Construction system and construction method

Abstract

The objective is to provide a construction system and method that allows pipelines to be laid on the shore side. [Solution] A construction system 1 for laying a pipeline 10 on the seabed using a laying vessel 20, wherein the construction system 1 includes a vessel 20 that pulls the underwater pipeline 10 toward the shore Q.

Description

Technical Field

[0008]

[0001] The present disclosure relates to a construction system and a construction method.

Background Art

[0002] Conventionally, pipelines have been laid underwater by a laying vessel. Patent Document 1 discloses a technique for laying a cable on the shore side by towing the cable by a ship.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technique described in Patent Document 1 does not lay the pipeline on the shore side.

[0005] The present disclosure has been made in view of the above, and an object thereof is to provide a construction system and a construction method capable of laying a pipeline on the shore side.

Means for Solving the Problems

[0006] A construction system according to an aspect of the present disclosure is a construction system for laying a pipeline underwater by a laying vessel, and includes a ship for towing the pipeline in water to the shore side.

Effects of the Invention

[0007] According to the present disclosure, it is possible to provide a construction system and a construction method capable of laying a pipeline on the shore side.

Brief Description of the Drawings

[0008] [Figure 1] Figure 1 is a plan view showing an example of a construction system according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a side view showing an example of the construction system according to this embodiment. [Figure 3] Figure 3 is a side view showing an example of a part of the construction system according to this embodiment. [Figure 4] Figure 4 is a plan view showing an example of a construction system according to another embodiment of the present disclosure. [Figure 5] Figure 5 is a flowchart showing an example of a construction method according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0009] An example of a construction system 1 according to one embodiment of this disclosure will be explained using the drawings. Figure 1 is a plan view showing an example of the construction system 1 according to this embodiment. Figure 2 is a side view showing an example of the construction system 1 according to this embodiment. Figure 3 is a side view showing an example of a part of the construction system 1 according to this embodiment. Figure 4 is a plan view showing an example of a construction system 1A according to another embodiment of the present disclosure.

[0010] Construction system 1 is a system for laying pipeline 10 on the seabed Ga using a pipeline laying vessel 20. Construction system 1 may be used, for example, in the sea, rivers, or lakes. Pipeline 10 is used, for example, for transporting oil or gas (e.g., carbon dioxide). Note that carbon dioxide may also be transported in the liquid phase under increased pressure, rather than in the gas phase. Figures 1 and 2 show the state in which the pipeline 10 is being sent out into the underwater Gb from the pipeline laying vessel 20. The pipeline 10 is sent out into the underwater Gb from the stern 21 of the pipeline laying vessel 20. The pipeline laying vessel 20 is fixed to the seabed Ga by, for example, an anchor (not shown). In addition to the anchor, the pipeline laying vessel 20 may also be positioned by, for example, a DP (Dynamic Positioning) System. The longitudinal direction of the pipeline laying vessel 20 is the X direction, the width direction is the Y direction, and the vertical direction is the Z direction.

[0011] The pipeline 10, sent out from the laying vessel 20 into the underwater Gb, settles on the seabed Ga in an S-shaped curve, which can cause stress (bending stress) to be generated in the pipeline 10, potentially leading to buckling. For this reason, a stinger (not shown) may be provided at the stern 21 of the laying vessel 20. The stinger is positioned at the stern 21 of the laying vessel 20 and is used to support the downward force in the Z direction acting on the pipeline 10, suppressing the generation of excessive stress on the pipeline 10 and safely sending the pipeline 10 to the seabed Ga. The pipeline 10 is positioned on the stinger on the laying vessel 20 and guided by the stinger to be sent out into the underwater Gb.

[0012] The construction system 1 includes a pipeline laying vessel (ship) 20 that tows the underwater pipeline Gb pipeline 10 toward the shore Q. In Figures 1 and 2, the longitudinal direction of the pipeline laying vessel 20 is oriented away from the shore Q toward the open sea R. The stern 21 of the pipeline laying vessel 20 is oriented toward the shore Q, and the bow 22 of the pipeline laying vessel 20 is oriented toward the open sea R. Alternatively, the longitudinal direction of the pipeline laying vessel 20 may be oriented approximately parallel to the quay direction QD. Alternatively, the stern 21 of the pipeline laying vessel 20 may be oriented toward the open sea R, and the bow 22 of the pipeline laying vessel 20 may be oriented toward the shore Q. In this embodiment, the pipeline 10 is towed by the pipeline laying vessel 20, but it is not limited to the pipeline laying vessel 20, and a different vessel may be used.

[0013] As shown in Figure 1, the pipeline 10 is laid on the seabed Ga from the pipeline laying vessel 20 toward the shore Q. The direction in which the pipeline 10 is towed from the starting position P1 of the pipeline 10 at the stern 21 of the pipeline laying vessel 20 is defined as the towing direction D1. In Figure 1, the towing direction D1 is indicated by an arrow. From the perspective of the pipeline 10, the direction in which the pipeline 10 is sent out from the pipeline laying vessel 20 (towing direction D1) is downstream, and the opposite direction is upstream. The construction system 1 is configured to lay the underwater pipeline 10 on the shore Q side by towing the pipeline 10 of Gb to the shore Q side using a pipeline laying vessel 20. With this configuration, the pipeline 10 can be laid on the shore Q side. This reduces the possibility of the pipeline laying vessel 20 running aground even in shallow waters such as the shore Q side. Furthermore, the construction system 1 according to this embodiment can also solve the problem of reducing the need to install towing equipment on or near the shore Q side.

[0014] Figures 1 and 2 show the case where the vessel towing the pipeline 10 towards shore Q is the pipeline layer 20, and the vessel towing the pipeline 10 towards shore Q and the pipeline layer 20 are the same. However, as shown in Figure 4, the vessel 20-1 towing the pipeline 10 towards shore Q may be different from the pipeline layer 20. In this case, vessel 20-1 may be a self-propelled vessel or a non-self-propelled vessel (e.g., a barge). With this configuration, a vessel 20-1, separate from the pipeline layer 20, tows the underwater pipeline 10 at Gb towards shore Q. This allows the pipeline 10 to be laid towards shore Q by vessel 20-1. Furthermore, if a smaller configuration of vessel 20-1 than the pipeline layer 20 is adopted, for example, the possibility of vessel 20-1 running aground in shallow areas such as shore Q can be reduced.

[0015] As described above, the construction system 1 according to this embodiment exhibits excellent effects particularly in the shallow area. "Shallow area" means that the distance 23Z between the ship bottom 23 and the water bottom Ga is less than or equal to a predetermined distance. When the distance 23Z is less than or equal to the predetermined distance, there is a possibility that the laying ship 20 may run aground. Also, when the draft approaches the water depth, there is a possibility that the laying ship 20 may run aground. "Draft" is the vertical distance D from the ship bottom 23 of the laying ship 20 floating in water to the water surface Gc (that is, the distance from the ship bottom to the waterline). The draft varies depending on, for example, the loading capacity of the ship, the ballast water, and the amount of fuel.

[0016] The construction system 1 may include a cable-like body (hereinafter also referred to as the first cable-like body) 30. The first cable-like body 30 is, for example, a wire. The cable-like body 30 is provided between the part (first part) 11 of the pipeline 10 on the side opposite to the laying ship 20 and the laying ship 20. The first part 11 is the part on the downstream side (traction direction D1 side) of the pipeline 10. One end 31 of the first cable-like body 30 is connected to the first part 11 of the pipeline 10, and the other end 32 of the first cable-like body 30 is connected to the laying ship 20. When the laying ship 20 pulls the first cable-like body 30 toward the offing R side, the pipeline 10 in the water Gb is pulled toward the shore Q side via the first cable-like body 30.

[0017] When the ship 20-1 is different from the laying ship 20, as shown in FIG. 4, a ship 20-1 different from the laying ship 20 may pull the first cable-like body 30 toward the offing R side. For example, when a ship 20-1 different from the laying ship 20 moves toward the offing R side, the pipeline 10 may be pulled toward the shore Q side via the first cable-like body 30.

[0018] With such a configuration, when pulling the pipeline 10 in the water Gb toward the shore Q side, since the laying ship 20 does not need to move to the shore Q side, the possibility that the laying ship 20 runs aground can be reduced.

[0019] The construction system 1 may include a direction conversion device 40. As shown in Figure 1, the direction changing device 40 is positioned on the shore Q side (towing direction D1 side) when viewed from the pipeline 10. The direction changing device 40 is positioned on the first cable 30 that connects the pipeline 10 and the laying vessel 20. The direction changing device 40 changes the pulling direction of the first cable 30 so that the pipeline 10 at underwater Gb is pulled towards the shore Q side via the first cable 30 when the laying vessel 20 pulls the first cable 30 towards the offshore R side. As shown in Figure 1, the first cable 30 is pulled at the return position P2 of the first cable 30 at the stern 21 of the laying vessel 20. The return position P2 is offset from the starting position P1 in the ship width direction (Y direction). The direction in which the first cable 30 is returned to the return position P2 is called the return direction D2. At the return position P2, the first cable 30 is pulled towards the return direction D2 side (offshore R side). In Figure 1, etc., the return direction D2 is indicated by an arrow.

[0020] If the vessel 20-1 is separate from the minelayer 20, as shown in Figure 4, the vessel 20-1 separate from the minelayer 20 may pull the first cable 30 towards the offshore R side. For example, the vessel 20-1 separate from the minelayer 20 may move towards the offshore R side and pull the first cable 30 towards the offshore side. In this case, the pulling direction of the first cable 30 is changed towards the shore Q side by the direction changing device 40, and the underwater Gb pipeline 10 is pulled towards the shore side via the first cable 30.

[0021] The construction system 1 may include a reaction force member (reaction force pile) 50 for the direction changing device 40 to obtain a reaction force. The reaction force member 50 can be a member that receives the reaction force from the direction changing device 40. The reaction force member 50 is connected to the direction changing device 40 as shown in Figure 1, etc. Although one reaction force member 50 is shown in Figure 1, etc., the number of reaction force members 50 is not limited to one, and two or more may be provided. Since the direction changing device 40 receives a reaction force from the reaction force member 50, the direction changing device 40 can be made less likely to move even if it is pulled by the first cable-like body 30.

[0022] The reaction force member 50 may be a pile 51 driven into the seabed ground (seabed) Ga. Since the pile 51 is driven into the seabed ground Ga, the pile 51 is firmly fixed to the seabed ground Ga. This makes it difficult for the direction changing device 40 to move even when pulled by the first cable-like body 30. The reaction force member 50 may be, for example, an anchor (not shown), a gravity foundation (not shown), or a jacket (not shown).

[0023] The direction changing device 40 may have a sheave (pulley) 41. The first cord-like body 30 is wrapped around the sheave 41. This allows the tensile direction of the first cord-like body 30 to be changed by the sheave 41.

[0024] A towed member 60 may be attached to the portion of the pipeline 10 opposite to the laying vessel 20 (first portion) 11. The towed member 60 is attached to the first portion 11 of the pipeline 10 on the towing direction D1 side (downstream side). The towed member 60 is also called a "pulling head." The towed member 60 is the member that is pulled when the pipeline 10 is pulled. When the towed member 60 is pulled in the sending direction (pulling direction D1), the pipeline 10 is sent out into the water Gb.

[0025] The traction member 60 comprises a joint portion 61, a connecting portion 62, and a main body portion 63. The joint 61 is joined to the first portion 11 of the pipeline 10, for example, by flange joining or welding. In the case of a flange joint type in which the tractioned member 60 is joined to the pipeline 10 by a flange joint, the joint portion 61 of the tractioned member 60 is joined to the flange joint portion of the first portion 11 of the pipeline 10. In the welded type where the towed member 60 is joined to the pipeline 10 by welding, the joint portion 61 of the towed member 60 is joined to the first portion 11 of the pipeline by welding. The welding of the joint portion 61 of the towed member 60 to the first portion 11 of the pipeline 10 can be performed using well-known welding methods such as arc welding or TIG welding.

[0026] The connecting portion 62 is, for example, a pad eye. The connecting portion 62 is connected to the first rope-like body 30 for pulling the pipeline 10.

[0027] The main body 63 is positioned between the joint 61 and the connecting part 62 in the longitudinal direction of the tractioned member 60. The main body 63 is, for example, cylindrical in shape, and is designed to allow water to flow inside. The main body 63 and the joint 61 are firmly connected, for example, by welding.

[0028] During the laying of pipeline 10, for example, when connecting pipeline 10 to a pipe that connects to an offshore platform, water (seawater) may be injected into the inside of pipeline 10. The towed member 60 may be equipped with a valve 64 for injecting water into the inside of the main body 63.

[0029] Since the first cable-like body 30 is connected to the towed member 60, the towed member 60 can be used as the part to which the first cable-like body 30 is connected, and there is no need to provide a part to which the first cable-like body 30 is connected in the pipeline 10 itself.

[0030] The construction system 1 may include a swivel 65 provided between the cable-like body (first cable-like body) 30 and the tractioned member 60. The first cable-like body 30 and the towed member 60 are connected by a swivel 65. This allows the first cable-like body 30 and the towed member 60 to be rotatably connected, making it difficult for the first cable-like body 30 to twist.

[0031] As shown in Figure 3, the construction system 1 may include a second cable-like body 70 between the first section 11 and the reaction member 50. The second cable-like body 70 is, for example, a wire. Figure 3 shows the pipeline 10 laid to a predetermined position on the shore Q side. In Figure 3, a towed member 60 is attached to the first section 11, and one end 71 of the second cable-like body 70 is attached to the towed member 60. Alternatively, one end 71 of the second cable-like body 70 may be attached to the towed member 60 via a shackle attached to the towed member 60. The other end 72 of the second cable-like body 70, opposite to the one end 71, may be attached to the reaction force member 50. Alternatively, the other end 72 of the second cable-like body 70 may be attached to a cable-like body (third cable-like body) 75 connecting the reaction force member 50 and the direction changing device 40, as shown in Figure 3. The third cable-like body 75 is, for example, a wire. The direction changing device 40 may be attached to the reaction force member 50.

[0032] The second rope-like body 70 is used when the pipeline 10 has been laid to a predetermined position on the shore Q side, and limits the distance between the first portion 11 of the pipeline 10 and the reaction force member 50. Since the second rope-like body 70 is used to limit the distance between the first portion 11 of the pipeline 10 and the reaction force member 50, it is sufficient for the length to prevent the distance from exceeding a predetermined distance. The second rope-like body 70 is shorter than the first rope-like body 30. By providing the second rope-like body 70, the movement of the first portion 11 of the pipeline 10 toward the offshore R side can be restricted.

[0033] The vessel 20-1 may be the minelayer vessel 20. In this case, it is not necessary to prepare a separate vessel 20-1 from the minelayer vessel 20. Also, in this case, as shown in Figure 1, the portion 10A of the pipeline 10 located outside the minelayer vessel 20 and the first cable-like body 30 may be misaligned when viewed along the vertical direction (Z direction). Viewed along the vertical, the pipeline 10, towed from the laying vessel 20 towards the shore Q, follows the towing direction D1, while the first cable-like body 30A(30), towed from the direction-changing device 40 to the laying vessel 20, follows the return direction D2. This misalignment prevents interference between the pipeline 10 and the first cable-like body 30. The first cable-like body 30A is the portion of the first cable-like body 30 from the direction-changing device 40 to the position where it is towed by the laying vessel 20 (from the position of the direction-changing device 40 to the return position P2). As shown in Figure 4, even when the vessel 20-1 is a different vessel from the laying vessel 20, the portion 10A of the pipeline 10 located outside the laying vessel 20 and the first cable-like body 30A are misaligned when viewed along the vertical direction. This prevents interference between the pipeline 10 and the first cable-like body 30.

[0034] The first rope 30 may be connected to one side of the laying vessel 20 in the width direction (Y direction). As shown in Figure 1, the first rope 30 is connected, for example, to a return position P2. A towing device (e.g., a winch) 24 is installed at the return position P2. The first rope 30 is towed by the towing device 24. The towing device 24 is adjustable in towing speed to provide the first rope 30 with an appropriate towing speed. In construction system 1, the traction device 24 pulls the first cable 30 towards the offshore R side, causing the tension direction of the first cable 30 to be changed towards the shore Q side by the direction changing device 40, and the underwater Gb pipeline 10 is pulled towards the shore Q side via the first cable 30. Thus, because construction system 1 is equipped with a direction changing device 40, the tension direction of the first cable 30 can be changed. This allows the pipeline 10 to be laid towards the shore Q side.

[0035] Furthermore, when the laying vessel 20 moves to the offshore R side and pulls the first cable 30 towards the offshore R side (return direction D2 side), the pulling direction of the first cable 30 is changed to the shore Q side by the direction changing device 40, and the underwater Gb pipeline 10 is pulled towards the shore Q side (pulling direction D1 side) via the first cable 30. In this way, the construction system 1 is equipped with a direction changing device 40, which allows the pulling direction of the first cable 30 to be changed. This enables the pipeline 10 to be laid towards the shore Q side.

[0036] Alternatively, the underwater Gb pipeline 10 may be pulled towards the shore Q side via the first cable 30 by the towing device 24 pulling the first cable 30 toward the shore Q side. Or, the underwater Gb pipeline 10 may be pulled towards the shore Q side via the first cable 30 by the laying vessel 20 moving toward the shore Q side and pulling the first cable 30 toward the shore Q side.

[0037] Since the first cable 30 is connected to one side of the laying vessel 20 in the width direction, the portion 10A of the pipeline 10 located outside the laying vessel 20 and the first cable 30 are misaligned when viewed along the vertical direction. This prevents interference between the pipeline 10 and the first cable 30.

[0038] If the vessel 20-1 is separate from the laying vessel 20, the first cable 30 may be connected to the vessel 20-1, as shown in Figure 4. In this case, the vessel 20-1 may be equipped with a towing device 24. The towing device 24 installed on the vessel 20-1 pulls the first cable 30 towards the offshore R side. Since the first cable 30 is connected to the vessel 20-1, the portion 10A of the pipeline 10 located outside the laying vessel 20 and the first cable 30 are misaligned when viewed along the vertical direction. This prevents interference between the pipeline 10 and the first cable 30. The vessel 20-1, separate from the laying vessel 20, may also be fixed to the seabed Ga by an anchor (not shown). As mentioned above, the vessel 20-1 may be a self-propelled vessel or a non-self-propelled vessel (e.g., a barge). It should be noted that the minelayer 20 may not be a dedicated minelayer, but rather a barge equipped with anchors, winches, tensioners, welding sheds, etc.

[0039] The pipeline 10 is composed of multiple pipes 10S connected together. The pipe-laying vessel 20 may be equipped with a welding machine (welding line) 80, and the pipeline 10 may be formed by welding the multiple pipes 10S together on the pipe-laying vessel 20 using the welding machine 80.

[0040] Next, an example of a construction method S1 according to one embodiment of the present disclosure will be described. Figure 5 is a flowchart of an example of a construction method according to the present embodiment. The same reference numerals are used for parts that are the same as in the above embodiment, and their descriptions are omitted. The differences will be mainly described.

[0041] Construction method S1 is a method for laying the pipeline 10 on the seabed Ga using a laying vessel 20. Construction method S1 comprises a reaction member installation step S10, a direction changing device installation step S11, a cable-like body installation step S12, a towing step S13, a second cable-like body installation step S14, and a towing stop step S15.

[0042] Step S10, the step of installing the reaction force member, is the step of installing a reaction force member 50 for the direction changing device 40 to obtain a reaction force. The reaction force member 50 can be any member that obtains a reaction force from the direction changing device 40. The reaction force member 50 may be a pile 51 driven into the seabed ground (seabed) Ga. The reaction force member 50 may be, for example, an anchor (not shown), a gravity foundation (not shown), or a jacket (not shown). The reaction force member 50 is connected to the direction changing device 40 as shown in Figure 3, etc. Since the direction changing device 40 obtains a reaction force from the reaction force member 50, the direction changing device 40 can be made less likely to move even if it is pulled by the first cable-like body 30.

[0043] The direction-changing device installation step S11 is a step in which a direction-changing device 40 is installed to change the direction of tension of the first cable-like body 30 so that the underwater pipeline 10 of Gb is pulled towards the shore Q side via the first cable-like body 30 when the laying vessel 20 pulls the first cable-like body 30 towards the offshore R side.

[0044] When the laying vessel 20 pulls the first cable 30 towards the offshore R side (return direction D2 side), the pulling direction of the first cable 30 is changed towards the shore Q side by the direction changing device 40, and the pipeline 10 is pulled towards the shore Q side (pulling direction D1 side) via the first cable 30. In this way, since the construction method includes the direction changing device installation step S11, the pulling direction of the first cable 30 can be changed. This makes it possible to lay the pipeline 10 towards the shore Q side.

[0045] The cable-like body installation process (first cable-like body installation process) S12 is a process of installing a cable-like body (first cable-like body) 30 between the part of the pipeline opposite to the laying vessel 20 (vessel 20-1 in Figure 4) (first part) 11 and the laying vessel 20. The first cable-like body 30 is, for example, a wire. In the towing process S13, the laying vessel 20 pulls the first cable-like body 30 towards the offshore R side, thereby towing the underwater Gb pipeline 10 towards the shore Q side via the first cable-like body 30.

[0046] With this configuration, when towing the underwater Gb pipeline 10 towards the shore Q side, the minelayer 20 does not need to move towards the shore Q side, thus reducing the possibility of the minelayer 20 running aground.

[0047] The towing process S13 is a process in which the pipeline 10 of underwater Gb is towed towards the shore Q by the pipeline laying vessel 20. Since the pipeline 10 is towed towards the shore Q in the towing process S13, the pipeline 10 can be laid towards the shore Q. This reduces the possibility of the pipeline laying vessel 20 running aground even in shallow waters such as the shore Q. Furthermore, the construction method according to this embodiment can also solve the problem of reducing the need to install towing equipment on or near the shore Q. In addition, towing the pipeline 10 in the towing process S13 may include both moving the pipeline 10 toward the shore Q side and keeping the pipeline 10 in place toward the shore Q side. For example, in the towing process S13, applying tension to the first rope-like body 30 to restrict the pipeline 10 from flowing toward the offshore R side may also be included in towing the pipeline 10 in the towing process S13.

[0048] Step S14, the second cable-like body installation step, is the step of installing the second cable-like body 70 between the first part 11 and the reaction force member 50. The second cable installation step S14 is performed after the pipeline 10 has been laid to a predetermined position on the shore Q side. The second cable 70 limits the distance between the first portion 11 of the pipeline 10 and the reaction member 50. Since the second cable 70 is used to limit the distance between the first portion 11 of the pipeline 10 and the reaction member 50, it is sufficient for the length to prevent the distance from exceeding a predetermined distance. Therefore, the second cable installation step can restrict the movement of the first portion 11 of the pipeline 10 toward the offshore R side. In this embodiment, the traction step S13 is still in progress, and the first cable 30 also restricts the movement of the pipeline 10 toward the offshore R side.

[0049] The traction stop step S15 is a step in which the traction step S13 is stopped after the second cable installation step S14. In the traction stop step S15, the traction device 24 is stopped. By stopping the traction of the first cable 30 in the traction stop step S15, the traction of the pipeline 10 can be stopped while the pipeline 10 is anchored to the reaction force member 50 via the second cable 70.

[0050] The technical scope of this disclosure is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of this disclosure. For example, the direction changing device 40 only needs to be configured to change the tensile direction of the first cable-like body 30. For example, it may be a steel pipe with a circular cross-section. The tensile direction of the first cable-like body 30 may be changed by wrapping the first cable-like body 30 around the steel pipe. In this case, a pile 51 may be used as the steel pipe. The construction system 1 does not need to be equipped with the direction changing device 40. The construction system 1 does not require the direction changing device 40 to be equipped with a reaction force member 50 for obtaining a reaction force. In construction system 1, the reaction member 50 does not have to be a pile 51 driven into the seabed ground Ga. The construction system 1 does not require the direction changing device 40 to have a sheave. In construction system 1, the towed member 60 may be attached to the end of the pipeline 10. In construction system 1, the towed member may not be attached. The construction system 1 does not necessarily have to include a swivel 65 provided between the first cable-like body and the tractioned member 60. The construction system 1 does not necessarily need to include the second cord-like body 70. Ship 20-1 does not have to be minelayer 20. In the construction system 1, the portion 10A of the pipeline 10 located outside the laying vessel 20 and the first cable-like body 30 do not need to be misaligned when viewed along the vertical direction. The first rope-like body 30 may be connected to one end of the minelayer 20 in the width direction. The first rope-like body 30 does not have to be connected to one portion of the minelayer 20 in the width direction.

[0051] The construction method S1 does not necessarily include a direction changing device installation step S11, which involves installing a direction changing device 40 to change the direction of tension of the first rope-like body 30 so that the underwater Gb pipeline 10 is pulled towards the shore Q side via the first rope-like body 30 when the ship 20 pulls the first rope-like body 30 towards the offshore R side. The construction method S1 does not necessarily have to include a reaction member installation step S10 in which the direction changing device 40 provides a reaction member 50 for obtaining a reaction force. Construction method S1 does not necessarily have to include the second cable-like body installation step S14. In construction method S1, it is not necessary to tow the underwater Gb pipeline 10 towards the shore Q using the laying vessel 20.

[0052] (Note) The above embodiment can be understood, for example, as follows:

[0053] <1> A construction system according to one aspect of the present disclosure is a construction system for laying a pipeline on the seabed using a pipeline laying vessel, comprising a vessel for towing the underwater pipeline toward the shore.

[0054] This configuration allows pipelines to be laid on the shore side. This reduces the possibility of pipeline laying vessels running aground even in shallow areas such as the shore. Furthermore, the construction system according to this embodiment solves the problem of reducing the need to install towing equipment on or near the shore.

[0055] <2> the above <1> The construction system may include a cable-like body (first cable-like body) provided between the portion of the pipeline opposite to the vessel (first portion) and the vessel, and the vessel pulls the cable-like body (first cable-like body) towards the open sea, thereby pulling the underwater pipeline towards the shore via the cable-like body (first cable-like body).

[0056] This configuration eliminates the need for the ship to move toward the shore when towing the underwater pipeline, thus reducing the possibility of the ship running aground.

[0057] <3> the above <2> The construction system may be configured to include a direction changing device that changes the direction of tension of the cable (first cable) so that the underwater pipeline is pulled towards the shore via the cable (first cable) when the ship pulls the cable (first cable) towards the open sea.

[0058] With this configuration, the construction system is equipped with a direction-changing device, which allows the tensile direction of the cable-like body (first cable-like body) to be changed.

[0059] <4> the above <3> The construction system may employ a configuration in which the direction changing device is equipped with a reaction force member for obtaining a reaction force.

[0060] With this configuration, the direction changing device receives a reaction force from the reaction force member, making it difficult for the direction changing device to move even when pulled by the cable-like body (first cable-like body).

[0061] <5> the above <4> The construction system may adopt a configuration in which the reaction member is a pile driven into the seabed ground.

[0062] This configuration makes it difficult for the direction-changing device to move even when pulled by the cord-like body (first cord-like body).

[0063] <6> the above <3> from <5> The construction system relating to any one of the above may employ a configuration in which the direction changing device has a sheave and the cable-like body (first cable-like body) is wrapped around the sheave.

[0064] With this configuration, the tensile direction of the cord-like body (first cord-like body) can be changed by the sheave.

[0065] <7> the above <3> from <5> A construction system relating to any one of the above may adopt a configuration in which a traction member is attached to the above part (first part), and the cable-like body (first cable-like body) is connected to the traction member.

[0066] With this configuration, the traction member can be used as the part to connect the cable-like body (first cable-like body), eliminating the need to provide a part to connect the cable-like body (first cable-like body) in the pipeline itself.

[0067] <8> the above <7> The construction system may also employ a configuration that includes a swivel provided between the cable-like body (first cable-like body) and the tractioned member.

[0068] With this configuration, the cable-like body (first cable-like body) and the tractioned member are rotatably connected, making it difficult for the cable-like body (first cable-like body) to twist.

[0069] <9> the above <4> from <8> A construction system relating to any one of the above may include a second cord-like body provided between the portion (first portion) and the reaction member, wherein the second cord-like body may be configured to limit the distance between the portion (first portion) and the reaction member.

[0070] With this configuration, the distance between the pipeline portion (first portion) and the reaction member is limited by the second cable-like body, thereby restricting the movement of the first portion of the pipeline towards the open sea.

[0071] <10> the above <1> from <9> The construction system relating to any one of the above may adopt a configuration in which the vessel is the mine-laying vessel.

[0072] This configuration eliminates the need to prepare a separate vessel from the minelayer.

[0073] <11> the above <2> from <10> The construction system relating to any one of the above may employ a configuration in which the vessel is the laying vessel, and the portion of the pipeline located outside the laying vessel and the cable-like body (first cable-like body) are misaligned when viewed along the vertical direction.

[0074] This configuration prevents interference between the pipeline and the first cable-like structure.

[0075] <12> the above <2> from <11> The construction system relating to any one of the above may adopt a configuration in which the cable-like body (first cable-like body) is connected to one side of the ship in the width direction of the ship-laying vessel.

[0076] With this configuration, the portion of the pipeline located outside the laying vessel and the first cable-like structure are misaligned when viewed along the vertical direction, thus preventing interference between the pipeline and the first cable-like structure.

[0077] <13> A construction method according to one aspect of the present disclosure is a construction method for laying a pipeline on the seabed using a pipeline laying vessel, comprising a towing step of pulling the underwater pipeline toward the shore using the vessel.

[0078] With this configuration, the pipeline is pulled towards the shore during the towing process, allowing the pipeline to be laid on the shore side. This reduces the possibility of the pipeline laying vessel running aground even in shallow areas such as the shore. Furthermore, the construction system according to this embodiment also solves the problem of reducing the need to install towing equipment on or near the shore.

[0079] <14> the above <13> The construction method relating to this may include a cable installation step in which a cable-like body (first cable-like body) is installed between the portion of the pipeline opposite to the vessel (first portion) and the vessel, and the towing step may adopt a configuration in which the vessel pulls the cable-like body (first cable-like body) towards the open sea, thereby towing the underwater pipeline towards the shore via the cable-like body (first cable-like body).

[0080] This configuration eliminates the need for the ship to move toward the shore when towing the underwater pipeline, thus reducing the possibility of the ship running aground.

[0081] <15> the above <14> The construction method may include a configuration comprising a step of installing a direction changing device, which changes the direction of tension of the cable (first cable) so that the underwater pipeline is pulled towards the shore via the cable (first cable) when the ship pulls the cable (first cable) towards the open sea.

[0082] With this configuration, the construction method includes a step for installing a direction-changing device, which allows the tensile direction of the cable-like body (first cable-like body) to be changed.

[0083] <16> the above <15> The construction method for the aforementioned direction changing device may include a step of installing a reaction force member to provide a reaction force member for obtaining a reaction force.

[0084] With this configuration, the direction changing device receives a reaction force from the reaction force member, making it difficult for the direction changing device to move even when pulled by the cable-like body (first cable-like body).

[0085] <17> the above <16> The construction method relating to this includes a second cable installation step of providing a second cable between the aforementioned part (first part) and the reaction member, and the second cable may be configured to limit the distance between the aforementioned part (first part) and the reaction member.

[0086] With this configuration, the distance between the pipeline portion (first portion) and the reaction member is limited by the second cable-like body, thereby restricting the movement of the pipeline portion (first portion) toward the open sea.

[0087] <18> the above <17> The construction method may also include a traction stop step in which the traction step is stopped after the second cable installation step.

[0088] With this configuration, the towing of the pipeline can be stopped by stopping the towing of the first cable-like body through the towing stop process.

[0089] <19> the above <13> from <18> The construction method relating to any one of the above may be configured such that the vessel is the laying vessel, and the towing process involves the laying vessel towing the underwater pipeline toward the shore.

[0090] This configuration eliminates the need to prepare a separate vessel from the minelayer. [Explanation of Symbols]

[0091] 1.1A Construction System 10 pipelines 11 parts (1st part) 20 minelayer 20-1 Ship 24 Traction device 30 Funicular body (1st funicular body) 40 Directional change device 41 Sieve 50 Reaction members 51 stake 60 Towed member 65 Swivel 70 Second funicular body 75 Funicular body (3rd funicular body) 80 Welding machines (welding lines) D1 Traction direction D2 Return direction P1 starting position P2 Return position Q shore R Oki S1 Construction method S10 Reaction member installation process S11 Direction change device installation process S12 Cable installation process S13 Towing process S14 Second cable installation process S15 Traction stop process

Claims

1. A construction system for laying pipelines on the seabed using a pipeline laying vessel, A vessel to tow the aforementioned underwater pipeline toward the shore, A cable-like body is provided between the portion of the pipeline opposite to the vessel and the vessel, Equipped with, A construction system in which the vessel pulls the cable-like body offshore, thereby pulling the underwater pipeline towards the shore via the cable-like body.

2. The construction system according to claim 1, further comprising a direction changing device for changing the direction of tension of the cable such that the vessel pulls the cable toward the open sea, thereby pulling the underwater pipeline toward the shore via the cable.

3. The construction system according to claim 2, wherein the direction changing device is equipped with a reaction force member for obtaining a reaction force.

4. The construction system according to claim 3, wherein the reaction member is a pile driven into the seabed ground.

5. The aforementioned direction changing device has a sheave, The construction system according to any one of claims 2 to 4, wherein the cable-like body is wrapped around the sheave.

6. A traction member is attached to the aforementioned portion. The construction system according to any one of claims 2 to 4, wherein the cable-like body is connected to the traction member.

7. The construction system according to claim 6, further comprising a swivel provided between the cable-like body and the tractioned member.

8. A second cord-like body is provided between the aforementioned portion and the reaction force member, The construction system according to claim 3 or 4, wherein the second cord-like body limits the distance between the portion and the reaction force member.

9. The construction system according to any one of claims 1 to 4, wherein the vessel is the laying vessel.

10. The aforementioned vessel is the aforementioned minelayer, The construction system according to any one of claims 1 to 4, wherein the portion of the pipeline located outside the laying vessel and the cable-like body are misaligned when viewed along the vertical direction.

11. The construction system according to claim 10, wherein the cable-like body is connected to one side of the ship in the width direction of the ship-laying vessel.

12. A construction method for laying a pipeline on the seabed using a pipeline laying vessel, A towing process involves pulling the underwater pipeline toward the shore using a ship, A rope-like structure is installed between the portion of the pipeline opposite to the vessel and the vessel, in a rope-like structure installation step. Equipped with, The towing step is a construction method in which the vessel pulls the cable-like body offshore, thereby towing the underwater pipeline towards the shore via the cable-like body.

13. The construction method according to claim 12, further comprising a step of installing a direction changing device, which changes the direction of tension of the cable such that the vessel pulls the cable toward the open sea, thereby pulling the underwater pipeline toward the shore via the cable.

14. The construction method according to claim 13, wherein the direction changing device includes a step of installing a reaction force member for obtaining a reaction force.

15. The process includes a second cable installation step in which a second cable-like body is provided between the aforementioned portion and the reaction force member, The construction method according to claim 14, wherein the second cord-like body limits the distance between the portion and the reaction force member.

16. The construction method according to claim 15, further comprising a traction stop step in which the traction step is stopped after the second cable-like body installation step.

17. The aforementioned vessel is the aforementioned minelayer, The construction method according to any one of claims 12 to 16, wherein the towing step involves towing the underwater pipeline toward the shore using the laying vessel.

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