Marine structure dismantling method and floating device

Abstract

To safely demolish and recover a marine structure including a tower.SOLUTION: A dissembling method for a marine structure includes a transporting step for transporting a floating device towards a tower provided on the marine structure, an installation step for installing the floating device beside the tower, a destruction step for tipping a body of the marine structure toward the floating body by cutting the tower, and a recovery step for recovering the structure of the marine structure. The floating device includes at least one column with a ballast tank, a plate member coupled to the column underwater in a state of having at least one column installed on the sea, and a support member coupled to the column on the water and capable of supporting the body of the marine structure collapsing toward the floating body device in a state of having at least one column installed on the sea.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for dismantling marine structures equipped with towers such as various observation facilities, communication facilities, lighting facilities, mining facilities, and power generation facilities (e.g., meteorological observation towers, power transmission towers, lighthouses, and offshore wind turbines), and a floating device used in this dismantling method. [Background technology]

[0002] Patent Document 1 discloses a dismantling method for a tower-supported chimney structure that includes a chimney body installed on a chimney base and a chimney support tower constructed around the chimney body on the chimney base without being connected to the chimney body, thereby eliminating the need for work at height. In this method, a removal portion is formed at the lowest position on the side of the chimney body in the direction of collapse, and a fixed state between a predetermined area on the opposite side of the collapse direction of the chimney support tower and the chimney base is released. Then, at least one of the chimney body and the chimney support tower is pushed down in the collapse direction, causing the chimney body and the chimney support tower to collapse simultaneously.

[0003] Patent Document 2 discloses a method for collapsing a chimney structure supported by three pillars. In this method, the lower portion of one of the three pillars located in the direction of collapse is removed, and the collapse axis is reinforced to improve the stability of the cylinder body in the direction of collapse. Then, the remaining two pillars are cut and lifted, causing the chimney structure to collapse around the cylinder body as its axis. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-327301 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-013300 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors of the present application are considering a method for dismantling an offshore structure equipped with a tower, in which high-altitude work is avoided as much as possible, the base of the tower is cut using a laser, explosion, or other mechanical method, and the main body of the offshore structure (the part of the offshore structure above the cut position) is toppled before being dismantled. However, when toppling the main body of the offshore structure, there is a risk that the main body of the offshore structure will sink into the sea and become impossible to recover.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a method for dismantling an offshore structure that can safely dismantle an offshore structure equipped with a tower and recover the main body of the offshore structure, and a floating device to be used in this dismantling method. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the method for dismantling an offshore structure according to the present disclosure comprises a transporting step of transporting a floating device toward a tower equipped on the offshore structure, an installation step of installing the floating device next to the tower, a collapse step of cutting the tower and tilting the main body of the offshore structure toward the floating device, and a recovery step of recovering the main body of the offshore structure, wherein the floating device comprises at least one column having an internal space formed therein, a plate member connected to the at least one column underwater when the at least one column is installed on the sea, and a support member connected to the column above water when the at least one column is installed on the sea, and capable of supporting the main body of the offshore structure tilted toward the floating device. [Effects of the Invention]

[0008] According to the method for dismantling an offshore structure disclosed herein, an offshore structure equipped with a tower can be safely dismantled and recovered. [Brief explanation of the drawings]

[0009] [Figure 1] 3 is a flowchart showing an outline of a method for dismantling a meteorological observation tower according to the first embodiment. [Figure 2]FIG. 2 is a diagram for explaining an example of a transport step shown in FIG. [Figure 3A] FIG. 3 is a side view showing a configuration of a part of the floating body device shown in FIG. [Figure 3B] FIG. 3 is a front view showing a partial configuration of the floating body device shown in FIG. [Figure 3C] 5A and 5B are diagrams illustrating the configuration of a recess in the support member according to the first embodiment. [Figure 4A] 3A and 3B are diagrams illustrating a configuration of a connecting member according to the first embodiment. [Figure 4B] 10A and 10B are diagrams illustrating configurations of connecting members according to some embodiments. [Figure 5] FIG. 2 is a diagram for explaining an example of the installation step shown in FIG. [Figure 6] FIG. 2 is a diagram for explaining an example of a collapse step shown in FIG. [Figure 7] FIG. 2 is a diagram for explaining an example of a collapse step shown in FIG. [Figure 8] FIG. 2 is a diagram for explaining an example of a collection step shown in FIG. [Figure 9] 10A and 10B are diagrams illustrating the configuration of a receiving member according to some embodiments. [Figure 10] 10 is a diagram showing a modified example of the receiving member shown in FIG. 9. FIG. [Figure 11] 10 is a flowchart showing an outline of a method for dismantling a tower-type marine structure according to a second embodiment. [Figure 12A] 10A and 10B are diagrams illustrating a configuration of a tower mounting member according to a second embodiment. [Figure 12B] FIG. 10 is a diagram showing a state in which a tower mounting member according to a second embodiment is mounted on a tower. [Figure 13] 10 is a flowchart showing an outline of a method for dismantling a wind turbine according to a modified example of the second embodiment. [Figure 14A] 10A and 10B are diagrams showing the configuration of a nacelle mounting member according to a modified example of the second embodiment. [Figure 14B] FIG. 10 is a view showing a state in which a nacelle mounting member according to a modified example of the second embodiment is mounted on a wind turbine body. [Figure 15] FIG. 10 is a view showing the state in which a lid member is provided on the tower. [Figure 16] 1 is a flowchart outlining a method for dismantling a wind turbine according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the invention. For example, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement exactly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. For example, expressions representing shapes such as a square shape or a cylindrical shape not only represent shapes such as a square shape or a cylindrical shape in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. On the other hand, the expressions "comprise," "include," "have," "includes," or "have" of one element are not exclusive expressions that exclude the presence of other elements.

[0011] The marine structure dismantling method and floating device according to each embodiment of the present disclosure are a method and device used when dismantling an marine structure. The marine structure is not particularly limited as long as it has a tower, and examples thereof include a meteorological observation tower, a power transmission tower, a lighthouse, and an offshore wind turbine. Furthermore, "dismantling" here does not mean the work of dismantling the offshore structure itself, but rather the work of detaching the offshore structure from its foundation fixed to the seabed and making it possible to move it from its installed location.

[0012] First Embodiment (Method of dismantling a weather observation tower) FIG. 1 is a flowchart showing an outline of a method for dismantling a meteorological observation tower 2A according to the first embodiment.

[0013] As shown in Figure 1, the method for dismantling a meteorological observation tower 2A according to the first embodiment includes a transportation step S101 of transporting a floating device 4 toward a tower 8A (column portion) provided on the meteorological observation tower 2A, an installation step S102 of installing the floating device 4 next to the tower 8A, a collapse step S103 of cutting the tower 8A and collapsing the main body 2a of the meteorological observation tower 2A toward the floating device 4, and a recovery step S104 of recovering the main body 2a of the meteorological observation tower 2A.

[0014] Fig. 2 is a diagram illustrating an example of the transporting step S101 shown in Fig. 1. As shown in Fig. 2, the meteorological observation tower 2A includes a tower 8A erected on a foundation 50 fixed to the seabed, and a plurality of branch-like projections 5 branching out and extending from the tower 8A. Each of the branch-like projections 5 is provided with a measuring device 9 for observing meteorological parameters (for example, wind direction, wind speed, temperature, humidity, or rainfall). The dashed line in Fig. 2 indicates a cutting position P1 at which the tower 8A is cut in a collapsing step S103, which will be described later.

[0015] As shown in FIG. 2, in the transportation step S101, the floating device 4 is towed by a ship 6 and transported to the location where the meteorological observation tower 2A is installed.

[0016] The floating device 4 will now be described. The floating device 4 is configured to float on seawater and includes columns 10, plate members 12, and support members 14. As will be described later, one plate member 12 and one support member 14 are connected to one column 10.

[0017] 3A is a diagram showing a partial configuration of the floating body device 4 shown in FIG. 2, where the floating body device 4 is viewed from the side. FIG. 3B is a diagram showing a partial configuration of the floating body device 4 shown in FIG. 2, where the floating body device 4 is viewed from the front. In this disclosure, the partial configuration of the floating body device 4 refers to one column 10, one plate member 12 connected to this column 10, and one support member 14 connected to this column 10. Hereinafter, the partial configuration of the floating body device 4 will be referred to as a "receiving member 11."

[0018] As illustrated in FIGS. 3A and 3B, the column 10 has a ballast tank 21. The column 10 is fabricated by preparing a plurality of flat panels, such as steel plates, and connecting (welding) these panels together. The column 10 has a cylindrical shape with a longitudinal direction in the up-down direction, and the depth (draft) to which the floating device 4 sinks in seawater can be adjusted by the amount of seawater injected into the ballast tank 21. The column 10 may have a rectangular cylindrical shape or a cylindrical shape with another cross-sectional shape, such as a cylinder. In the present disclosure, a case in which the column 10 has a rectangular cylindrical shape will be described as an example.

[0019] The plate member 12 has a plate shape and is connected to the column 10 underwater while the column 10 is installed on the sea. The plate member 12 is connected to the underside 15 of the column 10 such that the underside 13 of the plate member 12 hides the entire underside 15 of the column 10 when the column 10 is viewed from below. In other words, the area of ​​the underside 13 of the plate member 12 is larger than the area of ​​the underside 15 of the column 10. Note that the present disclosure is not limited to the plate member 12 being connected to the underside 15 of the column 10. In some embodiments, although not shown, the plate member 12 is connected to the side of the column 10. In this case, the entire plate member 12 may be submerged in the sea by adjusting the draft of the floating device 4.

[0020] The support member 14 is connected to the column 10 at sea while the column 10 is installed at sea. The support member 14 is configured to be able to support the main body 2a of the meteorological observation tower 2A that has fallen toward the floating device 4. In the embodiment illustrated in FIGS. 3A and 3B, the support member 14 is connected to the upper surface 17 of the column 10. In the first embodiment, as illustrated in FIG. 3B, the support member 14 includes a recess 16 that recesses toward the column 10. That is, the support member 14 receives the main body 2a of the meteorological observation tower 2A that is falling in the recess 16, preventing the main body 2a of the meteorological observation tower 2A from falling off the support member 14. The inner surface of the recess 16 is curved concavely so that the outer shape changes smoothly. The material of the support member 14 is not particularly limited and may be an elastic material such as rubber or a metal such as stainless steel. In this embodiment, the main body 2a of the meteorological observation tower 2A refers to the part of the meteorological observation tower 2A above the cutting position P1 of the tower 8A, and includes, for example, part of the tower 8A and part of the multiple branch-like projections 5.

[0021] 3C is a diagram illustrating the configuration of the recess 16 of the support member 14 according to the first embodiment. In FIG. 3C, the support member 11 (a part of the floating body device 4) shown in FIG. 2 is viewed from above. When the meteorological observation tower 2A is viewed from above, the direction in which the main body 2a of the meteorological observation tower 2A is tilted toward the floating body device 4 in the collapse step S103 is defined as the collapse direction d1, and the direction perpendicular to the collapse direction d1 is defined as the orthogonal direction d2. In the orthogonal direction d2, the recess 16 of the support member 14 is wider than the main body 2a of the meteorological observation tower 2A. In other words, when the length of the main body 2a of the meteorological observation tower 2A in the orthogonal direction d2 is defined as L1 and the length of the recess 16 of the support member 14 in the orthogonal direction d2 is defined as L2, L2 > L1 is satisfied.

[0022] Returning to Figure 2, the configuration of the floating body device 4 other than the receiving members 11 will be described. In the first embodiment, as illustrated in Figure 2, the floating body device 4 includes four receiving members 11 (columns 10, plate members 12, and support members 14). The floating body device 4 further includes connecting members 20 for connecting each of the four columns 10 in a row. The specific gravity of the connecting members 20 is, for example, 1.0 times or more and less than 1.2 times the specific gravity of seawater. The connecting members 20 are placed on at least one of the upper surfaces 19 of the four plate members 12.

[0023] FIG. 4A is a diagram illustrating the configuration of a connecting member 20 according to the first embodiment. In the first embodiment, as illustrated in FIG. 4A , the connecting member 20 includes a single plate-like member 22 having a longitudinal direction d3. Four insertion holes 24 are formed in the plate-like member 22 at intervals along the longitudinal direction d3. The insertion holes 24 are not particularly limited as long as they are configured to allow the insertion of the columns 10, and may have, for example, a rectangular shape. In some embodiments, the insertion holes 24 are configured to prevent rotation of the columns 10 inserted therein. For example, the length of one side of the rectangular insertion hole 24 is shorter than the diagonal length of the cross section of the column 10 having a square cylindrical shape. In the embodiment illustrated in FIG. 4A , the plate-like member 22 includes, between adjacent insertion holes 24, short-width portions 27 whose length in the width direction d4 intersecting with the longitudinal direction d3 is shortened. This configuration reduces the weight and manufacturing costs of the floating body device 4.

[0024] FIG. 4B is a diagram illustrating the configuration of a connecting member 20 according to some embodiments (embodiments different from the first embodiment). In the embodiment illustrated in FIG. 4B, the connecting member 20 includes a plurality of ring portions 26 and a connecting portion 29. The plurality of ring portions 26 are provided separately from one another. The ring portion 26 has a ring shape with one insertion hole 24 formed therein. As described above, this insertion hole 24 is not particularly limited as long as it is configured to allow the insertion of the column 10. The connecting portion 29 connects two adjacent ring portions 26. The connection method using the connecting portion 29 is not particularly limited. For example, the two adjacent ring portions 26 may be connected by a magnet, or the two adjacent ring portions 26 may be connected (mechanically connected) by a chain. When the connecting member 20 includes three or more ring portions 26, the three or more ring portions 26 are arranged in a row, and the connecting portion 29 is provided between the two adjacent ring portions 26.

[0025] 1, the method for dismantling a meteorological observation tower 2A according to the first embodiment further includes a connecting step S105 in which the four columns 10 are connected in a row using the connecting members 20 before the transporting step S101. That is, in the connecting step S105, the floating body device 4 is assembled. In the connecting step S105 according to the first embodiment, the four columns 10 are inserted into the four insertion holes 24 formed in the plate-like member 22, respectively, to thereby assemble the floating body device 4.

[0026] In some embodiments, the method for dismantling the meteorological observation tower 2A includes a connecting step S105 after the transporting step S101 and before the installing step S102. In this case, for example, the four receiving members 11 (columns 10, plate members 12, and support members 14) and the connecting member 20 are transported separately to the side of the tower 8A, and the four columns 10 are connected next to the tower 8A to assemble the floating body device 4. Alternatively, when the connecting member 20 has the configuration illustrated in Fig. 4B , the four receiving members 11 with the columns 10 inserted into the insertion holes 24 of the ring portions 26 are transported separately to the side of the tower 8A, and the four columns 10 are connected next to the tower 8A to assemble the floating body device 4.

[0027] Figure 5 is a diagram for explaining an example of the installation step S102 shown in Figure 1. As shown in Figure 5, in the installation step S102, the floating device 4 is installed next to the tower 8A. In the installation step S102, the floating device 4 is installed in the collapse direction d1 relative to the position of the tower 8A. The floating device 4 is floating on the sea surface next to the tower 8A. Here, "installing the floating device 4 next to the tower 8A" means, more specifically, that the floating device 4 is installed in the sea in any direction relative to the tower 8A so that the distance between the tower 8A and the floating device 4 is less than h, where h is the height of the tower 8A from the sea surface.

[0028] 5, in installation step S102, a portion of the tower 8A below the cutting position P1 is connected to one end 20a of the connecting member 20 on the tower 8A side by a first rope 23A. Furthermore, the other end 20b of the connecting member 20 on the opposite side from the tower 8A side is connected to the boat 6 by a second rope 23B. Then, the connecting member 20 is pulled by the boat 6.

[0029] Fig. 6 is a diagram for explaining an example of the collapsing step S103 shown in Fig. 1. Fig. 7 is a diagram for explaining an example of the collapsing step S103 shown in Fig. 1, and shows an example different from that in Fig. 6.

[0030] As shown in FIG. 6 , in the collapse step S103, two ships 6 pull the tower 8A in two different directions g1 and g2 using ropes 25 while cutting the tower 8A using a laser, explosion, or other mechanical method, thereby toppling the main body 2a of the meteorological observation tower 2A toward a direction d1 between the two directions g1 and g2. For example, two ships 6 may cut the tower 8A while pulling the tower 8A with equal force from two different directions g1 and g2 using ropes 25, thereby toppling the main body 2a of the meteorological observation tower 2A toward the direction d1 between the two directions g1 and g2. As shown in FIG. 6 , by cutting the tower 8A and toppling the main body 2a of the meteorological observation tower 2A toward the floating device 4 (in other words, by positioning the floating device 4 in advance in the direction d1 in which the main body 2a of the meteorological observation tower 2A will be toppling relative to the tower 8A), the main body 2a of the meteorological observation tower 2A can be easily recovered using the floating device 4.

[0031] 7, in the collapse step S103, a first incision C1, a second incision C2, and a third incision C3 are formed in the tower 8A by a mechanical method. First, the first incision C1 is formed in the tower 8A by mechanical cutting a1 in the base portion 8r of the tower 8A from the floating body device 4 side (one side) of the tower 8A so as not to penetrate the tower 8A (first cutting step). Next, a second incision C2 connected to the first incision C1 is formed in the tower 8A by mechanical cutting a2 in the base portion 8r of the tower 8A from the floating body device 4 side of the tower 8A at an angle different from the first incision C1 so as not to penetrate the tower 8A, and the portion (fragment) of the tower 8A between the first incision C1 and the second incision C2 is removed from the tower 8A (second cutting step). Then, a third notch C3 that connects to at least one of the first notch C1 and the second notch C2 is formed in the base portion 8r of the tower 8A by mechanical cutting a3 from the opposite side (other side) of the tower 8A to the floating body device 4 (third cutting step), thereby cutting the tower 8A. In the embodiment illustrated in Fig. 7, the first notch C1 and the third notch C3 are each formed in the base portion 8r of the tower 8A along the horizontal direction, and the second notch C2 is formed in the base portion 8r of the tower 8A obliquely from above to below.

[0032] In this way, by using the mechanical cutting a1 to a3, the main body 2a of the meteorological observation tower 2A can be tilted toward the floating device 4 without having to pull the tower 8A with the ship 6. This makes it easy to safely recover the main body 2a of the meteorological observation tower 2A using the floating device 4.

[0033] Incidentally, if there is a direction in which the branch-like projections 5 do not extend from the tower 8A, that direction may be set as the collapse direction d1. In this case, when the main body 2a of the meteorological observation tower 2A is in a fallen state, the direction in which the branch-like projections 5 do not extend from the tower 8A is downward. Also, if there is no direction in which the branch-like projections 5 do not extend from the tower 8A, the branch-like projections 5 extending in the collapse direction d1 may be cut off before cutting the tower 8A. This makes it possible to prevent the floating body device 4 from being damaged by the branch-like projections 5.

[0034] Fig. 8 is a diagram for explaining an example of the recovery step S104 shown in Fig. 1. As shown in Fig. 8, in the recovery step S104, the floating device 4 with the main body 2a of the meteorological observation tower 2A mounted thereon is transported to the shore, and the main body 2a of the meteorological observation tower 2A is pulled up onto land and recovered.

[0035] 8, in recovery step S104, the floating device 4 with the main body 2a of the meteorological observation tower 2A mounted thereon is towed by a ship 6 to the shore, and the main body 2a of the meteorological observation tower 2A is pulled onto land using a crane 28. Note that in recovery step S104, the main body 2a of the meteorological observation tower 2A may be disassembled into several parts at sea so that the weight of the object to be lifted by the crane 28 is within the allowable load of the crane 28. Furthermore, when the main body 2a of the meteorological observation tower 2A is to be lifted as a whole without being disassembled, the main body 2a of the meteorological observation tower 2A may be lifted using, for example, a large crane at a dock in a shipyard.

[0036] (Actions and Effects) The following describes the effects and advantages of the method for dismantling a meteorological observation tower 2A according to the first embodiment. According to the first embodiment, as illustrated in Fig. 1, a floating device 4 is installed next to the tower 8A prior to cutting the tower 8A, and the tower 8A is then cut and the main body 2a of the meteorological observation tower 2A is tilted toward the floating device 4. This prevents the main body 2a of the meteorological observation tower 2A from sinking into the sea using the floating device 4, and the main body 2a of the meteorological observation tower 2A can be recovered.

[0037] According to the first embodiment, when the support members 14 support the main body 2a of the meteorological observation tower 2A that has fallen toward the floating device 4, the drag acting on the plate members 12 can reduce the depth to which the floating device 4 sinks into the sea. In other words, it is possible to suppress the generation of waves when the floating device 4 receives the falling main body 2a of the meteorological observation tower 2A, and to suppress the scattering of debris and dust of the structure from the main body 2a of the meteorological observation tower 2A. Furthermore, by adjusting the amount of seawater injected into the ballast tank 21 of the column 10, the floating device 4 can keep the fallen main body 2a of the meteorological observation tower 2A above the sea.

[0038] According to the first embodiment, the tower 8A is cut and the main body 2a of the meteorological observation tower 2A is tilted toward the floating device 4, so the amount of work at height can be reduced compared to when scaffolding is erected around the tower 8A while the tower 8A remains standing and the meteorological observation tower 2A is dismantled by work at height. Therefore, the meteorological observation tower 2A can be safely dismantled and recovered.

[0039] According to the first embodiment, each of the four columns 10 is connected in a row by a connecting member 20, so that the main body 2a of the meteorological observation tower 2A can be supported by four receiving members 11 (columns 10, plate members 12, and support members 14).

[0040] According to the first embodiment, as illustrated in FIG. 4A, four insertion holes 24 are formed in the plate-like member 22, so that the four columns 10 (receiving members 11) can be easily connected in a row simply by inserting each of the four columns 10 into each of the four insertion holes 24.

[0041] According to the first embodiment, as illustrated in Figure 5, by pulling the second rope 23B with the ship 6, each of the four receiving members 11 connected in a row by the connecting member 20 can be positioned in a position suitable for supporting the main body 2a of the meteorological observation tower 2A that is falling toward the floating device 4.

[0042] According to the first embodiment, the specific gravity of the connecting member 20 is 1.0 to less than 1.2 times the specific gravity of seawater, so the connecting member 20 sinks in seawater. Therefore, the connecting member 20 is less susceptible to the effects of waves, allowing the four columns 10 to be connected in a row in a more stable manner. Furthermore, because the specific gravity of the connecting member 20 is less than 1.2 times that of seawater, the magnitude of the load applied to the columns 10 and the plate member 12 can be reduced. For example, when the floating device 4 receives the main body 2a of the falling meteorological observation tower 2A, the support member 11 sinks deeper than the connecting member 20 and rises due to the buoyancy of the support member 11. The sinking connecting member 20 then rests on the upper surface 19 of the plate member 12 of the rising support member 11. During this placement, the magnitude of the load applied to the plate member 12 can be reduced.

[0043] According to the first embodiment, the area of ​​the underside 13 of the plate member 12 is larger than the area of ​​the underside 15 of the column 10, so when the support member 14 supports the main body 2a of the meteorological observation tower 2A that is falling toward the floating device 4, the resistance acting on the plate member 12 is increased, and the depth to which the floating device 4 sinks into the sea can be reduced.

[0044] According to the first embodiment, as illustrated in Figure 3B, the support member 14 includes a recess 16, which prevents the main body 2a of the meteorological observation tower 2A that has fallen toward the floating device 4 from falling off the support member 14.

[0045] In the first embodiment, the floating body device 4 includes four support members 11 (four columns 10), but the present disclosure is not limited to this form. The floating body device 4 includes any number of support members 11. In some embodiments, the floating body device 4 includes one support member 11. In other words, the floating body device 4 includes one column 10. In this case, the floating body device 4 does not include a connecting member 20.

[0046] Fig. 9 is a diagram showing the configuration of the receiving member 11 according to some embodiments. As illustrated in Fig. 9, in some embodiments, the column 10 includes a first column member 32 and a second column member 34 that face each other across a gap 30 when viewed from the front of the floating device 4. Each of the first column member 32 and the second column member 34 has a cylindrical shape and has a ballast tank 21 inside.

[0047] 9, the plate member 12 connects the lower surface 36 of the first column member 32 and the lower surface 38 of the second column member 34. When the receiving member 11 is viewed from below, the lower surface 13 of the plate member 12 hides both the entire lower surface 36 of the first column member 32 and the entire lower surface 38 of the second column member 34.

[0048] 9, the support member 14 connects the upper surface 40 of the first column member 32 and the upper surface 42 of the second column member 34. In other words, the support member 14 is supported by the first column member 32 and the second column member 34.

[0049] 9, the support member 14 can be easily made wider compared to when the column 10 is made up of only the first column member 36 (in other words, when the receiving member 11 includes one column 10). Furthermore, because the plate member 12 connects the lower surface 36 of the first column member 32 and the lower surface 38 of the second column member 34, it is possible to prevent the first column member 32 or the second column member 34 from tipping over toward the gap 30.

[0050] Fig. 10 is a diagram showing a modified example of the receiving member 11 shown in Fig. 9. As shown in Fig. 10, in some embodiments, the support member 14 includes a sheet-like sheet member 44 arranged to cover the upper part of the gap 30. The sheet member 44 is, for example, a net or an air bag. The upper part of the gap 30 is the part above the seawater surface when the floating device 4 is floating on seawater.

[0051] 10 , one end of the sheet member 44 on the first column member 32 side is attached to a protrusion 46 that protrudes from the top surface 40 of the first column member 32. Similarly, the other end of the sheet member 44 on the second column member 34 side is attached to a protrusion 48 that protrudes from the top surface 42 of the second column member 34. If the sheet member 44 is a net, the sheet member 44 is coupled to the first column member 32 and the second column member 34 so that the net is slightly tensioned (the net does not hang down completely). In some embodiments, although not shown, one end of the sheet member 44 is attached to the side surface of the first column member 32, and the other end of the sheet member 44 is attached to the side surface of the second column member 34.

[0052] 10, a sheet member can be used as the support member 14. In addition, since the sheet member 44 covers the upper part of the gap 30, it is possible to reduce the amount of splashing water that occurs when the floating device 4 catches the main body 2a of the falling meteorological observation tower 2A.

[0053] Furthermore, when the marine structure is an offshore wind turbine, in order to prevent the blades of the wind turbine from hitting the floating device 4 and damaging the floating device 4 when supporting the wind turbine body that is falling towards the floating device 4, the wind turbine body may be tilted to the front or rear side of the wind turbine body in the collapse step S103. Alternatively, the blades may be removed before the wind turbine body is collapsed.

[0054] Second Embodiment (Method for dismantling tower-type marine structures) 11 is a flowchart showing an outline of a method for dismantling a tower-type marine structure according to Embodiment 2. The tower-type marine structure has a tower 8B, and is, for example, a meteorological observation tower, a power transmission tower, a lighthouse, a leg structure of a marine structure, or an offshore wind turbine.

[0055] As shown in Figure 11, the method for dismantling a tower-type marine structure according to the second embodiment includes a transporting step S201 of transporting a tower mounting member 60 toward the tower 8B, an attaching step S202 of attaching the tower mounting member 60 to a surface of the tower 8B that is above the cutting position P1 and faces the collapse direction (the surface that will enter the water), and a collapse step S203 of cutting the tower 8B and collapsing the tower 8B so that the surface to which the tower mounting member 60 is attached will enter the water.

[0056] The tower mounting member 60 will now be described. Fig. 12A is a diagram showing the configuration of the tower mounting member 60 according to the second embodiment. Fig. 12B is a diagram showing the tower mounting member 60 mounted on the tower 8B.

[0057] In the embodiment illustrated in FIG. 12A, the tower mounting member 60 includes a tower fitting portion 61 and a tower tip portion 62.

[0058] The tower fitting portion 61 has a cylindrical shape, and an insertion opening 63 into which the tower 8B is inserted is formed at one end 61a. The other end 61b of the tower fitting portion 61 is a position that comes into contact with the inserted tower 8B. In this way, the tower fitting portion 66 is capable of fitting the tower 8B.

[0059] The tower tip portion 62 is connected to the other end 61b of the tower fitting portion 61 and extends toward the opposite side from the insertion opening 63. The tower tip portion 62 has a tapered shape such that the width W of the interior space of the tower fitting portion 61 decreases toward the tip 64 (the end opposite the other end 61b of the tower fitting portion 61). When the mounting step S202 for mounting such a tower mounting member 60 is performed, the tower mounting member 60 is mounted to the main body 2b of the wind turbine 2B, as illustrated in FIG. 12B. In this state, the tower tip portion 62 tapers toward the collapse direction d1. Note that in this embodiment, the tower mounting member 60 has been described as being compatible with the cylindrical tower 8B. However, if the tower shape is rectangular, such as a square, the tower fitting portion 61 can be configured to correspond to the tower shape.

[0060] (Actions and Effects) According to the second embodiment, by tipping the tower 8B into the sea while the tower mounting member 60 is attached, the amount of splashing water generated when the tower 8B falls into the sea in the collapse step S203 can be reduced.

[0061] A modified example of the second embodiment will be described. Fig. 13 is a flowchart showing an outline of a method for dismantling an offshore wind turbine according to a modified example of the second embodiment. The description will be given taking as an example a case where the tower-type marine structure is an offshore wind turbine. Hereinafter, the offshore wind turbine will be simply referred to as wind turbine 2B. Note that in this modified example, the blades of wind turbine 2B have been removed in advance.

[0062] As illustrated in Figure 13, the method for dismantling an offshore wind turbine further includes a transporting step S204 of transporting the nacelle mounting member 65 towards the tower 8B equipped to the wind turbine 2B, and an attaching step S205 of attaching the nacelle mounting member 65 to the rear surface of the main body 2b of the wind turbine 2B in the nacelle 72 of the wind turbine 2B.

[0063] In the embodiment illustrated in Figure 13, before the transporting step S201 of transporting the tower mounting member 60, the transporting step S204 of transporting the nacelle mounting member 65 and the mounting step S205 of mounting the nacelle mounting member 65 are each performed.

[0064] In some embodiments, the transport step S201 of transporting the tower mounting member 60 and the transport step S204 of transporting the nacelle mounting member 65 are performed simultaneously. In some embodiments, the attaching step S202 of attaching the tower mounting member 60 is performed after the attaching step S205 of attaching the nacelle mounting member 65. In this case, the collapse step S203 is performed after the attaching step S202 of attaching the tower mounting member 60.

[0065] The nacelle mounting member 65 will now be described. Figure 14A is a diagram showing the configuration of a nacelle mounting member 65 according to a modified example of the second embodiment.

[0066] In the embodiment illustrated in FIG. 14A, the nacelle mounting member 65 includes a nacelle fitting portion 66 and a nacelle tip portion 67.

[0067] The nacelle fitting portion 66 has a cylindrical shape, and an insertion opening 68 for inserting the nacelle 72 is formed at one end 66a. The other end 66b of the nacelle fitting portion 66 is positioned to come into contact with the inserted nacelle 72. In this manner, the nacelle fitting portion 66 is capable of fitting the nacelle 72. Note that in the embodiment illustrated in FIG. 14A, the shape formed by the one end 66a of the nacelle fitting portion 66 is oval, but the present disclosure is not limited to this embodiment.

[0068] The nacelle tip portion 67 is connected to the other end 66b of the nacelle fitting portion 66, and extends in the direction opposite to the insertion opening 68. The nacelle tip portion 67 has a tapered shape such that the area A of the internal space of the nacelle fitting portion 66 decreases toward the tip 69 (the end opposite the other end 66b of the nacelle fitting portion 66). When the mounting step S205 for mounting such a nacelle mounting member 65 is performed, the nacelle mounting member 65 is mounted to the nacelle 72, as shown in Figure 14B. In this state, the nacelle tip portion 67 tapers as it moves in the collapse direction d1.

[0069] According to the modified example of the second embodiment, the main body 2b of the wind turbine 2B is toppled into the sea with the nacelle mounting member 65 attached in addition to the tower mounting member 60, which further reduces the amount of splashing water that occurs when the main body 2b of the wind turbine 2B topples into the sea in the toppling step S203. Note that in some embodiments, the main body 2b of the wind turbine 2B may be toppled into the sea with the nacelle mounting member 65 attached to the nacelle 72 without attaching the tower mounting member 60 to the main body 2b of the wind turbine 2B.

[0070] In the above-described embodiments, a method for dismantling a meteorological observation tower 2A, a method for dismantling a tower-type marine structure, and a method for dismantling a wind turbine 2B have been exemplified, but the present disclosure is applicable to methods for dismantling any marine structure equipped with a tower, not limited to the meteorological observation tower 2A, the tower-type marine structure, and the wind turbine 2B. The present disclosure is not limited to the above-described embodiments, and also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0071] For example, in the recovery step 104 according to the first embodiment, the floating device 4 with the main body 2a of the meteorological observation tower 2A mounted thereon is transported to the shore, and the main body 2a of the meteorological observation tower 2A is pulled onto land and recovered; however, in some embodiments, after the collapse step S103, the main body 2a of the meteorological observation tower 2A may be dismantled and recovered using a heavy machinery ship (not shown) or the like before being transported to the shore.

[0072] For example, when the method for dismantling a meteorological observation tower 2A according to the first embodiment is applied to a tower-type marine structure or a wind turbine 2B, before the collapsing step S103, cover members 80 for restricting the intrusion of seawater into the interior of the tower 8B may be provided at each of the base portion 8r of the tower 8B and the tip portion 8t of the tower 8B as shown in Fig. 15. That is, in some embodiments, as shown in Fig. 16, the method for dismantling a wind turbine 2B includes a cover installation step S106 in which cover members 80 are provided at each of the base portion 8r of the tower 8B and the tip portion 8t of the tower 8B before the collapsing step S203.

[0073] As a result, when the tower 8A is cut and the main body 2b of the wind turbine 2B is toppled in the collapse step S103, air leakage from inside the tower 8B due to intrusion of seawater into the inside of the tower 8B can be suppressed, making the tower 8B more likely to float in seawater. This makes it difficult for the tower 8B and the main body 2b of the wind turbine 2B to sink in the sea, and reduces the buoyancy required of the floating device 4 to float the tower 8B and the main body 2b of the wind turbine 2B in seawater. Furthermore, particularly in the case of a wind turbine, it is possible to suppress oil, dust, etc. inside the tower 8B of the wind turbine 2B from scattering or flowing out to the outside of the tower 8B.

[0074] It is desirable that the lid member 80 on the base portion 8r side be provided above the cutting position P1 of the tower 8B and at an appropriate distance from the cutting position P1 of the tower 8B so that it is not affected by the laser, explosion, or other mechanical methods of the tower 8B in the collapse step S103. Also, in some embodiments, a float member may be attached to the tower 8B instead of the lid member 80 in order to float the tower 8B.

[0075] The contents described in each of the above embodiments can be understood, for example, as follows.

[0076] [1] The method for dismantling a marine structure (2A) according to the present disclosure comprises: a transport step (S101) of transporting the floating device (4) toward towers (8A, 8B) provided on the marine structure; an installation step (S102) of installing the floating body device next to the tower; a collapse step (S103) of cutting the tower to collapse the main body (2a, 2b) of the marine structure toward the floating device; and a recovery step (S104) of recovering the main body of the marine structure, The floating device is At least one column (10) having a ballast tank (21); a plate member (12) connected to the at least one column underwater while the column is installed on the sea; The floating device is provided with a support member (14) that is connected to the at least one column on the water when the column is installed on the sea and is capable of supporting the main body of the marine structure that has been tilted toward the floating device.

[0077] According to the method described in [1] above, the floating device includes at least one column having a ballast tank, and a support member connected to the at least one column on the water surface while the column is installed on the sea surface, capable of supporting the main body of the offshore structure tilted toward the floating device. Therefore, by installing the floating device next to the tower prior to cutting the tower, and then cutting the tower and tilting the main body of the offshore structure toward the floating device, the floating device can be used to prevent the main body of the offshore structure from sinking into the sea and recover the main body of the offshore structure. Furthermore, the floating device includes a plate member connected to the at least one column underwater while the column is installed on the sea surface. Therefore, when the support member supports the main body of the offshore structure tilted toward the floating device, the drag acting on the plate member can reduce the depth to which the floating device sinks into the sea.

[0078] Furthermore, according to the method described in [1] above, the tower is cut and the main body of the marine structure is tilted toward the floating device, so the amount of work at height can be reduced compared to when scaffolding is erected around the tower while the tower remains standing and the marine structure is dismantled by working at height, and therefore the marine structure can be safely dismantled and recovered.

[0079] [2] In some embodiments, in the configuration described in [1] above, the at least one column includes a plurality of columns; The floating body device further includes a connecting member (20) for connecting each of the plurality of columns in a row, The method further includes a connecting step (S105) before the installing step, in which the plurality of columns are connected in a row by the connecting members.

[0080] The main body of an offshore structure often extends linearly. According to the method described in [2] above, the main body of an offshore structure extending linearly can be supported by a plurality of columns.

[0081] [3] In some embodiments, in the configuration described in [2] above, The connecting member includes one plate-like member (22) having a longitudinal direction, A plurality of insertion holes (24) are formed in the one plate-like member at intervals along the longitudinal direction, In the connecting step, each of the plurality of columns is inserted into each of the plurality of insertion holes.

[0082] According to the method described in [3] above, a plurality of columns can be easily connected in a row simply by inserting each of the plurality of columns into each of the plurality of insertion holes.

[0083] [4] In some embodiments, in the configuration described in [2] or [3] above, In the installation step, the tower and one end (20a) of the connecting member on the tower side are connected by a first rope (23A), the other end (20b) of the connecting member on the opposite side from the tower side is connected to a ship (6) by a second rope (23B), and the connecting member is pulled by the ship.

[0084] According to the method described in [4] above, each of the multiple columns connected in a row by connecting members can be positioned in a position suitable for supporting the main body of the marine structure falling toward the floating device.

[0085] [5] In some embodiments, in the configuration described in any one of [2] to [4] above, The specific gravity of the connecting member is 1.0 times or more and less than 1.2 times the specific gravity of seawater.

[0086] According to the method described in [5] above, the connecting members have a specific gravity of at least 1.0 times that of seawater, so they sink in seawater. This makes them less susceptible to the effects of waves, allowing multiple columns to be connected in a row in a more stable manner. Furthermore, because the connecting members have a specific gravity of less than 1.2 times that of seawater, the magnitude of the load applied to the columns and plate members can be reduced.

[0087] [6] In some embodiments, in the configuration described in any one of [1] to [5] above, The plate member is connected to the lower surface (15) of the column, The area of ​​the lower surface (13) of the plate member is larger than the area of ​​the lower surface of the column.

[0088] According to the method described in [6] above, when the support member supports the main body of the offshore structure that is falling toward the floating device, the resistance acting on the plate member can be increased, and the depth to which the floating device sinks into the sea can be reduced.

[0089] [7] In some embodiments, in the configuration described in any one of [1] to [6] above, The support member includes a recess (16) provided on an upper surface of the column and recessed toward the column, When the marine structure is viewed from above, if the direction in which the main body of the marine structure is tilted toward the floating device in the collapse step is defined as the collapse direction (d1), then in a direction (d2) perpendicular to the collapse direction, the recess is wider than the main body of the marine structure.

[0090] According to the method described in [7] above, it is possible to prevent the main body of the offshore structure that has fallen toward the floating device from falling off the support member.

[0091] [8] In some embodiments, in the configuration described in any one of [1] to [7] above, The at least one column includes a first column member (32) and a second column member (34) facing each other with a gap (30) therebetween, the plate member connects the lower surface (36) of the first column member and the lower surface (38) of the second column member, The support member connects the upper surface (40) of the first column member and the upper surface (42) of the second column member.

[0092] According to the method described in [8] above, the support member connects the upper surface of the first column member and the upper surface of the second column member, so the support member can be made wider easily compared to when the column is composed of only the first column member. Furthermore, according to the configuration described in [8] above, the plate member connects the lower surface of the first column member and the lower surface of the second column member, so it is possible to prevent the first column member or the second column member from tipping over toward the gap.

[0093] [9] In some embodiments, in the configuration described in any one of [1] to [7] above, the at least one column includes a first column member and a second column member facing each other with a gap therebetween; the plate member connects a lower surface of the first column member and a lower surface of the second column member, The support member includes a sheet-like sheet member (44) arranged to cover the upper portion of the gap.

[0094] According to the method described in [9] above, a sheet member can be used as the support member.

[0095]

[10] In some embodiments, in the configuration described in any one of [1] to [9] above, The collapsing step includes: a first cutting step of forming a first incision (C1) in the tower by mechanical cutting (a1) from one side of the tower in the horizontal direction so as not to penetrate the tower; a second cutting step of forming a second notch (C2) connected to the first notch in the tower by mechanically cutting (a2) the tower from the one side of the tower in the horizontal direction at an angle different from that of the first notch so as not to penetrate the tower; and a third cutting step of forming a third notch (C3) connected to at least one of the first notch and the second notch by mechanically cutting (a3) ​​the tower from the other side opposite to the one side of the tower in the horizontal direction.

[0096] According to the method described in

[10] above, the main body of the offshore structure can be tilted toward the floating device without towing the tower with a ship, which makes it easy to safely recover the main body of the offshore structure using the floating device.

[0097]

[11] In some embodiments, in the configuration described in any one of [1] to [9] above, In the collapsing step, the tower is cut while being pulled in two different directions.

[0098] According to the method described in

[11] above, by cutting the tower while pulling it in two different directions with an appropriate force, the main body of the offshore structure can be tilted in a desired direction between the two different directions. This makes it easy to recover the main body of the offshore structure using a floating device.

[0099]

[12] In some embodiments, in the configuration according to any one of [1] to

[11] above, Before the collapse step, a step (S106) is provided in which cover members (80) are provided at each of the base (8r) and tip (8t) of the tower to restrict the intrusion of seawater into the interior of the tower.

[0100] According to the method described in (12) above, when the tower is cut and the main body of the offshore structure is toppled in the collapse step, air leakage from the inside of the tower due to seawater entering the inside of the tower can be suppressed, making the tower more likely to float in seawater. This makes it difficult for the main body of the offshore structure to sink in the sea, and reduces the buoyancy required of the floating device to float the main body of the offshore structure in seawater. In addition, it is possible to suppress oil, dust, etc. inside the tower of the offshore structure from scattering or flowing out of the tower.

[0101]

[13] In some embodiments, in the method according to any one of [1] to

[12] above, In the recovery step, the floating device with the main body of the marine structure placed thereon is towed to land, and the main body of the marine structure is pulled up onto land.

[0102] According to the method described in (13) above, the main body of the marine structure can be safely recovered to land.

[0103]

[14] In some embodiments, in the method according to any one of [1] to

[13] above, the marine structure is a wind turbine (2B), In the collapsing step, the wind turbine body (2b) is collapsed to the front side or rear side of the wind turbine body.

[0104] According to the method described in

[14] above, by tilting the wind turbine body to the front or rear side of the wind turbine body, it is possible to prevent the floating body device from being damaged by the wind turbine blades.

[0105]

[15] The floating body device according to the present disclosure includes: A floating device used for dismantling marine structures, at least one column having a ballast tank; a plate member connected to the at least one column underwater while the column is installed on the sea; The floating device is provided with a support member that is connected to the at least one column on the water when the column is installed on the sea and is capable of supporting the main body of the marine structure tilted toward the floating device.

[0106] According to the configuration described in

[15] above, by installing a floating device next to the tower before cutting the tower, the tower can be cut and the main body of the offshore structure can be tilted toward the floating device, which can prevent the main body of the offshore structure from sinking into the sea and allow the main body of the offshore structure to be recovered. Furthermore, when the support members support the main body of the offshore structure that has tilted toward the floating device, the drag acting on the plate members can reduce the depth to which the floating device sinks into the sea. [Explanation of symbols]

[0107] 2A Weather Observation Tower 2a Main unit 2B Windmill 2b main body 4 Floating Device 6 ships 8A, 8B Tower 8r Root 8t tip 10 Column 12 Plate members 13 Underside of plate member 14 Support member 15 Underside of column 16 Recess 20 Connecting member 20a One end 20b Other end 21 Ballast Tank 22 Plate-shaped member 23A First Rope 23B Second Rope 24 Insertion hole 30 Gap 32 First column member 34 Second column member 36 Underside of first column member 38 Underside of second column member 40 Upper surface of first column member 40 Upper surface of second column member 44 Sheet material 60 Tower mounting member 65 Nacelle mounting member 72 Nacelle 80 Lid member C1 First cutting depth C2 Second cutting depth C3 Third cut S101 Transport Step S102 Installation Steps S103 Collapse Step S104 Collection step S105 Connecting Step S106 Lid installation step S201 Transport Step S202 installation steps S203 Collapse Step a1,a2,a3 mechanical cutting d1 Collapse direction d2 Orthogonal direction

Claims

1. a transporting step of transporting the floating body device toward a tower provided on the offshore structure; an installation step of installing the floating device next to the tower; a collapse step of cutting the tower and causing the main body of the marine structure to collapse toward the floating device; a recovery step of recovering the main body of the marine structure, The floating device is at least one column having a ballast tank; a plate member connected to the at least one column underwater while the column is installed on the sea; and a support member that is coupled to the at least one column on the water when the at least one column is installed on the sea and is capable of supporting the main body of the marine structure that has fallen toward the floating body device. Method for dismantling marine structures.

2. the at least one column includes a plurality of columns; The floating body device further includes a connecting member for connecting each of the plurality of columns in a row, The method further includes a connecting step of connecting each of the plurality of columns in a row using the connecting members before the installing step. The method for dismantling a marine structure according to claim 1.

3. the connecting member includes a plate-like member having a longitudinal direction, A plurality of insertion holes are formed in the one plate-like member at intervals along the longitudinal direction, In the connecting step, each of the plurality of columns is inserted into each of the plurality of insertion holes. The method for dismantling a marine structure according to claim 2.

4. In the installation step, the tower and one end of the connecting member on the tower side are connected by a first rope, the other end of the connecting member on the opposite side to the tower side is connected to a ship by a second rope, and the connecting member is pulled by the ship. A method for dismantling a marine structure according to claim 2 or 3.

5. The specific gravity of the connecting member is 1.0 times or more and less than 1.2 times the specific gravity of seawater. A method for dismantling a marine structure according to any one of claims 2 to 4.

6. the plate member is coupled to a lower surface of the column; The area of ​​the lower surface of the plate member is larger than the area of ​​the lower surface of the column. A method for dismantling a marine structure according to any one of claims 1 to 5.

7. the support member is provided on an upper surface of the column and includes a recess recessed toward the column, When the marine structure is viewed from above, a direction in which the main body of the marine structure is tilted toward the floating body device in the collapse step is defined as a collapse direction, and the recess is wider than the main body of the marine structure in a direction perpendicular to the collapse direction. A method for dismantling a marine structure according to any one of claims 1 to 6.

8. the at least one column includes a first column member and a second column member facing each other with a gap therebetween; the plate member connects a lower surface of the first column member and a lower surface of the second column member, The support member connects an upper surface of the first column member and an upper surface of the second column member. A method for dismantling a marine structure according to any one of claims 1 to 7.

9. the at least one column includes a first column member and a second column member facing each other with a gap therebetween; the plate member connects a lower surface of the first column member and a lower surface of the second column member, The support member includes a sheet-like sheet member arranged to cover an upper portion of the gap. A method for dismantling a marine structure according to any one of claims 1 to 7.

10. The collapsing step includes: a first cutting step of mechanically forming a first incision in the tower from one side of the tower in a horizontal direction so as not to penetrate the tower; a second cutting step of forming a second incision in the tower mechanically connected to the first incision at a different angle from the first incision from the one side of the tower in the horizontal direction so as not to penetrate the tower; and a third cutting step of mechanically forming a third notch in the tower from the other side opposite to the one side of the tower in the horizontal direction, the third notch connecting to at least one of the first notch and the second notch.

11. The method for dismantling a marine structure according to claim 10, wherein in the collapsing step, the tower is cut while being pulled in two directions different from each other.

12. a step of providing a cover member at each of the base portion and the tip portion of the tower to restrict intrusion of seawater into the interior of the tower before the collapsing step; A method for dismantling a marine structure according to any one of claims 1 to 11.

13. 13. A method for dismantling a marine structure according to any one of claims 1 to 12, wherein in the recovery step, the floating device with the main body of the marine structure mounted thereon is towed to land, and the main body of the marine structure is pulled up to the land.

14. the marine structure is a wind turbine, In the collapsing step, the wind turbine body is collapsed to a front side or a rear side of the wind turbine body. A method for dismantling a marine structure according to any one of claims 1 to 13.

15. A floating device used for dismantling marine structures, at least one column having a ballast tank; a plate member connected to the at least one column underwater while the column is installed on the sea; a support member that is coupled to the at least one column on the water when the at least one column is installed on the sea and that can support the main body of the marine structure that has fallen toward the floating body device; the support member is provided on an upper surface of the column and includes a recess recessed toward the column, When the marine structure is viewed from above, a direction in which the main body of the marine structure is tilted toward the floating device is defined as a collapse direction, and the recess is wider than the main body of the marine structure in a direction perpendicular to the collapse direction. Floating device.

16. A floating device used for dismantling marine structures, at least one column having a ballast tank; a plate member connected to the at least one column underwater while the column is installed on the sea; a support member that is coupled to the at least one column on the water when the at least one column is installed on the sea and that can support the main body of the marine structure that has fallen toward the floating body device; the at least one column includes a first column member and a second column member facing each other with a gap therebetween; the plate member connects a lower surface of the first column member and a lower surface of the second column member, The support member includes a sheet-like sheet member arranged to cover an upper portion of the gap. Floating device.

Images