JP2025001735A - Method for manufacturing cable laying structure, cable connection intermediate body, and cable laying structure - Google Patents

Abstract

[Problem] To stably connect a dynamic cable and above-water equipment. [Solution] A method for manufacturing a cable laying structure includes the steps of: preparing a static cable by pulling up an end of a static cable laid on the bottom of the water onto a laying ship; connecting the static cable and the dynamic cable with a joint on the laying ship; introducing the static cable, joint, and dynamic cable into the water in that order; and connecting the dynamic cable to a floating above-water equipment. [Selected Figure] Figure 1

Description

The present disclosure relates to a method for manufacturing a cable installation structure, a cable connection intermediate, and a cable installation structure.

A dynamic cable (also called a riser cable) is connected to the floating water facility in a bendable manner underwater (for example, Patent Document 1).

Japanese Patent Application Publication No. 3-143216

The objective of this disclosure is to stably connect dynamic cables and above-water facilities.

According to one aspect of the present disclosure,
a step of lifting an end of the static cable laid on the bottom of the water onto a laying ship and preparing the static cable;
connecting the static cable and the dynamic cable with a joint on the laying ship;
introducing the static cable, the joint and the dynamic cable in this order into water;
connecting the dynamic cable to a floating surface installation;
A method for manufacturing a cable laying structure is provided.

This disclosure allows for a stable connection between dynamic cables and above-water facilities.

FIG. 1 is a flow chart illustrating a method for manufacturing a cable pulling structure according to one embodiment of the present disclosure. FIG. 2 is a schematic diagram showing a part of a method for manufacturing a cable laying structure. FIG. 3 is a schematic diagram showing a part of a method for manufacturing a cable laying structure. FIG. 4 is a schematic side view showing the bending restraint portion. FIG. 5 is a schematic diagram showing a part of a method for manufacturing a cable laying structure. FIG. 6 is a schematic diagram showing a part of a method for manufacturing a cable laying structure. FIG. 7 is a schematic diagram showing a part of a method for manufacturing a cable laying structure. FIG. 8A is a schematic diagram showing a portion of a cable connection intermediate body. FIG. 8B is a schematic diagram showing a portion of the cable connection intermediate body. FIG. 9 is a schematic diagram showing a part of a method for manufacturing a cable laying structure. FIG. 10 is a schematic diagram showing a part of a manufacturing method of a cable laying structure. FIG. 11 is a schematic diagram illustrating a cable laying structure according to one embodiment of the present disclosure. FIG. 12 is a schematic side view showing a bending suppression portion according to the first modification. FIG. 13A is a schematic diagram showing a part of a manufacturing method of a cable laying structure according to the second modification. FIG. 13B is a schematic diagram showing a part of a manufacturing method of a cable laying structure according to the third modification.

[Description of the embodiments of the present disclosure]
<Findings gained by the inventors>
First, the findings of the present inventors will be described.

When connecting a dynamic cable to above-water facilities, it is necessary to stably connect the static cable, which has been laid on the bottom of the water in advance, the dynamic cable, and the above-water facilities.

In these cases, the following problems could arise during each process:

(i) Introducing the static cable into the water First, the terminal of the static cable, which has been laid on the bottom of the water, is pulled up onto the laying ship. On the laying ship, the pulled up static cable is connected to the dynamic cable. After that, the static cable is introduced into the water again.

At this time, the load of the static cable from the ship to the bottom of the water may cause excessive load to be applied to at least one of the joints and the dynamic cable on the laying ship. This may cause at least one of the joints and the dynamic cable to bend excessively.

(ii) Introduction of the joint into water The static cable and the dynamic cable are connected by a specified joint. The joint is constructed to be stronger than the cable. Therefore, when the joint is introduced into water through a curved chute provided at the stern, it is difficult for the joint to follow the chute. As a result, at least one of the static cable and the dynamic cable near the joint may bend excessively.

When connecting a dynamic cable to a surface facility, accessories such as the bend restraint section (described below) through which the dynamic cable passes may be fixed on the installation ship. This means that the dynamic cable cannot be flexibly bent as the joint is reoriented toward the water. As a result, at least one of the static cable and the dynamic cable near the joint is prone to localized excessive bending.

(iii) Bottom Landing Point of Dynamic Cable After the dynamic cable is introduced into the water, the area around the bottom landing point of the dynamic cable may be damaged due to friction with the bottom of the water as the dynamic cable changes its linearity. If the outer circumference of the dynamic cable is damaged, the insulation properties of the dynamic cable may be affected.

(iv) Connection of Bend Restraint Section When connecting a dynamic cable to an above-water facility, a bend restraint section that restrains bending of the dynamic cable may be installed in an area close to the lower end of the above-water facility.

Here, when the dynamic cable is connected to the floating facility, linear movement of the dynamic cable occurs due to tides. Alternatively, the floating floating facility floats on the water due to tides or wind.

Under such circumstances, if the bending restraint unit is arranged to be movable at any position on the dynamic cable, there is a possibility that the bending restraint unit may shift from the actual intended installation position due to the above-mentioned linear movement of the dynamic cable or the floating of the floating surface equipment. If the bending restraint unit shifts from the intended installation position, a diver will need to adjust the position of the bending restraint unit underwater. This may make it difficult to connect the bending restraint unit to the bottom end of the surface equipment.

On the other hand, a method can be considered in which the bending restraint section is placed at any position on the dynamic cable and towed with a towing wire. However, with this method, it is necessary to retrieve the towing wire after connecting the bending restraint section to the surface equipment.

This can lead to an unstable or complicated mechanism for attaching and detaching the towing wire. For example, a structure could be considered in which the towing wire is retrieved by breaking the locking portion of the towing wire. However, in this case, there is a risk that the broken pieces of the locking portion may get into the cable insertion hole of the bend suppression portion.

As a result of intensive research by the inventors based on the new problems (i) to (iv) above, the inventors have discovered a method and configuration that can stably connect static cables, dynamic cables, and above-water facilities.

The following disclosure is based on the above findings of the inventors.

<Embodiments of the present disclosure>
The embodiments of the present disclosure will be listed and described.

[1] A method for manufacturing a cable laying structure according to one aspect of the present disclosure includes:
a step of lifting an end of the static cable laid on the bottom of the water onto a laying ship and preparing the static cable;
connecting the static cable and the dynamic cable with a joint on the laying ship;
introducing the static cable, the joint and the dynamic cable in this order into water;
connecting the dynamic cable to a floating surface installation;
Equipped with.
This configuration enables the static cable, the dynamic cable, and the above-water facility to be connected stably.

[2] In the manufacturing method of the cable laying structure described in [1] above,
The step of preparing a static cable includes:
gripping the static cable with a stopper;
A step of lifting the stopper by a wire so that the stopper bears at least a part of the load of the static cable;
has.
With this configuration, it is possible to prevent excessive load from being placed on the cable due to the load of the static cable from the installation ship to the bottom of the water.

[3] In the manufacturing method of the cable laying structure according to the above [1] or [2],
The step of introducing the static cable, the joint and the dynamic cable into water in this order includes:
a step of lifting the vicinity of the joint using a lifting balance in which the joint, the static cable and the dynamic cable at positions near both ends of the joint are supported by slings;
a step of gradually changing a direction of the joint into the water while paying out the static cable into the water in a state in which the vicinity of the joint is supported by the hanging balance;
has.
With this configuration, it is possible to prevent at least one of the static cable and the dynamic cable in the vicinity of the joint from bending excessively.

[4] In the method for manufacturing a cable laying structure according to any one of [1] to [3] above,
The step of introducing the static cable, the joint and the dynamic cable into water in this order includes:
The method includes a step of attaching a protective tube for protecting the dynamic cable to the outer periphery of a region including a bottom landing point where the dynamic cable contacts the bottom of the water.
With this configuration, damage to the dynamic cable can be suppressed.

[5] In the method for manufacturing a cable laying structure according to any one of [1] to [4] above,
a step of connecting by the joint;
the step of introducing the static cable, the joint and the dynamic cable into water in this order;
This is carried out with the dynamic cable inserted into a cylindrical bending restraint section that restrains bending of the dynamic cable in an area near the lower end of the above-water equipment.
This configuration can simplify underwater work for divers.

[6] In the manufacturing method of the cable laying structure described in [5] above,
The step of connecting the dynamic cable to the surface facility includes:
determining a planned installation position of the bend restraint unit on the dynamic cable based on a length of the dynamic cable underwater and a current position of the floating surface equipment;
a step of temporarily fixing the bending suppression portion at the intended installation position;
pulling the dynamic cable with the bend restraint portion attached into the surface facility and fixing the bend restraint portion to the surface facility;
has.
This configuration makes it possible to carry out the surface equipment connection process smoothly and stably.

[7] In the manufacturing method of the cable laying structure described in [6] above,
In the step of specifying a planned installation position,
A position confirmation portion is provided on the outer periphery of the dynamic cable to enable visual confirmation of the intended installation position.
According to this configuration, the planned installation position of the bending restraint portion can be easily grasped.

[8] In the manufacturing method of the cable laying structure according to the above [6] or [7],
In the step of temporarily fixing the bending suppression portion,
A positional deviation control section for controlling positional deviation of the bending suppression section in the axial direction of the dynamic cable is arranged at least at a position close to a first axial end of the bending suppression section and a position close to a second end opposite the first end, so as to surround the outer periphery of the dynamic cable.
According to this configuration, it is possible to restrict deviation of the bending restraint portion from its intended installation position.

[9] In the method for manufacturing a cable laying structure according to any one of [1] to [8] above,
The step of connecting by the joint includes:
The method includes providing a bending restraint portion surrounding the outer periphery of the static cable or the dynamic cable to restrain bending of the static cable or the dynamic cable in a region close to an axial end of the joint.
This configuration makes it possible to suppress local and excessive bending of the static or dynamic cable in a region near the axial end of the joint.

[10] A cable connection intermediate according to one embodiment of the present disclosure,
A dynamic cable that is laid underwater and connected to a surface facility;
a bending suppression portion provided around an outer periphery of the dynamic cable and configured to suppress bending of the dynamic cable in a region close to a lower end of the above-water facility;
a position confirmation section provided on an outer periphery of the dynamic cable, the position confirmation section being capable of visually confirming a planned installation position of the bending restraint section;
Equipped with.
According to this configuration, the planned installation position of the bending restraint portion can be easily grasped.

[11] A cable connection intermediate according to one embodiment of the present disclosure,
A dynamic cable that is laid underwater and connected to a surface facility;
a bending suppression portion provided around an outer periphery of the dynamic cable and configured to suppress bending of the dynamic cable in a region close to a lower end of the above-water facility;
a positional deviation prevention member that is provided to surround an outer periphery of the dynamic cable at a position near a first end of the bending suppression portion in the axial direction and/or a position near a second end opposite to the first end, and that prevents the bending suppression portion from misaligning in the axial direction of the dynamic cable;
Equipped with.
According to this configuration, it is possible to restrict deviation of the bending restraint portion from its intended installation position.

[12] A cable laying structure according to one aspect of the present disclosure,
A static cable laid on the bottom of the water,
A dynamic cable that is laid underwater and connected to a floating surface facility;
a joint connecting the static cable and the dynamic cable;
Equipped with.
This configuration enables the static cable, the dynamic cable, and the above-water facility to be connected stably.

[13] In the cable laying structure described in [12] above,
The joint further includes a bending restraint portion that surrounds the outer periphery of the static cable or the dynamic cable and restrains bending of the static cable or the dynamic cable in a region close to an axial end of the joint.
This configuration makes it possible to suppress local and excessive bending of the static or dynamic cable in a region near the axial end of the joint.

[14] A cable laying structure according to one aspect of the present disclosure,
A dynamic cable that is laid underwater and connected to a floating surface facility;
a protective tube provided around an outer periphery of a region including a bottom landing point of the dynamic cable, the protective tube protecting the dynamic cable;
Equipped with.
With this configuration, damage to the dynamic cable can be suppressed.

[15] A cable laying structure according to one aspect of the present disclosure,
A dynamic cable that is laid underwater and connected to a floating surface facility;
a bending suppression portion provided around an outer periphery of the dynamic cable and configured to suppress bending of the dynamic cable in a region close to a lower end of the above-water facility;
a position confirmation portion provided on an outer periphery of the dynamic cable, the position confirmation portion being capable of visually confirming an installation position of the bending restraint portion;
Equipped with.
According to this configuration, unintended misalignment of the bending restraint portion can be immediately detected.

[Details of the embodiment of the present disclosure]
Next, an embodiment of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

<One embodiment of the present disclosure>
(1) Manufacturing method of cable laying structure (cable laying method)
A method for manufacturing a cable laying structure 10 according to this embodiment will be described with reference to FIGS.

[term]
Hereinafter, the static cable 120 may be abbreviated as "ST cable 120." The dynamic cable 140 may be abbreviated as "DM cable 140." The ST cable 120 and the DM cable 140 may be collectively referred to as "cable."

In the following, the "axial direction" of a cable refers to the direction along the central axis of the cable, and in some cases can be rephrased as the "longitudinal direction." The "radial direction" of a cable refers to the direction from the central axis of the cable toward the outer periphery, and in some cases can be rephrased as the "short direction." The "circumferential direction" of a cable refers to the direction along the outer periphery of the cable. The "cable laying direction" refers to the direction in which the cable is laid.

The same terminology as for cables can also be used for other linear or tubular components used in the manufacturing process.

[Connection target]
In the manufacturing method of the cable laying structure 10 of this embodiment, objects to be connected to each other include an ST cable 120, a DM cable 140, and an above-water facility 90.

(ST Cable)
The ST cable 120 is, for example, laid on the bottom of the water in advance. The ST cable 120 is, for example, configured as a CV cable (Cross-Linked Polyethylene insulated vinyl chloride sheath cable, also called an XLPE cable).

Specifically, the ST cable 120 has, for example, from the central axis to the outer periphery, a cable core, an interposer (not shown), a pressure tape (not shown), a seat tape (not shown), an iron wire exterior (armor) (not shown), and a corrosion protection layer (outer sheath) (not shown). The cable core has, for example, a conductor (not shown), an inner semiconductive layer (not shown), an insulating layer (not shown), an outer semiconductive layer (not shown), a semiconductive tape (not shown), a copper wire (not shown), a pressure tape (not shown), and a sheath (not shown). Note that a plurality of cable cores may be provided. When the ST cable 120 has a lead sheath, the sheath corresponds to the lead sheath as a water-impermeable layer and shielding layer, and a semiconductive tape is wound on the lead sheath. When the ST cable 120 does not have a lead sheath, the sheath contains polyethylene. The polyethylene constituting the sheath may be semiconductive.

(DM cable)
The DM cable 140 is, for example, laid to connect the ST cable 120 and the above-water facility 90 and rise vertically upward from the bottom of the water toward the above-water facility 90. The DM cable 140 is configured as a CV cable like the ST cable 120, except that, for example, the lead sheath is replaced with a copper wire shield as a shielding layer and a copper laminate or aluminum laminate as a water-blocking layer.

The DM cable 140 before installation is stored on the installation ship 80.

(Water facilities)
The water facility 90 is configured as a facility that performs at least one of power generation, power transmission, power transformation, and power distribution on the ocean (on the water). Specifically, the water facility 90 is, for example, an offshore wind power generation facility, an offshore power transformation facility, etc. Note that the location where the water facility 90 is provided may be, for example, not only the ocean, but also a lake, a river, etc.

[Laying ship]
The manufacturing method of the cable laying structure 10 of this embodiment is carried out mainly using a cable laying ship 80, for example.

As shown in Figures 2, 3, 4, etc., the cable laying ship 80 has, for example, a turntable (cable storage area) 820, a chute 840, a hoist 860, a winch 870, a bending suppression unit fixing unit 880, and a control unit 810.

The turntable 820 stores the DM cable 140 in a wound state, for example, on the cable laying ship 80.

The chute 840 is configured, for example, at the rear end (stern) of the cable laying vessel 80 to form an arc-shaped path for introducing the cable into the water and to send the cable out into the water.

The hoist 860 is configured to be supported, for example, by a sling 862 near the joint 300. Furthermore, the hoist 860 is configured to be movable, for example, along the cable laying direction on the cable laying ship 80.

The winch 870 is configured, for example, to pull a stopper 124 (described below) attached to a cable using a wire 126.

The bending suppression unit fixing unit 880 is configured to fix the bending suppression unit 200, for example, on the laying ship 80.

The control unit 810 is configured to control, for example, each part of the cable laying ship 80.

[Method of manufacturing cable installation structure]
As shown in FIG. 1, the manufacturing method of the cable laying structure 10 of this embodiment includes, for example, an ST cable preparation process S100, a cable connection process S200, a cable underwater introduction process S300, and an above-water facility connection process S400.

Sweet
[S100: ST cable preparation process]
First, as shown in FIG. 1, the terminal of the ST cable 120 laid on the bottom of the water is prepared on the cable laying ship 80.

The ST cable preparation process S100 in this embodiment includes, for example, an ST cable lifting process S120, a stopper gripping process S140, and an ST cable load bearing process S160.

(S120: Cable pulling process)
The terminal of the ST cable 120 is pulled up from the bottom of the water onto the cable laying ship 80.

Specifically, for example, a diver dives to the bottom of the water and hooks a wire (not shown) to a towing jig attached to the end of the ST cable 120. The wire is pulled by a winch (not shown) on the laying ship 80, thereby pulling the end of the ST cable 120 onto the laying ship 80 (recovering the end).

(S140: Stopper gripping process)
When the ST cable pulling up step S120 is completed, the ST cable 120 is gripped by a stopper 124 as shown in FIG.

The stopper 124 is configured to be detachable from the ST cable 120, for example. This allows the stopper 124 to be removed from the ST cable 120 when it is no longer needed.

Specifically, the stopper 124 is composed of, for example, a linear member (sling) wound around the outer circumference of the ST cable 120. The linear member has, for example, a first spiral portion wound in a spiral shape around the outer circumference of the ST cable 120, a turn-back point folded back at a predetermined position on the outer circumference of the ST cable 120, and a second spiral portion folded back from the turn-back point in a direction intersecting with the first spiral portion and wound in a spiral shape.

Alternatively, the stopper 124 may be formed, for example, from a cylindrical member formed by joining a pair of halves that surround the outer circumference of the ST cable 120.

In this embodiment, for example, two stoppers 124 (stopper 124a and stopper 124b, starting from the one closest to the bottom) are attached at a predetermined distance in the axial direction of the ST cable 120.

(S160: ST cable load bearing process)
3, while gradually introducing the ST cable 120 into the water, the stopper 124 is lifted by the wire 126, so that at least a part of the load of the ST cable 120 is borne by the stopper 124. This makes it possible to prevent excessive load from being applied to the cable due to the load of the ST cable 120 from the top of the laying ship 80 to the bottom of the water.

In this embodiment, a winch 870 provided on the middle level of the laying ship 80 is used to hoist the lower stopper 124a with a wire 126a. Furthermore, a winch (not shown) provided on the upper level of the laying ship 80 is used to hoist the upper stopper 124b with a wire 126b. By using two stoppers 124 to bear the load of the ST cable 120 in this way, even if the gripping force of one stopper 124 decreases, the ST cable 120 can be supported by the other stopper 124. In other words, the safety of the ST cable load bearing process S160 can be improved.

Once the load of the ST cable 120 has been borne by the stopper 124, the ST cable 120 is cut at a predetermined position, leaving the necessary length of the ST cable 120 for the cable connection process S200 described below.

[S200: Cable connection process]
When the ST cable preparation step S100 is completed, the ST cable 120 and the DM cable 140 are connected by a joint 300 on the cable laying ship 80, as shown in FIG.

The joint 300 has a certain rigidity to withstand impacts when laid on the bottom of the water. Specifically, the joint 300 has, for example, a conductor connection tube (not shown), a rubber unit (not shown), a metal tube (not shown), and an iron wire retaining portion (not shown). The conductor connection tube connects, for example, the conductor of the ST cable 120 and the conductor of the DM cable 140. The rubber unit is provided, for example, to surround the outer periphery of the area including the conductor connection tube, and is configured to ensure insulation around the area. The metal tube is provided, for example, to surround the outer periphery of the area including the rubber unit, and protects the rubber unit. The iron wire retaining portion is provided, for example, at both ends of the metal tube, and is configured to retain the iron wire exterior of the ST cable 120 and the iron wire exterior of the DM cable 140, respectively.

At this time, in this embodiment, the cable connection process S200 (and the cable underwater introduction process S300 described below) is performed with the DM cable 140 inserted through the cylindrical bending suppression section 200.

As shown in FIG. 4, the bending suppression section 200 is configured to suppress bending of the DM cable 140, for example, in an area close to the lower end of the surface facility 90. By using the bending suppression section 200, the DM cable 140 can be made more difficult to bend than a cable that does not have a bending suppression section. This makes it possible to suppress bending of the DM cable 140 at a radius of curvature smaller than the allowable radius of curvature.

Specifically, the bending suppression section 200 is configured as, for example, a so-called bend stiffener 200a. The bend stiffener 200a has, for example, a cylindrical section 212 and a flange section 214. One axial end of the bend stiffener 200a is referred to as a "first end," and the end opposite the first end is referred to as a "second end."

The cylindrical portion 212 is formed in a cylindrical shape so as to surround the outer circumference of the DM cable 140. The cylindrical portion 212 is not split in half. This simplifies the work of a diver connecting the bend stiffener 200a to the surface equipment 90 underwater.

The cylindrical portion 212 has, for example, a cable insertion hole 211 as a hollow portion. The DM cable 140 is inserted into the cable insertion hole 211. The inner diameter of the cable insertion hole 211 is larger than the outer diameter of the DM cable 140. This allows the DM cable 140 to move in the axial direction of the cable insertion hole 211 within the cable insertion hole 211.

The cylindrical portion 212 includes, for example, an elastic material. Examples of the elastic material of the cylindrical portion 212 include polyurethane. By making the cylindrical portion 212 out of such a material, bending of the DM cable 140 can be elastically suppressed.

The cylindrical portion 212 has, for example, a truncated cone shape. That is, the cylindrical portion 212 gradually expands in diameter from the first end to the second end in the axial direction of the cylindrical portion 212. This allows the DM cable 140 to bend to a certain extent in the area close to the first end of the cylindrical portion 212. On the other hand, the DM cable 140 becomes gradually more difficult to bend as it approaches the second end of the cylindrical portion 212.

The flange 214 is provided, for example, at the enlarged second end of the cylindrical portion 212. The flange 214 is, for example, disk-shaped and is provided so as to expand in the radial direction of the cylindrical portion 212.

The flange portion 214 has, for example, a bolt insertion hole (not shown). A bolt (not shown) that fixes the bend stiffener 200a to the lower end of the above-water equipment 30 is inserted into the bolt insertion hole.

The bend suppression unit 200 configured as the above-mentioned cylindrical bend stiffener 200a is placed on the bend suppression unit fixing unit 880 on the laying ship 80, for example, with the DM cable 140 inserted therethrough, and fixed to the bend suppression unit fixing unit 880. As a result, the payout path of the DM cable 140 is determined to be a horizontal straight line on the laying ship 80. The following cable underwater introduction process S300 is also performed with the bend suppression unit 200 fixed to the bend suppression unit fixing unit 880.

[S300: Cable underwater introduction process]
When the cable connection step S200 is completed, the ST cable 120, the joint 300 and the DM cable 140 are introduced into the water in this order.

In this embodiment, the underwater cable introduction process S300 includes, for example, a joint lifting process S320, a joint introduction process S340, and a protective tube installation process S360.

(S320: Joint lifting process)
When the cable connecting step S200 is completed, as shown in FIG. 3, a lifting scale 860 is used to support the vicinity of the joint 300 by a sling 862, and the vicinity of the joint 300 is lifted up.

At this time, in this embodiment, the hanging balance 860 supports the joint 300 and the ST cable 120 and the DM cable 140 at positions near both ends of the joint 300 with slings 862. Specifically, the slings 862 support two points of the joint 300 that are spaced apart by a predetermined distance across the axial center of the joint 300. The slings 862 support two points of the ST cable 120 that are spaced apart by a predetermined distance in the axial direction of the ST cable 120 at positions near the first axial end of the joint 300. The slings 862 support two points of the DM cable 140 that are spaced apart by a predetermined distance in the axial direction of the DM cable 140 at positions near the second end opposite the first axial end of the joint 300. With this configuration, the area near the joint 300 can be stably supported.

(S340: Joint introduction process)
Once the joint hoisting step S320 is completed, as shown in FIG. 5, with the vicinity of the joint 300 supported by a hoist balance 860, the ST cable 120 is let out into the water while the orientation of the joint 300 is gradually changed into the water.

Specifically, the ST cable 120 is paid out into the water while the hoist 860, which supports the vicinity of the joint 300, is moved on the laying ship 80 along the cable laying direction. At this time, tension is applied to the ST cable 120 by, for example, moving the laying ship 80 in the opposite direction to the direction in which the ST cable 120 is paid out. Once the hoist 860 passes the chute 840, the hoist 860 is gradually lowered. At this time, the length of the slings 862 is gradually extended, starting from the sling 862 that supports the position closest to the bottom of the water. This allows the alignment of the ST cable 120 to be made catenary-like, while gradually changing the orientation of the joint 300 into the water.

In this way, by gradually changing the orientation of the joint 300 toward the water, excessive bending of the cable can be prevented.

Once the joint 300 is oriented vertically and landed on the water, the support near the joint 300 by the hanging balance 860 is released while the weight of the ST cable 120 is borne by the stopper 124. Once the hanging balance 860 is released, the stopper 124 is removed. Then, the introduction of the cable into the water continues.

(S360: Protective tube installation process)
After the ST cable 120 and the joint 300 have been introduced into the water and the DM cable 140 has been landed on the water, a protective tube 146 for protecting the DM cable 140 is attached to the outer periphery of the area including the bottom landing point LP where the DM cable 140 touches the water bottom on the laying ship 80. This makes it possible to protect the DM cable 140 in the area including the bottom landing point LP, as shown in Figure 6.

Specifically, the protective tube 146 has, for example, a pair of semi-split cylindrical portions (not shown) and a band (not shown).

The pair of half-split cylinder sections are formed, for example, by dividing a cylinder in half at a cross section including the central axis of the cylinder. The pair of half-split cylinder sections are joined to each other with the DM cable 140 in between so as to surround the outer periphery of the DM cable 140.

Each of the half-cylinder sections contains, for example, a resin. Examples of the resin that constitutes the half-cylinder sections include polyurethane and hard rubber (ethylene propylene diene rubber (EPDM)).

The band is, for example, wrapped around the outer circumference of a pair of joined half-cylinder sections to tighten the pair of half-cylinder sections. This makes it possible to prevent the pair of half-cylinder sections from separating when, for example, the protective tube 146 rubs against the bottom of the water.

By attaching the protective tube 146 as described above to the DM cable 140, damage to the DM cable 140 can be suppressed.

At this time, in this embodiment, multiple protective tubes 146 are attached continuously along the axial direction of the DM cable 140. This makes it possible to protect the DM cable 140 over a predetermined length of area including the bottom landing point LP where the DM cable 140 touches the bottom of the water.

In this embodiment, the protective tube 146 is not attached to the area that is raised vertically above the bottom landing point LP of the DM cable 140 by more than a certain height. This ensures the flexibility of the DM cable 140 in the area where the shape of the DM cable 140 changes underwater.

Once the protective tube attachment process S360 is completed, as shown in FIG. 6, multiple buoys 142 are arranged at equal intervals over a predetermined length in the axial direction of the DM cable 140. This forms a float portion A (described below) that is held in the water in a convex arc shape facing vertically upward.

In this embodiment, for example, two float sections A are formed at a predetermined distance in the axial direction of the DM cable 140.

[S400: Water equipment connection process]
Once the desired length of cable has been introduced into the water, the DM cable 140 is connected to the floating surface facility 90 .

The above-water equipment connection process S400 of this embodiment includes, for example, a bending suppression section position determination process S420, a bending suppression section temporary fixing process S440, and a bending suppression section permanent fixing process S460.

(S420: bending suppression portion position identification process)
Here, as described above, when the DM cable 140 is connected to the surface facility 90, linear fluctuations of the DM cable 140 occur due to tides. Alternatively, the floating surface facility 90 floats on the water due to tides or wind.

Therefore, in this embodiment, the control unit 810 of the laying ship 80 determines the planned installation position of the bending suppression unit 200 on the DM cable 140 based on the length of the DM cable 140 underwater and the current position of the floating surface facility 90.

At this time, the control unit 810 of the cable laying ship 80 measures the length of the DM cable 140 that has been unwound, thereby obtaining information on the length of the DM cable 140 that has been introduced into the water.

At this time, for example, a GPS (Global Positioning System) receiver (not shown) installed on the surface facility 90 receives radio waves from GPS satellites to measure the current position of the surface facility 90. If the surface facility 90 does not have a permanent GPS receiver, a surveyor may use an antenna to measure the current position of the surface facility 90. After measuring the current position of the surface facility 90, the control unit 810 of the laying vessel 80 acquires the current position information of the surface facility 90 transmitted from the surface facility 90.

After acquiring the above-mentioned information, the control unit 810 of the laying vessel 80 calculates the position where the bending suppression unit 200 is connected to the surface facility 90 based on the length information of the DM cable 140 introduced underwater and the current position information of the surface facility 90. This identifies the position as the planned installation position of the bending suppression unit 200 on the DM cable 140.

Furthermore, in this embodiment, as shown in FIG. 8A, a position confirmation section 220 is provided on the outer periphery of the DM cable 140, which allows the intended installation position of the bending suppression section 200 to be visually confirmed. Specifically, the position confirmation section 220 is formed, for example, by applying paint that colors the outer periphery of the DM cable 140. Alternatively, the position confirmation section 220 may be formed, for example, by a tape having a color different from the color of the outer periphery of the DM cable 140.

In this embodiment, for example, the position confirmation unit 220 is provided in two locations. The position confirmation unit 220a is provided at a location where the first axial end of the bending suppression unit 200 is to be located. The position confirmation unit 220b is provided at a location where the second axial end opposite the first axial end of the bending suppression unit 200 is to be located. However, the position confirmation unit 220 may be provided in only one location.

(S440: bending suppression portion temporary fixing process)
When the bending restraint portion position specifying step S420 is completed, as shown in FIG. 7 and FIG. 8B, the bending restraint portion 200 is temporarily fixed at the intended installation position of the bending restraint portion 200.

In this embodiment, a position shift regulation section 240 that regulates the position shift of the bending suppression section 200 in the axial direction of the DM cable 140 is disposed at least at a position close to a first axial end of the bending suppression section 200 and a position close to a second end opposite the first end, so as to surround the outer periphery of the DM cable 140.

The misalignment regulating unit 240 is configured to be detachable from the DM cable 140, for example. This allows the misalignment regulating unit 240 to be removed from the DM cable 140 when it is no longer needed.

Specifically, the misalignment control unit 240 is configured, for example, in the same manner as the protective tube 146 described above. That is, the misalignment control unit 240 has, for example, a pair of half-cylinder portions (not shown) and a band (not shown).

The pair of half-split cylinder sections are formed, for example, by dividing a cylinder in half at a cross section including the central axis of the cylinder. The pair of half-split cylinder sections are joined to each other with the DM cable 140 in between so as to surround the outer periphery of the DM cable 140.

Each of the half-cylinder sections contains, for example, a resin. Examples of the resin that constitutes the half-cylinder sections include polyurethane and hard rubber (EPDM).

The band is, for example, wrapped around the outer circumference of a pair of joined half-cylinder sections to tighten the pair of half-cylinder sections. This makes it possible to prevent the pair of half-cylinder sections from separating when, for example, the protective tube 146 rubs against the bottom of the water.

By attaching the above-described misalignment control section 240 to the DM cable 140, it is possible to control misalignment of the bending suppression section 200 in the axial direction of the DM cable 140.

In this embodiment, for example, two misalignment regulating units 240 are arranged. That is, misalignment regulating unit 240a is arranged at a position close to the first axial end of bend suppression unit 200. Furthermore, misalignment regulating unit 240b is arranged at a position close to the second axial end of bend suppression unit 200. This makes it possible to regulate both misalignment of bend suppression unit 200 in the direction toward the terminal of DM cable 140 and misalignment of bend suppression unit 200 in the direction away from the terminal of DM cable 140, regardless of how the direction of gravity of bend suppression unit 200 changes depending on the orientation of the terminal of DM cable 140.

Furthermore, in this embodiment, as shown in FIG. 7, multiple floats 148 are attached to the DM cable 140 near the planned installation position of the bending suppression unit 200. Here, if the floats 148 are not attached to the DM cable 140, when the DM cable 140 is let out into the water, the terminal of the DM cable 140 will sink to the bottom of the water. In this case, in order to connect the DM cable 140 to the above-water facility 90, the DM cable 140 needs to be pulled up. In contrast, in this embodiment, as described above, multiple floats 148 are attached to the DM cable 140, so that the DM cable 140 can be kept floating on the water near the planned installation position of the bending suppression unit 200 to be connected to the above-water facility 90. This makes it unnecessary to pull up the DM cable 140.

The above steps form the cable connection intermediate 20 of this embodiment. The cable connection intermediate 20 includes, for example, a DM cable 140, a bending suppression section 200, a position confirmation section 220, and a position deviation control section 240. The cable connection intermediate 20 is used, for example, in the bending suppression section final fixing process S460 described below.

(S460: bending suppression portion final fixing process)
Once the bending restraint unit temporary fixing process S440 is completed, as shown in FIG. 9 , the DM cable 140 to which the bending restraint unit 200 is attached is pulled into the above-water facility 90, and the bending restraint unit 200 is fixed to the above-water facility 90.

In this embodiment, the bending suppression section final fixing process S460 is carried out as follows. The work underwater is carried out by diver D as appropriate.

First, a wire (not shown) connected to the winch 940 of the surface facility 90 is connected to the end of the DM cable 140. Next, the float 148 attached to the DM cable 140 is gradually removed, and the DM cable 140 is sunk. Once a predetermined length of the DM cable 140 has been sunk, the wire is pulled by the winch 940 of the surface facility 90, and the end of the DM cable 140 is pulled into the I-tube (cable introduction pipe) 920 of the surface facility 90.

At this time, the end of the DM cable 140 is introduced into the I-tube 920 with the cushioned bell mouth 910 placed at the lower end of the I-tube 920. This makes it possible to prevent damage to the DM cable 140 caused by contact between the DM cable 140 and the I-tube 920.

At this time, a stopper 280 that grips the DM cable 140 is attached near the positional deviation control section 240a of the bending suppression section 200. The stopper 280 is lifted by a wire using a winch (not shown) provided on the water facility 90, so that the stopper 280 bears at least a portion of the load when the DM cable 140 is raised.

When the end of the DM cable 140 emerges from the top end of the I-tube 920, remove all of the floats 148. Then, when the bending restraint section 200 reaches a position several meters below the bell mouth 910, temporarily suspend the raising of the DM cable 140.

After pausing, remove the misalignment control part 240b above the bending suppression part 200. After removing the misalignment control part 240b, resume starting up the DM cable 140.

When the bending suppression unit 200 approaches the lower end of the I-tube 920, as shown in FIG. 10, the bell mouth 910 is removed from the I-tube 920. Next, wires (symbols not shown) are passed through the bolt insertion holes of the flange 922 of the I-tube 920 from a pair of lever blocks (registered trademark) 924 provided on the outer circumferential side of the I-tube 920, and the wires are engaged with the bolt insertion holes of the flange 214 of the bending suppression unit 200.

In this state, the flange 914 of the bending restraint unit 200 is gradually lifted with a wire using each lever block (registered trademark) 924. At this time, with the DM cable 140 receiving the cable tension F and the force of the tidal current, the flange 914 of the bending restraint unit 200 is adjusted to fit the flange 922 of the I-tube 920. This causes the flange 914 of the bending restraint unit 200 to abut against the flange 922 of the I-tube 920. The flange 914 of the bending restraint unit 200 and the flange 922 of the I-tube 920 are then fixed together with a bolt.

After the bending suppression unit 200 is fixed to the I-tube 920, the terminal of the DM cable 140 is connected to a specified device of the surface facility 90. After connecting the DM cable 140, the lower misalignment control unit 240a of the bending suppression unit 200 is removed.

By the above steps, the cable laying structure 10 of this embodiment is manufactured as shown in Figure 11.

(2) Cable Laying Structure With reference to FIG. 11, a cable laying structure 10 according to one embodiment of the present disclosure will be described.

As shown in FIG. 11, the cable laying structure 10 includes, for example, an ST cable 120, a joint 300, a DM cable 140, a protective tube 146, a bending restraint section 200, and above-water equipment 90.

[ST cable, joint, DM cable, water facilities]
The ST cable 120 is laid on the bottom of the water. The joint 300 connects the ST cable 120 and the DM cable 140. The DM cable 140 is connected to the above-water facility 90. The above-water facility 90 is configured as a floating body that floats on the water.

(DM cable linearity)
Here, the DM cable 140 has, for example, a float portion A and a suspended portion B.

In this embodiment, the float section A is provided in two locations, for example, with a predetermined distance between them. The float section A1 is provided in a position farther from the surface equipment 90. The float section A2 is provided in a position closer to the surface equipment 90 than the float section A1.

In the float section A1, for example, multiple buoys 142 are arranged at equal intervals over a predetermined length in the axial direction of the DM cable 140. Both ends of the float section A1 are moored to the bottom of the water by ropes 144. As a result, the float section A is maintained in a convex arc shape that is convex upwards vertically due to the balance between the buoyancy acting on each buoy 142 in the water, the gravity acting on the DM cable 140, and the tension acting on the ropes 144.

Float section A2 is configured similarly to float section A1, except that it is not moored to the bottom of the water by a rope.

On the other hand, the hanging portion B is formed by hanging down in a catenary shape due to the weight of the DM cable 140, for example, between the float portion A1 and the float portion A2, and between the float portion A2 and the above-water facility 90.

With this configuration, the DM cable 140 is bent in an S-shape in the vertical direction. The linear movement of the DM cable 140 can suppress excessive tension or excessive bending in the DM cable 140 while allowing the floating water facility 90 to move.

[Protection tube]
The protective tube 146 is configured to be provided, for example, on the outer periphery of a region including a bottom landing point LP where the DM cable 140 contacts the bottom of the water, and to protect the DM cable 140. The protective tube 146 is maintained in a state of being attached to the outer periphery of the DM cable 140 even after the cable laying structure 10 is manufactured.

[Bending restraint section]
The bending suppression section 200 is provided, for example, so as to surround the outer periphery of the DM cable 140. The bending suppression section 200 is connected, for example, to the lower end of the I-tube 920 of the above-water facility 90. The bending suppression section 200 is configured, for example, to suppress bending of the DM cable 140 in a region close to the lower end of the above-water facility 90.

[Position confirmation section]
The position confirmation section 220 is provided, for example, on the outer periphery of the DM cable 140 and is configured to enable visual confirmation of the planned installation position of the bending restraint section 200 .

The position confirmation section 220 is provided, for example, in the cable connection intermediate body 20 shown in FIG. 8A in the bending suppression section temporary fixing process S440 described above, and is used to confirm the position of the bending suppression section 200 in the bending suppression section permanent fixing process S460. However, the position confirmation section 220 remains on the outer periphery of the DM cable 140 even after the cable laying structure 10 is manufactured.

(3) Summary of the Present Invention According to the present invention, one or more of the following advantages can be obtained.

(a) In the manufacturing method of the cable laying structure 10 of this embodiment, the terminal of the ST cable 120 is pulled up from the bottom of the water onto the laying ship 80, and the terminal of the ST cable 120 is prepared on the laying ship 80. Next, on the laying ship 80, the ST cable 120 and the DM cable 140 are connected by a joint 300. Next, the ST cable 120, the joint 300, and the DM cable 140 are introduced into the water in this order. After that, the DM cable 140 is connected to a floating above-water facility 90.

As described above, according to this embodiment, the ST cable 120, the DM cable 140, and the above-water facility 90 can be stably connected.

(b) In the ST cable preparation process S100 of this embodiment, the ST cable 120 is held by the stopper 124. In this state, the stopper 124 is lifted by the wire 126, so that the stopper 124 bears at least a portion of the load of the ST cable 120. This makes it possible to prevent excessive load from being placed on the cable due to the load of the ST cable 120 from the top of the laying ship 80 to the bottom of the water. As a result, it is possible to prevent excessive bending of at least one of the joint 300 and the DM cable 140, which are introduced into the water after the ST cable 120.

(c) In the cable underwater introduction process S300 of this embodiment, the vicinity of the joint 300 is hoisted using a hoisting balance 860 that supports the joint 300 and the ST cable 120 and DM cable 140 near both ends of the joint 300 with slings 862. With the vicinity of the joint 300 supported by the hoisting balance 860, the ST cable 120 is unwound into the water while the orientation of the joint 300 is gradually changed into the water. This makes it possible to prevent at least one of the ST cable 120 and the DM cable 140 near the joint 300 from bending excessively when the joint 300 is introduced into the water.

As described above, in this embodiment, accessories such as the bend suppression section 200 through which the DM cable 140 is inserted are fixed on the laying ship 80. In this state, the payout path of the DM cable 140 is set to a horizontal straight line on the laying ship 80.

In contrast, in this embodiment, the use of the hanging balance 860 allows the orientation of the joint 300 to be gradually changed toward the water. This allows the DM cable 140 to be maintained in a straight line near the fixed position of the bending suppression unit 200 on the laying ship 80, and prevents excessive load from being applied to the DM cable 140. As a result, localized and excessive bending of at least one of the ST cable 120 and the DM cable 140 near the joint 300 can be suppressed.

(d) In this embodiment, a protective tube 146 that protects the DM cable 140 is attached to the outer periphery of the area including the bottom landing point LP where the DM cable 140 touches the bottom of the water. This makes it possible to suppress damage to the DM cable 140 caused by friction between the DM cable 140 and the bottom of the water, even if the linearity of the DM cable 140 fluctuates. As a result, the insulation properties of the DM cable 140 can be stably maintained.

(e) In this embodiment, the cable connection process S200 and the underwater cable introduction process S300 are performed with the DM cable 140 inserted through the cylindrical bending suppression section 200.

Here, it is possible to consider a case where the bending suppression section 200 has a halved structure. In this case, in the surface equipment connection step S400, the halved bending suppression section 200 is joined underwater to connect the bending suppression section 200 to the I-tube 920 of the surface equipment 90. However, since joining the halved bending suppression section 200 is complicated, it may be difficult for diver D to work underwater.

In contrast, by pre-inserting the DM cable 140 through the cylindrical bending suppression section 200 rather than splitting it in half, the underwater work by the diver D in the surface equipment connection process S400 can be simplified. As a result, the surface equipment connection process S400 can be carried out smoothly and stably.

(f) In the above-water equipment connection process S400 of this embodiment, the planned installation position of the bend suppression unit 200 is identified on the DM cable 140 based on the length of the DM cable 140 underwater and the current position of the floating above-water equipment 90. Next, the bend suppression unit 200 is temporarily fixed to the planned installation position of the bend suppression unit 200. Thereafter, the DM cable 140 to which the bend suppression unit 200 is attached is pulled into the above-water equipment 90, and the bend suppression unit 200 is fixed to the above-water equipment 90. In this way, in this embodiment, the bend suppression unit 200 is connected to the above-water equipment 90 while managing the length of the DM cable 140.

In this embodiment, by determining the planned installation position of the bending suppression unit 200, it is possible to prevent unnecessary excess length of the DM cable 140 from occurring in the surface equipment connection process S400. Furthermore, even if linear fluctuations in the DM cable 140 or floating of the floating surface equipment 90 occur in the surface equipment connection process S400, it is possible to prevent the bending suppression unit 200 from shifting from the actual planned installation position. This makes it unnecessary for the diver D to adjust the position of the bending suppression unit 200 underwater. As a result, the bending suppression unit 200 can be easily connected to the lower end of the surface equipment 90.

As described above, in this embodiment, it is possible to carry out the surface equipment connection process S400 smoothly and stably.

(g) In the bending suppression unit position determination step S420 of this embodiment, a position confirmation unit 220 is provided on the outer periphery of the DM cable 140, which allows the intended installation position of the bending suppression unit 200 to be visually confirmed. This makes it easy to grasp the intended installation position of the bending suppression unit 200. Furthermore, even if an unintended positional shift of the bending suppression unit 200 occurs in the above-water equipment connection step S400, the positional shift of the bending suppression unit 200 can be immediately discovered.

(h) In the bending suppression unit temporary fixing step S440 of this embodiment, a positional deviation control unit 240 that controls the positional deviation of the bending suppression unit 200 in the axial direction of the DM cable 140 is arranged so as to surround the outer periphery of the DM cable 140 at least one of a position close to a first axial end of the bending suppression unit 200 and a position close to a second end opposite the first end. This makes it possible to control deviation of the bending suppression unit 200 from the intended installation position in the surface equipment connection step S400, even if linear fluctuation of the DM cable 140 or floating of the floating surface equipment 90 occurs.

As described above, by temporarily fixing the bending suppression unit 200 at the intended installation position using the position shift control unit 240, it is possible to eliminate the need for a towing wire for towing the bending suppression unit 200 and its locking unit. Furthermore, it is also possible to eliminate the need for a special mechanism for breaking the locking unit of the towing wire. This makes it possible to prevent broken pieces of the locking unit from getting into the cable insertion hole 211 of the bending suppression unit 200. As a result, the bending suppression unit 200 can be easily and stably connected to the lower end of the above-water equipment 90.

(4) Modifications of an embodiment The above-described embodiment can be modified as necessary as in the following modifications. Only elements different from the above-described embodiment will be described below, and elements substantially the same as those described in the above-described embodiment will be denoted by the same reference numerals and description thereof will be omitted.

<Modification 1>
12, in the first modification, the bend suppression section 200 that suppresses bending of the DM cable 140 in the region near the lower end of the surface facility 90 is configured as, for example, a so-called bend restrictor 200b. The bend restrictor 200b has, for example, a plurality of restrictor units 250. The plurality of restrictor units 250 are connected in a daisy chain.

The restrictor unit 250 has, for example, a first cylindrical portion 260 and a second cylindrical portion 270.

The first cylindrical portion 260 is, for example, cylindrically arranged so as to surround the outer periphery of the DM cable 140. The first cylindrical portion 260 has, for example, a cable insertion hole 251 as a hollow portion. The DM cable 140 is inserted into the cable insertion hole 251.

The first cylindrical portion 260 has, for example, an inner peripheral flange portion 262. The inner peripheral flange portion 262 protrudes, for example, from the axial end portion of the first cylindrical portion 260 in the radial direction toward the central axis.

The second cylindrical portion 270 is, for example, cylindrically arranged so as to surround the outer periphery of the DM cable 140. The second cylindrical portion 270 is, for example, connected to the axial end of the first cylindrical portion 260. The second cylindrical portion 270 has, for example, a cable insertion hole 251 that communicates with the first cylindrical portion 260 and through which the DM cable 140 is inserted.

On the other hand, a specific region of the second cylindrical portion 270 close to the first cylindrical portion 260 has, for example, an outer diameter smaller than the inner diameter of the first cylindrical portion 260. In other words, the second cylindrical portion 270 is designed to be able to fit inside the first cylindrical portion 260.

The second cylindrical portion 270 has, for example, an outer peripheral flange 272. The outer peripheral flange 272 protrudes, for example, from the axial end of the second cylindrical portion 270 opposite the first cylindrical portion 260 toward the radial outside of the second cylindrical portion 270.

The restrictor unit 250 having the above-mentioned configuration is, for example, split in half at a cross section including the central axis. The split restrictor unit 250 is coupled from the outside of the DM cable 140. Of the multiple restrictor units 250, the second cylindrical portion 270 of the first restrictor unit 250 is fitted into the first cylindrical portion 260 of the second restrictor unit 250. This allows the multiple restrictor units 250 to be connected in a daisy chain.

The cable laying structure 10 in variant 1 and other steps of its manufacturing method are similar to the above-described embodiment, except that the bend restraint section 200 is a bend restrictor 200b.

According to the first modification, among the multiple restrictor units 250, the second cylindrical portion 270 of the first restrictor unit 250 is fitted into the first cylindrical portion 260 of the second restrictor unit 250. This allows the outer peripheral flange 272 of the first restrictor unit 250 to move to the inner peripheral flange 262 of the second restrictor unit 250 and engage with the inner peripheral flange 262 of the second restrictor unit 250. As a result, excessive bending of the DM cable 140 can be suppressed while bending of the DM cable 140 is permitted within a certain range.

<Modification 2>
As shown in FIG. 13A , in the cable connecting step S200 of the second modified example, for example, a bending restraining portion 400 is provided near an end portion of the joint 300 in the axial direction.

The bending suppression section 400 is provided, for example, to surround the outer periphery of the ST cable 120 or the DM cable 140. The bending suppression section 400 is configured, for example, to suppress bending of the ST cable 120 or the DM cable 140 in a region close to the axial end of the joint 300. By using the bending suppression section 400, it is possible to make the ST cable 120 or the DM cable 140 more difficult to bend than a cable that does not have a bending suppression section.

Specifically, the bending restraint section 400 is configured as, for example, a so-called bend stiffener 400a. The bend stiffener 400a has, for example, a cylindrical section 412 and a flange section 414, similar to the bend stiffener 200a provided in an area close to the lower end of the water facility 90. The flange section 414 of the bend stiffener 400a is fixed to the joint 300 by, for example, a bolt or the like.

The cable laying structure 10 in variant 2 and other steps in its manufacturing method are similar to those of the above-described embodiment, except that a bending restraint section 400 is provided near the axial end of the joint 300.

According to variant example 2, by providing a bending suppression section 400 near the axial end of the joint 300, local and excessive bending of the ST cable 120 or DM cable 140 in the area close to the axial end of the joint 300 can be suppressed.

<Modification 3>
As shown in FIG. 13B, in the third modification, a bending suppression section 400 that suppresses bending of the ST cable 120 or the DM cable 140 in a region near the axial end of the joint 300 is configured, for example, as a so-called bend restrictor 400b.

The bend restrictor 400b of the third modification has, for example, a plurality of restrictor units 450, similar to the bend restrictor 200b of the first modification provided in an area near the lower end of the surface equipment 90. The plurality of restrictor units 450 are connected in a daisy chain from each of the axial ends of the joint 300 via a predetermined adapter (reference number not shown).

The restrictor unit 450 of the third modification has, for example, a first cylindrical portion 460 and a second cylindrical portion 470, similar to the restrictor unit 250 of the first modification. This allows the outer peripheral flange 472 of the first restrictor unit 450 to be moved to the inner peripheral flange (not shown) of the second restrictor unit 450 and engaged with the inner peripheral flange of the second restrictor unit 450.

The cable laying structure 10 in variant 3 and other steps of its manufacturing method are the same as those in variant 2 described above, except that the bend restraint section 400 is a bend restrictor 400b.

According to variant 3, by providing a bend restrictor 400b as a bending suppression section 400 near the axial end of the joint 300, the same effect as variant 2 can be obtained.

<Other embodiments of the present disclosure>
Although the embodiments of the present disclosure have been specifically described above, the present disclosure is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit and scope of the present disclosure.

In the above embodiment, the cable is configured as a power cable, but the cable may also include at least a portion of a communication cable such as an optical fiber.

In the ST cable preparation step S100 of the above embodiment, a case where two stoppers 124 are attached to the ST cable 120 has been described, but as long as safety is ensured, only one stopper 124 may be attached to the ST cable 120.

In the above embodiment, the cable connection intermediate 20 has both the position confirmation unit 220 and the misalignment control unit 240, but the present disclosure is not limited to this case. The cable connection intermediate 20 only needs to have at least one of the position confirmation unit 220 and the misalignment control unit 240. This makes it possible to obtain the effects of at least one of the position confirmation unit 220 and the misalignment control unit 240.

In the above embodiment, the cable connection intermediate body 20 has a misalignment regulating portion 240a provided near a first axial end of the bending suppression portion 200 and a misalignment regulating portion 240b provided near a second axial end opposite the first end, but the present disclosure is not limited to this case. The misalignment regulating portion 240 may be provided only in one of the positions near the first axial end of the bending suppression portion 200 or near the second axial end opposite the first end.

For example, if the terminal of the DM cable 140 is maintained facing vertically upward in the above-water equipment connection process S400, only the misalignment control unit 240a may be provided at a position close to the first axial end of the bending suppression unit 200, i.e., at a position far from the terminal of the DM cable 140. In this way, the installation position of the misalignment control unit 240 relative to the bending suppression unit 200 may be selected depending on the direction of gravity of the bending suppression unit 200 in the above-water equipment connection process S400.

In this embodiment, the cable laying structure 10 has been described as having an ST cable 120, a DM cable 140, and an above-water facility 90, but the present disclosure is not limited to this case. A cable laying structure 10 having at least one of the protective tube 146 and the position confirmation section 220 of the bending suppression section 200 may be applied to a structure that does not have an ST cable 120 and connects a first above-water facility 90 and a second above-water facility 90 only with a DM cable 140, for example.

<Additional Notes>
The following additional aspects of the present disclosure.

(Appendix 1)
a step of lifting an end of the static cable laid on the bottom of the water onto a laying ship and preparing the static cable;
connecting the static cable and the dynamic cable with a joint on the laying ship;
introducing the static cable, the joint and the dynamic cable in this order into water;
connecting the dynamic cable to a floating surface installation;
A method for manufacturing a cable laying structure comprising:

(Appendix 2)
The step of preparing a static cable includes:
gripping the static cable with a stopper;
A step of lifting the stopper by a wire so that the stopper bears at least a part of the load of the static cable;
A method for manufacturing a cable laying structure according to claim 1, comprising:

(Appendix 3)
The stopper is configured to be detachable from the static cable.

(Appendix 4)
The step of introducing the static cable, the joint and the dynamic cable into water in this order includes:
a step of lifting the vicinity of the joint using a lifting balance in which the joint, the static cable and the dynamic cable at positions near both ends of the joint are supported by slings;
a step of gradually changing a direction of the joint into the water while paying out the static cable into the water in a state in which the vicinity of the joint is supported by the hanging balance;
A method for manufacturing a cable laying structure according to any one of claims 1 to 3, comprising:

(Appendix 5)
The step of introducing the static cable, the joint and the dynamic cable into water in this order includes:
A manufacturing method for a cable laying structure according to any one of claims 1 to 4, further comprising a step of attaching a protective tube for protecting the dynamic cable to an outer periphery of an area including a bottom landing point of the dynamic cable where the dynamic cable contacts the bottom of the water.

(Appendix 6)
In the step of attaching the protective tube,
6. The manufacturing method of a cable laying structure according to claim 5, wherein the protective pipe is not attached to an area that is raised vertically above a predetermined height from the landing point of the dynamic cable.

(Appendix 7)
a step of connecting by the joint;
the step of introducing the static cable, the joint and the dynamic cable into water in this order;
The method for manufacturing a cable laying structure described in any one of Appendix 1 to Appendix 6, wherein the method is carried out in a state where the dynamic cable is inserted into a bending restraint section that restrains bending of the dynamic cable in a region near the lower end of the above-water facility.

(Appendix 8)
The step of connecting the dynamic cable to the surface facility includes:
determining a planned installation position of the bend restraint unit on the dynamic cable based on a length of the dynamic cable underwater and a current position of the floating surface equipment;
a step of temporarily fixing the bending suppression portion at the intended installation position;
pulling the dynamic cable with the bend restraint portion attached into the surface facility and fixing the bend restraint portion to the surface facility;
A method for manufacturing a cable laying structure according to claim 7, comprising:

(Appendix 9)
In the step of specifying a planned installation position,
The manufacturing method of the cable laying structure according to claim 8, further comprising providing a position confirmation part on an outer periphery of the dynamic cable, the position confirmation part enabling the intended installation position to be visually confirmed.

(Appendix 10)
In the step of temporarily fixing the bending suppression portion,
A manufacturing method for a cable laying structure described in Appendix 8 or Appendix 9, in which a position shift control section for controlling position shift of the bend suppression section in the axial direction of the dynamic cable is arranged so as to surround an outer periphery of the dynamic cable at least one of a position close to a first axial end of the bend suppression section and a position close to a second axial end opposite the first end.

(Appendix 11)
The method for manufacturing a cable laying structure according to claim 10, wherein the positional deviation control portion is configured to be detachable from the dynamic cable.

(Appendix 12)
The step of connecting by the joint includes:
A method for manufacturing a cable laying structure described in any one of Appendix 1 to Appendix 11, comprising a step of providing a bending suppression portion surrounding an outer periphery of the static cable or the dynamic cable to suppress bending of the static cable or the dynamic cable in a region near the axial end of the joint.

(Appendix 13)
A dynamic cable that is laid underwater and connected to a surface facility;
a bending suppression portion provided around an outer periphery of the dynamic cable and configured to suppress bending of the dynamic cable in a region close to a lower end of the above-water facility;
a position confirmation section provided on an outer periphery of the dynamic cable, the position confirmation section being capable of visually confirming a planned installation position of the bending restraint section;
A cable connection intermediate.

(Appendix 14)
A dynamic cable that is laid underwater and connected to a surface facility;
a bending suppression portion provided around an outer periphery of the dynamic cable and configured to suppress bending of the dynamic cable in a region close to a lower end of the above-water facility;
a positional deviation prevention member that is provided to surround an outer periphery of the dynamic cable at a position near a first end of the bending suppression portion in the axial direction and/or a position near a second end opposite to the first end, and that prevents the bending suppression portion from misaligning in the axial direction of the dynamic cable;
A cable connection intermediate.

(Appendix 15)
A static cable laid on the bottom of the water,
A dynamic cable that is laid underwater and connected to a floating surface facility;
a joint connecting the static cable and the dynamic cable;
A cable laying structure comprising:

(Appendix 16)
The cable laying structure of claim 15, further comprising a bending restraint portion surrounding the outer periphery of the static cable or the dynamic cable to restrain bending of the static cable or the dynamic cable in a region close to the axial end of the joint.

(Appendix 17)
A dynamic cable that is laid underwater and connected to a floating surface facility;
a protective tube provided around an outer periphery of a region including a bottom landing point of the dynamic cable, the protective tube protecting the dynamic cable;
A cable laying structure comprising:

(Appendix 18)
A dynamic cable that is laid underwater and connected to a floating surface facility;
a bending suppression portion provided around an outer periphery of the dynamic cable and configured to suppress bending of the dynamic cable in a region close to a lower end of the above-water facility;
a position confirmation portion provided on an outer periphery of the dynamic cable, the position confirmation portion being capable of visually confirming an installation position of the bending restraint portion;
A cable laying structure comprising:

10 Cable laying structure 20 Cable connection intermediate body 22 Cylindrical part 30 Water facility 80 Laying ship 90 Water facility 120 Static cable (ST cable)
124, 124a, 124b Stoppers 126, 126a, 126b Wire 140 Dynamic cable (DM cable)
142 Buoy 144 Rope 146 Protective tube 148 Float 200 Bending restraining portion 200a Bend stiffener 200b Bend restrictor 211 Cable insertion hole 212 Cylindrical portion 214 Flange portion 220, 220a, 220b Position confirmation portion 240, 240a, 240b Position deviation regulating portion 250 Restrictor unit 251 Cable insertion hole 260 First cylindrical portion 262 Inner peripheral flange portion 270 Second cylindrical portion 272 Outer peripheral flange portion 280 Stopper 300 Joint 400 Bending restraining portion 400a Bend stiffener 400b Bend restrictor 412 Cylindrical portion 414 Flange portion 450 Restrictor unit 460 First cylindrical portion 470 Second cylindrical portion 472 Outer peripheral flange 810 Control unit 820 Turntable 840 Chute 860 Suspension balance 862 Sling 870 Winch 880 Bending restraint unit fixing unit 910 Bell mouth 920 I-tube 922 Flange 924 Lever block (registered trademark)
940 Winch A, A1, A2 Float part B Suspension part D Diver F Cable tension LP Bottom landing point

Claims (15)

a step of lifting an end of the static cable laid on the bottom of the water onto a laying ship and preparing the static cable;
connecting the static cable and the dynamic cable with a joint on the laying ship;
introducing the static cable, the joint and the dynamic cable in this order into water;
connecting the dynamic cable to a floating surface installation;
A method for manufacturing a cable laying structure comprising: The step of preparing a static cable includes:
gripping the static cable with a stopper;
A step of lifting the stopper by a wire so that the stopper bears at least a part of the load of the static cable;
The method for manufacturing the cable laying structure according to claim 1, comprising: The step of introducing the static cable, the joint and the dynamic cable into water in this order includes:
a step of lifting the vicinity of the joint using a lifting balance in which the joint, the static cable and the dynamic cable at positions near both ends of the joint are supported by slings;
a step of gradually changing a direction of the joint into the water while paying out the static cable into the water in a state in which the vicinity of the joint is supported by the hanging balance;
The method for manufacturing a cable laying structure according to claim 1 or 2, comprising: The step of introducing the static cable, the joint and the dynamic cable into water in this order includes:
3. The method for manufacturing a cable laying structure according to claim 1, further comprising the step of attaching a protective tube for protecting the dynamic cable to an outer periphery of a region including a bottom landing point of the dynamic cable where the dynamic cable makes contact with the bottom of the water. a step of connecting by the joint;
the step of introducing the static cable, the joint and the dynamic cable into water in this order;
The method for manufacturing a cable laying structure according to claim 1 or 2, wherein the manufacturing method is carried out in a state where the dynamic cable is inserted into a bending restraint section that restrains bending of the dynamic cable in a region close to a lower end of the above-water facility. The step of connecting the dynamic cable to the surface facility includes:
determining a planned installation position of the bend restraint unit on the dynamic cable based on a length of the dynamic cable underwater and a current position of the floating surface equipment;
a step of temporarily fixing the bending suppression portion at the intended installation position;
pulling the dynamic cable with the bend restraint portion attached into the surface facility and fixing the bend restraint portion to the surface facility;
The method of claim 5, further comprising the steps of: In the step of specifying a planned installation position,
The method for manufacturing a cable laying structure according to claim 6, further comprising providing a position confirmation portion on an outer periphery of the dynamic cable, the position confirmation portion enabling the intended installation position to be visually confirmed. In the step of temporarily fixing the bending suppression portion,
7. The manufacturing method of a cable laying structure according to claim 6, further comprising: arranging a positional deviation control section for controlling positional deviation of the bending restraint section in the axial direction of the dynamic cable so as to surround an outer periphery of the dynamic cable at least one of a position close to a first axial end of the bending restraint section and a position close to a second axial end opposite the first end. The step of connecting by the joint includes:
3. The method for manufacturing a cable laying structure according to claim 1, further comprising a step of providing a bending suppression portion surrounding an outer periphery of the static cable or the dynamic cable to suppress bending of the static cable or the dynamic cable in a region close to an axial end of the joint. A dynamic cable that is laid underwater and connected to a surface facility;
a bending suppression portion provided around an outer periphery of the dynamic cable and configured to suppress bending of the dynamic cable in a region close to a lower end of the above-water facility;
a position confirmation section provided on an outer periphery of the dynamic cable, the position confirmation section being capable of visually confirming a planned installation position of the bending restraint section;
A cable connection intermediate. A dynamic cable that is laid underwater and connected to a surface facility;
a bending suppression portion provided around an outer periphery of the dynamic cable and configured to suppress bending of the dynamic cable in a region close to a lower end of the above-water facility;
a positional deviation prevention member that is provided to surround an outer periphery of the dynamic cable at a position near a first end of the bending suppression portion in the axial direction and/or a position near a second end opposite to the first end, and that prevents the bending suppression portion from misaligning in the axial direction of the dynamic cable;
A cable connection intermediate. A static cable laid on the bottom of the water,
A dynamic cable that is laid underwater and connected to a floating surface facility;
a joint connecting the static cable and the dynamic cable;
A cable laying structure comprising: The cable laying structure according to claim 12 , further comprising a bending restraint portion surrounding an outer periphery of the static cable or the dynamic cable to restrain bending of the static cable or the dynamic cable in a region close to an axial end of the joint. A dynamic cable that is laid underwater and connected to a floating surface facility;
a protective tube provided around an outer periphery of a region including a bottom landing point of the dynamic cable, the protective tube protecting the dynamic cable;
A cable laying structure comprising: A dynamic cable that is laid underwater and connected to a floating surface facility;
a bending suppression portion provided around an outer periphery of the dynamic cable and configured to suppress bending of the dynamic cable in a region close to a lower end of the above-water facility;
a position confirmation portion provided on an outer periphery of the dynamic cable, the position confirmation portion being capable of visually confirming an installation position of the bending restraint portion;
A cable laying structure comprising:

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