JP2008303970A - Ground-buried pressure resistant synthetic resin pipe and pipe reclaiming technique using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ground-buried pressure resistant synthetic resin pipe having sustainable pressure-proof strength with a pipe wall being thinned, improved flexibility, and reduced weight and manufacturing cost, and to provide a highly efficient pipe reclaiming technique using the same. <P>SOLUTION: One or more metal reinforcing wires 5 with synthetic resin coat layers 7 are attached in a similarly spiral manner onto inside faces 30 of mountain portions 3 of a spiral synthetic resin wall part constituting the pipe wall 2. The used metal reinforcing wires are metal wires approximately circular in a sectional view. When a partial molding including the mountain portions is extrusion molded and spirally wound thereon to form the pipe wall 2, the similarly extrusion-molded metal reinforcing wires 5 are continuously supplied to the inside faces of the mountain portions 3 of the partial molding and the outer faces of the coat layers 7 of the metal reinforcing wires 5 are attached onto the inside faces 30 of the mountain portions 3 with thermal fusion. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pipe mainly used as a protective pipe for inserting and protecting a power / communication cable such as a water pipe, a sewage (drainage) pipe, an electric wire or a telephone line, and more specifically, it is lightweight and flexible. In particular, the present invention relates to a pressure-resistant synthetic resin pipe for underground burying that has excellent workability and economy and has sufficient pressure-resistant strength, and enables an efficient pipe rehabilitation method.

  As this kind of underground pressure-resistant synthetic resin pipe, a synthetic resin pipe wall 102 is spirally waved as shown in FIG. 9 in order to facilitate handling during underground burying work or the like. Synthetic resin pipe 101 which is formed into a shape and has inner pipe wall 104 formed on the inner surface side thereof and has flexibility (flexibility) is widely used, but it is a strong earth when buried underground Since it is necessary to withstand the pressure, the tube wall 102 must be thick, and a large amount of synthetic resin material is required for molding, which increases the material cost and increases the weight and transportation and burial work. It was not easy.

  On the other hand, the thing which embed | buried the metal helical reinforcement strip | belt in the thickness of a pipe wall as what can make the wall thickness of a pipe wall thin is proposed (for example, refer patent documents 1-4). In particular, in Patent Document 1, the pipe extends over the entire wall portion of the crest portion of the spiral waveform forming the tube wall, the side wall portions connected to the crest portion, and the trough portion located on the tube axis side of the side wall portions. There is proposed a structure in which a reinforcing strip made of a thin metal plate is disposed on the synthetic resin wall forming the wall, and further, the reinforcing strip is overlapped and arranged at least at a part of the valley. Yes.

  However, in the case of embedding and forming such a metal reinforcing strip, the thickness of the tube wall can be reduced, but the weight is increased by the amount of the metal strip, and the spiral wave-shaped tube wall has a main body. In addition, the flexibility (flexibility) is impaired when the metal band plate is internally provided, which causes a reduction in workability. In addition, in order to embed and mold a metal strip in the tube wall, during the production, the metal strip is simultaneously extruded and embedded in the tube wall molded body. This increases the manufacturing cost.

  On the other hand, in concrete pipes frequently used in the sewerage business, corrosion due to hydrogen sulfide has become serious in recent years, and problems such as water leakage have occurred even in pipes that have less than their service life. As a method for restoring existing pipes that have already been used (pipe rehabilitation method), in addition to exchanging existing pipes by excavation, non-open-cutting pipe rehabilitation methods such as photo-curing method and heat-curing method are used. There is a method of inserting a flexible synthetic resin pipe with a small diameter and injecting a filler such as mortar into the gap between the pipes to integrate it with the existing pipe, but these conventional pipe rehabilitation methods are both labor and cost It was hanging.

  In particular, in the construction method in which a synthetic resin pipe is inserted and filled with mortar or the like, the synthetic resin pipe is required to have high flexibility because it is drawn into the existing pipe from a narrow manhole or the like. Therefore, it has been essential to maintain the compressive strength by integrating with an existing pipe with a filler.

Japanese Utility Model Publication No. 62-30080 JP-A-6-11076 Japanese Utility Model Publication No. 1-123421 Japanese Utility Model Publication No. 63-146286

  Therefore, in view of the above-mentioned situation, the present invention intends to solve the problem that the pressure wall strength can be maintained while reducing the wall thickness of the tube wall, the flexibility can be improved, the weight can be reduced, and the manufacturing cost can be reduced. The object is to provide a pressure-resistant synthetic resin pipe for underground burial that can be realized, and an efficient pipe rehabilitation method using the pipe.

  In order to solve the above-mentioned problems, the present invention is a synthetic resin pipe for underground embedding in which a pipe wall is formed in a spiral wave shape, and is provided in a mountain portion of a spiral synthetic resin wall part constituting the pipe wall. A pressure-resistant synthetic resin pipe for underground embedment, characterized in that a single or a plurality of metal reinforcing wires provided with a synthetic resin coating layer on the side surface, is also spirally attached.

  Here, it is preferable that the metal reinforcing wire is configured using a metal wire having a substantially circular cross-sectional view.

  In addition, when forming the tube wall by spirally winding a partially molded body including the extruded ridges, the extruded metal reinforcing wire is applied to the inner side surface of the ridge of the partially molded body. It is preferable to supply continuously and attach the outer surface of the coating layer of the metal reinforcing wire to the inner surface of the peak portion by heat fusion.

  Furthermore, it is preferable that both the portion including at least the peak portion of the tube wall and the coating layer of the metal reinforcing wire are molded using a polyethylene resin.

  Specifically, the spiral waveform is a substantially square waveform in cross-sectional view, and a substantially V-shaped groove portion provided with the metal reinforcing wire is provided along the central portion of the inner surface of the mountain portion. Is preferred.

  Further, it is preferable that an inner tube wall is provided on the inner peripheral side of the spiral wave-shaped tube wall, and a closed space is formed between the inner tube wall and the peak portion of the tube wall.

  Further, the present invention inserts the above-mentioned underground pressure-resistant synthetic resin pipe into the existing underground pipe, seals the gap between the pipes only at both ends, and fills other intermediate parts with a filler. There is provided a pipe rehabilitation method characterized in that the pressure-resistant synthetic resin pipe for underground burial itself is made to function as a rehabilitation pipe without being embedded.

  Here, on the inner peripheral surface is provided a thread groove that is screwed to the outer wall surface of the underground pressure-resistant synthetic resin tube, and the outer peripheral surface is in close contact with the inner peripheral surface of the existing underground tube, It is preferable to seal the gap end portion between the tubes with a socket member formed by a flange portion in contact with an end surface of the existing underground pipe.

  According to the pressure-resistant synthetic resin pipe for underground embedding according to the present invention as described above, the thickness of the pipe wall is reduced by reducing the amount of resin to reduce the weight, reduce the material cost, and improve the flexibility. Because it has a metal reinforcement wire on the side, the pressure resistance can be improved without hindering flexibility (good handling) like a conventional metal reinforcement strip embedded, The increase in weight due to the reinforcing wire is slight, and the overall weight can be significantly reduced as compared with the conventional one having a thick tube wall. Moreover, since it can manufacture easily only by attaching a metal reinforcement wire, it can manufacture at low cost compared with what embeds a metal reinforcement strip.

  Moreover, since it comprised using the metal wire of a cross-sectional view substantially circular shape as a metal reinforcement wire, it can maintain without impairing the outstanding flexibility of the spiral-wave-shaped tube wall while being able to provide sufficient pressure | voltage resistance.

  In addition, when forming the tube wall by spirally winding a partially molded body including the extruded ridges, the extruded metal reinforcing wire is applied to the inner side surface of the ridge of the partially molded body. Since the outer surface of the metal reinforcing wire is attached to the inner surface of the peak portion by heat fusion, it can be easily configured by fusion of the resins, and it can be efficiently manufactured at low cost. Can be manufactured.

  In addition, since the pipe wall at least including the peak portion and the metal reinforcing wire coating layer are molded using polyethylene resin, both the chemical resistance and the same type of resin are fused together. The strength can be further increased.

  Further, the spiral waveform is a substantially rectangular waveform in cross-section, and the substantially V-shaped groove portion provided with the metal reinforcing wire is provided along the central portion of the inner side surface of the mountain portion. Reinforcing wire adheres securely and does not peel off easily, improving pressure resistance and durability.

  Also, in the case where an inner tube wall is provided on the inner peripheral side of the spiral wave-shaped tube wall and a closed space is formed between the inner tube wall and the peak portion of the tube wall, a water pipe, a sewage (drainage) pipe Can be suitably used, and the pressure resistance is remarkably improved, and it is easy to provide a strength as a self-supporting pipe with a strength higher than the flat strength described in the vinyl chloride pipe for sewer JSWAS K-1. It becomes.

  As described above, the underground pressure-resistant synthetic resin pipe according to the present invention has both excellent flexibility and pressure resistance, and can be easily inserted into an existing pipe and can be used as a self-standing pipe. In order to provide pressure-resistant strength, the underground pressure-resistant synthetic resin pipe for underground burial of the present invention is inserted into the existing underground burial pipe, the gap between the pipes is sealed only at both ends, and other intermediate The part is not embedded with mortar or other filling material, and there is a gap as it is, and the underground pressure-resistant synthetic resin pipe itself functions as a rehabilitation pipe so that the pipe can be rehabilitated only by sealing the end. Can contribute to shortening the construction period and reducing costs.

  In addition, a cylindrical portion in which an inner peripheral surface is provided with a thread groove that is screwed into a pipe wall outer surface of the underground buried pressure-resistant synthetic resin pipe, and an outer peripheral surface is in close contact with the existing underground buried pipe inner peripheral surface; By sealing a gap end between the pipes through a socket member composed of a flange part that abuts an end face of an existing underground pipe, the end is sealed even in a narrow manhole. Can be performed efficiently.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram showing the overall configuration of a underground pressure-resistant synthetic resin pipe according to the present invention. FIGS. 1 to 3 show typical embodiments. 2 is a pipe wall, 3 is a peak, 4 is an inner pipe wall, and 5 is a metal reinforcing wire.

  As shown in FIGS. 1 and 2, the underground pressure-resistant synthetic resin pipe 1 according to the present invention is made of synthetic resin on the inner side surface 30 of the crest 3 of the helical synthetic resin wall part constituting the pipe wall 2. A single or a plurality of metal reinforcing wires 5 each having a coating layer 7 are also provided in a spiral shape.

  More specifically, as shown in FIG. 3 (a), a flat strip-shaped synthetic resin band 40 forming the inner tube wall 4 of the tube is sequentially wound spirally while polymerizing both side edge portions, On the surface, a band-shaped partial molded body 20 having a substantially U-shaped downward opening and a protruding edge in which both open end portions protrude in the lateral direction is formed on the inner surface of the crest 3 with a metal. The reinforcing wires 5 are sequentially wound spirally while being fused and integrated, and are integrally fused on the surface of the inner tube wall 4 so that the protruding edges overlap each other. The present invention is not limited to such a molding method. For example, as shown in FIG. 3 (b), the left side outward projecting edge is made longer by forming a partial molded body 20A corresponding to the partial molded body 20. It is good also as a structure which makes it the extended structure and the said projecting edge part obstruct | occludes the surrounding mouth part by the side of the pipe axis of a peak part, and comprises the continuous inner tube wall equivalent to said inner tube wall 4.

  The inner tube wall 4 has an inner surface formed in a substantially cylindrical shape, but may have a slightly uneven waveform. The synthetic resin constituting the tube wall 2 and the inner tube wall 4 is preferably a polyolefin-based resin such as polyethylene or polypropylene, particularly polyethylene resin from the viewpoint of chemical resistance. It is preferable to mold with high density polyethylene and the inner tube wall 4 with low density polyethylene, but it can also be composed of other synthetic resins.

  The metal reinforcing wire 5 is obtained by coating the outer peripheral surface of a metal wire 6 having a substantially circular cross-sectional view with the synthetic resin coating layer 7. As the metal wire 6 which is a core material, it is preferable to use a steel wire, a piano wire, a stainless steel wire or the like, and specifically, it is preferable to use a hard steel wire of about 60 carbon. The coating layer 7 is preferably made of a polyolefin resin such as polyethylene or polypropylene, particularly a polyethylene resin from the viewpoint of chemical resistance, as with the tube wall 2, but may be composed of other synthetic resins. From the viewpoint of compatibility (bonding strength) between the tube wall 2 (partial molded body 20) and the coating layer 7 at the time, it is more preferable to use the same type of synthetic resin. Since the present invention has such a structure in which the metal reinforcing wire 5 is attached to the inner side surface 30 of the mountain portion, it can exhibit excellent flexibility without hindering the flexibility of the tube itself, and at the same time, the mountain with respect to the pressure strength. The part is securely supported from the inner surface, giving excellent strength.

  The coating layer 7 of the metal reinforcing wire 5 is formed by extruding and coating the metal wire 6 together with the metal wire 6, but in addition to that, the surface of the metal wire 6 can be coated with a resin solution or immersed in the resin solution. For example, a conventionally known method can be adopted. In this example, the semi-cured metal reinforcing wire 5 extruded from the forming die is continuously supplied to the semi-cured tube wall partial molded body immediately after being extruded, and thereby the peak portion The tube is efficiently and easily formed while the inner surface and the outer surface of the coating layer 7 are fused and integrated.

  That is, when the tube wall is formed by spirally winding a partially molded body including the peak portion extruded as in the conventional manner, the metal reinforcing wire 5 that is also extruded is used as the partially molded body. It is possible to continuously supply to the inner side surface of the peak portion and to fuse the outer surface of the covering layer 7 of the metal reinforcing wire to the inner side surface of the peak portion so as to be easily integrated. The metal reinforcing wire 5 may be formed in advance and supplied to the inner side surface of the peak portion of the partial molded body, or may be heated and melted by a heating device when adhering to each other. Moreover, it is also possible to integrally mold the metal reinforcing wire together with the partially molded body. Furthermore, the metal reinforcing wire may be fixed to the inner side surface of the ridge using an adhesive. In this example, the peak portion 3 is formed in a substantially U shape opened downward, and a metal reinforcing wire 5 is attached to the inner peripheral surface thereof, but as a gable shape as shown in FIG. A substantially V-shaped groove portion 31 provided with a metal reinforcing wire 5 is provided along the central portion of the inner surface of the mountain portion 3, or a gently curved mountain shape as shown in FIG. If the metal reinforcing wire 5 is attached to the inner surface of the top portion, this is a preferred modification in that the joint strength can be further improved.

  In the present example, only one metal reinforcing wire 5 is attached to the mountain portion 3, but two or more wires are attached to the inner surface 30 of the mountain portion as shown in FIG. 4 (c). As a result, the pressure strength can be further improved. Although not shown, it is also possible to make the pipe wall into a double or more spiral wave shape and attach the metal reinforcing wires 5 to every other mountain portion or every two or more mountain portions. Such a double or more helical wave-shaped tube wall is formed by extruding a partially molded body having two or more crests, and the metal reinforcing wire 5 is formed only on one inner surface of the crest. Can be easily manufactured.

  The outer diameter of the metal reinforcing wire 5 is suppressed to a dimension that does not protrude at least from the valley portion of the tube wall 2 in a state of being attached to the tube wall 2, that is, a size that does not contact the inner tube wall 4. Is preferably set to a diameter of 1.0 to 1.6 mm, more preferably about φ1.2 mm, and the entire diameter including the coating layer 7 is set to about 2.0 mm. If the diameter of the metal wire as the core is too small with respect to the entire diameter, the metal wire is idle, and if it is too thick, it is difficult to form the coating of the coating layer 7. In addition, although the cross-sectional shape of the metal wire 6 is substantially circular in this example, as shown in FIGS. 4D and 4E, the cross-sectional shape is substantially square or flat plate shape, It is also possible to do. It is also a preferable example to increase the strength by increasing the diameter as a hollow metal wire in addition to the Muku metal wire so that the weight can be reduced at the same time.

  In the present embodiment, the inner tube wall 4 is provided on the inner peripheral side of the spiral wave-shaped tube wall 2, and a closed space is formed between the inner tube wall 4 and the tube wall crest 3 to reduce fluid resistance. However, the present invention is not limited to such a pipe structure at all, and as shown in FIGS. 5 (a) and 5 (b), the inner pipe wall 4 is not limited. Is not provided, and a metal reinforcing wire 5 is attached to the inner peripheral surface of the crest of a spiral wave-shaped tube in which a substantially U-shaped unevenness is formed continuously, or the crest and trough are continuously continuous Of a spiral wave-shaped tube forming a wave in the same manner, with a metal reinforcing wire 5 attached to the inner peripheral surface of the peak, or a spiral wave shape in which a peak and a valley are continuous in a substantially V-shaped cross-section or other polygonal shape It can also be configured as a tube mainly used as a protective tube for power / communication cables, such as a metal reinforcement wire 5 attached to the inner peripheral surface of the tube crest. It includes logical.

  Next, based on FIG. 6, the pipe rehabilitation method using the underground pressure-resistant synthetic resin pipe 1 of this embodiment will be described.

  In this example, a fume pipe is already installed as an underground pipe 9 (attachment pipe) attached between a house cottage 90 and a sewage main pipe 92, and a method of rehabilitating this will be described. The pipe rehabilitation is not limited to those from such households, but can be applied to rehabilitation of the main pipe and other pipes, and is attached to the manhole 91 instead of directly to the main pipe 92 as shown in FIG. It can also be suitably used for rehabilitation of underground pipes. In order to rehabilitate the underground pipe 9, the underground buried pressure-resistant synthetic resin pipe 1 is inserted into the underground pipe 9 from the house 90 side so that drainage does not flow into the gap between both pipes. Only the pipe opening process for sealing both end portions 93 and 94 is sufficient, and it is not necessary to completely integrate both the pipes.

  In other words, the other intermediate portion 95 needs to be filled with a filler such as mortar and integrated with the existing underground pipe 9 in the conventional construction method. The resin pipe 1 itself has excellent pressure strength, and has sufficient durability to support earth pressure even if the existing underground pipe 9 is damaged, so there is a gap as it is. Thus, the underground pressure-resistant synthetic resin pipe 1 itself can function as an independent drain pipe.

  In this example, the end portion can be sealed by attaching the socket member 8 as shown in FIG. 6B to seal the gap end portion 93 very easily. The socket member 8 comes into contact with the cylindrical portion 80 that is screwed into the outer periphery of the end portion of the underground buried pressure-resistant synthetic resin tube 1 to close the gap between the underground buried tube 9 and the end surface 9 a of the underground buried tube 9. The cylindrical portion 80 is provided with a thread groove 80 b that is screwed to the outer surface of the tube wall 2 of the underground pressure-resistant synthetic resin tube 1. The other end is sealed in a watertight manner by partially filling the gap with a filler. If this socket member 8 is attached to the upstream side of the drainage, that is, the house 90 side, the construction is easy and the penetration of the drainage into the gap of the drainage can be reliably prevented.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can of course be implemented in various forms without departing from the gist of the present invention.

(Flat strength test)
A pressure-resistant synthetic resin pipe for underground burial having the structure described in FIGS. 1 and 2 was prepared as Example 1, and a flat strength test prescribed in JSWAS K-1 was conducted. As Comparative Example 1, a comparison was made with the standard value of a conventional synthetic resin pipe having the structure described in FIG. Both tubes had the same size with an inner diameter of 101 mm, an outer diameter of 117 mm, and a spiral pitch of 15 mm. However, the wall thickness of Example 1 is set to about one third of that of Comparative Example 1. The results are shown in Table 1 below.

  As can be seen from Table 1, Example 1, which is a pressure-resistant synthetic resin pipe for underground burying of the present invention, has a thickness of 2 compared to that of the conventional Comparative Example 1 although the wall thickness is reduced. It can be seen that it has a flattening strength more than double. In addition, even with respect to the 5% flattened strength standard 1.7 kN / m of the hard vinyl chloride pipe for sewerage (φ100) defined in JSWAS K-1, Example 1 has a strength of about 1.67 times. It turns out that it has cleared enough.

(Flexibility test)
About the above-mentioned Example 1 and Comparative Example 1, the flexibility test was done, respectively. As the test body of each example, a specimen placed in a straight tube state at a measurement temperature for 2 hours or more is used. In this state, as shown in FIG. 8, the sag length h (mm) after 1 minute is measured, the 180 ° specimen is turned, h in the reverse direction is measured, and the average value is taken. The test temperature is 20 ° C. and 0 ° C., and the test body is 1.2 m or more. When h <100 mm at room temperature and no load, a weight t (kg) is added in units of 1 kg at a position 50 mm from the tip of the specimen, and measurement is performed at h ≧ 100. Moreover, in the test at 0 ° C., the measurement is performed with the same load as the test at room temperature. In this experiment, a weight of t = 3 kg was used. The results are shown in Table 2 below.

  As can be seen from Table 2, in Example 1, a reinforcing metal wire is attached to the inner peripheral surface of the ridge, but compared with the conventional Comparative Example 1, 1.52 times at 0 ° C., normal temperature It has 2.38 times the possibility of being excellent at 24.5 ° C, and has improved the pressure strength as described above, while improving the flexibility (goodness of handling) rather than hindering it. Was confirmed.

Explanatory drawing which shows the pressure | voltage resistant synthetic resin pipe | tube for underground embedment concerning the embodiment of the present invention. The longitudinal cross-sectional view which shows the principal part of the pressure-resistant synthetic resin pipe | tube for underground burying similarly. (A), (b) is explanatory drawing which similarly shows the shaping | molding method of the pressure | voltage resistant synthetic resin pipe | tube for underground burial. (A)-(e) is sectional drawing which shows the modification of the pressure | voltage resistant synthetic resin pipe | tube for underground burying similarly. (A), (b) is sectional drawing which shows the modification of the pressure | voltage resistant synthetic resin pipe | tube for underground burying similarly. (A), (b) is explanatory drawing of the pipe renovation method of this invention. Explanatory drawing which shows the other example of a pipe renovation construction method. Explanatory drawing which shows a flexibility test method. (A), (b) is explanatory drawing which shows the conventional synthetic resin pipe | tube for underground burial.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pressure-resistant synthetic resin pipe | tube for underground burying 2 Pipe wall 3 Mountain part 4 Inner pipe wall 5 Metal reinforcement wire 6 Metal wire 7 Covering layer 8 Socket member 9 Underground pipe 9a End surface 20 Partial molded object 20A Partial molded object 30 In Side surface 31 Groove portion 40 Synthetic resin band 80 Tubular portion 80b Screw groove 81 Flange portion 90 Household 91 Manhole 92 Sewage main pipe 93, 94 End portion 95 Intermediate portion 101 Synthetic resin pipe 102 Pipe wall 104 Inner pipe wall

Claims (8)

  A synthetic resin pipe for underground embedding in which a pipe wall is formed in a spiral wave shape, and a synthetic resin coating layer is provided on the inner side surface of a mountain portion of a spiral synthetic resin wall part constituting the pipe wall. Alternatively, a pressure-resistant synthetic resin pipe for underground embedment, wherein a plurality of metal reinforcing wires are also spirally attached.   2. The underground pressure-resistant synthetic resin pipe according to claim 1, wherein the metal reinforcing wire is configured by using a metal wire having a substantially circular cross-sectional view.   When forming the tube wall by spirally winding the partially molded body including the extruded ridges, the extruded metal reinforcing wire is continuously formed on the inner surface of the ridge of the partially molded body. The underground pressure-resistant synthetic resin pipe according to claim 1 or 2, wherein the outer surface of the metal reinforcing wire is attached to the inner side surface of the peak portion by heat fusion.   The pressure-resistant composition for underground embedment according to any one of claims 1 to 3, wherein a portion including at least a peak portion of the tube wall and a coating layer of a metal reinforcing wire are formed by using polyethylene resin. Resin tube.   5. The spiral coil according to claim 1, wherein the spiral waveform is a substantially rectangular waveform in cross-sectional view, and a substantially V-shaped groove portion provided with the metal reinforcing wire is provided along a central portion of the inner side surface of the mountain portion. The pressure-resistant synthetic resin pipe for underground burial according to 1.   The inner tube wall is provided on the inner peripheral side of the spiral wave-shaped tube wall, and a closed space is formed between the inner tube wall and the peak portion of the tube wall. The pressure-resistant synthetic resin pipe for underground burial described in 1.   The underground pressure-resistant synthetic resin pipe according to any one of claims 1 to 6 is inserted into an existing underground pipe, the gap between the pipes is sealed only at both ends, and other A pipe rehabilitation method characterized in that the intermediate part is not filled with a filler but has a gap as it is, and the underground pressure-resistant synthetic resin pipe itself functions as a rehabilitation pipe.   Provided on the inner peripheral surface is a thread groove that is screwed to the outer wall surface of the underground pressure-resistant synthetic resin pipe, and the outer peripheral surface is in close contact with the inner peripheral surface of the existing underground pipe, The pipe rehabilitation method according to claim 1, wherein a gap member between the pipes is sealed by interposing a socket member composed of a flange part in contact with an end face of the underground pipe.

Images