KR20160009326A - Pile construction method for supporting offshore structure - Google Patents

Abstract

The present invention relates to a method for constructing a pile for supporting an offshore structure. When the pile for supporting the offshore structure is constructed, the pile is provided with an additional load to be interpenetrated into the seafloor with a sufficient depth without a separate supporter such that the pile can rapidly and completely be constructed because bucking is not generated when the pile is driven. The pile constructing method to install the pile for supporting the offshore structure on the seafloor comprises: a step of inserting the additional load into the pipe; a step of connecting an internal lifting tool (ILT) to an end of the pile; a step of refloating the pile using a crane connected to the upper part of the ILT; a step of interpenetrating the pile into the seafloor by moving the crane downward; a step of removing the additional load and the ILT after the interpenetration is finished; and a step of driving the upper part of the pile where the ILT is removed to be positioned at a designed depth by a pile driver.

Description

[0001] PILE CONSTRUCTION METHOD FOR SUPPORTING OFFSHORE STRUCTURE [0002]

The present invention relates to a pile construction method for supporting an offshore structure, and more particularly, to a pile which supports the bottom of an offshore structure on the seabed ground, And a method of constructing the file so as not to occur.

An offshore structure is a structure that is installed on the sea or under the sea. It is classified into fixed type, semi-submerged type, floating type according to the depth of water. These marine structures are mainly used for exploration and extraction of energy sources such as oil and natural gas, and are also used for other leisure, harbor and environmental facilities. Common forms we can find are semi-submersible offshore structures and drill ships for oil and gas exploration and drilling.

In particular, in order to install a fixed type of offshore structure, a plurality of files should be installed on the underside of the soft ground so that the offshore structures are not shaken by waves.

Generally, pile construction methods for reinforcement of coastal soft ground or foundation of a building structure include pile piling directly on the ground and pile piling by digging the ground.

A method of directly piling a pile on the ground is to lift a weight such as a hammer by using the hydraulic pressure of a lifting rope or a hydraulic unit and then lower the pile to strike the upper portion of the pile to pile the pile on the ground.

Also, as a method for excavating the ground by piling the pile, the screw is pierced through the ground using the ground excavation equipment and the pile is buried in the piercing hole, so that the casing is used to prevent the collapse of the pierced ground. The ground excavation equipment consists of a screw auger and a casing auger installed on a standing leader in a heavy equipment such as a crane, and a screw and a casing installed on the bottom of the screw auger and casing auger, respectively, do. The casing is inserted into the ground and the screw rotating in the opposite direction is discharged to the outside of the casing and the pile is buried, and then the casing is taken out.

Conventionally, a pile construction method for supporting an offshore structure is similar to a method in which the pile is placed directly on the ground. Hereinafter, a pile construction method in which an offshore structure is installed and supported on the sea floor will be described.

FIG. 5 is an exemplary view showing a state in which a file for supporting an offshore structure is lifted, FIG. 6 is an exemplary view showing a state in which a file for supporting a conventional offshore structure is not fully penetrated into the undersea, FIG. 8 is an illustration showing a state in which an additional support is installed in a file; FIG.

As shown, in order to install a conventional pile for supporting an offshore structure, a barge (not shown) is anchored to the ocean, an ILT (Internal Lifting Tool) is connected to the upper part of the pile, After penetration down to the seabed, it is hovered by the hover 11. Here, the file refers to an empty steel pipe.

In this step, a) connecting to the end of a file using an internal lifting tool (ILT), which is a device for lifting a file; b) connecting a crane to the top of the ILT to lift the pile; c) lowering the crane to penetrate the pile into the bottom of the seabed; d) removing the ILT from the top of the file after intrusion; e) installing an additional support below the file in contact with the sea floor; f) hitching the top of the pile supported by the additional support up to the design depth using the plow.

The step of lowering the lifting rope of the crane and penetrating the bottom of the seabed is intruded up to a limit that can be penetrated to the seabed surface due to the weight of the file and the weight of the ILT.

However, if the self-weight of the file itself and the depth of penetration due to the weight of the ILT are insufficient, a buckling phenomenon occurs in which the file is rapidly bent due to the weight of the anti-aircraft. Therefore, conventionally, And attaching an additional support to the lower portion of the contacted file.

Buckling refers to a phenomenon in which a file suddenly bends when a load reaches a certain size when a compression load is applied to both ends of the file when the length of the file is larger than the dimension of the cross section. Files with buckling are structurally weak and can not be used as support for offshore structures.

Therefore, when the buckling phenomenon is expected to occur in the prior art, a step of installing a support around the pile to further reduce the buckling length before hitting the pile with the pile.

However, installing an additional support requires not only additional material costs but also all of the work is underwater, so it takes a lot of time and there is a problem that the air is delayed.

Korean Registered Patent No. 10-1240615 (Feb. Korean Utility Model Publication No. 10-2014-0003333 (May 2014.)

It is an object of the present invention to solve the above-mentioned problems, and it is an object of the present invention to provide an apparatus and a method for providing an additional load to a file, And to provide a way for the file construction to be completed quickly.

According to the present invention, there is provided a file construction method for installing a file for supporting an offshore structure on a seabed,

Charging an additional load into the file;

Connecting an internal lifting tool (ILT) to the end of the file;

Connecting a crane to the top of the ILT to salvage the pile;

Lowering the crane to penetrate the file into the sea floor;

Removing the additional load and ILT after intrusion;

And removing the ILT from the upper portion of the file to the design depth by using the hinge.

In a preferred embodiment, loading the additional load into the file may include loading a file having a stopper therein, and then charging an additional load connected to the ILT by a wire.

In a preferred embodiment, the additional load connected to the ILT by wire may be a horizontally pushed up position to the stopper forming point in the pile using a pressurizing means while the pile is installed horizontally.

In a preferred embodiment, the wire may be longer than the length between the ILT installed in the file and the additional load in contact with the stopper formed in the file.

As described above, according to the present invention, an additional weight can be provided inside a file when a file for supporting an undersea structure of an offshore structure is provided, thereby improving the stability of the file by maximizing the penetration depth of the file penetrated into the undersea, The advantage of being able to construct,

In addition, when installing a file for supporting an offshore structure, there is no need to install an additional support on the water to prevent buckling of the file as in the past, which is advantageous in that the installation cost of the offshore structure is lowered. It is a highly anticipated invention.

FIG. 1 is a flowchart illustrating a file construction process for supporting an offshore structure according to an embodiment of the present invention,
FIG. 2 is a view illustrating a structure in which an additional load is installed on a file for supporting an offshore structure according to an embodiment of the present invention.
FIG. 3 is an exemplary view showing a state in which a file for supporting an offshore structure is applied to an undersea under an additional load according to an embodiment of the present invention,
FIG. 4 is an exemplary view showing a state in which a file for supporting an offshore structure penetrated into a seabed according to an embodiment of the present invention is loaded without a support,
5 is an exemplary view showing a state in which a file for supporting a conventional offshore structure is lifted,
6 is an exemplary view showing a state in which a file for supporting a conventional offshore structure is not fully penetrated into the sea bed,
FIG. 7 is an exemplary view showing a state where an additional support is installed on a file for supporting a conventional offshore structure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

FIG. 1 is a flowchart illustrating a file construction process for supporting an offshore structure according to an embodiment of the present invention. FIG. 2 is a view illustrating a structure for installing additional loads on a file for supporting an offshore structure according to an embodiment of the present invention. And FIG. 3 is an exemplary view showing a state in which a load is applied to a file for supporting an offshore structure according to an embodiment of the present invention, and FIG. 4 is a cross- Fig. 8 shows an example of a state in which a file for supporting an infiltrated offshore structure is mounted without a support.

As shown in the figure, a construction method in which a file having an additional load is raised by using a crane,

a) an additional load applying step (S100) in which a file (pile) having a stopper formed therein is horizontally placed on a file support, and an ILT placed on an ILT mounting support is pushed up to a stopper forming point by means of pushing an additional load connected with a wire )Wow;

b) connecting (S200) the ILT loosely connected with the wire to the end of the file;

c) connecting a crane to an upper portion of the ILT to salvage the file (S300);

d) lowering the crane to penetrate the pile bottom (S400);

e) removing the additional load and ILT when the intrusion is completed (S500);

f) step S600 of moving the upper portion of the file from which the ILT is removed up to the design depth using the hover.

The construction method of the present invention having the above-described steps is a method of finishing the construction economically by improving the stability to avoid the buckling phenomenon by making the penetration depth of the file to the maximum and to work without additional support.

Specifically, the present invention relates to an ILT (Internal Lifting Tool) 4 (hereinafter referred to as " ILT ") installed on an ILT installation support 3 positioned adjacent to a pile support 2, And the additional load 6 connected to the wire 5 are pushed into the stopper 8 formed at a certain internal depth of the pile 1 by means of pushing means 7 such as a hydraulic jack. This is a simpler and safer operation than pushing the additional load into the vertically standing steel pipe file (1) by lifting the LLT. Positioning the additional load, which is a heavy item in the vertical standing file, is a risk of safety accident if the additional load hanging on the lifting line moving in the marine environment is fluctuated, So that a safe operation can be performed.

The stopper 8 supports the load when the file 1 is erected vertically and stably applies an additional load to the file.

When the additional load 6 is applied, the ILT 4 is connected to the file 1, and the crane 9 mounted on the barge or the like connects the lifting rope 10 to the upper portion of the ILT 4 to lift the file. The elevated file is gradually lowered to the seabed and the file touching the soft submarine ground is transmitted to the undersurface with the added weight, the weight of the file and the weight of the ILT. The initial penetration depth becomes maximum, so that the buckling phenomenon does not occur at the time of hitting.

Where the depth at which files are penetrated into the ocean floor is deeper than the median depth of the file. If this is intro- duced at this early stage, the condition of being able to install the anti-tackle 11 without additional support is improved remarkably.

On the other hand, when the additional load is pushed to the stopper of the inside of the file by using the hydraulic jack as the pushing means, the length of the wire connecting the additional load and the ILT is made long enough so that the influence of the additional load does not occur in the ILT .

The reason for this is that when the tension of the wire is directly applied to the ILT, a local load may be applied to the equipment, and the overall size of the ILT equipment itself becomes larger than that of the conventional equipment.

However, if the loose wire is connected to the additional load and the stopper supports the additional load, the ILT can simply lift the file without lifting the additional load even if the file is standing up.

In addition, when the ILT is removed enough to prevent buckling of the file due to the additional load, the ILT coupled to the top of the file can be easily removed without additional load. When the ILT is lifted off from the top of the file, the wire is slowly tensioned, lifting the additional load and pulling it out of the pile and removing it.

As mentioned above, when the ILT and the file with the additional load reach the sea floor, the penetration through the soft ground is intruded by the self weight. The depth of penetration is much more intruded than when there is no additional load, so that the buckling does not occur. The large intrusion depth of the file according to the present invention is the intrusion depth based on the use of the same standard as the conventional file.

When the ILT is removed from the upper portion of the file, the conventional airplane mounted on the barge or the like hits the upper portion of the file. At this time, due to the depth of the deeply-penetrated file, a uniform impact force is applied to the file when the hovering is performed, so that the buckling phenomenon in which the file is rapidly bent by the weight of the hovering does not occur.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims and their equivalents. Of course, such modifications are within the scope of the claims.

(1): File (2): File support
(3): ILT mounting support (4): ILT
(5): wire (6): additional load
(7): pushing means (8): stopper
(9): Crane (10): Lifting line
(11):

Claims (4)

A file construction method for installing a file for supporting an offshore structure on a seabed,
Charging an additional load into the file;
Connecting an internal lifting tool (ILT) to the end of the file;
Connecting a crane to the top of the ILT to salvage the pile;
Lowering the crane to penetrate the file into the sea floor;
Removing the additional load and ILT after intrusion;
And removing the upper portion of the file from which the ILT has been removed by using a hinge to a design depth.
The method according to claim 1,
Wherein the step of loading the additional load into the file includes loading a file having a stopper therein and then loading an additional load connected to the ILT by a wire.
The method of claim 2,
Wherein the additional load connected to the ILT by the wire is pushed in a horizontal direction to a stopper forming point inside the file by using a pushing means while the file is installed horizontally.
The method of claim 2,
Wherein the wire is longer than a length between an ILT installed in the file and an additional load in contact with the stopper formed in the inside of the file.

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