JPH0726706B2 - How to remove the underwater pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a water-bottom buried pipe for economically removing a water-bottom buried pipe such as an oil transmission pipe buried in a seabed or the like with a minimum amount of dredging work. Regarding the removal method.

[Conventional technology]

Conventionally, in order to remove the underwater buried pipe that is buried in the seabed, etc., after removing the sediment around the buried pipe over the entire length of the buried pipe with a grab dredging ship or water jet, cut the buried pipe to an appropriate length. Then, the method of hoisting by a hoist ship was taken.

However, if the removal of the water bottom buried pipe is performed by the conventional method, it is necessary to remove a considerable amount of sediment by dredging etc. over the entire extension of the buried pipe, and also a place to temporarily store the sediment is required, and the dredging work There was a problem that it became uneconomical because of the large scale.

[Problems to be Solved by the Invention]

The present invention has been made to solve the above conventional problems, and economical removal can be performed by reducing the amount of earth and sand dredged when removing the buried pipe buried in the water bottom. The problem to be solved is to provide a method for removing the underwater buried pipe.

[Means for Solving the Problems]

As a means for solving the above problems, the method for removing a submerged buried pipe of the present invention is, for each predetermined length of the submerged buried pipe, dredge the periphery of the buried pipe with a grab dredger or the like, and water by a diver. After excavating the earth and sand remaining around it by jet injection, etc., removing the earth and sand and cutting the buried pipe with a diver, etc., wire the cut buried pipe from the end of it from a crane ship, etc. While pulling up, the soil on the top of the buried pipe is gradually loosened by the high-pressure jet water ejected from the nozzle of the high-pressure water jet unit, etc. over the entire length of the cut length of the buried pipe. It is constructed by repeating the work of pulling it up on a ship, etc., and it is possible to remove the buried pipe over the entire length of the buried pipe without dredging the sediment above it. And it has a feature that kill.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1A is a side view showing the first dredging work of water bottom sediment when removing a water bottom buried pipe by the method of the present invention, FIG.
FIG. B is a front view of FIG. 1-A, FIG. 1-C is a plan view of FIG. 1-B, and FIG. 2 is a front view showing earth and sand removing work of an upper portion of a buried pipe by high-pressure jet water, and FIG. Is a side view showing the cutting work of the buried pipe, FIGS. 4 and 5 are side views showing the pulling work of the buried pipe, and FIG. 6 is an enlarged front view of the high-pressure water jet unit of FIG. Is.

First, as shown in FIG. 1-A, FIG. 1-B and FIG. 1-C, in this embodiment, a buried pipe 1 such as an oil feeding pipe buried in the ground of the water bottom B is shown in FIG. For each length D, the surroundings of the buried pipe 1 are dredged by the grabs 3 of the grab dredger 2, and the dredged earth and sand is shot 5 via the chute ship 4.
Thus, the temporary earth 6 is temporarily placed on the ground of the water bottom B in the vicinity thereof.

Next, as shown in FIG. 2, the diver 7 excavates the earth and sand remaining around the above-mentioned buried pipe 1 with a water jet using the fountain / jet dredger 21, and the earth and sand around the buried pipe 1 is excavated. Completely remove.

Further, as shown in FIG. 3, the digger 7 cuts the excavated buried pipe 1. In this embodiment, the buried pipe 1 is an oil feed pipe, which is shown in a cut state. The operation is performed while collecting the oil leaking from the pipe 1 using the oil recovery membrane 8.

That is, the oil recovered by the oil recovery film 8 stretched in water by the wire rope 9 in FIG. 3 is transferred onto the work boat 12 via the flexible hose 11 with the valve 14 suspended by the float 10. Is recovered in the recovered oil storage tank 13, while the air recovery compressor 8 on the work boat 12 sends air to the oil recovery film 8 via the air lift air supply hose 16.

Next, as shown in FIG. 4, the end of the cut buried pipe 1 is covered with a wire 17 and pulled up by a swing-type crane ship 18 while the earth and sand above the buried pipe 1 are cut and buried at a predetermined length D. A plurality of jet nozzles 20 extending from the high-pressure water jet unit 19 on the work boat 22 shown in FIG. 6 toward the water bottom B over the entire length of the pipe 1, for example, nine jet nozzles 20 in this embodiment.
The high-pressure jet water J ejected more gradually loosens, and the buried pipe 1 for each predetermined length D is pulled up by the crane ship 18.

In this case, as shown in FIG. 5, the buried pipe 1 is moved sequentially from the end of the buried pipe 1 where the slinging position of the wire 17 by the crane ship 18 is cut from the state of FIG. The work of hoisting up will be repeated, but
The buried pipe 1 pulled up in this way is carried on a berth 30 or the like moored on a crane boat 18 for pulling up.

〔The invention's effect〕

According to the method for removing a submerged buried pipe of the present invention described above, since only the cutting portion for each predetermined length of the buried pipe is dredged, the dredging work amount is significantly reduced, which is a very economical removal work. There is an effect.

In addition, the dredged soil can be temporarily placed near the dredged water bottom ground, and there is no need to provide a separate place for the dredged soil, which has the advantage of improving work efficiency.

[Brief description of drawings]

FIG. 1-A is a side view showing the first dredging work of water bottom sediment when removing a water bottom buried pipe by the method of the present invention, FIG. 1-B is a front view of FIG. 1-A, FIG. Figure C shows 1-B
Fig. 2 is a plan view, Fig. 2 is a front view showing the work of removing the sand from the upper part of the buried pipe by high pressure jet water, Fig. 3 is a side view showing the cutting work of the buried pipe, and Figs. FIG. 6 is a side view showing the pulling operation, and FIG. 6 is an enlarged front view of the high-pressure water jet unit of FIG. 4 in the AA direction. 1 ... buried pipe, 2 ... grab dredger, 17 ... wire,
18 …… Crane ship, 19 …… High pressure water jet unit, 20
...... Jet nozzle, B ... water bottom, D ... predetermined length, J
...... High pressure jet water.

Claims (1)

[Claims] 1. A water-bottomed buried pipe is dredged around a predetermined length thereof, and after removing the sand around the dredged buried pipe to cut the buried pipe, a wire is cut from the end of the buried pipe. A method of removing a submerged buried pipe in which the earth and sand above the buried pipe is gradually loosened by jetting high-pressure jet water over the entire length of the cut length of the buried pipe while pulling up with a cliff, and the buried pipe of each predetermined length is pulled up.