JPH028523B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a method for burying long submarine bodies (such as submarine cables and water pipes) during landing operations, and particularly relates to a method for guiding long submarine bodies floating on the sea to a burying machine. It is something.

PRIOR ART Many of the places where long submarine bodies are unloaded are so shallow that construction ships cannot enter. Therefore, normally, as shown in FIGS. 1 and 2, a long submarine body 10 is first brought out from a laying ship onto the sea surface 12, and a buoy 14 is attached to it to float it. Then the submarine long body 10
After pulling the tip of the cable up to land by a required length, the long submarine body 10 between the shore and the laying ship is buried in the ocean floor 16.

There are the following methods of burying it (Unexamined Japanese Patent Publication No.
57-46608).

That is, first, a small boat 18 with shallow water is prepared. Guide means, such as rollers 20, are provided on the small boat 18.

A towing wire 22 then connects the boat 18 and the burial machine 24. Note that 26 is a sled of the burying machine, 28 is a digging body, and 30 is a passage for the seabed long body 10. Note that 32 indicates a water jet for digging.

A channel conduit 34 is provided to guide the seabed elongated body 10 from the small boat 18 to the entrance of the passage 30 of the burial machine 24. This is a conventional birdcage link and is attached to the tow wire 22.

Then, for example, the burying machine 24 is strongly pulled by a tow wire 36 from a laying ship or the like via the small boat 18. As the burying machine 24 advances, the long seabed body 10 is gradually pulled into the water, but at that time, the buoy 14 is removed on the small boat 18, and the roller 20,
The conduit 34 enters the channel 30 in the burial machine 24 through the guide device and enters the groove 17 created by the burial machine 24.
It is being laid down inside.

However, the above method has the following problems.

(1) The angle α of the pulling wire 22 and the angle β of the excavating body 28 are not always equal. As described above, since the towing conduit 34 is attached to the tow wire 22 and the elongated seabed body 10 passes through the elongated seabed body 10, α is also the angle of the elongated seabed body 10 in the water. If α and β are different, the long seabed body 10 may be subjected to excessive bending at the entrance of the passage 30 and may be damaged.

Furthermore, when the seabed 16 is uneven, the burying machine 24 moves while pitching or yawing significantly. In those cases, the seabed elongated body 10 is connected to the passage 30 in the same manner as described above.
undergoes excessive bending at the entrance.

(2) The elongated submarine body 10 floating on the sea surface 12 is usually not straight but has a large snake shape. For this reason, the small boat 18 does not proceed immediately, but instead moves forward while swinging its bow toward the snaked long submarine body 10. Since the burying machine 24 is pulled through such a small boat 18, control of the burying machine 24 becomes very difficult.

(3) It takes time to install the pipeline 34.

There are problems such as.

It should be noted that the above problem is caused by the use of the skiff 18 and the conduit 34. Therefore, without using them, the whole of the floating long seabed body 10 sent out to sea from the laying ship was immediately sunk into the seabed 16, and the sunken long seabed body 10 was buried from the end by the burying machine 24. There is also a way to do so.

However, the long seabed body 10 sunk to the seabed 16 is not straight and often snakes. It is very difficult to pull the burying machine 24 along such a snaked long seabed body 10.

Purpose of the Invention Instead of using the method described immediately above in which the entire submarine elongated body 10 is sunk in the seabed 16 and then buried, it is possible to sequentially construct the submarine elongated body 10 floating on the sea as described at the beginning. This method uses a method of burying the vessel while being drawn into the water, and also eliminates the problems caused by using the small boat 18 and the conduit 34 described in (1) to (3) above.

Configuration of the invention (Figure 3) (1) A buoy 14 is attached to the long seabed body 10 and the sea surface 1
After that, the advancing burying machine 24 floats on the seabed long body 10 floating on the sea surface 12.
(2) Instead of using a small boat 18 as in the conventional example described above, the long submarine body 10 that is being pulled into the water is buried under the buoy 14.
(3) so that the seabed long body 10 has enough slack to fit into the passage 30 in the excavation body 28 of the burying machine 24 without being subjected to large bending; The number of buoys 14 attached to the long seabed body 10 underwater is determined, and the number is kept constant.
It is characterized in that the lowest one of the buoys 14 attached to the long seabed body 10 is successively removed underwater as the burying machine 24 advances.

Detailed explanation of the configuration (Figure 3) As mentioned above, in this case, without using the small boat 18,
The embedding machine 24 is pulled directly by the traction wire 36.
Note that the burying machine 24 may be made to run on its own.

It also eliminates the need to use the drain conduit 34 (more on this later), thereby eliminating the problems associated with the drain conduit 34.

First, near the coast, the long seabed body 10 from which the buoy 14 has been removed is connected to the passage 30 in the excavation body 28 of the burying machine 24.
will be sunk deep into the sea and installed on the seabed 16.

Then, the burying machine 24 is pulled strongly. Burying machine 24
As the seabed progresses, the long seabed body 10 floating on the sea is gradually drawn into the water from the end. At this time, the submarine elongated body 10 is pulled in with the buoy 14 attached without removing the buoy 14 on the sea surface 12 as described above.

However, the buoy 14 is not kept attached over the entire length of the long seabed body 10 from the sea surface 12 to the burial machine 24. So that the long seabed body 10 in the water can have an appropriate slack.
Determine the number of buoys 14 in the water. The appropriate slack is as follows. In other words, the long seabed body 10a (imaginary line) in “Figure 3” is the buoy 14.
This figure shows a large sagging state when all of the seabed bodies 10a are removed, but when this happens, the seabed elongated body 10a is forced to bend at the entrance of the passage 30 in the burying machine 24, and it is not smoothly inserted into the passage 30. cannot enter. Therefore, the buoyancy of the buoy 14 is used to reduce the slack so that the long submarine body 10 can enter the passage 30 without being subjected to large bends.

Once the number of buoys 14 in the water is determined as described above, as the burying machine 24 advances, the lowest (lowest) buoy 14 attached to the long seabed body 10 is (closer to the burial machine 24) are successively removed by, for example, a diver 38. That is, when one buoy 14 is pulled into the water, the lowest one buoy 14 is removed, and so on.

Note that the long seabed body 10 guided into the burying machine 24 is laid in the groove 17 created by the burying machine 24 as before.

While repeating the above steps, the seabed long body 10
Complete installation of.

Effects of the Invention (1) As the burying machine 24 advances, the long seabed body 10 is successively drawn into the water with the buoy 14 attached, and the long seabed body 10 is not subjected to large bending. The number of buoys 14 attached to the long seabed body 10 underwater is determined so that the buoys 14 have enough slack to fit into the passage 30 in the excavation body 28 of the burying machine 24, and the number is kept constant. In this way, the lowest one of the buoys 14 attached to the long seabed body 10 is removed one after another in the water as the burying machine 24 advances. There is no need to use the air conduit 34.

When using a conventional cable conduit 34, the cable conduit 34 is connected to the tow wire 22 as described above.
Since the long seabed body 10 is passed through the conduit 34, the inclination of the long seabed body 10 with respect to the seabed 16 in the water is determined by the tow wire 22, and therefore the buried machine In some cases, the submarine long body 10 was subjected to excessive bending at the entrance of the passage 30 of No. 24.

However, in this case, since the air conduit 34 is not used, these problems are eliminated.

Also, there is no need to take the trouble of installing the inlet conduit 34.

(2) Since the buoy 14 is attached to the long seabed body 10 underwater, the long seabed body 10 will not be subjected to excessive bending at the position where it is pulled into the water (A in Figure 3). If the buoy 14 is not attached, it will curve sharply at A, like the long seabed body 10a in "Figure 3").

(3) The long submarine body 10 floating on the sea surface 12 is usually snaked as described above, but in this case, it is connected to the burial machine 24 via the small boat 18 as in the past.
Since the purpose is not to tow and pull the seabed long body 1.
There is no particular problem even if 0 is snake.

[Brief explanation of drawings]

FIG. 1 is a side view for explaining the prior art, FIG. 2 is a plan view thereof, and FIG. 3 is an explanatory diagram of an embodiment of the present invention. 10: Long seabed body, 12: Sea surface, 14: Buoy,
16: Sea surface, 24: Buried machine, 36: Towing wire, 38: Diver.

Claims (1)

[Scope of Claims] 1. When unloading a long seabed body, a buoy is attached to the long seabed body to float it on the sea surface, and then a burial machine that is towed or moves under its own power, In the method for burying a long seabed body, the long seabed body is successively drawn into the water from one end and buried, in which the seabed long body is successively drawn into the water as the embedding machine advances as described above. The long body is drawn in with the buoy attached, and the seabed long body has enough slack to fit into the passage in the excavation body of the burying machine without being subjected to large bending. In order to determine the number of buoys attached to the elongated body and to keep the number constant, the lowest buoy attached to the elongated seabed body is used as the buoy when the burial machine advances. A method for burying an elongated body on the seabed, characterized by sequentially removing it underwater.