JPH11299035A - Submarine cable protecting construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a submarine cable protecting construction method by which the worker can induce a protecting mat accurately on a submarine cable, without being affected by the working environment, tidal currents, depth, etc., and can surely install the protecting mat without confirming the position of the submarine cable with a specified measuring device. SOLUTION: An arm 10 is attached to a cable landing guide means set in advance on a submarine cable 1, and one end of a guide wire 11 is attached to the rear end of the arm 10, and a pontoon is attached to the other end of the guide wire 11 so that it can always be confirmed, at sea, the position of the guide wire 11. While the laying of the submarine cable 1 is being conducted and while monitoring the landing situation of the submarine cable 1 with a video camera 14 mounted on the cable landing guide means, and when the protection of the submarine cable 1 becomes necessary, the construction boat is once stopped and recovers the pontoon, and fixed the top of the guide wire 11 which is hauled in attendant upon this onto the protecting boat, and passes a frame for protecting mat installation on this, and lowers this frame for protecting mat installation to the bottom of the sea along the guide wire 11, thus this serves the installation of the protecting mat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of protecting a submarine cable, and more particularly to a method of installing a submarine cable protection mat.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional example of a submarine cable protection method. The position of a submarine cable 1 laid on the seabed is confirmed by a positioning technology such as a DGPS system (differential GPS), and an anchor is installed. 8 to moor the protection ship 2.

[0003] Next, a protective mat 5 is mounted on the boat 6 on a frame 6 on which the underwater television camera and the tri-sponder are mounted, and the wire 4 wound around the winch 7 via the A-type frame 3 is loosened to mount the protective mat on the frame. A method is adopted in which the protection mat 5 is dropped on the seabed, the protection mat 5 is separated just above the seabed cable 1, and the protection mat 5 is installed.

[0004]

The above-mentioned prior art; the submarine cable protection method shown in FIG. 3 has the following problems.

A frame 6 used for installing the protective mat 5
The guide wire 4 used when lowering the seabed to the seabed is held only by the winch 7 on the protection ship 2, and the guidewire 4 becomes free on the seabed side. It will be difficult to accurately set it on top. (A) The frame 6 is easy to move due to the influence of the tide and has no stability. (B) When the work is performed in the deep sea exceeding 100 m, the twist of the guide wire 4 returns and the frame 6 rotates.

[0006] Since a series of work related to the protection method is performed after the submarine cable laying is completed, it is necessary to find out the position of the submarine cable laid by DGPS or the like, which is troublesome and inefficient.

Therefore, the problems to be solved by the present invention (objects)
Can accurately guide the protective mat on the submarine cable without being affected by the tide, depth, etc., and can securely install the protective mat without confirming the position of the submarine cable with a specific measuring device. To provide a cable protection method.

[0008]

SUMMARY OF THE INVENTION The submarine cable protection method provided by the present invention extends the arm backward to the cable bottom guide means which is preliminarily passed through the submarine cable and is located immediately before the bottom of the submarine cable. Attach so that
Attach one end of the guide wire to the rear end of this arm,
A pontoon is attached to the other end of this guide wire so that the position of the guide wire can always be confirmed on the sea behind the laying ship. While laying the submarine cable while monitoring the situation, when it became necessary to protect the submarine cable, the laying boat was temporarily stopped and the pontoon was recovered, and the guide wire pulled along with this was The upper end is fixed on a protective ship, a protective mat installation frame is passed through it, and the protective mat installation frame is lowered to the seabed along a guide wire to provide the protective mat.

According to the above protection method of the present invention, since the guide wire extends upward from the target to be protected; the bottom of the submarine cable behind the cable bottom guide means, and emerges above the sea, The position of the submarine cable can be clearly confirmed without conducting cable exploration before the protection work.

[0010] Further, since the guide wire is fixed to the cable bottom guide means on the sea bottom and to the protection ship at the sea, the protective mat installation frame lowered along the guide wire is not affected by the tide. The submersible cable can be guided directly above the submarine cable regardless of the depth, so that the protective mat can be securely installed at the position where the submarine cable is to be protected.

One arm is provided on each side of the cable bottom guide means, and a guide wire is attached to these arms, so that two guide wires flow behind the cable bottom guide means. The posture of the protective mat installation frame can be stabilized.

[0012] The guide wire is made longer than the maximum water depth of the cable laying route, and the pontoon is always floated on the sea, thereby making it easier to confirm the guide wire.

[0013]

1 and 2 show a preferred embodiment of a submarine cable protection method according to the present invention.
FIG. 1 shows the state of the submarine cable laying work and the preparatory work of the protection method, and FIG. 2 shows the actual work state of the protection method.

As shown in FIG. 1, the protection method of this embodiment uses a cable bottom guide means 9 on which a video camera 14 is mounted. Reference numeral 15 denotes an umbilical cable for supplying power to a video camera or the like, or connecting the video camera 14 to a monitor on a laid ship.

The cable bottom guide means 9 itself is already provided as a means for guiding the bottom of the submarine cable 1 by passing through the submarine cable 1 and being positioned immediately before the bottom of the submarine cable, but in this protective construction method, It consists of a method of using the cable bottom guide means 9 to develop unique technical means.

That is, the arm 10 is attached to both sides of the cable bottom guide means 9 so as to extend rearward, and one end of a guide wire 11 is attached to the rear end of the arm via a shackle 13, and the other end of the guide wire 11 is attached. Attach a pontoon 12 to the end, so that the guide wire 11
Flow two in parallel behind the cable bottom guide means,
This can be confirmed on the sea behind the laying ship.

The arm 10 is made of a steel material and welded to the cable bottom guide means 9 so that the arm 10 can withstand the total weight of the protective mat installation frame and the protective mat related to the guide wire in a later-described operation. To

The guide wire 11 is made longer than the maximum water depth of the cable laying route so that the pontoon 12 is always floated on the sea, so that the guide wire 11 can be surely confirmed on the sea. I have.

When the preparatory work for the protection method described above is completed, the submarine cable 1 is drawn out from the laying ship and laid on the seabed as shown in FIG. At this time, the submarine cable 1 is guided by the cable bottom guide means 9 immediately before landing on the seabed, then landed on the seabed, and is laid along a predetermined laying route. During this installation work, the video camera 14 constantly monitors the state of the bottom of the submarine cable 1.

If it is determined that protection is required at the portion where the submarine cable is laid, the laying ship is temporarily stopped, the pontoon 12 is recovered, and the operation proceeds to the actual work of the protection method. That is, as shown in FIG. 2, the upper ends of the two guide wires 11 brought together with the collection of the pontoons are fixed to winches or the like on the protection ship, and are stretched up and down at regular intervals as shown in FIG.

The protective mat installation frame 6 is connected to the guide wire 11 through a shackle so that the guide wire 4 can be passed through the shackle, and the guide wire 4 in the protective mat installation frame 6 is loosened by operating the winch, thereby providing protection. The protective mat installation frame 6 on which the mats 5 are installed is lowered to the seabed along the guide wire 11. Then, when they reach just above the submarine cable 1, the protection mat 5 is separated and installed on the submarine cable 1, and a series of actual operations is completed.

The protective mat 5 has a mat body filled with asphalt, concrete and mortar.

[0023]

According to the present invention as described above, the protective mat can be accurately guided on the submarine cable without being affected by the working environment; tide, depth, etc., and the position of the submarine cable can be determined by a specific measuring device. The intended task (objective) of providing a submarine cable protection method capable of securely installing a protection mat without confirmation can be achieved.

The effects of the submarine cable protection method of the present invention are as follows. Since the guide wire can be confirmed on the sea, exploration of the submarine cable is unnecessary, the work is easy, and exploration equipment such as DGPS is unnecessary, so that it is economical. A guide wire is fixed at the sea bottom (the target position of the protection mat and the top of the ship), and the frame for setting the protection mat passed through the guide wire is lowered. The mat can be guided and installed.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a preparatory work state of a protection method at the time of laying a submarine cable according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a production work situation of a protection method for a submarine cable according to the embodiment of the present invention.

FIG. 3 is an explanatory view showing a state of a protection method for a laid submarine cable in a conventional example.

[Explanation of symbols]

 1 Submarine Cable 9 Cable Bottom Device 10 Arm 11 Guide Wire 12 Pontoon 13 Shackle 14 Video Camera 15 Umbilical Cable

Claims (3)

[Claims] 1. A method of installing a protective mat on a submarine cable laid on the seabed, wherein the arm is provided on a cable-bottom guide means which is passed through the submarine cable in advance and is located immediately before the bottom of the submarine cable. Attach one end of the guide wire to the rear end of this arm and attach a pontoon to the other end of this guide wire so that the position of the guide wire can always be confirmed at sea behind the laying ship, While laying the submarine cable while monitoring the submarine cable landing status with a video camera mounted on the cable landing guide means in such a posture,
When it becomes necessary to protect the submarine cable, the laying boat is temporarily stopped to collect the pontoon, and the upper end of the guide wire drawn along with it is fixed on the protective ship, and a protective mat installation frame is attached to this. The submarine cable protection construction method, in which the frame for installing the protective mat is lowered to the seabed along a guide wire for the installation of the protective mat. 2. An arm is provided on each side of the cable bottom guide means, and one guide wire is attached to each of the arms, so that two guide wires flow behind the cable bottom guide means. Item 2. The submarine cable protection method according to Item 1. 3. The submarine cable protection method according to claim 1, wherein the guide wire is longer than the maximum water depth of the cable laying route so that the pontoon is always floated on the sea.