JP2001032962A - Method for laying water bottom pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lay a pipe economically with a simple facilities by attaching a plurality of counters which are independent from each other to a circumference of a light-weight pipe whose density is near the water, and connecting and fixing counter groups by tension members. SOLUTION: Many counters 2 such as lead, iron, and the like are attached at constant intervals around a generally commercial synthetic resin made light- weight pipe 1 for the ground whose specific gravity is near the water. The counter groups 2 are connected to each other by tension members 3 such as a fiber or steel made rope, the tension members 3 are fixed to the pipe 1, stress applied on the pipe 1 is shared, and bearing force of the pipe 1 is ensured. In this work, such a method that the counter 2 is attached to the pipe 1 at the factory to attach the tension members 3 on the laying ship, and such a method that the counter 2 and the tension members 3 are attached to the pipe 1 at the factory to lay them from the laying ship directly, are employed. It is thus possible to lay the mass-produced pipe with low costs on a deep water bottom for a long distance, and it is also possible to provide a large economical effect as laying of the pipe 1 is extended.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for laying a water bottom pipe.

[0002]

2. Description of the Related Art Conventionally, when water is pumped from a deep seabed having a depth of several hundred meters, the weight is large,
Heavy-duty pipes that are strong against pulling are laid by large laying vessels. The heavy equipment pipe is, for example, a pipe in which a polyethylene pipe a is covered with a number of steel wires b in parallel with the pipe as shown in FIG. 3 and the outer periphery thereof is further coated with asphalt c. Such a heavy equipment pipe does not rise because of its heavy weight, is not easily affected by waves, and is stable on the seabed. Furthermore, since a large number of steel wires are arranged in parallel to the axial direction, there is a large resistance to pulling, and there is no danger of breakage even if the terrain on the seabed is complicated.

[0003]

However, in the conventional method of laying a submarine pipe having such features,
There are the following problems. <A> Heavy equipment pipes are naturally expensive, and are uneconomical due to the material cost of the entire operation. <B> Handling large pipes requires large work boats and high construction costs. <C> Since heavy objects are handled on the sea where the working environment is not good, the construction period will be prolonged.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems.
An object of the present invention is to provide a method for laying a water bottom pipe, which can economically lay a pipe on the water bottom.

[0005]

In order to achieve the above object, a method of laying a water bottom pipe according to the present invention comprises a plurality of independent pipes arranged around a lightweight pipe having a specific gravity close to the specific gravity of water. The method is characterized by a method of laying a water bottom pipe, wherein the counter group is connected and connected by a tension member, and the tension member is fixed to the counter and laid on the water bottom.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

<A> Pipe to be used. As the pipe used for the laying of the present invention, a light-weight pipe 1 made of a general commercially available synthetic resin for land use is used. It is desirable that the general pipe 1 used on land not only does not require the size of its own weight but also is light on the contrary. Therefore, it is usually made of a material having a specific gravity as small as that of water. In addition, since a large tensile force does not act on the land at the time of laying or use, a small tensile strength is sufficient. Therefore, it is economical and functional enough for use on land, but when it is laid on a deep water floor, it responds to the demand that it can withstand a large tensile force and can be installed stably on the water bottom without being affected by ocean currents It is difficult.

<B> Counter. A counter 2 is attached around a lightweight pipe 1 having a specific gravity close to the specific gravity of water as described above. The counter 2 is an independent heavy object and is made of, for example, lead, iron, or the like. A large number of counters 2 are attached around the pipe 1 with a fixed interval therebetween. As the counter 2, for example, a member obtained by dividing an annular body into halves and connecting them by hinges can be used. If the semi-annular body is widely opened at the hinge portion, closed with the pipe 1 sandwiched and returned to the annular shape, the pipe 1 can be gripped from the outer periphery.

<C> Tensile material. The two groups of counters are connected by a tensile member 3. As the tensile member 3, a rope made of fiber or steel can be used. As the fibers, commercially available products such as chemical fibers such as natural fibers and synthetic resin fibers, and carbon fibers can be used as they are. Further, the shape is not limited to the rope shape, and a long strip-shaped tensile member 3 such as a strip steel can be used. The belt-shaped tension member 3 facilitates attachment to the counter 2. The tension member 3 is attached to one side of the pipe 1. Alternatively, a plurality of tension members 3 can be attached at equal intervals in the circumferential direction of the pipe 1. In the counter 2 having a structure in which the semi-tubular body is opened at the hinge portion, surrounds the pipe 1 from the outer periphery, and is closed again, the closing portion is combined in a comb tooth shape. Then, the teeth of the comb are formed in an outward groove shape, and the tension member 3 is accommodated in this groove and the teeth are caulked, so that the counter 2 securely grips the pipe 1 and the tension member of the counter 2 3 can be performed simultaneously. Tensile material 3 is pipe 1
By fixing to the pipe 1, it bears a stress such as tension applied to the pipe 1 and has a function of securing the proof stress of the pipe 1.

<D> Laying method. As described above, a large number of counters 2 are attached to the outer circumference of the on-shore pipe 1 that is lightweight and has low resistance to tensile force, and a counter is provided to obtain resistance to tensile and other stresses acting on the pipe. The two are connected by a tensile member 3. For both of these operations, it is possible to adopt a method in which a counter 2 is attached to a pipe 1 in a factory, and a tension member 3 is attached on a laying ship. Alternatively, it is also possible to adopt a method in which the counter 2 and the tension member 3 are attached to the pipe 1 at a factory, and the pipes 1 are laid at once from a laying boat. Alternatively, it is also possible to adopt a method in which the pipe 1, the counter 2, and the tension member 3 are simultaneously mounted on the deck of the laying ship and laid. In any method, even though the pipe 1 is lightweight and small in strength, it is not cut by a tensile force even if it is hung down to a deep water bottom of several hundred meters, and has a large weight. A stable posture can be secured.

[0011]

As described above, the method for laying a water bottom pipe according to the present invention has the following effects. <B> Inexpensive and mass-produced land-based pipes made of general synthetic resin can be laid for several kilometers or tens of kilometers on a deep water floor of several hundred meters. Therefore, the longer the length of the laying, the greater the economic effect. <B> The lack of weight of the land-based commercially available pipe 1 is solved by attaching the counter 2, and the lack of resistance to tension or the like is solved by connecting the counters 2 with the tension members 3. By solving the required conditions in a divided manner as described above, a highly reliable laid pipe 1 can be manufactured regardless of whether it is factory production or work on a laid ship. <C> Since the weight shortage of the onshore pipe 1 can be solved by the weight of the counter 2 and the number of installations, it is possible to freely adjust the weight according to the influence of the flow and waves on the water floor to be laid. Depending on the installation site, the most economical and reliable underwater pipeline can be installed.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an embodiment of a method for laying a water bottom pipe according to the present invention.

FIG. 2 is an explanatory view of an embodiment of a laying method performed by one tensile member.

FIG. 3 is an explanatory view of a conventional water bottom laying pipe.

Claims (4)

[Claims] 1. A plurality of independent counters are attached around a lightweight pipe composed of a specific gravity close to the specific gravity of water,
A method of laying a water bottom pipe, wherein the counter group is connected with a tension member, and the tension member is fixed to the counter and laid on the water bottom. 2. The method according to claim 1, wherein the counter is an annular body that grips the pipe from the outer periphery. 3. The method according to claim 1, wherein the tension member connecting the counters is a rope. 4. The method of laying a water bottom pipe according to claim 1, wherein the tension member connecting between the counters is a strip.