Method for installing jacket structure

Abstract

To provide a method for installing a jacket structure, which can soften strictness of pile positioning accuracy with a reduced installation cost.SOLUTION: This method for installing a jacket structure 100 which includes a plurality of leges 20 and a plurality of sleeves 30 provided for one of the legs 20 and supports an off-shore wind turbine comprises: a first step of installing a plurality of preceding piles P1; a second step of mounting the jacket structure 100 so as to insert corresponding one among the preceding piles P1 into one of the sleeves 30; and a third step of installing one or a plurality of succeeding piles P2 corresponding to the other sleeves 30 among the sleeves 30.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for installing a jacket structure. [Background technology]

[0002] Jacket structures are sometimes installed on the seabed to support structures such as offshore wind turbines. Patent Document 1, an example of prior art, discloses a technology in which a connecting portion of a jacket structure is first connected to the upper end of a pile already driven into the seabed, which is in the air, to create an interlocking state, and then the jacket structure is positioned using one of the piles that was initially interlocked, and then the other connecting portions of the jacket structure are fixed to the upper end of each of the other piles. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-201101 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional technology, all of the piles connected to the jacket structure are driven into the seabed in advance, so strict positional accuracy is required when installing the piles. In order to ensure strict positional accuracy when installing piles, it is possible to use mud mats or temporary piles. On the other hand, using mud mats or temporary piles to install the jacket structure increases the cost of installing the jacket structure, so there is also a demand to be able to install the jacket structure without using these.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a method for installing a jacket structure that relaxes the strictness of the pile positioning accuracy and reduces installation costs. [Means for solving the problem]

[0006] <1> A method for installing a jacket structure according to aspect 1 of the present invention is a method for installing a jacket structure that supports an offshore wind turbine, the jacket structure including at least three or more legs and a plurality of sleeves provided for each of the three or more legs, and is characterized by including a first step of installing a plurality of leading piles, a second step of placing the jacket structure so that any one of the plurality of leading piles is inserted into any one of the plurality of sleeves, and a third step of installing one or more trailing piles corresponding to the other sleeves of the plurality of sleeves.

[0007] According to the first aspect of the invention, in the first step, the pilot pile is installed. In the next second step, a pilot pile is inserted into one of the sleeves to install the jacket structure that will support the offshore wind turbine. Then, in the third step, the trailing piles are installed. In this way, by placing the jacket structure on the pilot piles that have been installed on the seabed in advance, it is possible to prevent the jacket structure from sinking into the seabed, which can occur when the jacket structure is installed on the seabed without installing the pilot piles on the seabed. Therefore, mud mats and temporary piles are not required, and the installation costs of the jacket structure can be reduced. Furthermore, by installing the trailing piles after the jacket structure has been placed, the number of leading piles that are installed on the seabed in advance can be reduced. Therefore, the strictness of the positional accuracy of the leading piles can be relaxed, and problems such as interference with the piles during installation of the jacket structure and making it impossible to install can be prevented.

[0008] <2> A jacket structure installation method according to a second aspect of the present invention is characterized in that, in the first aspect, the plurality of pilot piles are installed at corners of a substantially regular polygon in plan view.

[0009] According to the invention of aspect 2, the plurality of pilot piles are installed at the corners of a substantially regular polygon in plan view. In other words, the plurality of leading piles form a substantially regular polygon in a plan view. This makes it possible to make the strength of the jacket structure against wave forces acting on it isotropic in the state where the jacket structure is placed on the leading piles in the second step. Therefore, before the third step, in a state where the jacket structure is supported only by the leading piles, the jacket structure can be made more stable on the seabed. In this specification, strength against wave force means stability against tipping over.

[0010] <3> A jacket structure installation method according to aspect 3 of the present invention is characterized in that, in aspect 1 or aspect 2, the jacket structure includes four legs, the number of the plurality of pilot piles is four, and the four pilot piles are installed at the corners of an approximately square when viewed in a plane.

[0011] According to the invention of aspect 3, the four pilot stakes are installed at the corners of a substantially square in plan view. In other words, the four leading stakes form a substantially square in plan view. This makes it possible to make the strength of the jacket structure against wave forces acting on it isotropic in all directions when the jacket structure is connected to the seabed only by the leading piles in the second step. Therefore, in the state before the third step in which the jacket structure is connected only by the leading piles and placed on the seabed, the jacket structure can be made more stable on the seabed.

[0012] <4> A fourth aspect of the present invention relates to a jacket structure installation method according to the third aspect, characterized in that the jacket structure includes two sleeves for one leg of the four legs.

[0013] According to the fourth aspect of the invention, the jacket structure includes two sleeves for one leg. This allows one leading pile and one trailing pile to be assigned to one leg, making it possible to stabilize the support of that leg. Therefore, the jacket structure can be stabilized on the seabed. In addition, the invention of aspect 4 is realized by assigning one sleeve to each of the leading pile and the trailing pile, which allows the number of sleeves to be relatively reduced compared to when one leg includes three or more sleeves.

[0014] <5> A jacket structure installation method according to aspect 5 of the present invention is characterized in that, in any one of aspects 1 to 4, the multiple pilot piles are installed at the corners of a substantially symmetrical shape when viewed in a plane.

[0015] According to the invention of aspect 5, the plurality of pilot piles are installed at corners of a substantially symmetrical shape in a plan view. In other words, the plurality of leading piles form a substantially symmetrical figure in a plan view. This also includes cases where the arrangement of the leading piles is anisotropic. If the arrangement of the leading piles is anisotropic, then when the jacket structure is connected only by the leading piles and placed on the seabed in the second step, the jacket structure can be made particularly strong against wave forces in a particular direction. Therefore, even if the wave force from a particular direction is strong at the location where the jacket structure is installed, the jacket structure can be made more stable on the seabed before the third step, when the jacket structure is connected only by the leading piles and placed on the seabed.

[0016] <6> A jacket structure installation method according to aspect 6 of the present invention is characterized in that, in any one of aspects 1 to 5, the jacket structure includes four legs, the number of pilot piles is four, and the four pilot piles are installed at the corners of an approximately rectangular shape when viewed in a plane.

[0017] According to the sixth aspect of the invention, the four pilot stakes are installed at the corners of a substantially rectangular shape in plan view. In other words, the four leading stakes form a substantially rectangular shape in a plan view. As a result, when the jacket structure is connected only by the leading piles and placed on the seabed in the second step, the strength of the jacket structure against wave forces can be made particularly strong in the direction facing the short side of the approximately rectangular shape. Therefore, by having the short side of the approximately rectangular shape face the direction of strong wave forces at the location where the jacket structure is installed, the jacket structure can be made more stable on the seabed before the third step, when the jacket structure is connected only by the leading piles and placed on the seabed.

[0018] <7> A jacket structure installation method according to aspect 7 of the present invention is characterized in that, in any one of aspects 1 to 6, the jacket structure includes four legs, the number of pilot piles is four, and the four pilot piles are installed at corners of an approximately square or approximately rectangular shape in plan view, depending on the direction of wave force at the location where the jacket structure is installed.

[0019] According to the invention of aspect 7, the four pilot piles are installed at the corners of a substantially square or rectangular shape in plan view, depending on the direction of wave force at the location where the jacket structure is installed. In other words, depending on the direction of wave force at the location where the jacket structure is installed, it is determined whether the four leading piles should be installed to form an approximately square or an approximately rectangular shape in plan view. In this way, when the strength of the wave force is uniform regardless of direction, the leading piles are installed so that they form an approximately square in plan view, and when the wave force is strong from a specific direction, the leading piles are installed so that they form an approximately rectangular in plan view with the short side of the approximately rectangular shape facing the direction of the strong wave force, thereby making it possible to install the leading piles in a position that is more suitable for the characteristics of the location where the jacket structure is to be installed. Therefore, in the state before the third step where the jacket structure is connected to the seabed only by the leading piles and placed on the seabed, the jacket structure can be made more stable on the seabed.

[0020] <8> A jacket structure installation method according to aspect 8 of the present invention is characterized in that, in any one of aspects 1 to 7, multiple jacket structures are installed in the same wind farm or the same sea area, and the direction of the multiple jacket structures is determined according to the direction of wave force in the wind farm or the sea area.

[0021] Generally, a workboat stabilizes itself by pushing its bow against a boat landing using its propulsive force. If a boat landing is on the incoming side of the workboat, the force of the waves acts to push back the workboat approaching the boat landing. This allows the propulsive force of the vessel to be offset by the force of the waves, allowing the workboat to approach the boat landing at a slower speed and reducing the impact force upon contact. Therefore, according to the invention of aspect 8, the orientation of the multiple jacket structures is determined according to the direction of wave force in the wind farm or sea area where the jacket structures are installed. This makes it possible to determine the orientation of the jacket structures so that, for example, the boat landing that a work boat comes into contact with is positioned on the incident side. By arranging the jacket structures in this way, the impact force of the work boat when it comes into contact with the boat landing due to the force of waves can be reduced. This makes it easier for the work boat to access the jacket structure.

[0022] <9> A jacket structure installation method according to aspect 9 of the present invention is characterized in that, in any one of aspects 1 to 8, multiple jacket structures are installed in the same wind farm or the same sea area, and the direction of the multiple jacket structures is determined according to the direction of wave force at the position of each of the multiple jacket structures.

[0023] According to the ninth aspect of the invention, the directions of the plurality of jacket structures are determined according to the direction of wave force at the position of each of the plurality of jacket structures. This makes it possible to flexibly respond to the direction of wave forces that differ depending on the position of each of multiple jacket structures installed in the same wind farm or the same sea area.

[0024] <10> The jacket structure installation method of aspect 10 of the present invention is characterized in that, in any one of aspects 1 to 9, the installation position of the pilot pile is determined according to the direction and magnitude of the maximum wave force during the construction period of the jacket structure.

[0025] According to the invention of aspect 10, the installation positions of the pilot piles are determined according to the direction and magnitude of the maximum wave force during the construction period of the jacket structure. In this way, by determining the installation positions of the pilot piles according to the direction and magnitude of the maximum wave force during the construction period of the jacket structure, the jacket structure can be made more stable during the construction period. [Effects of the Invention]

[0026] According to the present invention, it is possible to provide a jacket structure installation method that reduces the strictness of the positional accuracy of the piles and reduces installation costs. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 2 is a front view of the jacket structure according to the embodiment. [Figure 2] FIG. 10 is a first schematic top view showing an example of the installation position of the pilot piles when installing the jacket structure according to the embodiment. [Figure 3] FIG. 10 is a second schematic top view showing an example of the installation position of the pilot piles when installing the jacket structure according to the embodiment. [Figure 4] FIG. 10 is a third schematic top view showing an example of the installation position of the pilot piles when installing the jacket structure according to the embodiment. [Figure 5]FIG. 10 is a fourth schematic top view showing an example of the installation position of the pilot piles when installing the jacket structure according to the embodiment. [Figure 6] FIG. 10 is a fifth schematic top view showing an example of the installation position of the pilot piles when installing the jacket structure according to the embodiment. [Figure 7] FIG. 10 is a sixth schematic top view showing an example of the installation position of the pilot piles when installing the jacket structure according to the embodiment. [Figure 8] FIG. 10 is a seventh schematic top view showing an example of the installation position of the pilot piles when installing the jacket structure according to the embodiment. [Figure 9] FIG. 13 is an eighth schematic top view showing an example of the installation position of the pilot piles when installing the jacket structure according to the embodiment. [Figure 10] FIG. 9 is a ninth schematic top view showing an example of the installation position of the pilot piles when installing the jacket structure according to the embodiment. [Figure 11] FIG. 10 is a 10th schematic top view showing an example of the installation position of the pilot piles when installing the jacket structure according to the embodiment. [Figure 12] FIG. 11 is an eleventh schematic top view showing an example of the installation position of the pilot piles when installing the jacket structure according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, a method for installing a jacket structure 100 according to one embodiment of the present invention will be described with reference to the drawings. First, the jacket structure 100 according to this embodiment will be described. FIG. 1 is a front view of a jacket structure 100 according to this embodiment. The jacket structure 100 shown in FIG. 1 is installed on the seabed S via piles P installed on the seabed S, and supports the offshore wind turbine 200. The jacket structure 100 includes a transition piece 10 , a leg 20 , and a sleeve 30 .

[0029] The transition piece 10 shown in FIG. Specifically, the lower end of the tower T of the offshore wind turbine 200 is connected to the transition piece 10. The transition piece 10 is supported by the legs 20 .

[0030] The leg 20 shown in FIG. 1 is a member that supports the transition piece 10 . At least three legs 20 are provided in the jacket structure 100 .

[0031] FIG. 2 is a first schematic top view showing an example of the installation position of the pilot pile P1 when installing the jacket structure 100 according to this embodiment. The jacket structure 100 shown in FIG. In other words, the jacket structure 100 shown in FIG.

[0032] The number of legs 20 provided in the jacket structure 100 is not limited to four. The number of legs 20 provided in the jacket structure 100 may be three or more, and may be five. The fewer the number of legs 20 provided on the jacket structure 100, the fewer the number of piles P that need to be installed, reducing the installation and operating costs of the jacket structure 100. The more legs 20 there are, the more piles P that need to be installed, which increases the installation costs, but as a result, it is easier to ensure the bearing capacity of the jacket structure 100. The number of legs 20 in the jacket structure 100 is preferably determined appropriately depending on the bearing capacity required for the jacket structure 100 and the ground conditions of the seabed on which it is to be installed.

[0033] As shown in FIG. 1, the sleeve 30 is provided at the lower end of the leg 20 with its opening facing outward in the vertical direction. The sleeve 30 may be any member that can be connected to the leg 20 by inserting the pile P therein. The sleeve 30 may be, for example, a cylindrical member. As shown in FIGS. 1 and 2, the sleeve 30 and the lower end of the leg 20 are connected by a connecting plate 30P. The upper end of the pile P is inserted into the sleeve 30. In this way, the sleeve 30 connects the leg 20 and the pile P. This also connects the jacket structure 100 to the piles P and fixes it to the seabed S. In FIG. 2, two sleeves 30 are provided for one leg 20. In addition, in FIG. 2, the leading piles P1 are installed so that the four legs 20 form a square in plan view, as will be described later.

[0034] FIG. 3 is a second schematic top view showing an example of the installation position of the pilot pile P1 when installing the jacket structure 100 according to this embodiment. The jacket structure 100 shown in FIG. In other words, the jacket structure 100 shown in FIG. In FIG. 3, two sleeves 30 are provided for one leg 20. In addition, in FIG. 3, as will be described later, the leading piles P1 are installed so that the four legs 20 form a rectangle in plan view.

[0035] FIG. 4 is a third schematic top view showing an example of the installation position of the pilot pile P1 when installing the jacket structure 100 according to this embodiment. The jacket structure 100 shown in FIG. In other words, the jacket structure 100 shown in FIG. In FIG. 4, two sleeves 30 are provided for one leg 20. In addition, in FIG. 4, as will be described later, the leading piles P1 are installed so as to form a rectangle on two opposing legs 20 of the four legs 20 in a plan view.

[0036] FIG. 5 is a fourth schematic top view showing an example of the installation position of the pilot pile P1 when installing the jacket structure 100 according to this embodiment. The jacket structure 100 shown in FIG. In other words, the jacket structure 100 shown in FIG. In FIG. 5, two sleeves 30 are provided for one leg 20. In addition, in FIG. 5, as will be described later, the leading piles P1 are installed so as to form a triangle on any three of the four legs 20 in plan view.

[0037] FIG. 6 is a fifth schematic top view showing an example of the installation position of the pilot pile P1 when installing the jacket structure 100 according to this embodiment. The jacket structure 100 shown in FIG. In other words, the jacket structure 100 shown in FIG. In FIG. 6, two sleeves 30 are provided for one leg 20. In addition, in FIG. 6, as will be described later, the leading piles P1 are installed so as to form a triangle on two opposing legs 20 of the four legs 20 in a plan view.

[0038] A plurality of sleeves 30 are provided for each of the plurality of legs 20 . The jacket structure 100 shown in FIGS. 2 to 6 has two sleeves 30 for each of the legs 20 provided therein. In other words, two sleeves 30 are provided for one leg 20 in FIGS. This allows two piles P to be connected to one leg 20.

[0039] FIG. 7 is a sixth schematic top view showing an example of the installation position of the pilot pile P1 when installing the jacket structure 100 according to this embodiment. The jacket structure 100 shown in FIG. In other words, the jacket structure 100 shown in FIG. In FIG. 7, three sleeves 30 are provided for one leg 20. In addition, in FIG. 7, as will be described later, the leading piles P1 are installed so that the four legs 20 form a square in plan view. The configuration shown in FIG. 7 differs from the configuration shown in FIG. 2 in the number of sleeves 30 provided for one leg 20.

[0040] FIG. 8 is a seventh schematic top view showing an example of the installation position of the pilot pile P1 when installing the jacket structure 100 according to this embodiment. The jacket structure 100 shown in FIG. In other words, the jacket structure 100 shown in FIG. In FIG. 8, three sleeves 30 are provided for one leg 20. In addition, in FIG. 8, as will be described later, the leading piles P1 are installed so that the four legs 20 form a square in plan view. The configuration shown in FIG. 8 differs from the configuration shown in FIG. 7 in terms of the position of the sleeve 30 assigned to the leading pile P1.

[0041] FIG. 9 is an eighth schematic top view showing an example of the installation position of the pilot pile P1 when installing the jacket structure 100 according to this embodiment. The jacket structure 100 shown in FIG. In other words, the jacket structure 100 shown in FIG. In FIG. 9, three sleeves 30 are provided for one leg 20. In addition, in FIG. 9, as will be described later, the leading piles P1 are installed so that the four legs 20 form a rectangle in plan view. The configuration shown in FIG. 9 differs from the configuration shown in FIG. 3 in the number of sleeves 30 provided for one leg 20.

[0042] FIG. 10 is a ninth schematic top view showing an example of the installation position of the pilot pile P1 when installing the jacket structure 100 according to this embodiment. The jacket structure 100 shown in FIG. In other words, the jacket structure 100 shown in FIG. In FIG. 10, three sleeves 30 are provided for one leg 20. In addition, in FIG. 10, as will be described later, the leading piles P1 are installed so as to form a rectangle on two opposing legs 20 of the four legs 20 in a plan view. The configuration shown in FIG. 10 differs from the configuration shown in FIG. 4 in the number of sleeves 30 provided for one leg 20.

[0043] FIG. 11 is a tenth schematic top view showing an example of the installation position of the pilot pile P1 when installing the jacket structure 100 according to this embodiment. The jacket structure 100 shown in FIG. In other words, the jacket structure 100 shown in FIG. In FIG. 11, three sleeves 30 are provided for one leg 20. In addition, in FIG. 11, as will be described later, the leading piles P1 are installed so as to form a triangle on any three of the four legs 20 in a plan view. The configuration shown in FIG. 11 differs from the configuration shown in FIG. 5 in the number of sleeves 30 provided for one leg 20.

[0044] FIG. 12 is an eleventh schematic top view showing an example of the installation position of the pilot pile P1 when installing the jacket structure 100 according to this embodiment. The jacket structure 100 shown in FIG. In other words, the jacket structure 100 shown in FIG. In FIG. 12, three sleeves 30 are provided for one leg 20. In addition, in FIG. 12, as will be described later, the leading piles P1 are installed so as to form a triangle on opposing legs 20 of the four legs 20 in a plan view. The configuration shown in FIG. 12 differs from the configuration shown in FIG. 6 in the number of sleeves 30 provided for one leg 20.

[0045] As shown in FIGS. 7 to 12, three sleeves 30 may be provided for one leg 20. However, the present invention is not limited to this, and four or more sleeves 30 may be provided as long as they do not interfere with the piles to be installed. The fewer the number of sleeves 30 per leg 20, the fewer the number of piles P that need to be installed, reducing the installation and operating costs of the jacket structure 100. On the other hand, the more sleeves 30 there are, the more piles P that need to be installed, which increases the installation costs, but increases the bearing capacity of the leg 20. The number of sleeves 30 for one leg 20 is preferably determined appropriately according to the number of piles P connected to one leg 20, which is determined based on the ground conditions of the seabed on which the jacket structure 100 is installed, etc. Regarding the number of piles P connected to one leg 20, the number of piles P can be increased when the bearing capacity required of the jacket structure 100 is relatively high or the ground is relatively soft, and the number of piles P can be reduced when the bearing capacity required of the jacket structure 100 is not relatively high or the ground is relatively strong.

[0046] In addition to the above configuration, the jacket structure 100 may also include a brace 40 as shown in FIG. The braces 40 connect the multiple legs 20 together and reinforce the jacket structure 100 .

[0047] (Method of installing jacket structure 100) Next, a method for installing the jacket structure 100 according to this embodiment will be described. A plurality of jacket structures 100 according to this embodiment are installed in the same wind farm or the same sea area, for example. In this case, it is preferable that the installation direction of the plurality of jacket structures 100 is determined according to the direction of wave force in the wind farm or the sea area. This makes it possible to make the jacket structure 100 more stable against wave forces in a wind farm or in an ocean area. Alternatively, the installation direction of the multiple jacket structures 100 may be determined according to the direction of wave force at the planned installation position of each of the multiple jacket structures 100.

[0048] Next, detailed steps for installing the jacket structure 100 will be described. In the following description, among the piles P to be installed on the seabed S, the piles to be installed in the first step described below will be referred to as the leading pile P1. Of the piles P installed on the seabed S, those installed in the third step described below are referred to as trailing piles P2.

[0049] The method for installing the jacket structure 100 according to this embodiment includes a first step, a second step, and a third step.

[0050] The first step is to install the leading pile P1. Specifically, the first step is to install the leading piles P1, P1, etc. on the seabed S while ensuring positional accuracy and dimensional accuracy of the spacing between the leading piles P1, P1, etc. so that the leading pile P1 can be connected to the multiple sleeves 30 provided on each leg 20 of the jacket structure 100. The installation position of the leading pile P1 is determined appropriately depending on the conditions of the location where the jacket structure 100 is installed, and details will be described later.

[0051] In the first step, it is preferable that at least three pilot piles P1 are installed for one jacket structure 100. As a result, the leading piles P1 form a polygonal shape in a plan view of the jacket structure 100, ensuring the stability of the jacket structure 100 that is placed on the seabed S in the second step described below. The center of gravity of the jacket structure 100 is preferably located within the polygon formed by the leading piles P1 in plan view, and more preferably at the center of the transition piece 10 in plan view. Furthermore, it is preferable that the installation of the plurality of pilot piles P1 be performed in a clockwise or counterclockwise order around the jacket structure 100 as the center. This can improve the workability of installing the plurality of leading piles P1.

[0052] In the first step, it is preferable to use a template to install the pilot pile P1 on the seabed S. The template is a marker member that is installed on the seabed S to allow the relative positions of multiple leading piles P1 to be fixed and installed. If a template is used to install the leading piles P1, the positional accuracy between the multiple leading piles P1 can be improved. The template has a plurality of holes for inserting the pilot piles P1, P1 . . . , and is provided with a plurality of holes of different dimensions to match the installation positions of the pilot piles P1 to be installed on the seabed S. The template may be left on the seabed S after the pilot pile P1 is installed in the first step, or may be removed before the second step. If the template is removed before the second step, one template can be used to install the leading piles P1 of multiple jacket structures 100 where the relative positions between the leading piles P1 are the same, thereby making it possible to standardize the positions between the multiple leading piles P1 among the multiple jacket structures 100. Furthermore, if the distance between the multiple pilot piles P1 installed using the template is different, the shape of the template will need to be modified, or multiple templates will be required depending on the distance between each pilot pile P1, P1, which will increase the manufacturing cost of the template. Therefore, when a template is used to install the leading piles P1, it is preferable that the pile-to-pile distances between the plurality of leading piles P1, P1 installed using the template be uniform from the viewpoint of template manufacturing costs. This reduces the manufacturing cost of the template.

[0053] The second step is a step of placing the jacket structure 100 so that one of the plurality of leading piles P1 installed in the first step is inserted into one of the plurality of sleeves 30 provided for one leg 20. That is, in the second step, the position of the sleeve 30 of the jacket structure 100 is aligned with the leading pile P1 installed on the seabed S, and the leading pile P1 is inserted into the sleeve 30. As a result, the pilot pile P1 and the sleeve 30 are connected, and the jacket structure 100 is placed on the seabed S.

[0054] The third step is to install the trailing pile P2. Specifically, the third step is a step of installing the trailing pile P2 on the seabed S so that the trailing pile P2 and the multiple sleeves 30 provided in the jacket structure 100 can be connected to each other. In the third step, one or more trailing piles P2 are inserted into one of the sleeves 30 provided for one leg 20 that is not connected to the leading pile P1. For example, if two sleeves 30 are provided for one leg 20 and a leading pile P1 is connected to one of the two sleeves 30, in the third step, a trailing pile P2 is connected to the other of the two sleeves 30. For example, if three or more sleeves 30 are provided for one leg 20 and a leading pile P1 is connected to one of the multiple sleeves 30, in the third step, a trailing pile P2 is connected to a sleeve 30 other than the sleeve 30 to which the leading pile P1 is connected. When all of the sleeves 30 provided for one leg 20 are already connected to the leading pile P1, the following pile P2 does not need to be connected to the sleeve 30. Alternatively, if two or more sleeves 30 are provided for one leg 20 and no leading pile P1 is connected to any of them, in the third step, a trailing pile P2 is connected to each of the multiple sleeves 30 to which no leading pile P1 is connected. However, it is not necessary that a pile be inserted into all of the plurality of sleeves 30, and it is not necessary that a pile be inserted into any of the plurality of sleeves 30.

[0055] The trailing pile P2 is inserted from above into the sleeve 30, which is a cylindrical member of the jacket structure 100 that was placed on the seabed S via the leading pile P1 in the second step, and is installed on the seabed S. In other words, the trailing pile P2 is set while being guided by the sleeve 30. This allows the trailing pile P2 and the sleeve 30 to be connected smoothly. The jacket structure 100 is installed on the seabed S through the above-mentioned first to third steps.

[0056] (Regarding the installation location of the leading pile P1) Next, the installation position of the pilot pile P1 when installing the jacket structure 100 on the seabed S will be described. The installation position of the leading pile P1 is appropriately selected from any of the examples described below. When multiple jacket structures 100 are installed in the same wind farm or the same sea area, the installation positions of the pilot piles P1 may be the same for the multiple installed jacket structures 100, or may be different for each. The installation position of the pilot pile P1 is determined depending on the direction of wave force at the location where the jacket structure 100 is installed. Alternatively, the installation position of the leading pile P1 may be determined according to the direction and magnitude of the maximum wave force during the construction period of the jacket structure 100.

[0057] (Example of the first installation position of the leading pile P1) In the first example of installation positions of the leading piles P1, the plurality of leading piles P1 are installed at the corners of a substantially regular polygon in plan view. In other words, the plurality of leading piles P1 form a substantially regular polygon in plan view. In this embodiment, an approximately regular polygon refers to a polygon in which the angle of each corner is within a range of ±5% or less of the angle of a regular polygon, or a polygon in which the length of each side is within a range of ±5% or less of the dimension of a regular polygon.

[0058] For example, if there are four pilot piles P1, that is, if four pilot piles P1 are installed in the first step, the four pilot piles P1 are installed at the corners of an approximately square when viewed in plan, as shown in Figures 2, 7, and 8. In other words, the four leading piles P1 are installed so as to form a substantially square in plan view. In this embodiment, a substantially square shape refers to a rectangle in which the angles of each corner are in the range of 85° to 95°, and in which the length of the shortest side of the rectangle is 90% or more of the length of the longest side.

[0059] When the four pilot piles P1 form an approximately square shape in plan view, it is preferable to select one sleeve 30 at a corresponding position from the multiple sleeves 30 provided on each of the four legs 20, as shown in Figures 2, 7, and 8, and install the pilot pile P1 on the seabed S so that the pilot pile P1 is inserted into the selected sleeve 30.

[0060] However, the present invention is not limited to this, and when the number of legs 20 in one jacket structure 100 is three, the three leading piles P1 may be installed so as to form a substantially equilateral triangle in plan view. Alternatively, when the number of legs 20 in one jacket structure 100 is five or six, the five or six leading piles P1 may be installed so as to form a substantially regular pentagon or a substantially regular hexagon in plan view. These approximately regular triangles, approximately regular pentagons, and approximately regular hexagons conform to the definition of an approximately polygon described above. The approximate polygon is not limited to these shapes, and the number of legs 20 in one jacket structure 100 may be seven or more.

[0061] By locating the plurality of leading piles P1 in such positions, the strength of the jacket structure 100 against wave forces can be made isotropic. The installation of the pilot pile P1 in the first installation position example is preferably used when the strength of wave force does not vary depending on the direction at the location where the jacket structure 100 is installed.

[0062] (Example of the second installation position of the leading pile P1) In the second example of installation positions of the leading piles P1, the leading piles P1 are installed at corners of a substantially symmetrical shape in a plan view. In other words, the plurality of leading piles P1 are installed so as to form a substantially symmetrical figure in a plan view. In this embodiment, a substantially symmetrical figure refers to a figure in which the error in shape between the figure on one side of a reference line or point and the figure on the other side is ±10% or less. Here, the error in the shapes of two figures is the ratio of the area of ​​the non-overlapping portion to the area of ​​the figure when the figure is superimposed on a symmetrical figure. Examples of substantially symmetrical shapes include rectangular shapes (substantially rectangular) and isosceles triangular shapes (substantially isosceles triangle).

[0063] For example, "approximately symmetrical" means that, for the lengths of corresponding sides of a figure on one side of a reference line or point and a figure on the other side, the shorter dimension is 90% or more of the longer dimension, or, for the sizes of corresponding angles, the smaller angle is 90% or more of the larger angle.

[0064] For example, if there are four pilot piles P1, that is, if four pilot piles P1 are installed in the first step, the four pilot piles P1 are installed at the corners of an approximately rectangular shape in a plan view, as shown in Figures 3, 4, 9, and 10. In other words, the four leading piles P1 are installed so as to form a substantially rectangular shape in a plan view. In this embodiment, a substantially rectangular shape refers to a quadrangle in which each corner angle is in the range of 85° to 95°.

[0065] For example, if there are three pilot piles P1, that is, if three pilot piles P1 are installed in the first step, the three pilot piles P1 are installed at the corners of an approximately isosceles triangle in plan view, as shown in Figures 5, 6, 11, and 12. In other words, the three leading piles P1 are installed so as to form a substantial isosceles triangle in plan view. In this embodiment, an approximately isosceles triangle is one in which the angle of the smaller base angle of the two base angles is 90% or more of the angle of the larger base angle, and the shorter dimension of the two equal sides is 90% or more of the longer dimension.

[0066] When three or four pilot piles P1 form an approximately symmetrical shape in a plan view, it is preferable to appropriately select a sleeve 30 to connect with the pilot pile P1 from the multiple sleeves 30 provided on each of the four legs 20, and install the pilot pile P1 on the seabed S so that the pilot pile P1 is inserted into the selected sleeve 30.

[0067] By installing the plurality of leading piles P1 at such positions, the jacket structure 100 can be made particularly strong against wave forces in a specific direction. For example, if the four leading piles P1 are installed so as to form a substantially rectangular shape in a plan view, the piles can be made particularly strong against wave forces in the direction in which the short sides of the substantially rectangular shape face. Therefore, when the leading pile P1 forms a substantially rectangular shape, it is preferable to install the leading pile P1 so that the short side of the substantially rectangular shape is substantially perpendicular to the traveling direction of the waves. The installation position of the pilot pile P1 in the second installation position example is preferably used when the wave force from a specific direction is strong at the location where the jacket structure 100 is installed.

[0068] When installing the jacket structure 100 on the seabed S, one of the two installation position examples described above is selected, and the pilot pile P1 is installed on the seabed S in the first step. When four pilot piles P1 are provided, it is preferable to install them at the corners of a substantially square or rectangular shape in plan view, depending on the direction of wave force at the location where the jacket structure 100 is installed.

[0069] As described above, according to the method for installing the jacket structure 100 according to this embodiment, in the first step, the pilot pile P1 is installed. In the next second step, the leading pile P1 is inserted into the sleeve 30, and the jacket structure 100 that supports the offshore wind turbine 200 is placed on the seabed S. Then, in the third step, the trailing pile P2 is installed. In this way, by placing the jacket structure 100 on the leading pile P1 that has been installed in advance on the seabed S, it is possible to prevent the jacket structure 100 from sinking into the seabed S or from sinking unevenly, which may occur if the jacket structure 100 is installed directly on the seabed S without installing the leading pile P1, which is a foundation pile, on the seabed S. Therefore, mud mats and temporary piles are not required. Furthermore, by installing the trailing pile P2 after placing the jacket structure 100 on the seabed S via the leading pile P1, the number of leading piles P1 that are installed on the seabed S in advance can be reduced, and the sleeve 30 can be used as a guide member for the trailing pile P2, so when installing the trailing pile, there is no concern about interference with the sleeve 30, unlike when installing the leading pile. Therefore, troubles in installing the jacket structure 100 can be reduced.

[0070] In the first installation position example, the plurality of pilot piles P1 are installed at the corners of a substantially regular polygon in plan view. In other words, in the first installation position example, the plurality of leading piles P1 form a substantially regular polygon in a plan view. This makes it possible to make the strength of the jacket structure 100 against wave forces acting on it isotropic in the state where the jacket structure 100 is placed on the leading piles P1 in the second step. Therefore, before the third step, in a state in which the jacket structure 100 is supported only by the leading piles P1, the jacket structure 100 can be stabilized on the seabed S.

[0071] In the first installation position example, the four leading stakes P1 may be installed at the corners of a substantially square in plan view. In other words, in the first installation position example, the four leading stakes P1 may form a substantially square shape in a plan view. As a result, in the second step, when the jacket structure 100 is connected only by the leading piles P1 and placed on the seabed S, the strength of the jacket structure 100 against wave forces can be made isotropic in all directions. Therefore, in the state before the third step in which the jacket structure 100 is connected only by the leading piles P1 and placed on the seabed S, the jacket structure 100 can be stabilized on the seabed S.

[0072] Additionally, the jacket structure 100 has two or more sleeves 30 for one leg 20 . This allows one leg 20 to be supported by one or more leading piles P1 and one or more trailing piles P2. Therefore, the jacket structure 100 can be made more stable on the seabed S. Furthermore, when two sleeves 30 are included for one leg 20, the number of sleeves 30 can be relatively reduced.

[0073] Furthermore, the plurality of leading piles P1 are installed at corners of a substantially symmetrical shape in plan view. In other words, the plurality of leading piles P1 form a substantially symmetrical figure in a plan view. This also includes cases where the arrangement of the leading piles is anisotropic, but if the arrangement of the leading piles is anisotropic, when the jacket structure 100 is connected only by the leading piles P1 and placed on the seabed S in the second step, the jacket structure 100 can be made particularly strong against wave forces in a specific direction. Therefore, even if the wave force from a particular direction is strong at the location where the jacket structure 100 is installed, by adjusting the installation positions of the multiple leading piles P1 in a planar view, the jacket structure 100 can be made more stable on the seabed S even before the third step, when the jacket structure 100 is connected only by the leading piles P1 and placed on the seabed S.

[0074] In the second installation position example, the four leading stakes P1 may be installed at the corners of a substantially rectangular shape in plan view. In other words, in the second installation position example, the four leading stakes P1 may form a substantially rectangular shape in a plan view. As a result, when the jacket structure 100 is connected only by the leading pile P1 and placed on the seabed S in the second step, the strength of the jacket structure 100 against wave forces can be made particularly strong in the direction facing the short side of the approximately rectangular shape. Therefore, by having the short side of the approximately rectangular shape face the direction of strong wave force at the location where the jacket structure 100 is installed, the jacket structure 100 can be made more stable on the seabed S even before the third step, when the jacket structure 100 is connected only by the leading pile P1 and placed on the seabed S.

[0075] In this embodiment, the four leading piles P1 may be installed at the corners of a substantially square or rectangular shape in plan view, depending on the direction of wave force at the location where the jacket structure 100 is installed. In other words, in this embodiment, depending on the direction of wave force at the location where the jacket structure 100 is installed, it is determined whether the four pilot piles P1 are installed to form an approximately square or an approximately rectangular shape in a plan view. As a result, when the strength of the wave force is uniform regardless of direction, the leading pile P1 is installed so that it forms an approximately square in plan view, and when the wave force is strong from a specific direction, the leading pile P1 is installed so that it forms an approximately rectangular in plan view with the short side of the approximately rectangular shape facing the direction of the strong wave force, thereby making it possible to install the leading pile P1 in a position that is more suitable for the characteristics of the location where the jacket structure 100 is installed. Therefore, even in the state before the third step in which the jacket structure 100 is connected only by the leading piles P1 and placed on the seabed, the jacket structure 100 can be made more stable on the seabed S.

[0076] Generally, a work boat stabilizes itself by pushing its bow against a boat landing using its propulsive force. If a boat landing is on the incoming side of the work boat, the force of the waves acts to push back the boat approaching the boat landing. This allows the propulsive force of the boat to be offset by the force of the waves, allowing the work boat to approach the boat landing at a slower speed and reducing the impact force upon contact. Therefore, the installation direction of the multiple jacket structures 100 may be determined according to the direction of wave force in the wind farm or sea area where the jacket structures 100 are installed. This allows the installation direction of the jacket structures 100 to be determined so that, for example, the boat landing that a work boat will come into contact with is positioned on the incident side. By arranging the jacket structures 100 in this manner, the impact force of the work boat when it comes into contact with the boat landing due to the force of waves can be reduced. This makes it easier for the work boat to access the jacket structure 100.

[0077] Furthermore, the installation direction of the multiple jacket structures 100 may be determined according to the direction of wave force at the position of each of the multiple jacket structures 100. This makes it possible to flexibly respond to the direction of wave force, which differs depending on the position of each of a plurality of jacket structures 100 installed in the same wind farm or the same sea area.

[0078] Furthermore, the installation position of the leading pile P1 may be determined depending on the direction and magnitude of the maximum wave force during the construction period of the jacket structure 100. In this way, by determining the installation position of the leading pile P1 according to the direction and magnitude of the maximum wave force during the construction period of the jacket structure 100, the jacket structure 100 can be made more stable during the construction period.

[0079] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the polygon formed by the leading piles P1 in a plan view of the jacket structure 100 does not have to be a substantially regular polygon as long as the center of gravity of the jacket structure 100 in a plan view is located inside the polygon. The polygon formed by the leading piles P1 in a plan view of the jacket structure 100 may be a simple rectangle, a triangle, or the like. Furthermore, a plurality of leading piles P1 may be installed for one leg 20. Also, although the number of legs is described as four, the number of legs is not limited as long as it is three or more.

[0080] Although the present specification has described a case where the jacket structure is installed on the seabed, the present invention is not limited to this. Examples of locations where the jacket structure to which the present invention can be applied include the bottom of water such as a lake bottom in addition to the bottom of the sea.

[0081] In addition, within the scope of the spirit of the present invention, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described modifications may be combined as appropriate. [Explanation of symbols]

[0082] 10 Transition Piece 20 Legs 30 sleeves 30P connection board 40 braces 100 Jacket structure 200 Offshore Wind Turbines P pile P1 Pilot Pile P2 trailing pile S submarine T Tower

Claims

1. 1. A method for installing a jacket structure supporting an offshore wind turbine, the jacket structure including at least three or more legs and a plurality of sleeves provided for each of the three or more legs, the method comprising: a first step of installing a plurality of pilot piles; a second step of placing the jacket structure so that one of the plurality of leading piles is inserted into one of the plurality of sleeves; and a third step of installing one or more trailing piles corresponding to other sleeves of the plurality of sleeves. How to install the jacket structure.

2. The plurality of leading piles are installed at corners of a substantially regular polygon in a plan view, A method for installing the jacket structure according to claim 1.

3. the jacket structure includes four legs; The number of the leading stakes is four, The four leading piles are installed at corners of a substantially square shape in a plan view. A method for installing the jacket structure according to claim 2.

4. The jacket structure includes two sleeves for one leg of the four legs. A method for installing the jacket structure according to claim 3.

5. The plurality of leading piles are installed at corners of a substantially symmetrical shape in a plan view, A method for installing the jacket structure according to claim 1.

6. the jacket structure includes four legs; The number of the leading stakes is four, The four leading piles are installed at corners of a substantially rectangular shape in a plan view. A method for installing the jacket structure according to claim 5.

7. the jacket structure includes four legs; The number of the leading stakes is four, The four leading piles are installed at corners of a substantially square or substantially rectangular shape in a plan view, depending on the direction of wave force at the location where the jacket structure is installed. A method for installing the jacket structure according to any one of claims 1 to 6.

8. A plurality of the jacket structures are installed in the same wind farm or the same sea area, The direction of the plurality of jacket structures is determined according to the direction of wave force in the wind farm or the sea area. A method for installing the jacket structure according to any one of claims 1 to 6.

9. A plurality of the jacket structures are installed in the same wind farm or the same sea area, The orientation of the plurality of jacket structures is determined according to the direction of wave force at the position of each of the plurality of jacket structures. A method for installing a jacket structure according to any one of claims 1 to 6.

10. The installation position of the pilot pile is determined according to the direction and magnitude of the maximum wave force during the construction period of the jacket structure. A method for installing the jacket structure according to any one of claims 1 to 6.

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