Pipe laying method and centering member
A compact centering member aligns pipe axes within conduits, addressing the challenges of pipe joining by reducing the risk of structural interference and costs, enabling efficient and cost-effective pipeline laying.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- KURIMOTO LTD
- Filing Date
- 2024-11-20
- Publication Date
- 2026-06-01
AI Technical Summary
Existing pipeline laying methods face challenges in smoothly joining straight, curved, or bent pipes within conduits due to the use of wide temporary support stands that can get caught on internal structures and incur high costs.
A compact centering member is installed on the inner surface of the preceding pipe, aligning the axes of subsequent pipes by being sandwiched between the inner surface of the preceding pipe's socket and the outer surface of the subsequent pipe's insertion end, allowing for smooth retrieval without rails and reducing material costs.
The method enables low-cost and efficient joining of pipes within conduits by minimizing the risk of the centering member getting caught and reducing material costs, while ensuring smooth alignment and retrieval.
Smart Images
Figure 2026089257000001_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a pipeline laying method and a centering member used in this method.
Background Art
[0002] As a pipeline laying method for transporting liquids such as water and sewage, a method has been conventionally adopted in which a ductile iron pipe is placed on a carrier vehicle and carried into a sheath pipe such as a newly installed propulsion pipe or a shield tunnel, and the joints of the ductile iron pipes are joined inside this sheath pipe. In this method, behind the preceding pipe inserted into the sheath pipe, a subsequent pipe is transported using a carrier vehicle, and after centering the insertion port of the subsequent pipe with respect to the receiving port of the preceding pipe using a hydraulic jack or the like provided on the carrier vehicle, the insertion port is placed in the receiving port. Next, in order to prevent the displacement of the rubber ring, the orientation of the subsequent pipe is adjusted so that the insertion port of the subsequent pipe is straight with respect to the receiving port of the preceding pipe, and the insertion port is inserted into the rubber ring.
[0003] In this method, in the case of straight pipes or cut pipes that require curved pipes or bent pipes, when placed on a carrier vehicle, the subsequent pipe brought in may interfere with the carrier vehicle and its orientation may not be adjustable. Therefore, for example, in Patent Document 1 below, before inserting the insertion port into the rubber ring of the receiving port, the carrier vehicle is pulled out from under the subsequent pipe, a temporary receiving stand is installed on the rails on which this carrier vehicle travels, and while placing the insertion port of the subsequent pipe on this temporary receiving stand, centering work is performed to align the center of this insertion port with the receiving port of the preceding pipe, and then the insertion port of the subsequent pipe is inserted into the rubber ring of the receiving port of the preceding pipe. Then, the receiving port of the subsequent pipe is lifted, and the temporary receiving stand is recovered by sliding it across the two rails.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] In the temporary support stand retrieval method employed in Patent Document 1, the temporary support stand is retrieved by sliding it across two rails. Therefore, the temporary support stand must be a member wider than at least the distance between the two rails, and if it were to fall off the rails during retrieval, it could get caught on internal structures (such as ribs) of the conduit, making retrieval difficult. In addition, in order to reliably support the insertion point of the heavy subsequent pipe, the structure must have a certain degree of rigidity, which leads to increased costs.
[0006] Therefore, the object of this invention is to provide a pipeline laying method that enables smooth and low-cost joining of a preceding pipe and a succeeding pipe within a conduit, and a centering member used in this pipeline laying method. [Means for solving the problem]
[0007] To solve the above problems, this invention provides: Installation process involves installing a centering member on the inner surface of the receiving end of the preceding pipe that has been brought into the sheath pipe, A centering step is performed by inserting the insertion end of the subsequent pipe, which has been brought into the sheath pipe, into the receiving end of the preceding pipe, and inserting the centering member into the gap between the inner surface of the receiving end of the preceding pipe and the outer surface of the insertion end of the subsequent pipe, thereby aligning the pipe axes of both pipes at the joint portion of the two pipes. After the centering process is completed, a recovery process is performed in which the centering member is pulled out from between the inner surface of the receiving end of the preceding pipe and the outer surface of the insertion end of the succeeding pipe and recovered. A pipeline laying method having the following was constructed (first configuration).
[0008] This design allows for the use of a relatively compact centering member compared to the conventional wide temporary support that spans two rails. This reduces the likelihood of problems such as the centering member getting caught on internal structures of the conduit during retrieval after the centering process, and allows for smooth joining of the leading and trailing pipes within the conduit. Moreover, since this centering member has a simple structure that is merely sandwiched in the gap between the inner surface of the leading pipe's socket and the outer surface of the trailing pipe's insertion point, it is possible to reduce costs related to joining work, such as the cost of the member itself.
[0009] In the first configuration, the centering member can be configured to have a plate-like portion with a thickness corresponding to the size of the radial gap between the inner surface of the socket of the preceding pipe and the outer surface of the insertion opening of the succeeding pipe (second configuration). In this way, the two pipes can be smoothly centered simply by placing the insertion opening of the succeeding pipe into the plate-like portion of the centering member provided on the inner surface of the socket.
[0010] In the second configuration, an extension piece is provided that protrudes from the gap on the plate-like portion, and moves away from the outer surface of the insertion opening of the subsequent pipe as it moves away from the plate-like portion (third configuration). In this way, when a wire or the like is attached to the extension piece and the centering member is retrieved by pulling the wire, problems such as the extension piece coming into contact with the outer surface of the subsequent pipe and causing damage to the outer surface can be suppressed.
[0011] In the second or third configuration, the plate-like portion is flat when unloaded, and when the weight of the subsequent pipe acts on it during the centering process, it can be configured to deform to conform to the inner surface of the socket of the preceding pipe (fourth configuration). In this way, the plate-like portion elastically deforms from a flat state to a curved state, which can mitigate the impact when the insertion end of the subsequent pipe is placed into the socket of the preceding pipe.
[0012] In the first to fourth configurations, a circumferential groove formed on the inner surface of the socket of the preceding pipe has a cutout portion formed in a part of the circumferential direction corresponding to the installation position of the centering member, and a lock ring is provided which elastically reduces in diameter so that a part of the inner diameter side protrudes from the circumferential groove, and the circumferential width of the cutout portion when the lock ring is wrapped around the outer surface of the insertion opening of the following pipe is wider than the circumferential width of the centering member (fifth configuration). In this way, when the lock ring is wrapped around the outer surface of the insertion opening of the following pipe, a gap is formed between the inner edge of the cutout portion of the lock ring and the centering member, so that the centering member is not caught between the cutout portions of the lock ring, and the centering member can be recovered smoothly in the recovery process.
[0013] In configurations 1 through 5, a configuration (configuration 6) is further provided, which includes a removal step after the centering step, in which the receiving end of the subsequent pipe is lifted and the rails for which the trolley that transports both pipes are run are removed. Unlike conventional methods in which the temporary support base is recovered using rails after the centering step, this invention does not require rails in the recovery step for recovering the centering members. Therefore, it becomes possible to recover the rails after the centering step, and costs can be reduced by reusing those rails.
[0014] In configurations 1 through 6, a configuration (configuration 7) can be used in which, during the recovery process, the receiving end of the subsequent pipe is lifted before the centering member is pulled out. This reduces the weight of the subsequent pipe acting on the centering member, allowing the centering member to be pulled out smoothly.
[0015] In the second to fourth configurations, a configuration (eighth configuration) can be adopted in which a fall prevention member is placed on the plate-shaped portion of the centering member on which the extension piece is formed, to prevent the centering member from falling out of the socket of the preceding pipe due to the weight of the extension piece. In this way, the centering member can be stably held in the socket of the preceding pipe, so that the centering process can be carried out smoothly.
[0016] In the pipeline laying method relating to the first to eighth configurations, A plate-like portion is inserted into the gap between the inner surface of the receiving end of the preceding pipe brought into the sheath pipe and the outer surface of the insertion end of the following pipe, An extended piece protruding from the gap and extending from the plate-like portion such that it moves further away from the outer surface of the insertion opening of the subsequent pipe as it moves away from the plate-like portion, A configuration (9th configuration) can be adopted that employs a centering member used in the laying of pipelines having the following characteristics. [Effects of the Invention]
[0017] In this invention, in the centering process for aligning the pipe axes at the joint between the leading pipe and the trailing pipe, the centering member is inserted into the gap between the inner surface of the receiving end of the leading pipe and the outer surface of the insertion end of the trailing pipe. This allows the joining work between the leading pipe and the trailing pipe inside the conduit to be performed smoothly and at low cost. [Brief explanation of the drawing]
[0018] [Figure 1A] This figure shows a first embodiment of the pipeline laying method according to the present invention, where (a) shows the state in which the trailing pipe has been transported to the rear of the preceding pipe, (b) shows the state in which the leading end has been placed into the receiving end after the leading and trailing pipes have been aligned, and (c) shows the state in which the receiving end of the trailing pipe is being lifted and the transport cart is being pulled out. [Figure 1B] Following Figure 1A, (a) shows the state with the pipe support attached to the socket of the subsequent pipe, (b) shows the state with the insertion end inserted until it hits the distance piece, (c) shows the state in which the centering member is being retrieved, and (d) shows the state after the thrust ring bolt has been unscrewed to increase the compression ratio of the rubber ring, and the insertion end has been further inserted to complete the joint connection. [Figure 2] Figure 1B shows enlarged views of the main parts in each state, where (a) is an enlarged view of Figure 1B(a), (b) is an enlarged view of Figure 1B(b), (c) is an enlarged view of Figure 1B(c), and (d) is an enlarged view of Figure 1B(d). [Figure 3] Front view of the trailing pipe being transported into the sheath pipe, as seen from the receiving end. [Figure 4]Front view showing the state where the lock ring is enlarged by the amplifier [Figure 5] Shows a centering member used in the pipeline laying method according to this invention. (a) is a plan view of the first example, (b) is a side view of the first example, (c) is a plan view of the second example, and (d) is a side view of the second example [Figure 6] Front view showing the state where the lock ring is wound around the insertion opening of the subsequent pipe [Figure 7] It is a view showing a second embodiment of the pipeline laying method according to this invention. (a) shows the state where a pipe support is provided at the receiving port of the subsequent pipe after removing the rail, and (b) is an enlarged view of the main part of (a) [Figure 8] Front view showing the state where the lock ring is enlarged by the amplifier [Figure 9] It is a view showing a third embodiment of the pipeline laying method according to this invention. (a) shows the state where the receiving port of the subsequent pipe is lifted and the centering member is about to be recovered, and (b) is an enlarged view of the main part of (a) [Figure 10] It is a view showing the main part of a fourth embodiment of the pipeline laying method according to this invention. (a) shows the state where the dropout prevention member is placed on the centering member (plate-like part), and (b) shows the state where the dropout prevention member is pushed into the inner side of the receiving port as the insertion port is inserted
Embodiments for Carrying out the Invention
[0019] The first embodiment of the pipeline laying method according to this invention will be described based on FIGS. 1A to 6. This pipeline laying method is a laying method for pipelines that transport liquids such as water and sewage. A ductile iron pipe is carried into a sleeve pipe 1 such as a newly installed propulsion pipe or a shield tunnel on a transport cart 2, and the joints of the ductile iron pipes are joined inside this sleeve pipe 1. As the sleeve pipe 1, for example, a steel segment having longitudinal ribs 1a extending axially and a flange 1b extending circumferentially on the inner surface (see FIG. 3) is used
[0020] In this pipeline laying method, first, as shown in Figure 1A(a), the trailing pipe 4 is brought in by a transport trolley 2 behind the preceding pipe 3, which has already been brought into the conduit pipe 1 and joined. The transport trolley 2 moves along the rail 6 (angle rail in this embodiment) by the driving force of the electric trolley 5.
[0021] A circumferential groove is formed on the inner surface of the socket of the leading pipe 3. A rubber ring 7 is provided in the circumferential groove to ensure watertightness between the two pipes 3 and 4, and a cutout section 9 (see Figure 4) is formed in a part of the circumferential direction corresponding to the installation position of the centering member 8. A lock ring 10 is provided that elastically reduces in diameter, causing a portion of its inner diameter to protrude from the circumferential groove. As shown in Figure 4, the cutout section 9 of the lock ring 10 is expanded by the expander 11 to facilitate the joining of the following pipe 4. A lock groove 12 into which the lock ring 10 fits is formed on the outer surface of the insertion opening of the following pipe 4 (see Figure 2(a)).
[0022] As shown in Figure 4, a float prevention material 13 is installed on the upper part of the lead pipe 3 to prevent the joined pipes 3 and 4 from floating up due to buoyancy when a filler material (such as mortar) is filled into the gap between the two pipes 3 and 4 that are joined to the sheath pipe 1. Note that if a filler material is not used, the installation of the float prevention material 13 can be omitted.
[0023] A centering member 8 is provided at the lower end of the inner surface of the socket of the preceding pipe 3 (installation process). The centering member 8 used in this embodiment (first example) has a plate-shaped portion 8a and an extended piece 8b that extends from the plate-shaped portion 8a so as it moves away from the plate-shaped portion 8a it moves away from the outer surface of the insertion opening of the following pipe 4.
[0024] The plate-like portion 8a is flat in an unloaded state and has a thickness (e.g., 2 mm) that corresponds to the size of the radial gap between the inner surface of the socket of the leading pipe 3 and the outer surface of the insertion opening of the leading pipe 4 when the leading pipe 3 is joined to the leading pipe 3. The size and shape of the plate-like portion 8a are not particularly limited, but it can be sized to be stably placed on the inner surface of the socket of the leading pipe 3 (e.g., a rectangular shape with a length of 110 mm in the direction perpendicular to the pipe axis and a length of 70 mm in the direction perpendicular to the pipe axis). The plate-like portion 8a is made of an elastic material such as a steel plate.
[0025] The extension piece 8b can be a tapered flat plate, bent downward from the plate-like portion 8a (for example, with a bending angle of 30 degrees), as shown in Figures 5(a) and 5(b). The size of the extension piece 8b is not particularly limited, but it is preferable that it be lighter than the plate-like portion 8a (for example, with a length in the axial direction of the pipe and a length perpendicular to the axial direction of the pipe being 70 mm on the plate-like portion 8a side and 40 mm on the tip side) so that the centering member 8 does not fall out of the receiving end of the preceding pipe 3 due to the weight of the extension piece 8b. A through hole is formed at the tip of the extension piece 8b, and a washer 8c is provided to match the through hole. A wire 14 (see Figure 2(a), etc.) is attached to the washer 8c (through hole). The wire 14 is passed along the outside of the following pipe 4 to its rear end.
[0026] The shape of the centering member 8 is not limited to this. For example, as shown in Figures 5(c) and 5(d), the extension piece 8b extending from the plate-shaped portion 8a has a first portion 8b1 that is bent so that it moves away from the outer surface of the insertion opening of the subsequent pipe 4 as it moves away from the plate-shaped portion 8a, and a second portion 8b2 that extends from the tip of the first portion 8b1 and is parallel to the plate-shaped portion 8a (second example). A through hole is formed at the tip of the second portion 8b2, and a washer 8c is welded to the through hole to reinforce it, and a wire 14 or the like can be attached to this through hole reinforced with the washer 8c.
[0027] Next, as shown in Figure 1A(b), the insertion end of the subsequent pipe 4 brought into the sheath pipe 1 is inserted into the socket of the preceding pipe 3, and the plate-shaped portion 8a of the centering member 8 is sandwiched in the gap between the inner surface of the socket of the preceding pipe 3 and the outer surface of the insertion end of the subsequent pipe 4, thereby aligning the pipe axes of both pipes 3 and 4 at the joint portion of both pipes 3 and 4 (centering process). When the weight of the subsequent pipe 4 acts on the plate-shaped portion 8a of the centering member 8 during this centering process, the flat plate-shaped portion 8a elastically deforms to conform to the inner surface of the socket of the preceding pipe 3. Alternatively, a centering member 8 can be used that is pre-formed so that the plate-shaped portion 8a conforms to the inner surface of the socket of the preceding pipe 3.
[0028] The expander 11, used to widen the cut portion 9 of the lock ring 10, is removed when the tip of the insertion opening of the subsequent tube 4 reaches the lock ring 10. Alternatively, the expander 11 may be pushed inward in the axial direction of the tube at the tip of the insertion opening to dislodge it from the cut portion 9 and then retrieved. Once the expander 11 is removed, the lock ring 10 shrinks in diameter due to its elasticity and becomes wrapped around the outer surface of the insertion opening. In this state, the circumferential width w1 of the cut portion 9 is wider than the circumferential width w2 of the centering member 8 (plate-shaped portion 8a), as shown in Figure 6, and a gap is created between the circumferential end of the centering member 8 and the circumferential end of the cut portion 9.
[0029] Once the alignment of both pipes 3 and 4 is complete, as shown in Figure 1A(c), the receiving end of the trailing pipe 4 is lifted with the jack 15 and the transport trolley 2 is pulled out from underneath the trailing pipe 4. Then, as shown in Figures 1B(a) and 2(a), a pipe support stand 16 is placed under the receiving end of the trailing pipe 4, straddling the two rails 6, and the receiving end that was lifted with the jack 15 is lowered and supported by the pipe support stand 16.
[0030] Furthermore, as shown in Figures 1B(b) and 2(b), a distance piece 17 is provided at the inner end of the inner surface of the socket of the leading pipe 3, which functions as a spacer to prevent the lock ring 10 provided on the inner surface of the socket from fitting into the lock groove 12 formed on the outer surface of the insertion opening. Then, the insertion opening of the trailing pipe 4 is inserted into the socket until the tip of the insertion opening abuts against the distance piece 17.
[0031] Once it is confirmed that there are no defects such as misalignment in the rubber ring 7, as shown in Figures 1B(c) and 2(c), the wire 14 attached to the centering member 8 is pulled to pull out the centering member 8 from between the inner surface of the socket of the leading pipe 3 and the outer surface of the insertion opening of the following pipe 4 and retrieve it from the outer surface side of the following pipe 4 (retrieval process). Then, as shown in Figures 1B(d) and 2(d), the distance piece 17 is removed, the push ring bolt (not shown) is unscrewed to compress the rubber ring 7 and increase the surface pressure of the rubber ring 7, and the insertion opening is inserted to the specified joint spacing to complete the joint connection.
[0032] In the pipeline laying method according to the first embodiment, a centering member 8, which is relatively more compact than a conventional wide temporary support stand, is provided on the inner surface of the receiving end of the leading pipe 3 (installation step), and after aligning the pipe axis between the leading pipe 3 and the trailing pipe 4 using this centering member 8 (centering step), the centering member 8 is retrieved (retrieval step). As a result, when retrieving the centering member 8 after the centering step, problems such as the centering member 8 getting caught on the internal structure of the conduit pipe 1 are less likely to occur, and the joining work of the leading pipe 3 and the trailing pipe 4 inside the conduit pipe 1 can be performed smoothly.
[0033] Moreover, since the centering member 8 has a simple structure that is merely sandwiched in the gap between the inner surface of the receiving end of the preceding pipe 3 and the outer surface of the insertion end of the following pipe 4, the costs associated with joining work, such as the cost of the material, can be reduced. Furthermore, in this embodiment, since the centering member 8 is retrieved from the outer side of the following pipe 4, there is no need to pass the wire 14 for pulling out the centering member 8 through the inside of the following pipe 4, which improves work efficiency.
[0034] Furthermore, since the centering member 8 has a plate-shaped portion 8a that is sandwiched between the inner surface of the socket of the preceding pipe 3 and the outer surface of the insertion opening of the following pipe 4, and an extended piece 8b that extends further away from the outer surface of the insertion opening of the following pipe 4 as it moves away from the plate-shaped portion 8a, when a wire 14 or the like is attached to the extended piece 8b and the centering member 8 is retrieved by pulling the wire 14, it is possible to suppress problems such as the extended piece 8b coming into contact with the outer surface of the following pipe 4 and damaging its outer surface.
[0035] Furthermore, the plate-shaped portion 8a of the centering member 8 is flat when unloaded, and when the weight of the subsequent pipe 4 acts on it during the centering process, the plate-shaped portion 8a elastically deforms from a flat state to a curved state so as to conform to the inner surface of the receiving end of the preceding pipe 3. This reduces the impact when the insertion end of the subsequent pipe 4 is placed into the receiving end of the preceding pipe 3.
[0036] Furthermore, when the lock ring 10, which is provided on the inner surface of the socket of the leading pipe 3 and has a cut portion 9 formed in a part of the circumferential direction corresponding to the installation position of the centering member 8, is wrapped around the outer surface of the insertion opening of the trailing pipe 4, the circumferential width w1 of the cut portion 9 is wider than the circumferential width w2 of the centering member 8. Therefore, the centering member 8 is not caught between the cut portions 9 of the lock ring 10. For this reason, the centering member 8 can be recovered smoothly during the recovery process.
[0037] A second embodiment of the pipeline laying method according to this invention will be described with reference to Figures 7 and 8. The pipeline laying method according to the second embodiment differs from the pipeline laying method according to the first embodiment in that it has a removal step in which the receiving end of the successor pipe 4 is lifted with a jack 15 and the transport trolley 2 is pulled out from under the successor pipe 4, and the rails 6 for which the transport trolley 2 is driven are removed, as shown in Figures 7(a) and 7(b), and the pipe support base 16 is provided so as to straddle the vertical ribs 1a of the conduit pipe 1, as shown in Figure 8, but the other configurations are the same.
[0038] Unlike conventional methods in which the temporary support base is recovered using rails 6 after the alignment process, the pipeline laying method according to the second embodiment does not require rails 6 in the recovery process for recovering the alignment member 8. Therefore, it is possible to recover the rails 6 after the alignment process, and costs can be reduced by reusing the rails 6.
[0039] A third embodiment of the pipeline laying method according to this invention will be described with reference to Figure 9. The pipeline laying method according to the third embodiment differs from the pipeline laying method according to the second embodiment in that, as shown in Figures 9(a) and 9(b), in the recovery process the receiving end side of the subsequent pipe 4 is lifted with a jack 15 and then the centering member 8 is pulled out; all other configurations are the same.
[0040] In the pipeline laying method according to the third embodiment, the weight of the subsequent pipe 4 acting on the centering member 8 is reduced, allowing the centering member 8 to be pulled out smoothly.
[0041] A fourth embodiment of the pipeline laying method according to this invention will be described with reference to Figure 10. The pipeline laying method according to the fourth embodiment differs from the pipeline laying method according to the third embodiment in that, as shown in Figure 10(a), in the installation process, a fall prevention member 18 (weight) is placed on the plate-shaped portion 8a of the centering member 8 on which the extension piece 8b is formed, to prevent the centering member 8 from falling out of the socket of the preceding pipe 3 due to the weight of the extension piece 8b. The other configurations are the same. As shown in Figure 10(b), the fall prevention member 18 placed on the socket of the preceding pipe 3 is pushed to the back of the socket by the insertion opening of the subsequent pipe 4 inserted into the socket, and is then retrieved.
[0042] In the pipeline laying method according to the fourth embodiment, the centering member 8 can be stably held in the receiving end of the lead pipe 3, thus enabling the centering process to be carried out smoothly.
[0043] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. Accordingly, the scope of the invention is indicated by the claims rather than by the foregoing description and is intended to include the meaning of equivalents of the claims and all modifications thereof. [Explanation of symbols]
[0044] 1. Sheath tube 1a Longitudinal ribs 1b Flange 2. Transport cart 3 Preceding pipe 4. Successor pipe 5. Electric trolley 6 rails 7 Rubber rings 8. Centering component 8a Plate-like part 8b Extension piece 8c washer 9 Excision part 10 Lock Rings 11 Magnifier 12 lock grooves 13. Anti-float material 14 wires 15 Jack 16 Tube holder 17 Distance Pieces 18. Detachment prevention member w1 Circumferential width of the excised area w2 Circumferential width of centering member
Claims
1. Installation process includes providing a centering member (8) on the inner surface of the receiving end of the lead pipe (3) that is brought into the sheath pipe (1), The centering process involves inserting the insertion end of the subsequent pipe (4), which has been brought into the sheath pipe (1), into the receiving end of the preceding pipe (3), and inserting the centering member (8) into the gap between the inner surface of the receiving end of the preceding pipe (3) and the outer surface of the insertion end of the subsequent pipe (4), thereby aligning the pipe axes of both pipes (3, 4) at the joint portion of both pipes (3, 4), After the centering process is completed, a recovery process is performed in which the centering member (8) is pulled out from between the inner surface of the receiving end of the preceding pipe (3) and the outer surface of the insertion end of the following pipe (4) and recovered. A method for laying pipelines.
2. The pipeline laying method according to claim 1, wherein the centering member (8) has a plate-like portion (8a) with a thickness corresponding to the size of the radial gap between the inner surface of the receiving end of the preceding pipe (3) and the outer surface of the insertion end of the following pipe (4).
3. The pipeline laying method according to claim 2, wherein an extended piece (8b) is provided on the plate-shaped portion (8a) such that it protrudes from the gap and moves away from the outer surface of the insertion opening of the subsequent pipe (4) as it moves away from the plate-shaped portion (8a).
4. The pipeline laying method according to claim 2, wherein the plate-like portion (8a) is flat when unloaded, and deforms to conform to the inner surface of the receiving end of the preceding pipe (3) when the weight of the subsequent pipe (4) acts on it during the centering process.
5. A pipe laying method according to any one of claims 1 to 4, wherein a circumferential groove formed on the inner surface of the socket of the preceding pipe (3) has a cut-out portion (9) formed in a part of the circumferential direction corresponding to the installation position of the centering member (8), and a lock ring (10) is provided which elastically reduces in diameter so that a part of the inner diameter side protrudes from the circumferential groove, and the circumferential width (w1) of the cut-out portion (9) when the lock ring (10) is wrapped around the outer surface of the insertion opening of the following pipe (4) is wider than the circumferential width (w2) of the centering member (8).
6. The pipeline laying method according to claim 1, further comprising a removal step of lifting the receiving end of the subsequent pipe (4) and then removing the rail (6) on which a transport trolley (2) for transporting both pipes (3, 4) is driven.
7. The pipeline laying method according to claim 1, wherein in the recovery step, the receiving end of the subsequent pipe (4) is lifted and the centering member (8) is pulled out.
8. The pipeline laying method according to claim 3, wherein a fall prevention member (18) is placed on the plate-shaped portion (8a) of the centering member (8) on which the extension piece (8b) is formed, to prevent the centering member (8) from falling out of the receiving end of the preceding pipe (3) due to the weight of the extension piece (8b).
9. A plate-like portion (8a) is inserted into the gap between the inner surface of the receiving end of the preceding pipe (3) brought into the sheath pipe (1) and the outer surface of the insertion end of the following pipe (4), An extended piece (8b) is provided on the plate-shaped portion (8a) such that it protrudes from the gap and moves away from the outer surface of the insertion opening of the subsequent pipe (4) as it moves away from the plate-shaped portion (8a), A centering member used in the laying of pipelines having [a specific feature / feature].