JPS583509A - Method of laying and burying submarine cable by conduit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for installing submarine cables, water pipes, etc. on the seabed.

Traditionally, submarine cables have been installed using EK and buried.
As shown in Figure 1, a large number of ring-shaped metal fittings called 1114 pipes 4 are lined up and attached to the towing wire 8 that connects the burial machine 1 on the seabed and the laying work boat 2t, and a couple A is installed in each of the conduit pipes 4. Then, the cable A is supported by the towing wire 8 through the pipe 4, and the cable A is passed through the Hibiki 41w4 by the length that the burial machine 1 moves forward, while preventing the cable A from falling freely due to its own weight due to the water depth. A known method is to install and proceed.

This method does not require any free-falling of the couple, does not require difficult operations such as brake control, etc., and is widely used as a very effective cable feeding method for signal production and the installation of bottomless power cables.

However, due to recent power supply location and other issues, everyone! If the power transmission valley cover of li1 is large9, and the installation range is limited, or if three ultra-large submarine cables are laid and buried at the same time, the weight of cable A supported by conduit 4 will be large. ], a new problem arises in that it is no longer possible to maintain the catenary shape suitable for laying the conduit 4, and the cable A cannot be fed out.

For example, in the case of supporting three cables of 75 edges/bulk with a sound conduit, when water tl 40 m fiM f tows the burial machine 1 having an underwater weight of 201, the construction work vessel 2 and the burial machine 1
There is a limit to the catenary shape suitable for laying the tow wire 8, that is, the cable conduit 4, between the cables 10 and 10, and if the cable depth or water depth exceeds that, the catenary shape is no longer suitable for the cable, and the catenary shape is no longer suitable for installation near the water surface. If the cable A were not inserted vertically, the alignment of the w-special pipe 4 would be disrupted, making it impossible to lay the couple A.

In other words, the catenary shape of the I#14 pipe 4 is determined by the length of the cable 1, the water depth, and the resistance of the burial machine 1.
As shown by the broken line in Figure 1, from the laying work vessel 2 to the general machine I.
While the catenary shape maintains a substantially linear angle at t, the cable A is smoothly fed out to the burial machine L.

However, when the product of cable weight x water depth becomes large, the resistance of the digging machine 1 alone cannot maintain the catenary shape suitable for laying, and even if the cable laying work vessel 2 stops moving, the cable weight alone causes the burying machine 1 to move forward. As shown by the solid line in FIG. 1, the burying machine 1 approaches the laying work vessel 2, and the catenary shape of the sound conduit 4 has a vertical portion 4a at the top and a horizontal portion 4 at the bottom.
b has occurred.

In the vertical portion 4a, as shown in FIG.
! The tube 4 is twisted in the furnace tube 4, making it impossible to feed out the cable A.

In addition, there is a problem that the cable A cannot be cleaned smoothly in the horizontal portion 4b, and it becomes impossible to lay the cable A due to the vertical portion 4a.

This invention was made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a method that can install heavy pulls and water pipes in deep water locations. .

The structure of the present invention is such that the towing wire to which the sound conduit is attached is suspended midway from a construction work boat to maintain the catenary shape used for laying the tatami conduit.

The present invention will now be explained based on the embodiment shown in FIG.

As shown in the figure, the tow wire 8 connected to the excavation machine 1 is taken by a winch 5 on the construction work boat 2 via a sheave 6,
A cable coil 7 made by winding the cable A into a coil is loaded so that the work boat 2 can move the burial site 1 forward. A large number of 41 fathom tubes 4 are connected to the pulling wire 8.
The couple Ati, arranged in a line and drawn out from the cable coil through the guide device 8, is guided through the analogous conduit 4 to the excavator 4 & 1, and the excavator 1 runs in front of the excavator 9. The lengths are drawn out one after another and buried in the sea rat.

In order to prevent the catenary shape suitable for laying the above-mentioned I#I4 pipe 4 from collapsing due to the amount of cable A, the middle of the towing wire 8 is suspended from 2 to 8 points from above the work boat 2 using a wire 9. I support mh.

To attach each suspension 9 wires 90 to the work boat 2, we used a Yagura IQ installed on the East Ship 2 as shown in the figure so that a part of it protruded out of the ship, but other supporting ditches protruding into the sea were used. :#Lt
May be adopted.

In this way, when the tow wire 3 that supports the weight of the cable A is suspended from the work boat 2 by the hanging wire 9, the weight of the cable A is supported by the hanging shear wire 9. Since part of the weight of the cable will be transferred to the tow wire 3 and the burial machine 1 will not move forward due to the weight of the cable, the catenary shape suitable for laying the I# conduit 4 is designed as shown in Fig. 2. Therefore, even a heavy cable A can be laid.According to the present invention, even a heavy cable A can be laid. ) Since the cable is suspended by a wire, part of the weight of the cable can be supported by the hanging wire, and the catenary shape suitable for installing acoustic conduits is always maintained, making it possible to carry heavy cables in deep water. For example, it is possible to lay three cables of 75 kg/m at a depth of 40 m or more.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a conventional burying method, and FIG. 2 is an explanatory diagram of a burying method according to the present invention. 1... Burying machine 2... Work boat 8... Towing wire 4... Four pipes 9... Hanging shear wire 10...
・Yagura A...Cable Figure 1 Figure 2

Claims (1)

[Claims] When installing or burying cables, water pipes, etc. along the inside of the conduits along the inside of the conduits for S-bottom Km from the installation work boat, attach the tatami conduits of rhombus-sized tatami conduits to the tow wires in a nine-way arrangement. A method for laying and burying submarine cables, etc. using tatami conduits, which is characterized in that the work is carried out while maintaining the tenary shape (which supports tm* and is suitable for guiding III conduits).