JPH09200940A - Method of laying underwater cable repair connection box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a cable from becoming smaller than the tolerable radius of curvature when laying a repair connection box, in the repair work of an underwater cable. SOLUTION: On a work boat 5, the section 1a without a damage to an existing underwater cable 1 and a cut-in cable 1d substituted for the section removed by the damage are connected with each other through a repair connection box 2, and a float 10 is attached to the repair connection box 2. The repair connection box 2 and the float 10 are thrown into water while advancing the work boar 5 so as to lay the repair connection box 10 on the bottom of water. The underwater weight of the repair connection box 2 becomes the same as a cable by the buoyancy of the float 10, and the repair connection box 2 sinks slowly in the water, and lands on the bottom of the water slowly. Accordingly, the cable can be prevented easily and surely from being curved to be smaller than the tolerable radius of curvature by the weight of the repair connection box 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new cable that replaces an existing submarine cable part that has not been damaged and a part that has been removed due to damage in the submarine cable repair work when the existing submarine cable (mainly a submarine cable) is damaged. That is, the present invention relates to a method for laying a water-bottom cable repair connection box in which a repair connection box for connecting an interrupt cable is laid on the water bottom.

[0002]

2. Description of the Related Art FIGS. 4 (a) and 4 (b) show how to repair a submarine cable when an existing submarine cable is damaged.
Fig. 4 (a) shows the situation before the repair of the submarine cable, and Fig. 4 (b) shows the situation after the repair. In the figure, 1 is an existing water bottom cable, 1a and 1b are undamaged portions of the water bottom cable 1, and 1c is a damaged portion (a portion between AB).
In the repair work of the submarine cable 1, the damaged portion 1c of the submarine cable 1 is cut and removed, and the removed portion 1c is removed.
Instead of this, a new cable, that is, an interrupted cable 1d is laid. In this case, first, the existing water bottom cable 1a and the interruption cable 1d are connected via the repair connection box 2, and after the repair connection box 2 is laid on the water bottom, the other end of the interruption cable 1d and the other end are connected. Existing submarine cable 1b
Are connected via the repair junction box 3 and then this repair junction box 3 is laid on the bottom of the water.

Conventionally, when the first repair junction box 2 connecting the above-mentioned interrupt cable 1d and one existing underwater cable 1a is laid on the water bottom, the repair junction box 2 is simply combined with the interrupt cable 1d and the underwater cable 1a. It was submerged.

[0004]

In the work of laying the repair junction box 2 described above, if the bending radius of the cable (water bottom cable 1a or interrupting cable 1d) becomes smaller than the allowable bending radius, the cable may be damaged. Because there is
It is necessary to prevent the cable from being bent smaller than the allowable bending radius. However, in the conventional method of laying the repair junction box, the portion of the submarine cable 1a near the repair junction box 2 is easily bent smaller than the allowable bending radius. There was a problem. That is, since the repair junction box 2 is simply submerged,
The heavy repair junction box 2 suddenly sank and dropped a little more violently to the bottom of the water, so that the existing submarine cable 1a
Also, there is a problem that a portion that can be bent smaller than the allowable bending radius is likely to occur on either side of the interruption cable 1d.

The present invention has been made to solve the above-mentioned conventional drawbacks, and is a method of laying a submarine cable repair connection box capable of easily and reliably preventing the cable from becoming smaller than the allowable bending radius. The purpose is to provide.

[0006]

A method of laying a submarine cable repair junction box of the present invention which solves the above problems connects an existing submarine cable part without damage and an interrupt cable replacing the part removed by damage. A floating body is attached to the repair connection box, and the repair connection box and the floating body are put into water while the work boat is moving forward to lay the repair connection box on the bottom of the water.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will now be described with reference to FIGS.
This will be described with reference to FIG. The procedure for repairing the submarine cable when the present invention is applied is the same as that described with reference to FIGS. 4 (a) and 4 (b), but in this embodiment, the first repair junction box 2 is laid. is there. First, on the work boat 5, a cable that replaces the existing one water-bottom cable 1a that is not damaged and the damaged portion 1c, that is, the interruption cable 1
d is connected via the repair junction box 2. Interruption cable 1
The d is fed from the cable supply device 6 of the drum winding type, the coil taking type, or the turntable type on the work boat 5. Next, the floating body 10 is attached to the repair connection box 2. Then, the repair junction box 2 and the floating body 10
As shown in FIG. 2, the work boat 5 is put into the water from the stern, and then the work boat 5 is advanced as shown by an arrow to lay the repair connection box 2 on the bottom of the water as shown in FIG. Then, the floating body 10 is collected. It is appropriate that the floating body 10 generate buoyancy such that the underwater weight of the repair junction box 2 becomes the same as that of the cable. As the floating body 10, for example, Styrofoam, a rubber balloon, a rubber balloon housed in a frame, or any other suitable body can be used.

If the repair joint box 2 is put into the water from the work boat 5 without attaching the floating body, the heavy repair joint box 2 suddenly sinks and drops a little more violently to the bottom of the water. On both sides of the submarine cable 1a and the interrupting cable 1d, a portion bendable smaller than the allowable bending radius is likely to occur. However, in the above-mentioned laying method, since the underwater weight of the repair connection box 2 is almost the same as the cable due to the buoyancy of the floating body 10, the repair connection box 2 thrown into water gently sinks and the bottom of the water quietly. Therefore, it is extremely unlikely that the cables 1a and 1d will be bent to a radius smaller than the allowable bending radius. The linear control of the cable, that is, whether the cable is kept larger than the allowable bending radius can be easily performed on the work boat 5 by controlling the cable tension.

After the repair connection box 2 is laid,
When installing the second repair connection box 3 connecting the other end of the interruption cable 1d and the other water bottom cable 1b on the water bottom,
Normally, the repair junction box 2 needs to be moved in the left-right direction of the work boat 5, so the method of the present invention is not necessarily appropriate, but the method of the present invention is adopted for the second repair junction box. It does not exclude things.

[0010]

According to the present invention, the floating body is attached to the repair connection box to lay the repair connection box. Therefore, the underwater weight of the repair connection box when laying the repair connection box is reduced, and the weight of the repair connection box is reduced. It is possible to easily and surely prevent the cable from being bent smaller than the allowable bending radius. Therefore, the workability of laying the repair junction box is also improved.

[Brief description of drawings]

FIG. 1 is a side view illustrating an embodiment of a method of laying a water-bottom cable repair junction box of the present invention, showing a situation before the repair junction box is put into water.

FIG. 2 is a side view for explaining a step following FIG. 1 in the laying method of the one embodiment, showing a state where the repair connection box is put into water.

FIG. 3 is a side view for explaining a step following FIG. 2 in the laying method of the one embodiment, showing a state in which the repair connection box has landed on the water bottom.

[Fig. 4] Fig. 4 is a view for explaining the repair procedure of the submarine cable when the submarine cable is damaged.

[Explanation of symbols]

 1 Underwater cable 1a Undamaged part of existing underwater cable 1d Interruption cable 2 Repair connection box 5 Work boat 10 Floating body

Claims (2)

[Claims] 1. A floating body is attached to a repair connection box that connects an existing undamaged cable and an interrupted cable that replaces the part removed due to damage, and the repair connection box and the floating body are moved while the work boat is being advanced. A method for laying a submerged cable repair connection box, which comprises immersing the repair connection box in water to lay it on the bottom of the water. 2. The method for laying a submerged cable repair junction box according to claim 1, wherein the floating body is one that causes buoyancy so that the underwater weight of the repair junction box is substantially the same as the cable.