Suction foundation

Abstract

To ensure strength of a foundation body even when the foundation body is divided.SOLUTION: A suction foundation 100 comprises: a foundation body 10 including a ceiling wall 11 and a cylindrical side wall 12 extending downward from the ceiling wall 11 in the direction of a predetermined axis C and inserted into the underwater ground G; a columnar base 2 connected to the ceiling wall 11 and extending in the vertical direction; and a plurality of vertical walls 3 connected to the base 2 and arranged radially at intervals in the circumferential direction around the axis C, extending downward from the base 2. At least one of the ceiling wall 11 and the side wall 12 includes a plurality of segments divided in the circumferential direction. Radial inner ends of the plurality of vertical walls 3, centered on the axis C, are connected to an outer peripheral surface of the base 2. The ceiling wall 11 is connected to the base 2 and the plurality of vertical walls 3. The side wall 12 is connected to the ceiling wall 11 and the plurality of vertical walls 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology disclosed herein relates to a suction foundation. [Background technology]

[0002] Patent Document 1 discloses a suction foundation that is installed on underwater ground. The suction foundation comprises a ceiling wall and side walls that extend downward from the outer periphery of the ceiling wall. The ceiling wall and side walls form the foundation body. The side walls of the foundation body are inserted into the ground. A superstructure such as an offshore wind turbine is attached to the ceiling wall of the foundation body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-23838 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the foundation body may be divided. That is, the foundation body may be composed of divided bodies. This makes it easy to assemble the suction foundation because it is only necessary to transport the smaller divided bodies when assembling the suction foundation. However, if the foundation body is divided, there is a risk that the strength of the foundation body may be insufficient.

[0005] The technology disclosed herein has been made in consideration of these points, and its purpose is to ensure the strength of the foundation body even when the foundation body is divided. [Means for solving the problem]

[0006] The suction foundation disclosed herein comprises a foundation body including a ceiling wall and cylindrical side walls extending downward from the ceiling wall in the direction of a predetermined axis and penetrating into the underwater ground, a columnar base connected to the ceiling wall and extending in the vertical direction, and a plurality of vertical walls arranged radially at intervals in the circumferential direction around the axis, connected to the base, and extending downward from the base, at least one of the ceiling wall and the side walls includes a plurality of divided bodies divided in the circumferential direction, and the radial inner ends of the plurality of vertical walls centered on the axis are connected to the outer peripheral surface of the base, the ceiling wall is connected to the base and the plurality of vertical walls, and the side walls are connected to the ceiling wall and the plurality of vertical walls. [Effects of the Invention]

[0007] Even if the foundation body is divided, the strength of the foundation body can be ensured. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic diagram of a suction foundation in place. [Figure 2] FIG. 2 is a perspective view showing a schematic diagram of a suction foundation. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 5 is an explanatory diagram showing the suction foundation before the penetration process. [Figure 6] FIG. 6 is an explanatory view showing a state in which the foundation main body has reached the ground in the penetration step. [Figure 7] FIG. 7 is an explanatory diagram showing a state in which the foundation body has penetrated into the ground due to a suction load. [Figure 8] FIG. 8 is a perspective view that schematically shows a suction foundation according to a modified example. [Figure 9] FIG. 9 is a cross-sectional view for explaining another example of the dividing position of the side peripheral wall. [Figure 10] FIG. 10 is a cross-sectional view illustrating another example of the division position of the side peripheral wall. [Figure 11] FIG. 11 is an explanatory diagram showing a schematic diagram of a state in which a plurality of suction foundations are installed. DETAILED DESCRIPTION OF THE INVENTION

[0009] Exemplary embodiments will now be described in detail with reference to the accompanying drawings.

[0010] FIG. 1 is an explanatory diagram showing a schematic diagram of a suction foundation 100 installed. The suction foundation 100 is a foundation for installing a superstructure on or underwater, and is sunk into underwater ground G. In the example of FIG. 1, the suction foundation 100 is a foundation for installing a superstructure on water. The superstructure is, for example, a wind turbine 9. The suction foundation 100 comprises a foundation body 10, a columnar base 2 extending in the vertical direction, and a plurality of vertical walls 3 connected to the base 2. In the present disclosure, "two members being connected" includes not only cases where the two members are directly connected, but also cases where the two members are indirectly connected via another member.

[0011] The foundation body 10 is formed in the shape of a container with a closed upper end and an open lower end. The foundation body 10 is also called a bucket. The foundation body 10 includes a ceiling wall 11 and a cylindrical side wall 12 that extends downward from the ceiling wall 11 in the direction of a predetermined axis C and penetrates into the underwater ground G. In this example, the axis C extends vertically. The ceiling wall 11 and the side wall 12 are formed, for example, from steel plates.

[0012] FIG. 2 is a perspective view showing a schematic diagram of the suction foundation 100. In this example, the ceiling wall 11 is formed in a substantially circular ring shape that extends horizontally. The ceiling wall 11 is arranged coaxially with the axis C. The ceiling wall 11 has a through-hole 18 at approximately the center. The base 2 is arranged in the through-hole 18.

[0013] The side peripheral wall 12 is formed in a substantially cylindrical shape. The upper end of the side peripheral wall 12 is connected to the periphery of the ceiling wall 11 by, for example, welding. The ceiling wall 11 and the side peripheral wall 12 define an internal space 15 of the foundation body 10.

[0014] Hereinafter, the direction of the axis C will be simply referred to as the "axial direction." The circumferential direction centered on the axis C will be simply referred to as the "circumferential direction." The radial direction centered on the axis C will be simply referred to as the "radial direction." The side facing the axis C in the radial direction will be referred to as the "radially inner side." The side opposite the axis C in the radial direction will be referred to as the "radially outer side." A cross section perpendicular to the axis C will be referred to as an "orthogonal cross section."

[0015] The base 2 supports the superstructure. In this example, the base 2 is formed in a cylindrical shape. In this example, the base 2 is hollow and closed at the lower end. The base 2 extends in the axial direction or in a direction inclined relative to the axial direction. In this example, the base 2 extends in the axial direction and is arranged coaxially with the axis C. The upper end 21 (see Figure 1) of the base 2 is arranged above the water. A superstructure such as a wind turbine 9 (see Figure 1) is installed on the upper end 21 of the base 2. In this example, the lower end 22 of the base 2 is located below the ceiling wall 11. The base 2 is formed, for example, from a steel plate.

[0016] As shown in FIG. 1 , in this example, the foundation body 10 further defines a filling space 16 into which the filling material 7 is filled when the side peripheral wall 12 penetrates the ground G. That is, the filling space 16 is a space defined by the ceiling wall 11, the side peripheral wall 12, and the ground G. The filling space 16 is part of the internal space 15. As the filling material 7 filled in the filling space 16 hardens, the load of the foundation body 10 may act appropriately on the ground G via the filling material 7.

[0017] A frictional force acts on the side walls 12 that penetrate into the ground G. This firmly fixes the suction foundation 100 to the ground G. In addition, when an external force acts on the suction foundation 100, negative pressure is generated inside the foundation body 10, increasing the pull-out resistance. This ensures the stability of the suction foundation 100.

[0018] A drain pipe 41 is provided in the foundation body 10. The drain pipe 41 is a pipe for forcibly draining water from inside the foundation body 10. The drain pipe 41 is connected to the internal space 15 in the ceiling wall 11. A drain hole 51 is formed through the ceiling wall 11. The drain pipe 41 is connected to the drain hole 51. In other words, the drain pipe 41 communicates with the internal space 15 via the drain hole 51. A valve 42 is provided above the drain pipe 41 (specifically, above the water surface). The valve 42 switches the drain pipe 41 between open and closed.

[0019] A drainage pump 43 is connected to the drainage pipe 41. When the drainage pump 43 is operated, water inside the foundation body 10 is discharged to the outside of the foundation body 10 through the drainage pipe 41. The drainage pipe 41 is used when the foundation body 10 penetrates the ground G. By draining water through the drainage pipe 41, penetration of the foundation body 10 into the ground G is promoted.

[0020] A water supply pipe 44 is provided in the foundation body 10. The water supply pipe 44 is a pipe for supplying water to the inside of the foundation body 10 when the suction foundation 100 is removed. A water supply hole 52 is formed through the ceiling wall 11. The water supply pipe 44 is connected to the water supply hole 52. In other words, the water supply pipe 44 communicates with the interior space 15 via the water supply hole 52. A valve 45 is provided above the water supply pipe 44 (specifically, above the water surface). The valve 45 switches the water supply pipe 44 between open and closed.

[0021] A water supply pump 46 is connected to the water supply pipe 44. When the water supply pump 46 is operated, water is supplied to the inside of the foundation body 10 via the water supply pipe 44. The water supply pipe 44 is used when removing the suction foundation 100. Supplying water via the water supply pipe 44 promotes the floating of the foundation body 10 from the ground G.

[0022] The multiple vertical walls 3 reinforce the foundation body 10 and improve the connection strength between the foundation body 10 and the base 2. Specifically, the multiple vertical walls 3 prevent deformation such as buckling of the foundation body 10 during and after penetration of the suction foundation 100, and peeling of the ceiling wall 11 from the base 2. Each vertical wall 3 is formed, for example, from a steel plate. Each vertical wall 3 is formed in a plate shape. In this example, the shape of each vertical wall 3 is approximately rectangular when viewed from the thickness direction. That is, each vertical wall 3 has a longitudinal direction, a thickness direction, and a lateral direction that is perpendicular to both the longitudinal direction and the thickness direction.

[0023] As shown in FIG. 2 , the vertical walls 3 are radially arranged at intervals in the circumferential direction. In this example, the vertical walls 3 are arranged at equal intervals in the circumferential direction. In this example, the number of the vertical walls 3 is four. Specifically, the vertical walls 3 are arranged such that the short side direction of each vertical wall 3 is approximately parallel to the radial direction and the long side direction of each vertical wall 3 is approximately parallel to the axial direction. The vertical walls 3 extend downward from the base 2. That is, the lower ends 33 of the vertical walls 3 are located below the lower end 22 of the base 2. In this example, with respect to the axial position, the position of the lower ends 33 of the vertical walls 3 approximately coincides with the position of the lower end 17 of the side peripheral wall 12. The upper ends 32 of the vertical walls 3 are located above the lower end 22 of the base 2. The upper ends 32 of the vertical walls 3 are located below the upper end 21 of the base 2 (see FIG. 1 ).

[0024] In this example, at least one of the multiple vertical walls 3 protrudes radially outward from the side peripheral wall 12. Specifically, all of the vertical walls 3 protrude radially outward from the side peripheral wall 12. In this example, at least one of the multiple vertical walls 3 protrudes upward from the top wall 11. Specifically, all of the vertical walls 3 protrude upward from the top wall 11.

[0025] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. Specifically, FIG. 3 is an orthogonal cross-section intersecting with the top wall 11. At least one of the top wall 11 and the side peripheral wall 12 includes a plurality of segments divided in the circumferential direction. Specifically, at least one of the top wall 11 and the side peripheral wall 12 is configured by connecting a plurality of segments divided in the circumferential direction. In this example, both the top wall 11 and the side peripheral wall 12 are configured by connecting a plurality of segments divided in the circumferential direction. That is, the top wall 11 includes a plurality of first segments 61 divided in the circumferential direction. In this example, the number of the plurality of first segments 61 is four. The side peripheral wall 12 includes a plurality of second segments 62 divided in the circumferential direction. In this example, the number of the plurality of second segments 62 is four. Between each two circumferentially adjacent vertical walls 3 (hereinafter simply referred to as "each two vertical walls 3") among the multiple vertical walls 3, one first divided body 61 among the multiple first divided bodies 61 and one second divided body 62 among the multiple second divided bodies 62 are arranged.

[0026] The multiple first divided bodies 61 are arranged side by side in the circumferential direction. In this example, each first divided body 61 is formed in a fan shape with a notched center. In this example, as described above, the multiple vertical walls 3 are arranged at equal intervals in the circumferential direction, so the shape and size of each first divided body 61 are approximately the same.

[0027] The multiple second divided bodies 62 are arranged side by side in the circumferential direction. In this example, each second divided body 62 is formed in a curved plate shape. In this example, since the multiple vertical walls 3 are arranged at equal intervals in the circumferential direction as described above, the shape and size of each second divided body 62 are approximately the same.

[0028] More specifically, at least one vertical wall 3 of the multiple vertical walls 3 passes between two circumferentially adjacent first dividers 61 of the multiple first dividers 61 and penetrates the ceiling wall 11. In this example, each vertical wall 3 of the multiple vertical walls 3 passes between two corresponding circumferentially adjacent first dividers 61 and penetrates the ceiling wall 11. At least one vertical wall 3 of the multiple vertical walls 3 passes between two circumferentially adjacent second dividers 62 of the multiple second dividers 62 and penetrates the side peripheral wall 12. In this example, each vertical wall 3 of the multiple vertical walls 3 passes between two corresponding circumferentially adjacent second dividers and penetrates the side peripheral wall 12.

[0029] Next, the connection between the base 2, the vertical walls 3, the ceiling wall 11, and the side peripheral walls 12 will be described in detail.

[0030] The radially inner ends of the vertical walls 3 are connected to the outer peripheral surface of the base 2. More specifically, among the inner end edges of the vertical walls 3, upper portions having a predetermined vertical length are connected to the outer peripheral surface of the base 2 by, for example, welding.

[0031] The ceiling wall 11 is connected to the base 2 and the plurality of vertical walls 3. The side peripheral walls 12 are connected to the ceiling wall 11 and the plurality of vertical walls 3.

[0032] Specifically, of the multiple first division bodies 61, two circumferentially adjacent first division bodies 61 (hereinafter simply referred to as "two first division bodies 61") are connected to a vertical wall 3 that passes between the two first division bodies 61. That is, the two first division bodies 61 are indirectly connected to each other via the vertical wall 3 that passes between the two first division bodies 61. Of the multiple second division bodies 62, two circumferentially adjacent second division bodies 62 (hereinafter simply referred to as "two second division bodies 62") are connected to a vertical wall 3 that passes between the two second division bodies 62. That is, the two second division bodies 62 are indirectly connected to each other via the vertical wall 3 that passes between the two second division bodies 62.

[0033] In this example, each vertical wall 3 of the multiple vertical walls 3 is connected to two corresponding first division bodies 61 adjacent to each other in the circumferential direction, and is also connected to two corresponding second division bodies 62 adjacent to each other in the circumferential direction. Specifically, between each pair of vertical walls 3, one first division body 61 is connected to each of the two vertical walls 3 and the base 2. More specifically, one end of each first division body 61 in the circumferential direction is connected to one side surface in the thickness direction of one of the two vertical walls 3, for example, by welding. The other end of each first division body 61 in the circumferential direction is connected to one side surface in the thickness direction of the other of the two vertical walls 3, for example, by welding. A radially inner end of each first division body 61 is connected to the outer peripheral surface of the base 2, for example, by welding.

[0034] Between each pair of vertical walls 3, one second divided body 62 is connected to each pair of vertical walls 3. Specifically, one circumferential end of one second divided body 62 is connected, for example, by welding, to one side surface in the thickness direction of one of the two vertical walls 3. The other circumferential end of one second divided body 62 is connected, for example, by welding, to one side surface in the thickness direction of the other of the two vertical walls 3.

[0035] Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 2. One first division 61 and one second division 62 are connected to each other. Specifically, the radially outer peripheral edge of one first division 61 is connected to the upper end of one second division 62 by, for example, welding.

[0036] Next, an example of an assembly method for the suction foundation 100 will be described. For example, first, multiple vertical walls 3 are attached radially to the outer periphery of the base 2, for example, by welding. Then, one second division body 62 is placed between every two vertical walls 3. Then, one second division body 62 is attached to every two vertical walls 3, for example, by welding. The above-mentioned attachment process is performed for all four second division bodies 62. This forms the side peripheral wall 12. Then, one first division body 61 is placed above the one second division body 62, between every two vertical walls 3. Then, the radially outer peripheral edge of the one first division body 61 is attached to the upper end of the second division body 62, both circumferential ends of the one first division body 61 are attached to each of the two vertical walls 3, and the radially inner end of the one first division body 61 is attached to the outer periphery of the base 2, for example, by welding. The above-mentioned attachment process is performed for all four first division bodies 61. As a result, the ceiling wall 11 is formed and connected to the base 2. In this manner, the suction foundation 100 is assembled.

[0037] In the suction foundation 100, the ceiling wall 11 includes multiple first segments 61. The side peripheral wall 12 includes multiple second segments 62. As described above, when assembling the suction foundation 100, the divided first segments 61 are assembled to form the ceiling wall 11, and the divided second segments 62 are assembled to form the side peripheral wall 12. That is, in the suction foundation 100, the individual components are miniaturized during assembly. This facilitates the transportation of the individual components, and as a result, the suction foundation 100 can be easily assembled. In particular, in this example, the multiple vertical walls 3 are arranged at equal intervals in the circumferential direction, so the first segments 61 and the second segments 62 can have the same shape and size. This minimizes the number of different components constituting the foundation body 10.

[0038] Next, a method for installing the suction foundation 100 will be described. Fig. 5 is an explanatory diagram showing the suction foundation 100 before the penetration step. Fig. 6 is an explanatory diagram showing the state in which the foundation body 10 has reached the ground G in the penetration step. Fig. 7 is an explanatory diagram showing the state in which the foundation body 10 has penetrated into the ground G by the suction load.

[0039] First, as shown in Figure 5, the foundation body 10 without the wind turbine 9 (see Figure 1) installed thereon is towed to the installation site. Then, penetration of the foundation body 10 into the ground G begins. More specifically, the foundation body 10 sinks to the seabed due to its own weight or ballast load. As shown in Figure 6, the lower end 17 of the side peripheral wall 12 penetrates to a certain extent into the ground G due to the own weight or ballast load of the foundation body 10.

[0040] Next, by operating the drainage pump 43, the water in the internal space 15 of the foundation body 10 is forcibly drained to the outside of the foundation body 10 through the drainage hole 51 and the drainage pipe 41. At this time, the valve 45 is closed and the valve 42 is open. This forced drainage generates a pressure difference between the inside and outside of the foundation body 10. A suction load due to the pressure difference acts on the foundation body 10, and the side wall 12 further penetrates into the ground G. In this way, as shown in FIG. 7, the foundation body 10 penetrates into the ground G. After this, a filling pump (not shown) fills the filling space 16 with a filling material 7 (see FIG. 1). The filling material 7 is grout, mortar, or the like. After the installation of the suction foundation 100 is complete, the wind turbine 9 is installed on the foundation body 10. Specifically, the wind turbine 9 is installed above the base 2.

[0041] When the suction foundation 100 is inserted, a pressure difference between the inside and outside of the foundation body 10 can cause a force that deforms the foundation body 10. In the suction foundation 100, the multiple first segments 61 are connected circumferentially via the multiple vertical walls 3 to form the ceiling wall 11. Therefore, even if the aforementioned force acts on the ceiling wall 11, the multiple vertical walls 3 prevent the ceiling wall 11 from deforming. In other words, the multiple vertical walls 3 function as ribs that reinforce the ceiling wall 11. Similarly, in the suction foundation 100, the multiple second segments 62 are connected circumferentially via the multiple vertical walls 3 to form the side peripheral wall 12. Therefore, even if the aforementioned force acts on the side peripheral wall 12, the multiple vertical walls 3 prevent the side peripheral wall 12 from deforming. Furthermore, the radially inner ends of the multiple vertical walls 3 are connected to the outer peripheral surface of the base 2. Therefore, the multiple vertical walls 3, together with the base 2, can prevent the ceiling wall 11 and the side peripheral wall 12 from deforming. That is, by connecting the multiple vertical walls 3 to the base 2, the base 2 can be used to ensure the strength of the ceiling wall 11 and the side walls 12. In this way, by providing the multiple vertical walls 3 on the foundation body 10, the strength of the foundation body 10 can be ensured even when the foundation body 10 is divided.

[0042] In particular, in this example, the multiple vertical walls 3 are arranged at equal intervals in the circumferential direction, so the strength of the foundation body 10 can be ensured evenly in the circumferential direction. Furthermore, the multiple vertical walls 3 protrude radially outward beyond the side peripheral walls 12, so the strength of the side peripheral walls 12 can be more reliably improved. Furthermore, the multiple vertical walls 3 protrude upward beyond the top wall 11. Therefore, the strength of the top wall 11 can be more reliably improved.

[0043] 8 is a perspective view showing a schematic diagram of a suction foundation 200 according to a modified example. The shape of each vertical wall 203 of the suction foundation 200 differs from that of the suction foundation 100. The following description will focus on the configuration of the suction foundation 200 according to the modified example that differs from the suction foundation 100.

[0044] In the suction foundation 200, at least one of the vertical walls 203 has a notched radially inner and lower corner. In this example, all of the vertical walls 203 have a notched radially inner and lower corner. More specifically, in a portion of each vertical wall 203 located below the lower end 22 of the base 2 and inside the side peripheral wall 12, the radial width decreases from top to bottom. In other words, in a portion of each vertical wall 203 located below the lower end 22 of the base 2 and inside the side peripheral wall 12, the width tapers from top to bottom.

[0045] Furthermore, radially outer and upper corners of the portions of the vertical walls 203 that protrude above the ceiling wall 11 are cut out. In this example, radially outer and upper corners of the portions of all the vertical walls 203 that protrude above the ceiling wall 11 are cut out. Specifically, in the portions of each vertical wall 203 that protrude above the ceiling wall 11, the radial width decreases from the bottom to the top. In other words, the portions of each vertical wall 203 that protrude above the ceiling wall 11 taper from the bottom to the top.

[0046] In the suction foundation 200, at least one of the vertical walls 203 has a notched radially inner and lower corner, thereby reducing the penetration resistance from the ground G. Specifically, the vertical wall 203 having a notched radially inner and lower corner can reduce the contact area between the vertical wall 203 and the ground G during penetration, compared to a vertical wall whose radially inner and lower corners are notched. As a result, the penetration resistance from the ground G can be reduced. Furthermore, because the radially inner and lower corners are notched, the weight of the vertical wall 203 can be reduced compared to a vertical wall whose radially inner and lower corners are notched. This allows the vertical wall 203 to be easily transported during assembly of the suction foundation 200, etc. Furthermore, because the radially outer and upper corners of the portions of the vertical walls 203 that protrude above the ceiling wall 11 are notched, the weight of the vertical wall 203 can be further reduced.

[0047] Other Embodiments As described above, the above embodiment has been described as an example of the technology disclosed in this application. However, the technology of the present disclosure is not limited to this and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate. Furthermore, the components described in the above embodiment can be combined to create new embodiments. Furthermore, the components described in the accompanying drawings and detailed description may include not only components essential for solving the problem, but also components that are not essential for solving the problem in order to exemplify the technology. Therefore, the fact that these non-essential components are described in the accompanying drawings or detailed description should not be interpreted as immediately determining that these non-essential components are essential.

[0048] For example, the shape of the foundation body 10 is not limited to a substantially cylindrical shape. The foundation body 10 can be formed into any shape as long as it has a ceiling wall 11 and a peripheral side wall 12 and is open at the bottom. For example, the foundation body 10 may be formed into a rectangular tube shape, such as a substantially square or pentagonal cross section. The foundation body 10 may also be formed so that the ceiling wall 11 is shaped like a curved dome. Furthermore, the shape of the ceiling wall 11 is not limited to a circular ring shape, and may simply be a disk shape. In this case, the base 2 may be connected to the ceiling wall 11 by connecting the lower end 22 of the base 2 to the top surface of the ceiling wall 11.

[0049] The foundation body 10 does not need to define the filled space 16 when the side peripheral wall 12 is inserted into the ground G. In other words, the entire side peripheral wall 12 may be inserted into the ground G.

[0050] The shape of the base 2 does not have to be cylindrical. The shape of the base 2 may be, for example, a columnar shape having a polygonal cross section. The base 2 may be solid instead of hollow.

[0051] As long as each vertical wall 3 is connected to the ceiling wall 11, the side peripheral walls 12, and the base 2, the shape of each vertical wall 3 when viewed from the thickness direction is not limited. The number of multiple vertical walls 3 is not limited. In other words, the number of divisions of the ceiling wall 11 and the number of divisions of the side peripheral walls 12 are not limited. The number of multiple vertical walls 3 may be two, three, five or more. The multiple vertical walls 3 do not have to be arranged at equal intervals in the circumferential direction.

[0052] Each vertical wall 3 may be formed by connecting multiple members. For example, each vertical wall 3 may be formed by connecting a plate-shaped first member arranged above the top surface of the ceiling wall 11 and a plate-shaped second member arranged below the top surface of the ceiling wall 11. The thickness of the first member may be the same as or different from the thickness of the second member. For example, the thickness of the first member may be greater than the thickness of the second member. A flange extending in the thickness direction of the first member may be arranged on the exposed portion of the side surface of the first member in a direction perpendicular to the thickness direction. This can improve the strength of the first member. The first member is more susceptible to load than the second member. As a result, the strength of the entire vertical wall 3 can be effectively improved.

[0053] In the example shown in FIG. 2, all of the vertical walls 3 protrude radially outward from the side peripheral wall 12, but at least one of the vertical walls 3 may protrude radially outward from the side peripheral wall 12. Furthermore, with regard to the radial position, the outer end of each of the vertical walls 3 may be substantially coincident with the outer peripheral surface of the side peripheral wall 12. Furthermore, in the example shown in FIG. 2, all of the vertical walls 3 protrude upward from the top wall 11, but at least one of the vertical walls 3 may be substantially coincident with the top surface of the top wall 11, with regard to the axial position. Furthermore, with regard to the axial position, the upper end 32 of each of the vertical walls 3 may be substantially coincident with the top surface of the top wall 11. Furthermore, with regard to the axial position, the lower end 33 of each of the vertical walls 3 may be located above the lower end 17 of the side peripheral wall 12.

[0054] In the example shown in FIG. 2 , both the top wall 11 and the side peripheral wall 12 are divided in the circumferential direction, but it is sufficient if at least one of the top wall 11 and the side peripheral wall 12 is divided in the circumferential direction. For example, the top wall 11 may be divided in the circumferential direction, and the side peripheral wall 12 may not be divided in the circumferential direction, i.e., may be formed as a single unit. In this case, the radially outer outer end of each vertical wall 3 may be connected to the inner circumferential surface of the side peripheral wall 12. For example, the side peripheral wall 12 may be divided in the circumferential direction, and the top wall 11 may not be divided in the circumferential direction, i.e., may be formed as a single unit. In this case, the upper end 32 of each vertical wall 3 may be connected to the bottom surface of the top wall 11.

[0055] Furthermore, in the example shown in FIG. 2 , the division positions of the side peripheral wall 12 coincide with the positions of the vertical walls 3 in the circumferential direction, but the division positions of the side peripheral wall 12 do not have to coincide with the positions of the vertical walls 3 in the circumferential direction. FIGS. 9 and 10 are cross-sectional views (specifically, orthogonal cross-sectional views) illustrating other examples of the division positions of the side peripheral wall 12. For example, as shown in FIG. 9 , the division positions of the side peripheral wall 12 may coincide with the positions of some of the vertical walls 3 in the circumferential direction. For example, as shown in FIG. 10 , the division positions of the side peripheral wall 12 may be located between two circumferentially adjacent vertical walls 3. In the example shown in FIGS. 9 and 10 , two circumferentially adjacent second segments 61 are directly connected to each other. The radially outer ends of the multiple vertical walls 3 are connected to the inner circumferential surface of the side peripheral wall 12. Furthermore, for example, in the example shown in FIG. 2 , one second segment 62 disposed between two circumferentially adjacent vertical walls 3 may be further divided in the circumferential direction. Similarly, the division positions of the ceiling wall 11 do not have to coincide with the positions of the vertical walls 3 in the circumferential direction. For example, in the example shown in Fig. 2, one first divided body 61 arranged between two vertical walls 3 adjacent in the circumferential direction may be further divided in the circumferential direction.

[0056] In the example shown in FIG. 8 , all vertical walls 203 have radially inner and lower corners cut out, but at least one vertical wall 203 may have radially inner and lower corners cut out. For example, of the four vertical walls 203, two vertical walls 203 may have radially inner and lower corners cut out, and the other two vertical walls 203 may not have radially inner and lower corners cut out. This reduces penetration resistance while ensuring sufficient strength of the foundation body 10. Similarly, in the example shown in FIG. 8 , all vertical walls 203 have radially outer and upper corners cut out of the portions protruding upward from the ceiling wall 11, but at least one vertical wall 203 may have radially outer and upper corners cut out of the portions protruding upward from the ceiling wall 11.

[0057] Furthermore, the superstructure installed on the suction foundation 100 is not limited to the wind turbine 9. The superstructure may be a wind observation tower, a caisson, or the like.

[0058] In the example shown in FIG. 1, one suction foundation 100 (i.e., a mono-bucket) supports the superstructure (i.e., the wind turbine 9), but multiple suction foundations 100 (i.e., multi-bucket) may support the superstructure. FIG. 11 is an explanatory diagram showing a schematic diagram of multiple suction foundations 100 installed. The number of suction foundations 100 is not limited, but in this example, there are three. The three suction foundations 100 are arranged in a triangular shape when viewed from the axial direction. A jacket 8 is connected to the upper end of each base 2 of each suction foundation 100. The jacket 8 includes multiple frames 81. Each frame 81 is, for example, a steel pipe. The jacket 8 transmits the weight of the superstructure and external forces acting on the superstructure (wind load, earthquake load, etc.) to the multiple suction foundations 100, thereby stably supporting the superstructure. The superstructure (not shown) is installed above the jacket 8.

[0059] [Aspect] The above-described embodiment is a specific example of the following aspects.

[0060] (Aspect 1) The suction foundation 100, 200 comprises a foundation body 10 including a ceiling wall 11 and a cylindrical side wall 12 extending downward from the ceiling wall 11 in the direction of a predetermined axis C and inserted into the underwater ground; a columnar base 2 connected to the ceiling wall 11 and extending in the vertical direction; and a plurality of vertical walls 3, 203 arranged radially at intervals in the circumferential direction around the axis C, connected to the base 2, and extending downward from the base 2, wherein at least one of the ceiling wall 11 and the side wall 12 includes a plurality of divided bodies divided in the circumferential direction, and the radial inner ends of the plurality of vertical walls 3, 203 centered on the axis C are connected to the outer peripheral surface of the base 2, the ceiling wall 11 is connected to the base 2 and the plurality of vertical walls 3, and the side wall 12 is connected to the ceiling wall 11 and the plurality of vertical walls 3.

[0061] According to this configuration, the multiple vertical walls 3,203 are connected to both the ceiling wall 11 and the side peripheral wall 12. Therefore, even if a pressure difference occurs between the inside and outside of the foundation main body 10 when the suction foundation 100, 200 is inserted and a force that would deform the ceiling wall 11 acts on the ceiling wall 11, the multiple vertical walls 3,203 prevent the ceiling wall 11 from deforming. In other words, the multiple vertical walls 3,203 function like ribs that reinforce the ceiling wall 11. Similarly, even if a pressure difference occurs between the inside and outside of the foundation main body 10 when the suction foundation 100, 200 is inserted and a force that would deform the side peripheral wall 12 acts on the side peripheral wall 12, the multiple vertical walls 3,203 prevent the side peripheral wall 12 from deforming. Furthermore, because the radial inner ends of the multiple vertical walls 3,203 are connected to the outer peripheral surface of the base 2, the multiple vertical walls 3,203 can prevent the ceiling wall 11 and the side peripheral wall 12 from deforming together with the base 2. That is, by connecting the multiple vertical walls 3, 203 to the base 2, the base 2 can be used to ensure the strength of the ceiling wall 11 and the side walls 12. In this way, even if the foundation body 10 is divided, the strength of the foundation body 10 can be ensured by the multiple vertical walls 3, 203.

[0062] (Aspect 2) In the suction foundation 100, 200 described in aspect 1, the ceiling wall 11 includes a plurality of first division bodies 61 divided in the circumferential direction, and at least one of the plurality of vertical walls 3,203 passes between two circumferentially adjacent first division bodies 61 of the plurality of first division bodies 61 and penetrates the ceiling wall 11, and the two first division bodies 61 are connected to the vertical wall 3,203 that passes between the two first division bodies 61.

[0063] According to this configuration, even if the ceiling wall 11 is divided, the strength of the foundation body 10 can be ensured by the multiple vertical walls 3, 203.

[0064] (Aspect 3) In the suction foundation 100, 200 described in aspect 1 or 2, the side peripheral wall 12 includes a plurality of second division bodies 62 divided in the circumferential direction, and at least one vertical wall 3,203 of the plurality of vertical walls 3,203 passes between two second division bodies 62 adjacent to each other in the circumferential direction and penetrates the side peripheral wall 12, and the two second division bodies 62 are connected to the vertical wall 3,203 that passes between the two second division bodies 62.

[0065] According to this configuration, even if the side peripheral wall 12 is divided, the strength of the foundation body 10 can be ensured by the multiple vertical walls 3, 203.

[0066] (Aspect 4) In the suction foundation 100, 200 described in any one of aspects 1 to 3, the ceiling wall 11 includes a plurality of first division bodies 61 divided in the circumferential direction, the side peripheral wall 12 includes a plurality of second division bodies 62 divided in the circumferential direction, at least one vertical wall 3,203 of the plurality of vertical walls 3,203 passes between two circumferentially adjacent first division bodies 61 of the plurality of first division bodies 61 and penetrates the ceiling wall 11, and passes between two circumferentially adjacent second division bodies 62 of the plurality of second division bodies 62 and penetrates the side peripheral wall 12, the two first division bodies 61 are connected to the vertical wall 3,203 that passes between the two first division bodies 61, and the two second division bodies 62 are connected to the vertical wall 3,203 that passes between the two second division bodies 62.

[0067] According to this configuration, even if both the ceiling wall 11 and the side peripheral wall 12 are divided, the strength of the foundation body 10 can be ensured by the multiple vertical walls 3, 203.

[0068] (Aspect 5) In the suction foundation 100, 200 described in any one of aspects 1 to 4, the ceiling wall 11 includes a plurality of first division bodies 61 divided in the circumferential direction, and the side peripheral wall 12 includes a plurality of second division bodies 62 divided in the circumferential direction, and between each two vertical walls 3,203 adjacent to each other in the circumferential direction among the plurality of vertical walls 3,203, one first division body 61 of the plurality of first division bodies 61 and one second division body 62 of the plurality of second division bodies 62 are arranged, and each vertical wall 3,203 of the plurality of vertical walls 3,203 passes between two corresponding first division bodies 61 adjacent to each other in the circumferential direction, penetrates the ceiling wall 11, and is connected to the corresponding two first division bodies 61, and passes between two corresponding second division bodies 62 adjacent to each other in the circumferential direction, penetrates the side peripheral wall 12, and is connected to the corresponding two second division bodies 62.

[0069] According to this configuration, all of the first divisional bodies 61 are connected in the circumferential direction via multiple vertical walls 3, 203 to form the ceiling wall 11. Similarly, all of the second divisional bodies 62 are connected in the circumferential direction via multiple vertical walls 3, 203 to form the side peripheral wall 12. This makes it possible to further secure the strength of the foundation body 10.

[0070] (Aspect 6) In the suction foundation 200 according to any one of the first to fifth aspects, at least one of the vertical walls 203 has a corner portion on the inside and below in the radial direction cut out.

[0071] This configuration reduces the penetration resistance from the ground G when the suction foundation 200 is penetrated. In addition, because the radially inner and lower corners are cut out, the weight of the vertical wall 203 can be reduced compared to when the radially inner and lower corners are not cut out. This makes it possible to easily transport the vertical wall 203 when assembling the suction foundation 200, etc.

[0072] (Aspect 7) In the suction foundation 100, 200 according to any one of aspects 1 to 6, the plurality of vertical walls 3, 203 are arranged at equal intervals in the circumferential direction.

[0073] According to this configuration, the strength of the foundation body 10 can be ensured evenly in the circumferential direction.

[0074] (Aspect 8) In the suction foundation 200 according to any one of aspects 1 to 7, the radially outer and upper corners of the portions of the vertical walls 203 that protrude above the ceiling wall 11 are cut out.

[0075] According to this configuration, the radially outer and upper corners of the portions of the multiple vertical walls 203 that protrude above the ceiling wall 11 are cut out, so the weight of the vertical walls 203 can be reduced compared to when the radially outer and upper corners of the portions of the multiple vertical walls 203 that protrude above the ceiling wall 11 are not cut out. This makes it possible to easily transport the vertical walls 203 when assembling the suction foundation 200, etc. [Explanation of symbols]

[0076] 100,200 Suction base 2. Bass 3,203 vertical walls 9 windmill 10 Base body 11 Ceiling Wall 12 Side walls 22 Bottom edge of base 32,232 Top of vertical wall 33 Bottom edge of vertical wall 61 1st division body 62 Second division body C axis center G Ground

Claims

1. a foundation body including a ceiling wall and a cylindrical side wall extending downward from the ceiling wall in a direction of a predetermined axis and inserted into the underwater ground; a columnar base connected to the ceiling wall and extending in the vertical direction; a plurality of vertical walls arranged radially at intervals in a circumferential direction around the axis, connected to the base, and extending downward from the base; At least one of the ceiling wall and the side peripheral wall includes a plurality of divided bodies divided in the circumferential direction, Inner ends of the vertical walls in a radial direction about the axis are connected to an outer peripheral surface of the base, the ceiling wall is connected to the base and the vertical walls, A suction foundation in which the side peripheral wall is connected to the ceiling wall and the plurality of vertical walls.

2. The suction foundation according to claim 1, the ceiling wall includes a plurality of first division bodies divided in the circumferential direction, At least one of the plurality of vertical walls passes between two circumferentially adjacent first division bodies among the plurality of first division bodies and penetrates the ceiling wall, A suction foundation in which the two first divisions are connected to the vertical wall that passes between the two first divisions.

3. The suction foundation according to claim 1, the side peripheral wall includes a plurality of second division bodies divided in the circumferential direction, At least one of the plurality of vertical walls passes between two circumferentially adjacent second division bodies among the plurality of second division bodies and penetrates the side peripheral wall, A suction foundation in which the two second division bodies are connected to the vertical wall passing between the two second division bodies.

4. The suction foundation according to claim 1, the ceiling wall includes a plurality of first division bodies divided in the circumferential direction, the side peripheral wall includes a plurality of second division bodies divided in the circumferential direction, At least one of the plurality of vertical walls passes between two circumferentially adjacent first division bodies among the plurality of first division bodies, penetrating the ceiling wall, and passes between two circumferentially adjacent second division bodies among the plurality of second division bodies, penetrating the side peripheral wall, the two first divided bodies are connected to the vertical wall passing between the two first divided bodies, A suction foundation in which the two second division bodies are connected to the vertical wall passing between the two second division bodies.

5. The suction foundation according to claim 1, the ceiling wall includes a plurality of first division bodies divided in the circumferential direction, the side peripheral wall includes a plurality of second division bodies divided in the circumferential direction, one first division body of the plurality of first division bodies and one second division body of the plurality of second division bodies are disposed between each two vertical walls adjacent to each other in the circumferential direction among the plurality of vertical walls, A suction foundation in which each vertical wall of the plurality of vertical walls passes between two corresponding first division bodies adjacent to each other in the circumferential direction, penetrates the ceiling wall, and is connected to the corresponding two first division bodies, and passes between two corresponding second division bodies adjacent to each other in the circumferential direction, penetrates the side peripheral wall, and is connected to the corresponding two second division bodies.

6. The suction foundation according to any one of claims 1 to 5, A suction foundation in which a radially inner and lower corner of at least one of the plurality of vertical walls is cut out.

7. The suction foundation according to any one of claims 1 to 5, A suction foundation in which the plurality of vertical walls are arranged at equal intervals in the circumferential direction.

8. The suction foundation according to any one of claims 2, 4 and 5, A suction foundation in which the radially outer and upper corners of the portions of the vertical walls that protrude above the ceiling wall are cut out.

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