that extends along the axis of the existing pipe 1. The spacer 60 is provided with a driving screw 61 and a butt bolt 62. The driving screw 61 is driven into the existing pipe 1 and the butt bolt 62 is butted against the existing pipe 1, thereby fixing the spacer 60 to the existing pipe 1 in a manner that allows the height of the spacer 60 to be adjusted.
When the top of the rehabilitation pipe 9 hits the underside of the spacer 60, the distance between the tops of the existing pipe 1 and the rehabilitation pipe 9 is maintained, and the bottom of the rehabilitation pipe 9 is kept seated on the bottom of the existing pipe 1.

When the pipe making machine 20 produces the rehabilitated pipe 9 at the bend 10, as shown by the two-dot chain line 9' in Figure 3, the rehabilitated pipe 9 expands radially outward over time in the upper quarter 12a of the outer periphery 12 at and around the bend 10, attempting to enter the space 12s defined by the spacer 60, etc. Accordingly, as shown by the two-dot chain line 9" in Figure 3, the rehabilitated pipe 9 also tends to contract radially inward in the upper quarter 11a of the inner periphery 11 at and around the bend 10. This causes the rehabilitated pipe 9 to bias toward the outer periphery 12, distorting its cross-sectional shape. The rehabilitated pipe 9 has slight flexibility due to the elasticity of the fitting 22, but if it cannot adequately conform to the bend in the existing pipe, it will attempt to return to a straight shape.

As shown in Figure 1, the "inner side 11" includes not only the bent portion 10 but also the inner side of the adjacent straight pipe portion near the bent portion. Similarly, the "outer side 11" includes not only the bent portion 10 but also the outer side of the adjacent straight pipe portion near the bent portion.

As shown in FIG. 1, in order to correct or prevent the above-mentioned bias and distortion, a tension jig 30 is prepared when manufacturing a pipe at a bent portion 10 .
As shown in Figure 3, the tensioning jig 30 is placed inside the rehabilitating pipe 9 at or near the bent section 10. Only one tensioning jig 30 is required. The tensioning jig 30 includes a tensioning member 31 and a pressing member 40. The tensioning member 31 includes a main tension rod 32 and two (or more) branch tension rods 33. The main tension rod 32 extends linearly.

A roughly Y-shaped branch joint 34 (branch section) is provided in the middle of the main tension rod 32 in its extension direction. Two branch tension rods 33 extend from the branch joint 34 at an angle to the main tension rod 32, on opposite sides of the main tension rod 32. The main tension rod 32 and the two (or more) branch tension rods 33 are arranged on the same plane.

Here, the portion 32a of the main tension rod 32 that is further distal than the branch joint 34 can also be seen as the third branch tension rod. Therefore, three branch tension rods 32a, 33, and 33 branch out and extend in three directions from the branch joint 34.

A presser member 40 is attached to the tip of each branch tension rod 32a, 33 via a jack 41. The jack 41 includes a lever nut 42, a male-threaded shaft 43 threaded onto the nut 42, and a presser support portion 44. By turning the nut 42, the shaft 43 moves forward and backward in the axial direction of the corresponding branch tension rod 32a, 33. A U-shaped presser support portion 44 is attached to the tip of the shaft 43. The presser member 40 is fitted into and supported by the presser support portion 44. Consequently, the presser member 40 is supported at the tip of the tension member 31.

As shown in Figure 4, the pressing member 40 is formed, for example, by a rectangular parallelepiped with thick ends. As shown in Figure 3, the three pressing members 40 of the branch tension rods 32a, 33, and 33 are spaced apart in the width direction perpendicular to the longitudinal direction of the tension member 31. In other words, the pressing members 40 extend in the width direction of the tension member 31. Preferably, the three pressing members 40 are arranged on an imaginary arc with the same curvature as the circumference of the rehabilitation pipe 9.

The length _L40 (FIG. 4) of each pressing member 40 along a direction intersecting both the longitudinal direction and the width direction of the tension member 31 (the pipe axis direction of the rehabilitation pipe 9) is sufficiently shorter than the distance _D40 (FIG. 3) between adjacent pressing members 40 ( _L40 < _D40 ). The length _L40 of each pressing member 40 is preferably _L40 = several hundred millimeters or less, and more preferably _L40 = approximately 200 mm.

The tensioning jig 30 is used as follows.
1, a tensioning jig 30 is installed inside the rehabilitating pipe 9 at or near the bent portion 10. Preferably, the tensioning jig 30 is installed several tens of centimeters to several meters ahead of the bent portion 10 in the extension direction of the rehabilitating pipe 9, more preferably about one meter ahead.

More specifically, as shown in Figure 3, the tensioning member 31 of the tensioning jig 30 is angled and spanned in the radial direction of the rehabilitating pipe 9 at installation position P30. The tip 31a of the tensioning member 31 faces the upper quarter 11a of the inner loop side 11 at installation position P30 near the bend. The base end 31b of the tensioning member 31 faces the lower quarter 12b of the outer loop side 12 at installation position P30. A through hole 9f is formed in the lower quarter 12b of the rehabilitating pipe 9, and the base end 31b of the tensioning member 31 is passed through the through hole 9f and abutted against the inner surface of the existing pipe 1.

The width direction of the tension member 31, which is perpendicular to the longitudinal direction (laying direction), is aligned with the circumferential direction of the rehabilitation pipe 9. It does not need to be oriented strictly in the circumferential direction, and may be aligned with the spiral winding direction of the rehabilitation pipe 9.

Then, the pressing members 40 extending in the width direction are pressed against the circumferential pressed area R of the inner surface of the rehabilitation pipe 9. The pressed area R mainly includes the upper quarter 11a of the inner circumferential side 11 at installation position P30 (near the bend). The lower end of the pressed area R may extend into the lower quarter 11b of the inner circumferential side 11. It is sufficient that the majority of the multiple pressing members 40 are pressed against the inner circumferential surface of the upper quarter 11a of the rehabilitation pipe 9, and some pressing members 40' may be pressed against the inner circumferential surface of the lower quarter 11b of the rehabilitation pipe 9.

Furthermore, by extending the jack 41, the tensioning members 31 are tensioned, which presses each pressing member 40 firmly against the inner surface of the rehabilitation pipe 9. Therefore, the pressure-receiving area R of the rehabilitation pipe 9 is pressed outward in the pipe diameter direction by the tensioning jig 30. The base end 31b (reaction force receiving portion) of the tensioning member 31 abuts against the existing pipe 1 on the opposite side of the pressure-receiving area R in the pipe diameter direction, generating a reaction force to the pressure.

This corrects or prevents the rehabilitating pipe 9 from shifting toward the outer circumferential side 12, allowing the rehabilitating pipe 9 to be positioned in the correct position exactly halfway between the inner circumferential side 11 and the outer circumferential side 12. Furthermore, distortion of the cross section of the rehabilitating pipe 9 can be corrected, maintaining a perfectly circular cross-sectional shape. This improves the finished shape of the rehabilitating pipe 9.

By pressing a plurality of points in the pressed range R of the rehabilitating pipe 9 with a plurality of pressing members 40, it is possible to prevent the pressing force from concentrating on only one point of the rehabilitating pipe 9, and to prevent one point of the rehabilitating pipe 9 from being locally dented.
Only one tensioning jig 30 is required. Therefore, the curled trailing band portion 8b is less likely to get caught or tangled on the tensioning jig 30. Even if it does get caught or tangled, it can be easily untangled. Therefore, a decrease in yield can be prevented.
As a result, even if there is a bent section 10 (non-straight pipe section), good pipe production can be performed using the inner circumference restrictor-less pipe production machine 20 while correcting or preventing bias in the rehabilitated pipe 9 without causing a decrease in yield.

After the rehabilitating pipe 9 has been manufactured in this manner, or before the pipe manufacturing is completed, the tensioning jig 30 is removed.
After pipe manufacturing, the inter-pipe space 1s between the rehabilitating pipe 9 and the existing pipe 1 is filled with a backfill material (not shown) such as mortar. At this time, the spacer 60 prevents the rehabilitating pipe 9 from floating. This keeps the rehabilitating pipe 9 in a state where it is seated on the bottom of the existing pipe 1, and the downward slope of the rehabilitating pipe 9 can be maintained.
The rehabilitation pipe 9 is arranged in a regular position with its deviation toward the outer periphery corrected, so that the backfilling material can be filled evenly on the inner periphery and outer periphery.
Thereafter, the backfill material is hardened, and the existing pipe 1 and the rehabilitation pipe 9 are structurally integrated via the backfill material.
The removal process of the tensioning jig 30 may be carried out during the curing of the backfill material or after it has hardened.

Next, another embodiment of the present invention will be described. In the following embodiment, the same reference numerals will be used in the drawings to simplify the description of the same components as those already described.
<Modification of the installation position of the tension jig (FIG. 5)>
The installation position P30 of the tensioning jig is not limited to being forward of the bent portion 10 in the extension direction of the rehabilitation pipe 9 ( FIG. 1 ).
As shown in FIG. 5( a ), a tensioning jig 30 may be installed at the bent portion 10 .
As shown in FIG. 5B, the tensioning jig 30 may be disposed in the vicinity of the bent portion of the straight pipe portion 9b, rearward of the bent portion 10 in the extension direction of the rehabilitating pipe 9.
As shown in FIG. 5( c ), two tensioning jigs 30 may be disposed in the vicinity of the bent portion of the straight pipe portions 9 a and 9 b before and after the bent portion 10 in the extension direction of the rehabilitating pipe 9 .

Second Embodiment (FIG. 6)
As shown in Figure 6, in a tensioning jig 30B according to the second embodiment of the present invention, the branch tension rod 33 and branch joint 34 (Figure 2) are not provided in the tension member 31. Instead, a pressing member 70 is provided via a jack 41 at the tip of the main tension rod 32 of the tension member 31. The pressing member 70 is formed in an arc (arch) shape and extends from the tip of the main tension rod 32 to both sides in the width direction of the tension member 31. The length of the arc-shaped pressing member 70 is matched to the length of the pressed range R. The outer peripheral surface 71 of the pressing member 70 facing outward in the pipe diameter direction is formed in an arc shape with a curvature that matches the inner peripheral surface of the rehabilitating pipe 9.

The arc-shaped pressing member 70 has three (plural) piece support portions 72 spaced apart from one another in the direction of extension of the arc. Each piece support portion 72 is U-shaped or L-shaped and has a storage recess 72a that opens toward the outer periphery of the pressing member 70. A rectangular parallelepiped pressing piece 73 is stored and supported in the storage recess 72a of each piece support portion 72. The outer surface 73a of the pressing piece 73 facing outward in the pipe diameter direction is flush with the outer periphery 71 of the arc-shaped pressing member 70.
The outer surface 73a of the pressing piece 73 may be slightly protruded from the outer peripheral surface 71 of the arc-shaped pressing member 70. The pressing piece 73 may essentially function as a pressing member.
Both ends of the pressing piece 73 along the tube axis direction (the direction perpendicular to the plane of the paper in FIG. 6) may protrude from the arc-shaped pressing member 70.

A jack 41 is provided between the tip of the tension member 31 and the center of the arc-shaped pressing member 70. By operating the jack 41, the arc-shaped pressing member 70, including the pressing piece 73, moves forward and backward in the longitudinal direction of the tension member 31.

A base end presser member 40B, consisting of a rectangular parallelepiped with a thick end, is attached to the base end 31b of the tension member 31 via a base end jack 41B, which has a similar structure to the tip jack 41. The base end presser member 40B is fitted into and supported by a U-shaped presser support portion 44B of the base end jack 41B.

In the second embodiment, similar to the first embodiment and its modified examples (FIGS. 1 to 5), a tensioning jig 30B is installed at an angle inside the rehabilitating pipe 9 at or near the bent portion 10. The extension direction of the arc-shaped pressing member 70 is aligned with the circumferential direction of the rehabilitating pipe 9, and the outer surface 71 of the pressing member 70 and the outer surface 73a of the pressing piece 73 are abutted against the pressed range R that includes the upper quarter of the inner circumferential surface of the rehabilitating pipe 9 on the inner side.
The base end pressing member 40B of the tension member 31 abuts against the inner peripheral surface of the rehabilitating pipe 9 on the opposite side in the pipe diameter direction from the pressed range R. It is not necessary to form a through hole 9f in the rehabilitating pipe 9.
Next, by operating the tip jack 41 or the base jack 41B, the pressing member 70 presses the pressed area R of the rehabilitating pipe 9 outward in the pipe diameter direction. This makes it possible to correct or prevent the rehabilitating pipe 9 from being biased toward the outer circumferential side 12.

Third Embodiment (FIG. 7)
As shown in Figure 7, a tensioning jig 30C according to a third embodiment of the present invention has a base-end branch joint 35 and two base-end branch tension rods 36 provided at the base end of a tensioning member 31. The base-end branch joint 35 has a structure in which the tip branch joint 34 is inverted 180 degrees. The two base-end branch tension rods 36 extend from the base-end branch joint 35 at an angle to the base end of the main tension rod 32 and in opposite directions, sandwiching the main tension rod 32 between them. The base end of the main tension rod 32 and the two base-end branch tension rods 36 each penetrate the rehabilitation pipe 9 and abut against the lower quadrant of the outer periphery 12 of the existing pipe 1. This allows reaction force to be obtained at three points when pressing the compressed range R of the rehabilitation pipe 9.
In addition, a base end pressing member 40B (see Figure 6) may be provided on the base end of the main tension rod 32 and the two base end branch tension rods 36, and these base end pressing members 40B may be pressed against the inner surface of the rehabilitation pipe 9.

<Fourth embodiment (FIG. 8)>
As shown in Figure 8, in a tensioning jig 30D according to a fourth embodiment of the present invention, one branch tension rod 33 branches off obliquely from the main tension rod 32 of a tensioning member 31 via a Y-shaped branch joint 34D. A pressing member 40 is provided at the tip of each of the main tension rod 32 and the branch tension rod 33. Therefore, the tensioning jig 30D is provided with two pressing members 40. These two pressing members 40 are pressed against the upper quarter 11a of the inner circumferential side 11 of the inner circumferential surface of the rehabilitation pipe 9. The angle of the main tension rod 32 is tilted more vertically than in the first embodiment (Figure 3).

Fifth Embodiment (FIGS. 9 and 10)
As shown in Figure 9, in the fifth embodiment of the present invention, a step 1d (non-linear portion) is formed in the existing pipe 1. Pipe sections 1e and 1f on either side of the step 1d in the pipe axis direction of the existing pipe 1 are vertically offset. The pipe axis of the higher pipe section 1f is offset upward from the pipe axis of the lower pipe section 1e.

As shown in Figures 9 and 10, the fifth embodiment uses a tensioning jig 30 similar to that used in the first embodiment. The tensioning jig 30 is installed inside the rehabilitating pipe 9 at or near the step 1d. Preferably, the tensioning jig 30 is installed in the lower pipe section 1e, approximately several tens of centimeters to several meters behind the step 1d in the extension direction of the rehabilitating pipe 9, and more preferably approximately one meter behind.

As shown in Figure 10, the tensioning member 31 of the tensioning jig 30 is suspended in the vertical direction, i.e., in the height direction of the step portion 1d. Three (multiple) pressing members 40 at the upward-facing tip ends of the tensioning member 31 are pressed against a circumferential pressing range R' centered on the top of the rehabilitating pipe 9. The downward-facing base end of the tensioning member 31 penetrates the bottom of the rehabilitating pipe 9 and abuts against the bottom of the existing pipe 1.

Furthermore, the extension and retraction amounts of the three (multiple) jacks 41 are adjusted relative to one another, and thus the protruding heights of the three (multiple) presser members 40 are adjusted relative to one another. In particular, the presser members 40 on both sides protrude more than the central presser member 40. These presser members 40 press the rehabilitating pipe 9 upward, i.e., toward the tip of the tension member 31, and obliquely to both sides in the width direction of the tension member 31. As a result, the cross-sectional shape of the rehabilitating pipe 9 is deformed into an ellipse with the vertical direction (height direction of the step portion 1d) as the minor axis direction.

This cross-sectional deformation allows the bottom of the rehabilitating pipe 9 to be raised and positioned higher than the bottom of the higher-side pipe section 1f. This makes it easy to manufacture the rehabilitating pipe 9 so that it can climb over the step 1d from the lower-side pipe section 1e. Even if the height of the step 1d is somewhat large, it can be climbed over reliably.

Sixth Embodiment (FIG. 11)
As shown in Figure 11, the sixth embodiment of the present invention is a modification of the fifth embodiment (Figures 9 and 10), in which the pipe axis of the existing pipe 1 is offset diagonally at the step 1d. The pipe sections 1e and 1f on either side of the step 1d in the pipe axial direction are not only offset vertically but also horizontally (left and right in Figure 11) perpendicular to the pipe axial direction. In this case, the tensioning members 31 of the tensioning jig 30 are placed diagonally across the diagonal height of the step 1d. This deforms the cross-sectional shape of the rehabilitating pipe 9 into an ellipse whose minor axis is the diagonal direction (the height direction of the step 1d), allowing the pipe to be manufactured so as to overcome the step 1d.
When the both side portions 1e, 1f are misaligned in the horizontal direction, the tension member 31 is bridged horizontally (in the height direction of the step portion 1d).

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 number of pressing members 40 is not limited to three (FIG. 3) or two (FIG. 8), but may be four or more. Four or more pressing members 40 may be provided at intervals in the width direction of the tension member 31.
In the first embodiment ( FIG. 3 ) and the like, the portion 32 a of the main tension rod 32 that is further distal than the branch joint 34 may be omitted. That is, the distal end of the main tension rod 32 may be disposed in the middle of the tension member 31 in the spanning direction, and a plurality of branch tension members 33 may branch off from the distal end of the main tension rod 32, with a pressing member 40 provided at the distal end of each of these branch tension members 33.
In the first embodiment (Figure 3) etc., the base end 31b of the tension member 31 may have a base end pressing member 40B similar to that of the second embodiment (Figure 6), and the base end pressing member 40B may be abutted against the inner surface of the rehabilitation pipe 9.
In the second embodiment (FIG. 6), the base end pressing member 40B may be omitted, and the base end 31b of the tension member 31 may pass through the rehabilitation pipe 9 and abut against the existing pipe 1, as in the first embodiment (FIG. 3), etc. The pressing member 70 in the second embodiment (FIG. 6) may have a surface 71 facing outward in the pipe diameter direction that is arc-shaped and convex outward, and the surface of the pressing member 70 facing inward in the pipe diameter direction does not necessarily have to be arc-shaped and may be a flat surface, etc.
The tension member 31 is preferably linear, but does not have to be linear as long as it can absorb the reaction force of the pressing member 40, and may be, for example, bent.
One spacer 60 is provided at the top of the pipe, but multiple spacers may be provided at the top of the pipe.

The present invention can be applied, for example, to the rehabilitation of aging sewer pipes.

1 Existing pipe 1d Step section (non-linear section)
1e Low-level side pipe portion 1f High-level side pipe portion 8 Belt-shaped member 9 Rehabilitation pipe 10 Bent portion 20 Pipe manufacturing machine without inner circumference restrictor 30 Tensioning jig 30B, 30C, 30D Tensioning jig 30C Tensioning jig 31 Tensioning member 32 Main tension rod 33 Branch tension rod 34, 34D Branch joint (branch portion)
35 Base end branch joint 36 Base end branch tension rod 40 Pressing member 40B Base end pressing member 41 Jack 41B Base end jack 11 Inner circumferential side 11a Upper quarter 11b Lower quarter 12 Outer circumferential side 12a Upper quarter 12b Lower quarter 70 Pressing member 73 Pressing piece R Pressed area R' Pressed area

Claims (6)

A method for rehabilitating an existing pipe, comprising: constructing a spiral-shaped rehabilitation pipe by spirally winding a strip-shaped member around the inner periphery of an existing pipe having a non-straight pipe portion including a bent portion;
A tension member of a tension jig is spanned in the pipe diameter direction inside the non-straight pipe portion or the vicinity thereof, and the width direction of the tension member is oriented in the pipe circumferential direction;
The tip of the tension member is directed toward the upper quarter portion of the inner circumference of the bent portion or its vicinity,
The base end of the tension member is abutted against the rehabilitating pipe toward the bent portion or the lower quarter portion on the outer periphery thereof , or is passed through the rehabilitating pipe and abutted against the existing pipe,
A method for rehabilitating an existing pipe, characterized in that a pressing member provided at the tip of the tension member so as to extend in the width direction pushes the upper quarter of the inner side of the bent portion or its vicinity in the rehabilitated pipe outward in the pipe radial direction. A method for rehabilitating an existing pipe, comprising: constructing a spiral-shaped rehabilitation pipe by spirally winding a strip-shaped member around the inner periphery of an existing pipe having a non-straight pipe portion including a step portion;
The tensioning member of the tensioning jig is bridged in the pipe diameter direction and thus in the height direction of the step portion inside the non-straight pipe portion or the vicinity thereof , and the width direction of the tensioning member is oriented in the pipe circumferential direction,
The base end of the tension member is passed through the rehabilitation pipe and abutted against the existing pipe,
A method for rehabilitating an existing pipe , characterized in that a pressing member provided at the tip of the tension member and extending in the width direction presses the rehabilitation pipe outward in the pipe diameter direction, and also diagonally toward the tip side of the tension member and on both sides in the width direction, so that the cross-sectional shape of the rehabilitation pipe becomes an ellipse with the height direction as the minor axis direction. A method for rehabilitating an existing pipe, comprising: constructing a spiral-shaped rehabilitation pipe by spirally winding a strip-shaped member around the inner periphery of an existing pipe having a non-straight pipe portion including a bent portion or a stepped portion;
A tension member of a tension jig is spanned in the pipe diameter direction inside the non-straight pipe portion or the vicinity thereof, and the width direction of the tension member is oriented in the pipe circumferential direction;
The base end of the tension member is abutted against the rehabilitating pipe or passed through the rehabilitating pipe and abutted against the existing pipe,
a pressing member provided at the tip of the tension member so as to extend in the width direction, which presses the rehabilitating pipe outward in the pipe diameter direction;
A method for rehabilitating an existing pipe, characterized in that a spacer is provided at the top of the existing pipe to be interposed between the existing pipe and the rehabilitating pipe. The tension member includes a main tension rod and a plurality of branch tension rods branched from the main tension rod,
A method for rehabilitating an existing pipe according to any one of claims 1 to 3, characterized in that the pressing member is provided at the tip of each of the branch tension rods, or at the tip of each of the main tension rod and the branch tension rod . 5. The method for rehabilitating an existing pipe according to claim 4 , wherein the length of each pressing member along the axial direction of the rehabilitating pipe is shorter than the distance between adjacent pressing members. A method for rehabilitating an existing pipe described in any one of claims 1 to 3, characterized in that the pressing member extends in the width direction of the tension member, and the surface of the pressing member facing outward in the pipe diameter direction is formed in an arc shape.