JPS5953772B2 - How to lay a linear body on the seabed - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for laying linear bodies such as electric cables and water pipes on the seabed.

When a linear body is installed on the seabed, a protective tube is attached to the linear body to prevent the linear body from being damaged by various obstacles on the seabed.

These protective tubes are usually short and halved, and are attached to the linear body in sequence and tightened with bolts.

If these protective tubes are attached on the laying ship before the linear body is brought into the sea, the flexibility of the linear body will be reduced, so when the linear body with the protective tube attached is unwound, its own weight will cause most of the damage. Since it hangs down vertically and therefore bends at an angle of nearly 90° near the seabed, there is a risk that the linear body and the protection tube may be damaged.

For this reason, in the past, after the linear body was laid on the seabed, a diver attached a protective tube to the linear body on the seabed.

However, this method takes a long time and is inefficient.
Furthermore, it was not possible to install linear bodies in deep waters where diving was impossible.

An object of the present invention is to lay a linear body on the seabed that can be laid efficiently without requiring diving work, and in which the linear body and protective pipe are not damaged during installation. The purpose is to provide a method.

Embodiments of the present invention will be described in detail with reference to the drawings.
Figures 1 and 2 show the method of the present invention, in which a drum 14 containing a wire body 12 such as an electric cable to be laid on the seabed and a winch 18 containing a tension wire 16 are mounted on a laying ship 10. has been done.

A large number of protection pipes 20 are prepared on this laying ship,
These protective tubes are mounted on the drum 14 on the protective tube installation workbench 22.
They are sequentially attached onto the linear bodies 12 pulled out from the wafer and bolted as shown in FIG.

The tension wire 16 pulled out from the winch 18 is
As shown in FIGS. 1 and 2, the anchor 30 passes through the tension gauge 24 and the guide sheep 26 and is fixed at a predetermined position on the seabed 28.

A suspension workbench 32 is provided at the rear of the installation ship 10, and on this workbench, protective tubes 20 attached to the linear body 12 are suspended from tension wires 16 at intervals in the axial direction.

FIG. 3 shows an example of a means for suspending the protective tube 20 on the tension wire 16. Suspension rings 34 are clamped to the tension wire 16 at intervals in the axial direction, and the linear body 1
A connecting ring 36 is provided on the protective pipe 20A, which is attached to the protective pipe 20A corresponding to the hanging ring 34 on
At the top, the hanging ring 34 and the connecting ring 36 are connected by a connecting fitting 38.

It is preferable that this connecting metal fitting can be opened and closed with one touch.
Carabiner metal fittings used for mountain climbing are used.

In addition, in FIGS. 1 and 2, the reference numeral 40 is a guide member that guides the linear body with a protective tube suspended from the tension wire 16 into the sea.

The laying ship 10 travels to the left in FIG. 1 at a predetermined speed while paying out the linear body 12 and the tension wire 16.

The protective tubes 20 are sequentially attached to the linear bodies 12 on the protective tube installation workbench 22 of the installation ship 10, and the linear bodies with protective tubes are suspended from the tension wires 16 on the suspension workbench 32, and then placed into the sea. When retracted, the linear body with protective tube is guided to the seabed 28 at a predetermined catenary angle by the tension wire 16.

This catenary angle can be sufficiently confirmed on board the laying vessel by the movement of the pointer of the tension meter 24.

Therefore, if the tension wire 16 becomes slack and the reading of the tension meter 24 becomes small, the catenary angle is large and the protective tube-attached linear body exceeds its allowable range of flexibility, so the winch 1
The pulling speed of the tension wire 16 from 8 is slowed down to reduce the catenary angle.

In this way, the linear body with a protective tube can be brought into the sea at an appropriate catenary angle while monitoring the tension of the tension wire 16 with the tension meter 24.

In FIG. 1, position A of the tension wire 16 is the position when no linear body with a protective tube is suspended thereon, and position B is a position corresponding to the maximum allowable catenary angle of the linear body with a protective tube. be.

According to the present invention, as described above, the protective tube can be attached to the linear body on the laying ship rather than on the seabed, so the work efficiency can be significantly improved without requiring a diver, so it can be done in a short time. The work can be done economically, and since the linear body with the protective tube is suspended with a tension wire to maintain an appropriate catenary angle, the linear body and the protective tube will not be damaged by exceeding the allowable curvature. Furthermore, it can be easily installed even in deep sea areas with fast currents.

[Brief explanation of the drawing]

1 and 2 are a side view and a top view of a state in which the method of the present invention is carried out, and FIG. 3 is an enlarged side view of means for suspending a linear body with a protective tube from a tension wire. 10... Laying ship, 12... Linear body, 1
4...Drum, 16...Tension wire, 18...Winch, 20, 20A...
...Protection tube, 24...Tension meter, 28...
... Seabed, 30 ... Anchor, 34 ... Curved suspension ring, 36 ... Connection ring, 38 ... Connection fitting.

Claims (1)

[Scope of Claims] 1. A method for laying a linear body on the seabed, in which a large number of half-split protection pipes are attached to the linear body when the linear body is pulled out from a drum on a laying ship and is laid on the seabed. , the pulling end of a tension wire pulled out from a winch mounted on the laying ship is fixed in a predetermined position, the protective tube is sequentially attached to the linear body on the laying ship, and then the tension wire is attached to the tension wire in its axial direction. The wire is laid by suspending the protective tubes attached to the linear body at intervals, and bringing the tension wire and the linear body to which the protective tubes are attached into the sea. A method of laying a structure on the seabed. 2 Hanging rings are clamped to the tension wires at intervals in the axial direction, a protective pipe corresponding to the hanging rings has a connecting ring, and the tension wire and the protective pipe are connected to each other by a connecting fitting to connect the hanging ring and the connecting ring. A method of laying on the seabed the linear bodies according to claim 1, which are connected and suspended by.