Buried pipe, joint member, buried pipe connection structure, and buried pipe installation method

Abstract

An underground pipe 11 comprises a plurality of inner pipes 11 that each have a hollow portion 111 capable of housing a cable 9, an outer pipe 12 that houses the plurality of inner pipes 11 and has an inner surface T2 having portions which are in contact with the respective outer surfaces T1 of the plurality of inner pipes 11, and a protective member 13 that is provided in spaces demarcated by the outer surfaces T1 of the plurality of inner pipes 11 and the inner surface T2 of the outer pipe 12. The strength of the protective member 13 is higher than that of the plurality of inner pipes 11 and the outer pipe 12.

Description

[Technical Field]

[0001] The present disclosure relates to a buried pipe, a joint member, a buried pipe connection structure, and a buried pipe installation method. [Background technology]

[0002] It is known that buried pipes are used to house various cables such as optical fibers and power transmission lines when they are buried underground. When buried pipes are formed by burying them underground, such as under roads, there is a high risk that the buried pipes will be damaged by excavation machines such as cutters during road construction work in shallow sections where the soil cover, which is the depth from the ground surface to the buried pipe, cannot be sufficiently secured.

[0003] In order to prevent damage to buried pipelines in shallow sections, it is known to install sign sheets indicating that the buried pipeline is buried, or iron, ceramic, or metal plates to prevent heavy machinery from entering, between the ground surface and the buried pipeline (Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-355758 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-143355 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-180166 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional configurations, the structure for preventing damage to buried pipelines is installed outside the buried pipeline, so a certain amount of space is required between the ground surface and the buried pipeline. However, when the soil cover is shallow or when buried objects are congested, it is difficult to ensure the distance from the ground surface to the buried pipeline, and the conventional configuration may not be able to adequately protect the buried pipeline.

[0006] The object of the present disclosure is to provide a buried pipe, a joint member, a buried pipe connection structure, and a buried pipe installation method that can adequately protect the buried pipeline even when it is difficult to ensure the distance from the ground surface to the buried pipe. [Means for solving the problem]

[0007] In one embodiment, the buried pipe comprises a plurality of inner pipes each having a hollow portion capable of accommodating a cable, an outer pipe that accommodates the plurality of inner pipes and has an inner surface having a portion that contacts the outer surface of each of the plurality of inner pipes, and a protective member provided in a space partitioned by the outer surfaces of the plurality of inner pipes and the inner surface of the outer pipe, wherein the strength of the protective member is greater than that of the plurality of inner pipes and the outer pipes.

[0008] A coupling member according to one embodiment is a coupling member for joining buried pipes, and comprises an inner pipe having a hollow portion that can be fitted with the connection portion of the buried pipe, an outer pipe that houses the inner pipe and has an inner surface having a portion that contacts the outer surface of the inner pipe, and a protective member provided in a space partitioned by the outer surface of the inner pipe and the inner surface of the outer pipe, wherein the strength of the protective member is greater than that of the inner pipe and the outer pipe, and the inner pipe has a fitting portion such that there is a gap between the inner pipe and the connection portion when the connection portion is fitted.

[0009] A connection structure according to one embodiment is a connection structure for buried pipes comprising buried pipes and a joint member for joining the buried pipes, wherein the buried pipes comprise: a plurality of first inner pipes each having a hollow portion capable of accommodating a cable; a first outer pipe that accommodates the plurality of first inner pipes and has an inner surface having a portion that contacts the outer surface of each of the plurality of first inner pipes; a first protective member provided in a space defined by the outer surfaces of the plurality of first inner pipes and the inner surface of the first outer pipe; and a connecting portion connectable to the joint member and having a hollow portion that communicates with the hollow portions of the plurality of first inner pipes, The strength of the material is higher than that of the plurality of first inner pipes and the first outer pipe, and the joint member comprises a second inner pipe having a hollow portion that can be fitted with the connection portion of the buried pipe, a second outer pipe that accommodates the second inner pipe and has an inner surface with a portion that contacts the outer surface of the second inner pipe, and a second protective member provided in a space partitioned by the outer surface of the second inner pipe and the inner surface of the second outer pipe, and the strength of the second protective member is higher than that of the second inner pipe and the second outer pipe, and the second inner pipe has a fitting portion such that there is a gap between the second inner pipe and the connection portion when the second inner pipe is fitted.

[0010] In one embodiment, a method for installing a buried pipe comprises connecting a first buried pipe comprising a plurality of first inner pipes each having a hollow portion capable of accommodating a cable, an outer pipe that accommodates the plurality of first inner pipes and has an inner surface having a portion that contacts the outer surface of each of the plurality of first inner pipes, and a protective member provided in a space partitioned by the outer surfaces of the plurality of first inner pipes and the inner surface of the outer pipe, wherein the strength of the protective member is greater than that of the plurality of first inner pipes and the outer pipe, and a second buried pipe comprising a plurality of second inner pipes each having a hollow portion capable of accommodating the cable, in accordance with the condition of the pipeline buried underground, and inserting the first buried pipe into an opening of the pipeline. [Effects of the Invention]

[0011] According to one embodiment of the present disclosure, even when it is difficult to ensure a distance from the ground surface to the buried pipe, the buried pipe can be appropriately protected. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view showing an example of the configuration of a buried pipe according to one embodiment. [Figure 2A] FIG. 10 is a cross-sectional view showing another example of the configuration of the buried pipe according to the embodiment. [Figure 2B] FIG. 10 is a cross-sectional view showing another example of the configuration of the buried pipe according to the embodiment. [Figure 3A] FIG. 2 is a cross-sectional view showing an example of the protective member of FIG. [Figure 3B] FIG. 2 is a cross-sectional view showing an example of the protective member of FIG. [Figure 3C] FIG. 2 is a cross-sectional view showing an example of the protective member of FIG. [Figure 3D] FIG. 2 is a cross-sectional view showing an example of the protective member of FIG. [Figure 3E] FIG. 2 is a cross-sectional view showing an example of the protective member of FIG. [Figure 4] 1 is a schematic diagram showing an example of a buried pipe connection structure in which multiple buried pipes are connected by joint members, the buried pipe connection structure being arranged in an underground pipeline. FIG. [Figure 5A] 1 is a perspective view showing an example of an inner pipe structure formed by integrally molding a plurality of inner pipes. FIG. [Figure 5B] FIG. 5B is a side view of the inner tube structure of FIG. 5A. [Figure 5C] 5B is a cross-sectional view of the inner pipe structure taken along line AA in FIG. 5A. [Figure 6A] FIG. 2 is a perspective view showing an example of an inner tube of a joint member. [Figure 6B] FIG. 6B is a front view of the inner tube of the joint member of FIG. 6A. [Figure 6C] 6C is a cross-sectional view of the inner pipe of the joint member of FIG. 6B taken along line BB. [Figure 7] FIG. 10 is a diagram showing an example in which two inner pipe structures are connected by an inner pipe of a joint member. [Figure 8A] 1 is a schematic diagram showing an example of a buried pipe connection structure in which a plurality of buried pipes are connected by joint members and arranged in an underground pipeline. [Figure 8B]1 is a schematic diagram showing an example of a buried pipe connection structure in which a plurality of buried pipes are connected by joint members and arranged in an underground pipeline. [Figure 9] 10 is a flowchart showing a procedure for installing a buried pipe in a pipeline. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In each drawing, parts having the same configuration or function are denoted by the same reference numerals. In the description of this embodiment, duplicated descriptions of the same parts may be omitted or simplified as appropriate.

[0014] (buried pipes) The buried pipe 1 (1a-1i) of the present disclosure includes a configuration for protecting the buried pipeline within the buried pipe 1 (1a-1i), thereby reducing the protection space compared to conventional configurations and making it possible to protect the buried pipeline even when it is difficult to ensure a sufficient distance (depth) from the road surface. FIG. 1 is a cross-sectional view showing an example configuration of a buried pipe 1 (1a) according to one embodiment. The buried pipe 1a protects various cables 9, such as optical fibers and power transmission lines, that are buried underground. The buried pipe 1a is installed in a pipeline L that has been previously installed underground. As shown in FIG. 1, the buried pipe 1a includes a plurality of inner pipes 11, an outer pipe 12, and a protection member 13.

[0015] The inner pipe (cable protection pipe) 11 is a tubular member having a hollow portion 111 capable of accommodating the cable 9. The outer pipe 12 is a tubular member accommodating the multiple inner pipes 11 and the protective member 13. As shown in FIG. 1 , the outer pipe 12 has an inner surface T2 having a portion that contacts the outer surface T1 of each of the multiple inner pipes 11. Both the inner pipe 11 and the outer pipe 12 can be made of any material. For example, the inner pipe 11 and the outer pipe 12 may be made of synthetic resin materials such as calcium carbonate-containing rigid polyvinyl chloride, polyethylene, polypropylene, and ABS (acrylonitrile butadiene rubber styrene), or metals including steel. The outer pipe 12 may be fixed underground using members such as joints.

[0016] The protective member 13 is a member provided in a space defined by the outer surfaces T1 of the multiple inner pipes 11 and the inner surface T2 of the outer pipe 12. The strength of the protective member 13 is greater than that of the inner pipe 11 and the outer pipe 12. The protective member 13 may be made of any strong material, for example, ceramic such as titanium boride, or tungsten. In this manner, in this embodiment, by providing the protective member 13, which is stronger than the inner pipe 11 and the outer pipe 12, in the space adjacent to the outer surface T1 of the inner pipe 11, the cable 9 housed in the inner pipe 11 can be protected even if an excavation machine such as a cutter comes into contact with the buried pipe 1a. Therefore, even if it is difficult to ensure a sufficient distance between the ground surface G and the buried pipe 1a, it is possible to appropriately protect the buried pipeline.

[0017] Furthermore, ceramics such as titanium boride are vulnerable to impact, and when an excavating machine such as a cutter comes into contact with them, they may crack and scatter, resulting in a reduction in the protective performance of the cable 9. In this embodiment, the protective member 13 is confined in the space defined by the outer surfaces T1 of the multiple inner tubes 11 and the inner surface T2 of the outer tube 12, so even if the protective member 13 cracks, it is possible to prevent the protective performance from being reduced due to the protective member 13 scattering.

[0018] The buried pipe 1a may be constructed by molding the multiple inner pipes 11 and the multiple outer pipes 12 separately and housing the multiple inner pipes 11 together with the protective member 13 within the outer pipe 12. Alternatively, the buried pipe 1a may be constructed by molding the multiple inner pipes 11 and the outer pipe 12 as a single unit and inserting the protective member 13 between the outer surface T1 of the multiple inner pipes 11 and the inner surface T2 of the outer pipe 12. This construction method of molding the inner pipes 11 and the outer pipe 12 as a single unit and then inserting the protective member 13 to construct the buried pipe 1a is easier to construct than the construction method of covering the protective member 13 with the resin that is the material for the inner pipes 11 and the outer pipe 12.

[0019] While FIG. 1 shows an example of a buried pipe 1a having three inner pipes 11, the number of inner pipes 11 included in the buried pipe 1 is arbitrary. For example, the buried pipe 1 may have two inner pipes 11 or four or more inner pipes 11. FIGS. 2A and 2B are cross-sectional views showing other configuration examples of the buried pipe 1 according to one embodiment. FIG. 2A shows an example of a buried pipe 1b having two inner pipes 11. FIG. 2B shows an example of a buried pipe 1c having four inner pipes 11.

[0020] The region 18 formed by the contact of the outer surfaces T1 of the multiple inner pipes 11 may be hollow, or may be filled with the material that constitutes the inner pipes 11, thereby integrally molding the multiple inner pipes 11. Although FIGS. 1, 2A, and 2B show an example in which the cross-sectional shapes of the inner pipes 11 and outer pipes 12 are circular, the cross-sectional shapes of the inner pipes 11 and outer pipes 12 are not limited to circular. For example, the cross-sectional shapes of the inner pipes 11 and outer pipes 12 may be circular, elliptical, polygonal, or a combination thereof. Although FIGS. 1, 2A, and 2B show an example in which all of the multiple inner pipes 11 have the same size and shape, the size and shape of each inner pipe 11 may differ.

[0021] 1, 2A, and 2B show an example in which the protective member 13 has a shape that fills the space defined by the outer surfaces T1 of the multiple inner pipes 11 and the inner surface T2 of the outer pipe 12, but the shape of the protective member 13 is arbitrary. Figures 3A to 3E are cross-sectional views showing an example of the protective member 13 of Figure 1.

[0022] The buried pipe 1d in Fig. 3A is provided with a protective member 13a having an arch-shaped (fan-shaped) cross section. The arch-shaped protective member 13a can provide a wide protection range.

[0023] The buried pipe 1e in Figure 3B is equipped with a protective member 13b having a pentagonal cross section. The pentagonal protective member 13b has a structure in which the tip of the arch-shaped protective member 13a is cut off and the arch (arc) portion is made straight. The pentagonal protective member 13b can provide a protective area as wide as the arch-shaped protective member 13a.

[0024] The buried pipe 1f in Figure 3C includes a protective member 13c with an L-shaped cross section. The L-shaped protective member 13f allows for a wider protective range. Furthermore, the L-shaped protective member 13f allows for a smaller volume than the arch-shaped protective member 13a, making it possible to construct a protective structure more inexpensively than the arch-shaped protective member 13a.

[0025] The buried pipe 1g in Fig. 3D includes a protective member 13d with a rod-shaped cross section. The buried pipe 1h in Fig. 3E includes a protective member 13e with a circular cross section. The rod-shaped protective member 13d and the circular protective member 13e allow the volume of the protective member to be reduced, making it possible to construct a protective structure at low cost.

[0026] 3A to 3E, when the protective member 13 does not fill the space defined by the outer surface T1 of the inner pipe 11 and the inner surface T2 of the outer pipe 12, a region 19 exists between the outer surface T1 of the inner pipe 11, the inner surface T2 of the outer pipe 12, and the protective member 13. Such a region 19 may be hollow, or may be filled with the material constituting the inner pipe 11 or the outer pipe 12, so that multiple inner pipes 11 are molded integrally, or multiple inner pipes 11 and outer pipes 12 are molded integrally.

[0027] (Buried pipe connection structure) Fig. 4 is a schematic diagram showing an example of a buried pipe connection structure 3 in which a plurality of buried pipes 1 are connected by joint members 2 and placed in an underground pipeline L. As shown in Fig. 4, a plurality of buried pipes 1 can be connected using joint members 2 that join the buried pipes 1, and installed in a pipeline L provided below the ground surface G. In the example of Fig. 4, the buried pipe connection structure 3 is installed in the pipeline L provided between manholes 60a and 60b.

[0028] As will be described in detail below, the coupling member 2 according to this embodiment includes an inner pipe 21 that can be fitted with the connection portion 151 of the buried pipe 1. The inner pipe 21 of the coupling member 2 has a fitting portion 212 that has a gap (clearance) between it and the connection portion 151 of the buried pipe 1 when the inner pipe 21 is fitted with the connection portion 151 of the buried pipe 1. Therefore, the buried pipe 1 can be tilted up to a certain angle relative to the coupling member 2 while remaining connected to the coupling member 2. Therefore, according to the connection structure 3 for a buried pipe 1 according to this embodiment, even if there is a bent section in the pipeline L as shown in FIG. 4, the buried pipeline can be appropriately protected without installing a protective structure on the outside of the pipeline L.

[0029] The buried pipe 1i constituting such a buried pipe connection structure 3 will be described with reference to Figures 5A to 5C. Figure 5A is a perspective view showing an example of an inner pipe structure 15 formed by integrally molding a plurality of inner pipes 11. Figure 5B is a side view of the inner pipe structure 15 of Figure 5A. Figure 5C is a cross-sectional view of the inner pipe structure 15 at AA of Figure 5A.

[0030] As shown in FIGS. 5A and 5C, in the buried pipe 1i, three inner pipes 11 are integrally molded to form an inner pipe structure 15. As shown in FIG. 5C, an outer pipe 12 having an inner surface T2 that contacts the outer surface T3 of the inner pipe structure 15 is provided around the inner pipe structure 15, and a protective member 13 is provided in the space defined by the outer surface T3 of the inner pipe structure 15 and the inner surface T2 of the outer pipe 12. That is, the buried pipe 1i includes such an inner pipe structure 15, outer pipe 12, and protective member 13. As shown in FIGS. 5B and 5C, the inner pipe structure 15 includes connecting portions 151 at both ends of the inner pipe main body 155 that can be connected to joint members 2 that join multiple components. The outer pipe 12 and protective member 13 are provided around the inner pipe main body 155.

[0031] Each connecting portion 151 has a hollow portion 154 that communicates with the hollow portions 111 of the multiple inner pipes 11. An outer surface T3 of the connecting portion 151 is provided with a concave-convex structure 152 that substantially engages with a fitting portion 212 provided on the inner pipe 21 of the coupling component 2 when the inner pipe 21 of the coupling component 2, which will be described later with reference to Figures 6A to 6C, is fitted into the connecting portion 151. The concave-convex structure 152 is structured to create a gap between the fitting portion 212 and the inner pipe 21 of the coupling component 2 when the inner pipe 21 of the coupling component 2 is fitted into the connecting portion 151. The connecting portion 151 is provided with a member 153 that receives the inner pipe 21 of the coupling component 2 when the inner pipe 21 of the coupling component 2 is fitted into the connecting portion 151, preventing further movement of the coupling component 2.

[0032] Next, the joint member 2 that connects buried pipes 1i will be described with reference to Figures 6A to 6C. Figure 6A is a perspective view showing an example of the inner pipe 21 of the joint member 2. Figure 6B is a front view of the inner pipe 21 of the joint member 2 of Figure 6A. Figure 6C is a cross-sectional view of the inner pipe 21 of the joint member 2 at BB in Figure 6B. As shown in Figure 6B, the joint member 2 that joins the buried pipe 1 includes the inner pipe 21, an outer pipe 22, and a protective member 23.

[0033] The inner pipe 21 is a tubular member having a hollow portion 211 that can fit into the connecting portion 151 of the buried pipe 1. The outer pipe 22 is a tubular member that houses the inner pipe 21 and the protective member 23. As shown in FIG. 6B , the outer pipe 22 has an inner surface T5 that has a portion that contacts the outer surface T4 of the inner pipe 21. Both the inner pipe 21 and the outer pipe 22 can be made of any material. For example, the inner pipe 21 and the outer pipe 22 may be made of synthetic resin materials such as calcium carbonate-containing hard polyvinyl chloride, polyethylene, polypropylene, ABS (acrylonitrile butadiene rubber styrene), or metals including steel.

[0034] The protective member 23 is a member provided in the space defined by the outer surface T4 of the inner pipe 21 and the inner surface T5 of the outer pipe 22. The strength of the protective member 23 is greater than that of the inner pipe 21 and the outer pipe 22. The protective member 23 may be made of any strong material, for example, ceramic such as titanium boride, or tungsten. By providing the protective member 23, which is stronger than the inner pipe 21 and the outer pipe 22, in the space adjacent to the outer surface T4 of the inner pipe 21, the cable 9 housed in the inner pipe 21 can be protected even if an excavation machine such as a cutter comes into contact with the joint member 2. Therefore, the buried pipeline can be appropriately protected even in the area of ​​the joint member 2. Furthermore, similar to the buried pipe 1, the protective member 23 of the joint member 2 is confined in the space partitioned by the outer surface T4 of the inner pipe 21 and the inner surface T5 of the outer pipe 22, so that even if the protective member 23 is cracked, it is possible to prevent a decrease in protective performance due to the protective member 23 scattering.

[0035] Furthermore, similar to the buried pipe 1, the inner pipe 21 and outer pipe 22 of the joint member 2 may be molded separately, and the inner pipe 21 together with the protective member 23 may be housed in the outer pipe 22 to form the buried pipe 1a. Alternatively, the inner pipe 21 and outer pipe 22 may be molded integrally, and the protective member 23 may be inserted between the outer surface T4 of the inner pipe 21 and the inner surface T5 of the outer pipe 22 to form the joint member 2. This construction method of molding the inner pipe 21 and outer pipe 22 integrally in advance and then inserting the protective member 23 to form the joint member 2 is easier to construct than the construction method of forming the joint member 2 by covering the protective member 23 with the resin that is the material for the inner pipe 21 and outer pipe 22.

[0036] 6B shows an example in which the protective member 23 has a shape that fills the space defined by the outer surface T4 of the inner pipe 21 and the inner surface T5 of the outer pipe 22, but similar to the buried pipe 1, the protective member 23 of the joint member 2 may have any shape. For example, the protective member of the joint member 2 may have the same shape as the protective member 13 of the buried pipe 1 described with reference to FIGS. 3A to 3E.

[0037] 6A to 6C, the coupling member 2 has a fitting portion 212 on the inner surface S6 of the inner pipe 21. When the connecting portion 151 of the buried pipe 1 is fitted into the hollow portion 211 of the inner pipe 21, the fitting portion 212 approximately engages with the concave-convex structure 152 of the connecting portion 151. Here, the fitting portion 212 has a structure such that when the connecting portion 151 of the buried pipe 1 is fitted, a gap is formed between the fitting portion 212 and the concave-convex structure 152 of the connecting portion 151. Therefore, the buried pipe 1 can be tilted up to a certain angle with respect to the coupling member 2 while remaining connected to the coupling member 2.

[0038] Fig. 7 is a diagram showing an example in which two inner pipe structure portions 15 (of buried pipes 1) are connected by an inner pipe 25 of a joint member 2. In Fig. 7, the outer pipe 12 and protective member 13 of the buried pipe 1, and the outer pipe 22 and protective member 23 of the joint member 2 are omitted. As shown in Fig. 7, by providing a gap between the connection portion 151 of the buried pipe 1 and the inner pipe 25 of the joint member 2, the connection structure 3 of the buried pipe 1 can be bent.

[0039] (Method of installing buried pipes) 8A and 8B are schematic diagrams showing an example of a state in which a connection structure 3 for buried pipes 1, which is formed by connecting multiple buried pipes with joint members, is placed in an underground pipeline L. In the example of FIGS. 8A and 8B, the pipeline L is installed between manholes 60a and 60b. FIGS. 8A and 8B show an example in which there is a sufficient distance between the pipeline L and the ground surface G near the manholes 60a and 60b, but there is a shallow section along the way where the distance between the pipeline L and the ground surface G is small. In such a situation, methods for installing the connection structure 3 for buried pipes 1 in the shallow section include a method of excavating the area near the shallow section and a method of pushing the connection structure 3 through manholes 60 (60a, 60b).

[0040] Figure 8A shows the process of installing a buried pipe by excavating the ground to expose the shallow section of the pipeline L and inserting the buried pipe connecting structure 3 through the opening L1 of the exposed pipeline L.

[0041] FIG. 8B shows how buried pipes 1 are installed without excavating the ground. FIG. 8B shows how buried pipes 1, which have been previously connected by coupling members 2, are pushed into and installed through opening 61a of manhole 60a. When installing a buried pipe connection structure by pushing it through manhole 60 (60a, 60b) in this way, the pipeline L on which the connection structure is installed may include a section where the distance between pipeline L and the ground G is sufficient and where the need for a protective structure is not high. Therefore, as shown in FIG. 8B, a buried pipe connection structure 3 (with protective members 13, 23) with a protective structure and a buried pipe connection structure 4 (without protective members 13, 23) without a protective structure may be combined to install the connection structure in pipeline L, depending on the distance between pipeline L and the ground G. In this way, by combining and installing a buried pipe connecting structure 3 with a protective structure and a buried pipe connecting structure 4 without a protective structure according to the needs of the protective structure, it is possible to reduce the amount of protective materials 13, 23 used, which are generally expensive, and reduce installation costs.

[0042] 9 is a flowchart showing the procedure for installing the buried pipe 1 in the pipeline L. The processing of each step may be performed by an operator.

[0043] In step S1, a buried pipe connection structure is constructed by combining a buried pipe with a protective structure (first buried pipe) and a buried pipe without a protective structure (second buried pipe) depending on the situation in which the pipeline L is laid. The buried pipe with a protective structure is the buried pipe 1 described with reference to Figures 1 to 3E, etc. The buried pipe without a protective structure includes multiple inner pipes with hollow portions capable of accommodating cables 9. For example, the buried pipe without a protective structure may be configured by removing the protective member 13 from the buried pipe 1. The buried pipe with a protective structure and the buried pipe without a protective structure may be connected by a joint member 2. However, in the connection structure 4 for buried pipes without a protective structure, they may be connected by a joint member that does not include the protective member 23. The combination of buried pipes with protective structures and buried pipes without protective structures may be determined based on the distance between the pipeline L and the ground surface G, etc., and depending on the situation, such as the need for protective structures in the pipeline L buried underground.

[0044] In step S2, the connecting structure constructed in step S1 is inserted and installed through the opening of the pipeline L. For example, a connecting structure 3 for buried pipes with a protective structure and a connecting structure 4 for buried pipes without a protective structure may be inserted through the opening 61a of the manhole 60a. Then, the processing of the flowchart ends.

[0045] The present disclosure is not limited to the above-described embodiments. Instead of executing the steps in the chronological order as described, the steps in the flowcharts may be executed in parallel or in a different order depending on the processing capabilities of the devices executing the steps or as needed. Other modifications are possible without departing from the spirit of the present disclosure.

[0046] The following additional notes are provided regarding the above-described embodiments.

[0047] (Additional note 1) a plurality of inner tubes each having a hollow portion capable of accommodating a cable; an outer tube containing the plurality of inner tubes and having an inner surface with a portion in contact with the outer surface of each of the plurality of inner tubes; a protective member provided in a space defined by the outer surfaces of the inner pipes and the inner surface of the outer pipe; Equipped with The strength of the protective member is greater than that of the plurality of inner pipes and the outer pipe. Buried pipe. (Additional note 2) The buried pipe according to claim 1, wherein the inner pipes and the outer pipe are integrally molded. (Additional note 3) 3. The buried pipe according to claim 1, wherein the protective member has a shape that fills a space defined by the outer surfaces of the inner pipes and the inner surface of the outer pipe. (Additional note 4) 3. The buried pipe according to claim 1 or 2, wherein the protective member has an arch-shaped, pentagonal, L-shaped, rod-shaped, or circular cross section. (Additional note 5) 5. The buried pipe according to any one of claims 1 to 4, further comprising a connecting portion having a hollow portion that communicates with the hollow portions of the inner pipes and that can be connected to a joint member that joins multiple members. (Additional note 6) A joint member for joining buried pipes, an inner pipe having a hollow portion that can be fitted into the connection portion of the buried pipe; an outer tube containing the inner tube and having an inner surface with a portion in contact with the outer surface of the inner tube; a protective member provided in a space defined by an outer surface of the inner pipe and an inner surface of the outer pipe; Equipped with The strength of the protective member is greater than that of the inner pipe and the outer pipe, the inner pipe has a fitting portion that has a gap between it and the connecting portion when the connecting portion is fitted to the inner pipe; Joint material. (Additional note 7) A buried pipe connection structure comprising a buried pipe and a joint member that joins the buried pipe, The buried pipe is a plurality of first inner tubes each having a hollow portion capable of accommodating a cable; a first outer tube that houses the plurality of first inner tubes and has an inner surface having a portion that contacts the outer surface of each of the plurality of first inner tubes; a first protective member provided in a space defined by outer surfaces of the plurality of first inner tubes and an inner surface of the first outer tube; a connecting portion connectable to the coupling member and having a hollow portion communicating with the hollow portions of the plurality of first inner pipes; Equipped with the first protective member has a strength greater than that of the plurality of first inner tubes and the first outer tube; The coupling member is a second inner pipe having a hollow portion that can be fitted into the connection portion of the buried pipe; a second outer tube that houses the second inner tube and has an inner surface that has a portion that contacts the outer surface of the second inner tube; a second protective member provided in a space defined by an outer surface of the second inner tube and an inner surface of the second outer tube; Equipped with the second protective member has a strength greater than that of the second inner pipe and the second outer pipe; the second inner tube has a fitting portion that has a gap between it and the connecting portion when the connecting portion is fitted to it; Buried pipe connection structure. (Additional note 8) a first buried pipe comprising: a plurality of first inner pipes each having a hollow portion capable of accommodating a cable; an outer pipe accommodating the plurality of first inner pipes and having an inner surface with a portion in contact with the outer surface of each of the plurality of first inner pipes; and a protective member provided in a space defined by the outer surfaces of the plurality of first inner pipes and the inner surface of the outer pipe, wherein the strength of the protective member is greater than that of the plurality of first inner pipes and the outer pipe; a second buried pipe including a plurality of second inner pipes each having a hollow portion capable of accommodating the cable; The method for installing buried pipes comprises connecting the above-mentioned pipes to the pipes buried underground in accordance with their conditions and inserting them through the opening of the pipes. [Explanation of symbols]

[0048] 1(1a~1i) Buried pipe 11 Inner tube 111 Hollow part 12 Outer tube 13, 13a to 13e Protective members 15 Inner tube structure 151 Connection 152 Uneven structure 153 Components 154 Hollow part 155 Inner pipe body 18 areas 19 areas 2 Joint 21 Inner tube 212 Fitting part 22 Outer tube 23 Protective Materials 252 Uneven part 3,4 Buried pipe connection structure 9 Cable 60a, 60b manholes 61a, 61b opening G Surface L pipe L1 opening T1, T3, T4 outer surface T2, T5, T6 inner surface

Claims

1. a plurality of inner tubes each having a hollow portion capable of accommodating a cable; an outer tube containing the plurality of inner tubes and having an inner surface with a portion in contact with the outer surface of each of the plurality of inner tubes; a protective member provided in a space defined by the outer surfaces of the inner pipes and the inner surface of the outer pipe; Equipped with The strength of the protective member is greater than that of the plurality of inner pipes and the outer pipe. Buried pipe.

2. The buried pipe according to claim 1 , wherein the plurality of inner pipes and the outer pipe are integrally molded.

3. The buried pipe according to claim 1 , wherein the protective member has a shape that fills a space defined by outer surfaces of the plurality of inner pipes and an inner surface of the outer pipe.

4. The buried pipe according to claim 1 , wherein the protective member has an arch-shaped, pentagonal, L-shaped, rod-shaped, or circular cross section.

5. The buried pipe according to claim 1 , further comprising a connecting portion having a hollow portion that communicates with the hollow portions of the plurality of inner pipes and that is connectable to a joint member that joins a plurality of members.

6. A joint member for joining buried pipes, an inner pipe having a hollow portion that can be fitted into the connection portion of the buried pipe; an outer tube containing the inner tube and having an inner surface with a portion in contact with the outer surface of the inner tube; a protective member provided in a space defined by an outer surface of the inner pipe and an inner surface of the outer pipe; Equipped with The strength of the protective member is greater than that of the inner pipe and the outer pipe, the inner pipe has a fitting portion that has a gap between it and the connecting portion when the connecting portion is fitted to the inner pipe; Joint material.

7. A buried pipe connection structure comprising a buried pipe and a joint member that joins the buried pipe, The buried pipe is a plurality of first inner tubes each having a hollow portion capable of accommodating a cable; a first outer tube that houses the plurality of first inner tubes and has an inner surface having a portion that contacts the outer surface of each of the plurality of first inner tubes; a first protective member provided in a space defined by outer surfaces of the plurality of first inner tubes and an inner surface of the first outer tube; a connecting portion connectable to the coupling member and having a hollow portion communicating with the hollow portions of the plurality of first inner pipes; Equipped with the first protective member has a strength greater than that of the plurality of first inner tubes and the first outer tube; The coupling member is a second inner pipe having a hollow portion that can be fitted into the connection portion of the buried pipe; a second outer tube containing the second inner tube and having an inner surface with a portion in contact with the outer surface of the second inner tube; a second protective member provided in a space defined by an outer surface of the second inner tube and an inner surface of the second outer tube; Equipped with the second protective member has a strength greater than that of the second inner pipe and the second outer pipe; the second inner pipe has a fitting portion that has a gap between it and the connecting portion when the connecting portion is fitted thereto; Buried pipe connection structure.

8. a first buried pipe comprising: a plurality of first inner pipes each having a hollow portion capable of accommodating a cable; an outer pipe accommodating the plurality of first inner pipes and having an inner surface having a portion in contact with the outer surface of each of the plurality of first inner pipes; and a protective member provided in a space defined by the outer surfaces of the plurality of first inner pipes and the inner surface of the outer pipe, wherein the strength of the protective member is greater than that of the plurality of first inner pipes and the outer pipe; a second buried pipe including a plurality of second inner pipes each having a hollow portion capable of accommodating the cable; The method for installing buried pipes comprises connecting the above-mentioned pipes to the pipes buried underground in accordance with their conditions and inserting them through the opening of the pipes.

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