JP2002340230A - Pipe laying method of seawater intake pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately seat an intake of a seawater intake pipe on a sea bottom seating point, smoothly pumping up seawater, prevent a collapse of the seawater intake pipe at piping time, and prevent the useless excess length from appearing in the seawater intake pipe. SOLUTION: This pipe laying method of the seawater intake pipe 1 lays the seawater intake pipe 1 on the sea bottom between a land side landing point 7 and a sea side sea bottom seating point. A laying barge 2 mounted with the seawater intake pipe 1 is stopped in an oversea position 7A near the landing point 7. After delivering and laying the seawater intake pipe 1 thereby up to the landing point 7 while pressurizing the seawater intake pipe 1 by fluid from the inside, the laying barge 2 is sailed up to the sea side sea bottom seating point or the oversea position in the vicinity, and the seawater intake pipe 1 is thereby similarly delivered and laid while pressurizing the seawater intake pipe 1 by the fluid from the inside. The intake side of the seawater intake pipe 1 removed from the laying barge 2 is precipitated up to the sea bottom seating point in a state of opening the intake in the sea side oversea position, and the seawater intake pipe 1 is laid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for laying a seawater intake pipe on the seabed between a landing point on the land side and a seating point on the seabed on the seaside.

[0002]

2. Description of the Related Art In recent years, developments have been made in which a seawater intake pipe is laid on a deep sea floor having a depth of 200 m or more, and deep seawater (deep water) is pumped through the seawater intake pipe and used in a wide range of industrial fields. Conventionally, as a method of laying a seawater intake pipe used for pumping such deep seawater, the following method is considered.

[0003] That is, as shown in Fig. 4 (a), a laid boat 2 equipped with a seawater intake pipe 1 is navigated to a sea-side position 3A of a seaside seating point 3 at the sea side, and at that sea-level position 3A, a seawater intake pipe is provided. Attach the water intake 1A to the water intake support frame 4,
The seawater intake pipe 1 is drawn out from the storage section 6 of the laid boat 2 by the brake device 5 and settles down to the seabed seating point 3, and the intake support frame 4 is installed on the seabed at the seabed seating point 3, and the intake port of the seawater intake pipe 1 is installed. 1A is seated on the sea floor.

[0004] Next, as shown in FIG.
From the marine position 3A on the sea side to the marine position 7A (see FIG. 5) near the landing point 7 on the land side in the direction of the arrow, and the seawater intake pipe 1 is drawn out from the laid ship 2 by the brake device 5. It is laid on the sea floor.

Next, as shown in FIG. 5 (a), when the laying boat 2 reaches the land-side sea level 7A, the laying boat 2 is stopped and the laying boat 2 is moved to the state shown in FIG. As shown, for example, a U-turn is made 180 degrees clockwise in the figure. next,
At that position, the seawater intake pipe 1 is laid from the
The seawater intake pipe 1 is floated by a large number of buoys 8 at predetermined intervals so that the fed seawater intake pipe 1 does not sink in the sea, thereby forming a substantially U-shaped loop in the seawater intake pipe 1.
In such a state, the valley portion 1B of the loop is pulled to the landing point 7 by the pulling wire 9.

Next, the remaining length 1C of the seawater intake pipe 1 from the valley portion 1B of the loop on the landing point 7 side to the rear end of the seawater intake pipe 1 on the laying ship side is cut and removed, and the buoy 8 is cut off. Is removed, and the seawater intake pipe 1 on the sea at the remaining portion of the loop from which the extra length 1C has been removed is settled to the seabed, and the installation of the seawater intake pipe 1 is completed. Thereafter, a seawater outlet corresponding to the above-mentioned cutoff of the seawater intake pipe 1 is connected to the water pit 10,
Seawater pumped through the seawater intake pipe 1 can be stored.

[0007]

The conventional laying method is a method of laying a seawater intake pipe 1 by navigating a laying ship 2 from the sea side to the land side. Therefore, the seawater intake pipe 1 laid first on the sea floor is used.
The water intake side is free without restraint. For this reason, the seawater intake pipe is bent under the influence of the tidal current until the intake side of the seawater intake pipe 1 sinks to the deep seabed seating point 3, and the intake 1A of the seawater intake pipe 1 is connected to the seabed. It is difficult to accurately seat at the seating point. In addition, since the intake 1A side of the seawater intake pipe 1 is settled almost vertically downward from the sea to the seabed, and then sharply curved in a catenary shape, an excessive bending force acts on the intake side of the seawater intake pipe 1. The intake may be deformed or damaged, or may be buried under the seabed, making it impossible to pump seawater smoothly. Further, when the seawater intake pipe 1 is fed out by the brake device 5 and dropped into the sea while being guided by the chute, the seawater intake pipe 1 may be crushed by a large lateral pressure by the brake device 5 or the chute, and the installation may be difficult. is there. Further, the seawater intake pipe 1 is unloaded at the landing point 7
When landing at seawater, there is a problem that extra length is generated in the seawater intake pipe 1 and it is wasted.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and enables the intake of a seawater intake pipe to be accurately seated at a seabed seating point, enables smooth pumping of seawater, and prevents collapse of a seawater intake pipe during installation. The present invention further provides a method of laying a seawater intake pipe in which wasteful extra length is not produced in the seawater intake pipe.

[0009]

According to the present invention, there is provided a method of laying a seawater intake pipe on a seabed between a landing point on the land side and a seating point on the seabed on the seaside. In, the laying boat equipped with the seawater intake pipe is stopped at a sea position near the landing point, and after this, the seawater intake pipe is extended from the inside to the landing point while being pressurized with a fluid, and then laid, the laying boat is located on the land side. While sailing from the offshore position to the offshore seating point on the sea side or to the offshore position in the vicinity thereof, a seawater intake pipe is similarly extended from the inside while being pressurized with a fluid, and laid out, and laid at the seaside position on the seaside. The intake side of the seawater intake pipe removed from the ship is settled down to the seabed seating point with the intake opening open and laid, and the intake port is seated on the seabed at that point.

According to the above laying method, a laying ship is navigated from the land side to the sea side to lay the seawater intake pipe.
It is at the final stage of laying that the intake side of the seawater intake pipe is settled to the deep seabed seating point, and by the time the intake side of the seawater intake pipe is settled to the seabed seating point,
Most seawater intake pipes are already laid in place on the sea floor,
It is restrained from moving easily due to frictional resistance with the seabed. Therefore, while the intake side of the seawater intake pipe is settled to the seabed seating point, the seawater intake pipe is not largely bent by the tide, and the intake of the seawater intake pipe can be accurately seated at the seabed seating point. .

[0011] Further, as the intake side of the seawater intake pipe sinks to the seabed seating point, the catenary-like curve of the seawater intake pipe in the sea becomes loose, so that the intake side of the seawater intake pipe cannot be placed on the intake side of the seawater intake pipe. Deformation of the water intake,
Damage and burial on the sea floor can be avoided, and seawater can be pumped smoothly.

Further, since the seawater intake pipe is extended from the laying vessel while being pressurized with fluid from inside, the seawater intake pipe is not crushed during the installation, and the seawater intake pipe can be laid smoothly. In addition, it is economical because there is no extra length when laying seawater intake pipes.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a laying state near a landing point on the land side of a seawater intake pipe. The components having the same configuration and function as those of the laying method described in the related art are denoted by the same reference numerals.

First, a laid boat 2 equipped with a seawater intake pipe 1
The ship (including the buried ship and the workboat) is navigated to the marine position 7A near the landing point 7 on the land side, and is stopped at the position 7A. As the seawater intake pipe 1, for example, a flexible composite plastic pipe in which the outside of a plastic inner pipe is metal-reinforced is used. Next, the seawater intake pipe 1 is connected to the brake device 5.
Out of the storage section 6 of the laying ship 2 and a wire 11
And pull it into the landing site 7 side. Then, the seawater intake pipe 1 discharged from the laying boat 2 to the sea is maintained in a state of being floated by a large number of buoys 8 so as not to settle on the seabed.

Further, the seawater intake pipe 1 is unreeled from the laying boat 2 by the brake device 5 and is extended to the sea while being guided by the chute. For example, it is pressurized with fresh water such as industrial water or drinking water. Thereby, even if a large external force is applied to the seawater intake pipe 1 by the brake device 5 or the like, the seawater intake pipe 1 is not crushed and damaged, and can maintain a circular or other predetermined shape. As a method of pressurizing the seawater intake pipe 1 with a fluid from the inside thereof, the seawater intake pipe 1 may be filled with fresh water under pressure before the seawater intake pipe 1 is mounted on the laying ship 2, or the seawater intake pipe 1 may be pressurized. When the water pipe 1 is mounted on the laying boat 2 or when the seawater intake pipe 1 is drawn out from the laying boat 2 and laid,
The fresh water may be filled under pressure. In addition,
As the fluid to be filled into the seawater intake pipe 1 under pressure, seawater or compressed air may be used in addition to the fresh water. The pressure for pressurizing the seawater intake pipe 1 from the inside varies depending on the material of the seawater intake pipe 1, the inner diameter (outer diameter), the pipe wall thickness, the installation length, the installation water depth, and the like, but is in the range of 50 to 300 kPa. It is desirable to set appropriately.

Before mounting the seawater intake pipe 1 on the laid boat 2,
When the seawater intake pipe 1 is filled with fresh water under pressure, both ends of the seawater intake pipe 1 are hermetically sealed at a production plant of the seawater intake pipe 1 for shipping inspection of the seawater intake pipe 1. The water pipe 1 may be filled with fresh water under pressure to perform an airtightness test on it, and after completion of the test, may be carried out by applying a predetermined internal pressure without draining water. Adopting the method is desirable because it saves time and effort.

When the seawater intake pipe 1 is mounted on the laid boat 2 or when the seawater intake pipe 1 is drawn out from the laid boat 2 and laid, the freshwater is filled into the pipe 1 by pressurization. ,
Fresh water may be pressure-filled from either one or both sides of the front and rear ends of the seawater intake pipe 1.

Next, when the distal end (seawater outlet) of the seawater intake pipe 1 reaches the landing point 7, the seawater intake pipe 1
Of the seawater intake pipe 1 is fixed, the buoy 8 for floating the seawater intake pipe 1 is removed, and the seawater intake pipe 1 between the laying ship 2 and the landing point 7 is settled on the sea floor. And lay it.

Next, as shown in FIG. 2, the laid ship 2 is moved from the land-side sea-side position 7A (see FIG. 1) to the sea-side submarine seating point 3 or a sea-side position 3A near the sea-side position 3A (see FIG. 3). In the same manner as in the direction of the arrow, the seawater intake pipe 1 is pulled out from the laying vessel 2 by the brake device 5 while being pressurized with the water from the inside, and laid along a predetermined route on the seabed while being dropped into the sea by the shooter. .

Next, as shown in FIG. 3, when the laid boat 2 reaches the sea-side position 3A on the sea side, the laid boat 2 is stopped at that position. Then, the intake port 1A of the seawater intake pipe 1 is removed from the storage section 6 of the laid boat 2, and the intake port 1A of the seawater intake pipe 1 is attached to the intake port support frame 4 on the laid boat 2. Next, an intake port hanging frame 4 is attached to the intake port support frame 4, and the wire 12 is connected to an elevator 13 such as a winch provided on the laying boat 2, and the elevator 13 is driven to lower the wire 12. At the marine position 3A, the water intake support frame 4, that is, the water intake 1A, enters the sea and is positioned under the sea just below the sea surface. Then, the intake port 1A of the seawater intake pipe 1 is opened by the diver in the sea, and the seawater intake pipe 1 is opened.
The wire 12 is lowered while discharging the fresh water into the sea under pressure, and the intake supporting frame 4, that is, the intake side of the seawater intake pipe 1 is moved with the intake opening 1 </ b> A opened. It is settled gradually toward the seabed seating point 3 and installed on the seabed.

As the seawater intake pipe 1 sinks in the sea, water pressure is applied to the seawater intake pipe 1 from the outside and the water pressure increases in proportion to the water depth.
Seawater having the same water pressure enters from A, and an internal water pressure equal to the external water pressure is applied to the seawater intake pipe 1, so that no internal or external force acts on the seawater intake pipe 1. Therefore, the seawater intake pipe 1
Is not crushed by seawater pressure.

In this manner, the intake port 1 of the seawater intake pipe 1
By laying A on the seabed at the point 3, the installation of the seawater intake pipe 1 is completed. With such a laying method, the intake port 1A of the seawater intake pipe 1 can be accurately seated on the seabed at the seabed seating point 3. In addition, as the intake 1A side of the seawater intake pipe 1 is settled to the seabed sitting point 3,
Since the catenary-like curve of the seawater intake pipe 1 in the sea is loosened, no excessive bending force acts on the intake 1A side of the seawater intake pipe 1, and the intake 1A is deformed, damaged, and damaged to the seabed. Burial can be avoided and seawater can be pumped smoothly. Further, since the seawater intake pipe 1 is extended from the laying boat 2 while being pressurized from the inside with a fluid, the seawater intake pipe 1 may be crushed even if it is subjected to a large side pressure by the brake device 5 or the shooter during the installation. No, seawater intake pipe 1
Can be laid smoothly.

When the intake port 1A is opened in the seawater intake pipe 1, the intake port 1A of the seawater intake pipe 1 is removed from the storage section 6 of the laid ship 2 after removing the intake port 1A side. May be carried out until the intake support frame 4 attached with is settled in the sea just below the sea surface. However, when the fluid to be pressurized and filled in the seawater intake pipe is a liquid such as fresh water or seawater, the seawater intake pipe 1 is pressurized and filled into the seawater intake pipe 1 before the intake port 1A enters the sea. Since the fresh water that has been released may be released into the atmosphere vigorously and reduce workability,
As described above, it is desirable to open the water intake 1A when the water intake 1A enters the sea just below the sea surface.

Further, while the intake port 1A of the seawater intake pipe 1 is settled and seated from the sea position 3A to the seabed seating point 3, the laying boat 2 sails a predetermined distance in the direction away from the landing point 7 on the right side of FIG. This is preferable because the sinking of the intake port support frame 4 can be performed more smoothly and easily.

Further, the intake wire hanging wire 12 is
The intake support frame 4 may be removed after it has been installed on the seabed. However, without removing the intake support frame 4, a buoy (not shown) is attached to the upper end of the wire, and the upper end is floated on the sea. Alternatively, it may be used as a sign for confirming the seating position of the water intake 1A. This is preferable because maintenance such as repairing or replacing the intake port support frame 4 is easy after the seawater intake pipe is laid.

When the installation of the seawater intake pipe 1 is completed in this way, as shown in FIG. 1, a seawater intake port of the seawater intake pipe 1 is inserted into an intake pit 10 installed at the landing point 7 of the seawater intake pipe 1. And a pumping pump (not shown) is used to store seawater pumped through the intake port 1A of the seawater intake pipe 1 through the pipe. The connection of the seawater intake to the intake pit 10 is not made after the seawater intake pipe 1 is laid, but is the seawater intake pipe 1 laid at the landing point 7 completed?
Alternatively, it may be performed during the installation of the seawater intake pipe 1 from the landing point 7 side to the seabed seating point 3 side.

[0027]

As described above, according to the present invention,
In a method of laying a seawater intake pipe on the seabed between a landing point on the land side and a seabed seating point on the seaside, a laid boat equipped with a seawater intake pipe is stopped at a sea position near the landing point, and the seawater After drawing out and laying the intake pipe to the landing point while pressurizing the intake pipe with the fluid from the inside, the laid ship is made to sail from the land-side offshore position to the sea-side seabed seating point or a sea-side position near the seaside, and from there, the seawater is taken up. Similarly, the water pipe is drawn out from the inside while being pressurized with a fluid, and laid out, and at the seaside position on the sea side, the intake side of the seawater intake pipe removed from the laying boat sinks to the seabed seating point with the intake opening open. The seawater intake pipe was bent by the tidal current while the intake side of the seawater intake pipe was settled to the seabed seating point because the intake port was seated on the seabed at that point. Is that it is not, the water intake of sea water intake pipe can be accurately seated on the seabed seating point.

Further, as the intake side of the seawater intake pipe sinks to the seabed seating point, the catenary-like curve of the seawater intake pipe in the sea becomes loose. Deformation of the water intake,
Damage and burial on the sea floor can be avoided, and seawater can be pumped smoothly.

Further, since the seawater intake pipe is drawn out from the laying vessel while being pressurized from the inside with a fluid, the seawater intake pipe is not crushed during the installation, and the seawater intake pipe can be laid smoothly. In addition, it is economical because there is no extra length when laying seawater intake pipes.

[Brief description of the drawings]

FIG. 1 shows one embodiment of the present invention, and is an explanatory view of a state in which a seawater intake pipe is laid near a landing point on a land side.

FIG. 2 is an explanatory diagram showing a state in which a seawater intake pipe is laid from a landing point side to a seabed-side seating point on the sea side in the above laying method.

FIG. 3 is an explanatory view showing a state in which, in the above-described laying method, an intake support frame to which an intake of a seawater intake pipe is attached is settled to a seabed seating point, and the intake is seated on the seabed.

FIG. 4 shows a conventional method of laying a seawater intake pipe,
(A) is an explanatory view of a laid state of a seawater intake pipe at a seabed seating point, and (B) is an explanatory view of a state of laying a seawater intake pipe from a seabed sitting point to a landing point.

FIG. 5 is a schematic plan view showing a state in which a seawater intake pipe is laid in the vicinity of a landing point in a conventional laying method.
(B) is a schematic plan view of a state in which the laying ship is turned 180 degrees from the state of (A) to lay the seawater intake pipe to the landing point.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Seawater intake pipe 1A Intake 1B Valley 1C Extra length 2 Laying ship 3 Sea bottom seating point 3A Offshore position 4 Intake port support frame 5 Brake device 6 Storage unit 7 Landing point 7A Offshore position 8 Buoy 9 Towing wire 10 Intake pit 11 Retraction wire 12 Intake port hanging wire 13 Elevator

Claims (1)

[Claims] 1. A method for laying a seawater intake pipe on a seabed between a landing point on the land side and a seabed seating point on the seaside, wherein the laying boat equipped with the seawater intake pipe is located near the landing point. And then laying out the seawater intake pipe from the inside to the landing point while pressurizing the seawater intake pipe with fluid from the inside, and then laying the laid ship from the land-side offshore position to the seaside seating point on the seaside or in the vicinity thereof. At the same time, the seawater intake pipe is similarly extended from the inside while being pressurized with fluid from the inside, and laid out. At the seaside position on the sea side, the intake side of the seawater intake pipe removed from the laid boat is used as its intake port. A method for laying a seawater intake pipe, comprising: sinking a seawater to a seabed seating point in a state where it is open, and laying the water intake port on the seabed at the point.