JP7475243B2 - Protective structure for long seabed objects and method for protecting long seabed objects using the same - Google Patents

Description

The present invention relates to a protective structure for long undersea objects such as undersea cables and pipes, and in particular to a protective structure and a method for protecting long undersea objects that can reliably protect the objects regardless of the presence or absence of tidal currents.

In recent years, wind power generation facilities have been widely constructed offshore, where winds blow more stably and at higher speeds than on land.
Electricity generated by offshore wind power generation facilities is transmitted to land via cables, which are laid on the seabed when underwater.

Patent Document 1 discloses a means for protecting a cable laid on the seabed (hereinafter referred to as a "submarine cable") from collisions with ship anchors, fishing gear, and boulders.
The protective means disclosed in Patent Document 1 is for protecting pipes including submarine cables and pipelines for gas, oil, etc., and involves installing bag-shaped foot protection materials to cover the submarine cables and pipes.

JP 2011-139629 A

In order to adequately protect long undersea cables and pipes, the foot protection materials must be installed continuously and without any gaps.
Since bag-type root reinforcement materials are subject to the effects of tides and other factors during construction, it is difficult to install them securely in the designated location.
In addition, the inside of the base protection material is filled with a filler material such as aggregate, which may damage the submarine cable or pipe.

The present invention aims to provide a protective structure that can reliably protect long undersea objects such as undersea cables and pipes regardless of the presence or absence of tidal currents, and a method for protecting long undersea objects using the same.

The first invention of the present application is a protective structure for a long-length seabed object that covers and protects a long-length seabed object laid on the seabed, and comprises a sheet material that is water permeable and can be used to cover the long-length seabed object , and a plurality of root protection materials that are fixed integrally to the upper surface of the sheet material in advance with intervals that allow them to be installed across the long-length seabed object and have a positioning function for the sheet material , and each of the plurality of root protection materials has a bag body made of knitted fabric and a filling material filled inside the bag body, and the plurality of root protection materials can be laid on the seabed ground with the sheet material covering the long-length seabed object .
A second aspect of the present invention is the protective structure of the first aspect, wherein the sheet material is in a mesh shape.
The third invention of the present application is a method for protecting long-length seabed objects, which involves covering and protecting a long-length seabed object laid on the seabed with a protective structure , and is characterized in that the protective structure for the long-length seabed object of the first or second invention is used, the footing material is suspended while the sheet material is stretched out, the protective structure is suspended, the protective structure is lowered into the sea, and with the long-length seabed object to be protected covered with the sheet material, the multiple footing materials are placed on the seabed ground, and the long-length seabed object is protected by the sheet material.

With the above-mentioned configuration, the present invention has at least one of the following effects.
<1> Because the sheet material is water permeable, it can be lowered to a designated location without being affected by currents or other factors, and can reliably protect long objects on the seabed. In addition, the installation work is easy.
<2> Because it is made of sheet material, it will not damage long objects on the seabed.
<3> Since long seabed objects are protected by sheet material, the foot protection material only needs to be provided at specified intervals, making it possible to produce the protective structure at low cost.
<4> Since the long seabed object is protected by a sheet material having a large area, a wide area of the long seabed object can be covered and protected at once, thereby shortening the construction time.

FIG. 1 is an explanatory diagram of a protective structure for a long undersea object according to the present invention; FIG. 2 is an explanatory diagram of the protective structure for the long seabed object of the present invention; Illustration of foot protection material An explanatory diagram of a method for constructing a protective structure according to the present invention.

The following describes in detail the protection structure for long seabed objects and the method for protecting long seabed objects of the present invention with reference to the drawings.

<1> Configuration of protective structure (Figs. 1 and 2)
The protective structure 1 of the present invention is intended to protect a submarine cable 4 laid on ground G such as the seabed, and comprises a sheet material 2 for covering the submarine cable 4, and a foot protection material 3 for fixing the sheet material 2 onto the ground G.
In this example, the protective structure 1 is described as protecting a submarine cable 4, but is not limited to this and can protect long objects (hereinafter referred to as "submarine long objects") laid on the seabed, such as pipes including gas and oil pipelines.

<2> Sheet Material The sheet material 2 has a predetermined area and is made of a water-permeable mesh or sheet body that has flexibility capable of following the shape of the submarine cable 4 and the undulations of the ground G.
In this example, a mesh sheet made of polyester fiber is used as the sheet material 2. However, the present invention is not limited to this, and for example, a mesh body made of the same resin fiber or polyethylene resin, or a nonwoven fabric or multi-layered fabric made of other suitable materials may be used, but care should be taken to select a material and structure that has water permeability, sufficient tensile strength, and abrasion resistance.

<3> Foot protection material (Fig. 3)
The foot protection material 3 is a member for holding down the sheet material 2 by load and fixing it onto the ground G.
The root protection material 3 comprises at least a bag body 31 and a filling material 32 filled inside the bag body 31.
The bag body 31 is made of a bag-shaped knitted fabric. More specifically, the bottom net is formed by narrowing the lower end of a cylindrical raschel knitted fabric made of, for example, polyester fiber, nylon fiber, or polyethylene fiber, and the opening on the upper end side is formed as the bag mouth. The mesh size of the bag body 31 is set so that the filling material 32 does not leak out.
The bag body 31 has a lifting rope 33 used for lifting and a mouth tying rope 34 for closing the mouth of the bag body 31.
The hanging rope 33 and the mouth tying rope 34 are attached by passing through the mesh near the mouth of the bag body 31 and going around it. The mouth tying rope 34 is located higher than the hanging rope 33 (closer to the bag mouth).
The filler 32 may be made of natural aggregate such as boulders, concrete rubble, or various types of fired waste.

<4> Placement of root protection material on sheet material The root protection material 3 is fixed to the sheet material 2 at several points on the lower part by connecting materials 35 such as ropes to the mesh of the bag body 31 of the root protection material 3 and the mesh of the sheet material 2.
Since the root reinforcement material 3 is a component intended to fix the sheet material 2 onto the ground G, it does not need to be installed without any gaps; it only needs to be installed at a specified interval, for example near the four corners of the expanded sheet material 2, so the protective structure 1 can be manufactured inexpensively.

<5> Protective Function of the Protective Structure The protective structure 1 of the present invention covers the submarine cable 4 with the sheet material 2, thereby protecting the submarine cable 4 from collisions with ship anchors, fishing gear, and boulders.
By covering the submarine cable 4 with the sheet material 2, gravel tends to accumulate on the upper part of the sheet material 2, and scouring around the submarine cable 4 is prevented.

<6> Method for protecting long seabed objects The suspension rope 33 of the protective structure 4, which is previously integrated with the sheet material 2 and the foot protection material 3, is attached to a suspension jig 5, and the suspension jig 5 is suspended above the sea surface above the submarine cable 4 to be protected by a crane (not shown) of a work ship or the like (FIG. 4(a)). The suspension jig 5 has a length approximately equal to the spacing of the foot protection materials 3 so that the sheet material 2 can be suspended in a stretched state.
Then, the hanging jig 5 is lowered into the sea, the sheet material 2 is laid on the submarine cable 4 to be protected, and the base protection material 3 is placed on the ground G with the submarine cable 4 covered with the sheet material 2 (FIG. 4(b)). Since the sheet material 2 is flexible, it deforms to follow the outer shape of the submarine cable 4 and protects the submarine cable 4. Moreover, the sheet material 2 itself will not damage the submarine cable 4.
Since the sheet material 2 is water permeable, it can be lowered to a specified position without being affected by tidal currents, etc., and installation work is easy. In addition, since the submarine cable 4 is protected by the sheet material 2 having a large area, a wide area of the submarine cable can be covered and protected at once, and construction time is shortened.

Reference Signs List 1 Protective structure 2 Sheet material 3 Foot protection material 31 Bag body 32 Filling material 33 Suspension rope 34 Tie-down rope 35 Connecting material 4 Submarine cable 5 Suspension jig

Claims (3)

A protection structure for a long undersea object that covers and protects a long undersea object laid on the seabed,
A sheet material having water permeability and capable of covering the seabed long object across the seabed long object ;
A plurality of foot protection materials are fixed integrally to the upper surface of the sheet material at intervals that allow the foot protection materials to be installed across the seabed long object , and have a positioning function for the sheet material .
Each of the plurality of foot protection materials has a bag body made of a knitted fabric and a filling material filled inside the bag body ,
The plurality of footing materials can be laid on the seabed ground with the sheet material covering the seabed long object .
A protective structure for long seabed objects. The protective structure for a long seabed object according to claim 1, characterized in that the sheet material is mesh-like. A method for protecting a long undersea object by covering the long undersea object laid on the seabed with a protective structure, comprising the steps of :
Using the protective structure for a long seabed object according to claim 1 or 2,
The protective structure is suspended by suspending the foot protection material while the sheet material is stretched.
The protective structure is lowered into the sea,
The method is characterized in that, with the long seabed object to be protected covered with the sheet material, the plurality of foot protection materials are placed on the seabed ground, and the long seabed object is protected by the sheet material.
A method for protecting long seabed objects.

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