JP2020122286A - Foundation structure for offshore wind power generation and construction method of foundation structure for offshore wind power generation - Google Patents

Abstract

To provide a foundation structure for offshore wind power generation and a construction method of foundation structure for offshore wind power generation capable of reducing the construction period and construction cost by greatly reducing the size of the gravity foundation installed on the seabed.SOLUTION: An outer shell 5 with a transition piece 9 fixed and transport is towed to the site and is submerged on bedrock 1 on the seabed, and the outer shell 5 is filled with concrete 19; thereby a direct foundation 21 is installed on the bedrock 1. Subsequently, on the direct foundation 21, a tower 23, which is a substructure of an offshore wind power on which a windmill tower 47 is to be installed, is installed. Then, a ground anchor 39 is placed by using a guide hole 35 of a fixing plate 25 formed on the sea part of the tower 23 and a sheath pipe 11 embedded in the direct foundation 21 as a guide and an anchor body 37 is formed on the bedrock 1 and the lower end of the ground anchor 39 is fixed. A fixing tool 41 is attached and the upper end of the ground anchor 39 is fixed to the fixing plate 25.SELECTED DRAWING: Figure 5

Description

The present invention relates to an offshore wind power generation foundation structure and a method for constructing an offshore wind power generation foundation structure.

The basic types of offshore wind turbines include monopile foundations, pile foundations and gravity foundations. When installing an offshore wind turbine in the open ocean where the seabed is hard, the gravity foundation is effective. When installing an offshore wind turbine in a relatively shallow sea area, install a footing pile foundation on the seabed, and use a machine on the work stage installed above the footing to drive the pile to the seabed using various machines. There is also a basic structure or the like that is installed and the head is fixed to the footing (for example, refer to Patent Document 1).

Japanese Patent No. 4696854

However, in the foundation type using piles such as the method described in Patent Document 1, it is assumed that it takes time to drive the piles or the rocks break when the piles are driven, especially when the seabed is rock. It may not be possible to obtain support. However, in the gravity type foundation without pile driving, the size of the offshore wind turbine has increased in recent years, and it is not easy to construct a gravity type foundation of a size corresponding to it.

The present invention has been made in view of the above-mentioned problems, and an object thereof is to construct a foundation structure for offshore wind power generation in which a gravity type foundation installed on a seabed can be significantly downsized to reduce a construction period and a construction cost. And to provide a method of constructing a foundation structure for offshore wind power generation.

In order to achieve the above-mentioned object, a first invention is a foundation structure for offshore wind power generation, which is a direct foundation installed on the seabed, and an offshore installation installed on the direct foundation with a windmill tower installed above. A lower structure for wind power generation, wherein the direct foundation and the lower structure are fixed to a seabed by a ground anchor, and one end of the ground anchor is fixed to the seabed. The end is a foundation structure for offshore wind power generation, characterized in that it is fixed to a fixing portion formed on a sea portion of the lower structure.

In the first aspect of the present invention, by using the direct foundation and the ground anchor together, vertical force can be introduced by the ground anchor to enhance stability against falling due to wave force, etc. The size can be significantly reduced, and the construction period and construction cost can be reduced. Further, since the other end of the ground anchor is fixed to the fixing portion formed in the sea portion of the lower structure, diver work in water is not required when constructing the ground anchor.

At least a part of the ground anchor may penetrate the inside of the lower structure. In this case, the lower structure is a steel or concrete tower, the inside of the tower is filled with a filling material, and the fixing portion is fixed to the inside of the tower at an upper portion of the filling material. Is desirable.
By penetrating the ground anchor inside the lower structure, the ground anchor can be protected from corrosion by seawater and damage by floating debris. Further, by filling the inside of the tower with the filling material, it is possible to increase the weight of the foundation structure for offshore wind power generation and maintain stability against wave forces and the like.

At least some of the ground anchors may be arranged outside the lower structure. In this case, the ground anchors may be arranged so as to be inclined with respect to the vertical direction, and the plurality of ground anchors may be arranged so that the intervals between the ground anchors become wider as they go downward.
By arranging the ground anchor on the outer side of the lower structure or arranging the ground anchor at an angle with respect to the vertical direction, it is possible to perform a rational arrangement so that the effect of the ground anchor can be better obtained. Further, the ground anchor can be arranged so as not to directly penetrate the foundation.

The direct foundation has an outer shell, sand or concrete filled in the outer shell, and a transition piece fixed to the outer shell, and the lower structure is joined to the transition piece. Is desirable.
If the direct foundation is composed of prefabricated shell and sand or concrete filled in the field, the foundation can be easily installed directly on the seabed.

A second invention is a foundation structure for offshore wind power generation, which is a direct foundation installed on the seabed, an undersea wind power generation substructure installed on the direct foundation, and a wind turbine tower is installed on an upper portion, The direct foundation includes an outer shell, sand or concrete filled in the outer shell, and a transition piece fixed to the outer shell, and the lower structure is the transition piece. And the direct foundation and the lower structure are fixed to the seabed by a ground anchor, which is a foundation structure for offshore wind power generation.

In the second invention, by directly using the ground anchor together with the ground anchor, vertical force can be introduced by the ground anchor to enhance stability against falling due to wave forces, etc. The size can be reduced, and the construction period and construction cost can be reduced. In addition, by constructing the direct foundation with a prefabricated outer shell and sand or concrete filled in the field, the foundation can be easily installed directly on the seabed.

When the outer shell of the direct foundation is filled with sand or concrete, it is preferable that a sheath pipe is embedded in the direct foundation and the ground anchor penetrates the sheath pipe and is fixed to the ground.
By embedding the sheath tube, the ground anchor can be easily penetrated directly into the foundation.

An optical fiber sensor may be arranged on the ground anchor, and the tension of the ground anchor may be measured by the optical fiber sensor.
As a result, the malfunction of the ground anchor can be remotely managed during service, and the safety of the foundation structure can be ensured.

A third aspect of the present invention is a method of constructing a foundation structure for offshore wind power generation, which includes a step a of directly installing a foundation on a seabed, and a substructure of an offshore wind power generation in which a windmill tower is installed on the direct foundation. Step b of installing the body, step c of fixing one end of the ground anchor to the seabed, and step d of fixing the other end of the ground anchor to the fixing portion formed on the sea portion of the lower structure. And a construction method of an offshore wind power generation foundation structure.

According to the third aspect of the present invention, by using the direct foundation and the ground anchor together, it is possible to introduce vertical force by the ground anchor to enhance stability against falling due to wave force, etc. The size can be significantly reduced, and the construction period and construction cost can be reduced. Further, by fixing the other end of the ground anchor to the fixing portion formed on the sea portion of the lower structure, diver work underwater is not necessary when constructing the ground anchor.

The step a includes a step e of towing the outer shell to which the transition piece is fixed and transporting the outer shell to the site to deposit the outer shell on the seabed, and a step f of filling the outer shell with concrete or sand. It is desirable to have
If the prefabricated outer shell is sunk and filled with concrete or sand on site, the foundation can be easily installed directly on the seabed.

A fourth invention is a method of constructing a foundation structure for offshore wind power generation, in which an outer shell to which a transition piece is fixed is towed and transported to a site, and the outer shell is sunk on the seabed, By affixing concrete or sand to the base, a step of directly installing the foundation on the seabed, a step b of fixing one end of the ground anchor to the seabed, and another end of the ground anchor fixing on the direct foundation. A method for constructing a foundation structure for offshore wind power generation, comprising: step c; and step d: installing a lower structure for offshore wind power generation in which a wind turbine tower is installed on the direct foundation. is there.

In the fourth invention, by directly using the ground anchor together with the ground anchor, vertical force can be introduced by the ground anchor to enhance stability against falling due to wave force, etc. The size can be reduced, and the construction period and construction cost can be reduced. In addition, the foundation can be easily installed directly on the seabed by sinking a prefabricated shell and filling it with concrete or sand on site.

When directly filling the outer shell of the foundation with concrete or sand, a sheath pipe is embedded in the direct foundation, the concrete or sand is filled outside the sheath pipe, and the ground anchor is inserted into the sheath pipe. It is desirable to settle on the ground.
By embedding the sheath tube, the ground anchor can be easily penetrated directly into the foundation.

ADVANTAGE OF THE INVENTION According to this invention, the construction method of the foundation structure for offshore wind power generation and the foundation structure for offshore wind power generation which can reduce a construction period and a construction cost significantly by downsizing the gravity type foundation installed in the seabed can be provided.

The figure which shows the process of depositing the outer shell 5 on the bedrock 1 of the seabed. The figure which shows the process of installing the tower 23 directly on the foundation 21. The figure which shows the process of setting the ground anchor 39. The figure which shows the process of setting the ground anchor 39. The figure which shows the process of installing the windmill tower 47 in the tower 23. The figure which shows the horizontal cross section of the foundation structure 45. The enlarged view of the anchor body 37 vicinity. The figure which shows the basic structure 45a. The figure which shows the basic structure 45a. The figure which shows the example in which the ground anchor was arrange|positioned inclining with respect to the vertical direction. The figure which shows the example in which the ground anchor was arrange|positioned inclining with respect to the vertical direction. The figure which shows the process of constructing the foundation structure 45d. The figure which shows basic structure 45e. The figure which shows the example which filled the filling sand 53. The figure which shows the example which has arrange|positioned the optical fiber sensor 55. FIG.

Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a process of depositing an outer shell 5 on a bedrock 1 on the seabed. FIG. 1A shows a state in which the outer shell 5 is towed, and FIG. 1B shows a state in which the outer shell 5 is sunk.

In the process shown in FIG. 1, as shown in FIG. 1A, the outer shell 5 is towed on the sea surface 3 and transported to the construction site. As shown in FIG. 1, a transition piece 9 is fixed to the outer shell 5. In the transition piece 9, a sheath pipe 11 that penetrates the bottom surface 7 of the outer shell 5 is arranged, and a lower end portion of the sheath pipe 11 is closed by a lid 15. The outer shell 5 is made of precast concrete, steel or the like which is manufactured in advance in a factory or the like. Reinforcing bars 13 are arranged in the outer shell 5.

After the outer shell 5 has been towed to the site, water is poured into the outer shell 5 and the transition piece 9 and is sunk on the bedrock 1 on the seabed as shown in FIG. 1(b).

FIG. 2 is a diagram showing a process of directly installing the tower 23 on the foundation 21. 2A shows a state in which the foundation 21 is directly installed, and FIG. 2B shows a state in which the tower 23 is installed. The tower 23 is a lower structure for offshore wind power generation in which a wind turbine tower 47 (see FIG. 5) is installed on the upper portion. The tower 23 is made of steel or concrete.

In the process shown in FIG. 2, underwater non-separable concrete is poured into the outer shell 5 and the transition piece 9 by using the injection pipe 17 as shown in FIG. The concrete 19 is filled outside the sheath pipe 11. As a result, the transition piece 9 is fixed to the outer shell 5, and the direct foundation 21 in which the outer shell 5 is filled with the concrete 19 is installed on the bedrock 1. Further, the sheath tube 11 is directly embedded in the foundation 21.

After the concrete 19 is filled, before the concrete 19 is hardened, the tower 23 is inserted into the transition piece 9 as shown in FIG. 2B, and the underwater inseparable grout material 27 is inserted into the gap between the tower 23 and the transition piece 9. To fill. Thereby, the tower 23 is directly installed on the foundation 21 and joined to the transition piece 9, and the gravity foundation 22 is constructed.

Inside the tower 23, a fixing plate 25 is provided above the sea surface 3. The fixing plate 25 is supported by a bracket (not shown) and fixed to the inner peripheral surface of the tower 23. The fixing plate 25 has a guide hole 35 and a filling hole 26. The guide hole 35 is provided at a position corresponding to the ground anchor 39 (see FIG. 3) in plan view. The filling hole 26 is preferably provided so as not to be continuous with the guide hole 35.

3 and 4 are views showing a process of placing the ground anchor 39. In the process shown in FIG. 3, the working deck 29 is installed on the sea part of the tower 23, and the rock bed 1 is drilled by the crawler drill 31 on the deck 29 while the casing wall 33 protects the hole wall. The lid 15 of the sheath pipe 11 is removed at an appropriate time before drilling the bedrock 1.

Then, the ground anchor 39 is placed, and the lower end of the ground anchor 39 is fixed to the bedrock 1 by the anchor body 37. At this time, the guide hole 35 and the sheath pipe 11 are used as guides for the casing pipe 33. Further, as shown in FIG. 4, the upper end of the ground anchor 39 is fixed to the fixing plate 25 by the fixing tool 41. The reaction force of the ground anchor 39 on the fixing tool 41 side is transmitted to the tower 23 via the fixing plate 25.

FIG. 5: is a figure which shows the process of installing the windmill tower 47 in the tower 23. As shown in FIG. In the process shown in FIG. 5, the filling sand 43 is filled in the tower 23 using the filling holes 26 of the fixing plate 25. As a result, the foundation structure 45 for offshore wind power generation is completed. When the basic structure 45 is completed, the flange 24 at the upper end of the tower 23 and the flange 46 at the lower end of the wind turbine tower 47 are joined to each other, and the wind turbine tower 47 is installed above the tower 23.

FIG. 6 is a view showing a horizontal cross section of the foundation structure 45. FIG. 6 is a cross-sectional view taken along the arrow AA shown in FIG. FIG. 7 is an enlarged view of the vicinity of the anchor body 37.

As shown in FIG. 6, the ground anchor 39 is arranged on, for example, two concentric circles. Here, if the ground anchor 39-1 arranged on the outer side and the ground anchor 39-2 arranged on the inner side are sufficiently separated, as shown in FIG. 7A, the anchor body 37-1 and the anchor body 37-1 37-2 and 37-2 can be formed in the same depth. If the ground anchors 39-1 and 39-2 are close to each other, it is desirable to form the anchor bodies 37-1 and 37-2 at different depths as shown in FIG. 7B. ..

As described above, in the foundation structure 45 of the first embodiment, the direct foundation 21 and the ground anchor 39 are used together, and the vertical force of the restraint required for satisfying the stability against the fall or the withdrawal due to the wave force is grounded. By introducing the force into the anchor 39, the force on the pushing side can be directly transmitted from the foundation 21 to the bedrock 1, and the ground anchor 39 can resist the force on the pulling side. Further, by filling the inside of the tower 23 with the filling sand 43, the weight of the gravity foundation 22 can be increased. Therefore, even if the direct foundation 21 installed on the bedrock 1 on the seabed is significantly downsized, it is possible to maintain stability against wave forces and the like.

Further, by fixing the upper end of the ground anchor 39 to the fixing plate 25 formed on the sea part of the tower 23, the ground anchor 39 can be constructed without diver work in water. Further, by arranging the ground anchor 39 so as to penetrate the inside of the tower 23, it is possible to protect the ground anchor 39 from corrosion due to seawater and damage due to floating debris.

In the first embodiment, after the outer shell 5 to which the transition piece 9 is fixed is sunk on the bedrock 1, the outer shell 5 is filled with concrete 19 so that the direct foundation 21 can be easily constructed. .. Further, by embedding the sheath pipe 11 in the concrete 19, the ground anchor 39 can easily be directly passed through the foundation 21.

Hereinafter, another example of the present invention will be described as second to fourth embodiments. Each embodiment will be described about different points from the embodiments described so far, and similar configurations will be denoted by the same reference numerals in the drawings and the like, and description thereof will be omitted. Further, the configurations described in the respective embodiments, including the first embodiment, can be combined as needed.

The second embodiment will be described. 8 and 9 are views showing a basic structure 45a according to the second embodiment of the present invention. 9 is a sectional view taken along the arrow BB shown in FIG.

The basic structure 45a mainly differs from the basic structure 45 of the first embodiment in that the ground anchor 39a is arranged outside the tower 23.

In the foundation structure 45 a, the sheath tube 11 a directly buried in the foundation 21 a is arranged outside the transition piece 9. Further, the fixing plate is not provided inside the tower 23, but the guide hole 35a is provided in the fixing table 29a installed outside the tower 23 above the sea surface 3. Further, a sheath tube 49 extending from the guide hole 35a to the sheath tube 11a is arranged. The fixing table 29a is provided in a permanent manner, and has a thickness capable of fixing the ground anchor 39a.

When constructing the foundation structure 45a, the foundation 21a is directly installed by the same procedure as in the first embodiment, the tower 23 is directly installed on the foundation 21a, and then the guide hole 35a and the sheath tube 11a are fixed as guides. The bedrock 1 is drilled from the stand 29a using a machine (not shown), and the sheath tube 49 is installed. Then, the ground anchor 39a is inserted into the sheath tube 49 and driven. The lower end of the ground anchor 39a is fixed to the bedrock 1 by the anchor body 37a, and the upper end is fixed to the fixing table 29a by the fixing tool 41a. Then, the filling sand 43 is filled in the tower 23 to complete the foundation structure 45a, and the wind turbine tower 47 is installed on the upper portion of the tower 23.

As shown in FIG. 9, the ground anchors 39a are, for example, doubly arranged inside the outer shell 5a of the foundation structure 21a. In the example shown in FIG. 8, the outer and inner anchor bodies 37a are formed at the same depth, but the anchor bodies 37a may be formed at different depths as in the example shown in FIG. 7B.

As described above, also in the foundation structure 45a of the second embodiment, the direct foundation 21a and the ground anchor 39a are used together, the inside of the tower 23 is filled with the filling sand 43, and the outer shell deposited on the bedrock 1 is used. By filling concrete 5a with concrete 19 and embedding sheath tube 11a in concrete 19, the same effect as that of the first embodiment can be obtained.

In the second embodiment, by fixing the upper end of the ground anchor 39a to the fixing table 29a formed on the sea portion of the tower 23, the ground anchor 39a can be constructed without diver work in water. Further, by arranging the ground anchor 39a on the outside of the tower 23, the effect of the ground anchor 39a can be obtained better than when it is arranged on the inside. Further, by providing the sheath tube 49, it is possible to prevent the ground anchor 39a from being corroded by seawater and being damaged by drifting matter.

In addition, although the ground anchor 39a is arranged vertically in the second embodiment, the ground anchors are arranged so as to be inclined with respect to the vertical direction, and the intervals between the plurality of ground anchors are arranged so as to widen downward. You may.

10 and 11 are views showing an example in which the ground anchors are arranged so as to be inclined with respect to the vertical direction. In the basic structure 45b shown in FIG. 10, the intervals between the plurality of ground anchors 39b widen as they go downward. The ground anchor 39b is directly embedded in the foundation 21b obliquely and is driven by using the sheath pipe 11b penetrating the outer shell 5b and the guide hole 35b as guides, and the lower end is fixed to the bedrock 1 by the anchor body 37b and the upper end is a fixing tool. It is fixed to the fixing table 29b at 41b. The fixing base 29b is provided in a permanent manner, and has a thickness capable of fixing the ground anchor 39b.

In the basic structure 45c shown in FIG. 11, the intervals between the plurality of ground anchors 39c become wider as they go downward. The ground anchor 39c does not directly penetrate the foundation 21c, the lower end is fixed to the bedrock 1 by the anchor body 37c, and the upper end is fixed to the fixing table 29c by the fixing tool 41c. Therefore, the foundation structure 45c does not require a sheath tube that directly penetrates the outer shell 5c of the foundation 21c. The fixing base 29c is provided in a permanent manner, and has a thickness capable of fixing the ground anchor 39c.

Also in the foundation structures 45b and 45c, by arranging the ground anchors 39b and 39c on the outside of the tower 23, the effect of the ground anchor can be obtained better than when arranging the ground anchors on the inside. In the basic structures 45b and 45c, the fixing bases 29b and 29c are made smaller and the fixing portions of the ground anchors 39b and 39c are brought closer to the tower 23 side, which is structurally advantageous as compared with the case where the fixing portions are provided at a position away from the tower 23. become. Further, by providing the sheath pipes 49b and 49c, it is possible to prevent the ground anchor from being corroded by seawater and being damaged by drifting substances. Furthermore, in the foundation structure 45c, the ground anchor 39c can be arranged without directly penetrating the foundation 21.

A third embodiment will be described. FIG. 12: is a figure which shows the process of constructing the foundation structure 45d. FIG. 12A shows a state in which the ground anchor 39d is placed, and FIG. 12B shows a state in which the tower 23 is installed.

In the step shown in FIG. 12A, the outer shell 5d having the sheath pipe 11d arranged on the outer side of the transition piece 9 is sunk on the bedrock 1 on the seabed by the same procedure as that of the first embodiment. The inside and the transition piece 9 are filled with concrete 19. The concrete 19 is filled outside the sheath pipe 11d. As a result, the transition piece 9 is fixed to the outer shell 5d, and the direct foundation 21d having the concrete 19 filled in the outer shell 5d is installed on the bedrock 1. Further, the sheath tube 11d is directly embedded in the foundation 21d.

Then, the bedrock 1 is drilled from the workbench 51 installed near the site using a machine not shown, and the ground anchor 39d is placed. The work table 51 is an SEP (self-lifting work table ship) or the like. At this time, the sheath tube 11d is used as a guide. The lower end of the ground anchor 39d is fixed to the bedrock 1 by the anchor body 37d, and the upper end of the ground anchor 39d is directly fixed to the upper surface of the foundation 21d by the fixing tool 41d.

In the step shown in FIG. 12B, the tower 23 is inserted into the transition piece 9 and the gap between the tower 23 and the transition piece 9 is filled with the grout material 27 in the same procedure as in the first embodiment. As a result, the tower 23 is directly installed on the foundation 21d and joined to the transition piece 9. Then, the filling sand 43 is filled in the tower 23 to complete the foundation structure 45d for offshore wind power generation.

Thus, also in the foundation structure 45d of the third embodiment, by directly using the foundation 21d and the ground anchor 39d and filling the inside of the tower 23 with the filling sand 43, it is installed on the bedrock 1 on the seabed. Even if the direct foundation 21d is significantly downsized, it is possible to maintain stability against wave forces and the like.

In the third embodiment as well, the foundation 21d can be easily constructed directly by placing concrete 19 on the sunk outer shell 5d. Further, by embedding the sheath pipe 11d in the concrete 19, the ground anchor 39d can easily be directly passed through the foundation 21d.

A fourth embodiment will be described. FIG. 13 is a diagram showing a foundation structure 45e according to the fourth embodiment of the present invention.

The basic structure 45e mainly differs from the basic structure 45 of the first embodiment in that the outer shell 5e of the direct foundation 21e has a blade opening 61 at the outer edge portion of the lower surface.

The seabed on which the foundation structure 45e is constructed has a sedimentary layer 59 in the surface layer and a supporting bedrock 1a below the sedimentary layer 59. In the foundation structure 45e, the lower end portion of the blade opening 61 of the outer shell 5e reaches the support bedrock 1a. Further, the anchor body 37e of the ground anchor 39e is formed in the supporting rock 1a.

When constructing the foundation structure 45e, the foundation 21e is directly sunk on the seabed in the same procedure as in the first embodiment, and the tower 23 is installed directly on the foundation 21e. At this point, the lower end of the blade opening 61 has not reached the supporting bedrock 1a.

After the tower 23 is installed, the ground anchor 39e is placed by the same procedure as in the first embodiment. The lower end of the ground anchor 39e is fixed to the supporting rock 1a by the anchor body 37e, and the upper end is fixed to the fixing plate 25 by the fixing tool 41. The blade edge 61 of the foundation 21e directly presses into the deposition layer 59 by introducing a tension force when fixing the ground anchor 39e. At this time, in order to ensure that the lower end portion of the blade opening 61 reaches the support bedrock 1a, the deposition layer 59 around the blade opening 61 may be excavated if necessary.

When the foundation 21e and the tower 23 are directly fixed to the support bedrock 1a by the ground anchor 39e in a state where the blade mouth 61 reaches the support bedrock 1a, the tower 23 is filled with the filling sand 43 to complete the foundation structure 45e. A windmill tower 47 is installed above 23.

According to the fourth embodiment, the same effect as that of the first embodiment can be obtained. In addition, in the fourth embodiment, the foundation structure 45e can be constructed without excavating the sedimentary layer 59 of the surface layer of the seabed by directly providing the cutting edge 61 on the foundation 21e. Therefore, the sedimentary layer 59 is excavated. The construction period can be shortened and the construction cost can be significantly reduced as compared with the case where the foundation structure is constructed.

In addition, in the first to third embodiments, the ground anchors are arranged in a double layer, but they may be arranged in a single layer or in a triple layer or more.

Further, in the first to fourth embodiments, the concrete 19 is directly placed in the outer shell of the foundation, but the filling material for the outer shell is not limited to concrete. FIG. 14 is a diagram showing an example in which the filled sand 53 is filled. Like the direct foundation 21f shown in FIG. 14, the upper shell 5f may be filled with the filling sand 53 without opening the upper surface of the outer shell 5f. In addition, in the first, second, and fourth embodiments, a direct foundation having another configuration may be installed instead of the direct foundation in which the sunk outer shell is filled with the filling material.

In the first to fourth embodiments, the filling sand 43 is filled inside the tower 23, but the filling material of the tower 23 is not limited to this. For example, the fluidized soil using the earth and sand material generated at the site due to the drilling of the seabed ground such as the bedrock 1 may be used as the filling material.

In the first to fourth embodiments, the optical fiber sensor 55 may be arranged on the ground anchor 39. FIG. 15 is a diagram showing an example in which the optical fiber sensor 55 is arranged. In the basic structure 45f shown in FIG. 15, the optical fiber sensor 55 is incorporated in the strand of the ground anchor 39, and the optical fiber sensor 55 is connected to the control device 57. In the basic structure 45f, the tension of the ground anchor 39 can be measured by the optical fiber sensor 55. If the control device 57 transmits the measured value of the tension when the offshore wind turbine is in service, the malfunction of the ground anchor 39 can be remotely controlled, and the safety of the foundation structure 45f can be ensured. The measurement of tension is not limited to the optical fiber sensor, and may be performed by a sensor using magnetism.

In the first embodiment, an example in which all the ground anchors 39 penetrate the inside of the tower 23, and in the second embodiment, an example in which all the ground anchors 39a are arranged outside the tower 23 have been shown. A part of the ground anchor may be arranged so as to penetrate the inside of the tower 23, and the rest may be arranged outside the tower 23.

The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to these examples. It is obvious to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and it is obvious that they also belong to the technical scope of the present invention. Understood.

1, 1a………… Bedrock 3 ……… Sea surface 5, 5a, 5b, 5c, 5d, 5e, 5f ……… Outer shell 7 ……… Bottom surface 9 ……… Transition piece 11, 11a, 11b, 11d…… … Sheath tube 13 ……… Reinforcing bar 15 ……… Lid 17 ……… Injection tube 19 ……… Concrete 21, 21a, 21b, 21c, 21d, 21e, 21f ……… Direct foundation 22 ……… Gravity foundation 23 … Tower 24… Flange 25… Fixing plate 26… Filling hole 27… Grout material 29… Deck 29a, 29b, 29c …Fixing stand 31… Crawler drill 33 ……… Casing pipe 35, 35a, 35b ……… Guide hole 37, 37-1, 37-2, 37a, 37b, 37c, 37d, 37e ……… Anchor body 39, 39-1, 39-2, 39a , 39b, 39c, 39d, 39e.........Grand anchor 41, 41a, 41b, 41c, 41d... Fixing device 43... Filling sand 45, 45a, 45b, 45c, 45d, 45e, 45f.... Basic structure 46…………Flange 47…………Windmill tower 49, 49b, 49c ………Sheath tube 51…………Workbench 53…………Sand filling sand 55…………Optical fiber sensor 57…………Control device 59 ………Sedimentary layer 61 ……… Blade edge

Claims (13)

A foundation structure for offshore wind power generation,
A direct foundation installed on the seabed,
An offshore wind power generation substructure installed directly on the foundation and having a windmill tower installed above,
Equipped with,
The direct foundation and the lower structure are fixed to the seabed by a ground anchor,
A base structure for offshore wind power generation, wherein one end of the ground anchor is fixed to a seabed, and the other end of the ground anchor is fixed to a fixing portion formed on a sea portion of the lower structure. The foundation structure for offshore wind power generation according to claim 1, wherein at least a part of the ground anchors penetrates through the inside of the lower structure. The lower structure is a steel or concrete tower, the inside of the tower is filled with a filling material, and the fixing portion is fixed inside the tower at the upper portion of the filling material. The offshore wind power generation foundation structure according to claim 2. The foundation structure for offshore wind power generation according to any one of claims 1 to 3, wherein at least a part of the ground anchors is arranged outside the lower structure. The offshore wind power generation foundation according to claim 4, wherein the ground anchors are arranged so as to be inclined with respect to the vertical direction, and the plurality of ground anchors are arranged such that the intervals between the plurality of ground anchors become wider as they go downward. Construction. The direct foundation has an outer shell, sand or concrete filled in the outer shell, and a transition piece fixed to the outer shell,
The foundation structure for offshore wind power generation according to any one of claims 1 to 5, wherein the lower structure is joined to the transition piece. A foundation structure for offshore wind power generation,
A direct foundation installed on the seabed,
An offshore wind power generation substructure installed directly on the foundation and having a windmill tower installed above,
Equipped with,
The direct foundation has an outer shell, sand or concrete filled in the outer shell, and a transition piece fixed to the outer shell,
The offshore wind power generation foundation structure, wherein the lower structure is joined to the transition piece, and the direct foundation and the lower structure are fixed to a seabed by a ground anchor. 8. The foundation for offshore wind power generation according to claim 6, wherein a sheath pipe is embedded in the direct foundation, and the ground anchor penetrates the sheath pipe and is fixed to the ground. Construction. An optical fiber sensor is arranged on the ground anchor, and the tension of the ground anchor can be measured by the optical fiber sensor, and the offshore wind power generation according to any one of claims 1 to 8. For foundation structure. A method of constructing a foundation structure for offshore wind power generation, comprising:
Step a of installing the foundation directly on the seabed,
A step b of installing a substructure for offshore wind power generation, in which a wind turbine tower is installed on an upper part, directly on the foundation;
Step c of fixing one end of the ground anchor to the seabed,
A step d of fixing the other end of the ground anchor to a fixing portion formed on the sea portion of the lower structure,
A method for constructing a foundation structure for offshore wind power generation, comprising: The step a is
A step e of towing the outer shell to which the transition piece is fixed, transporting it to the site, and submerging the outer shell on the seabed;
A step f of filling the outer shell with concrete or sand,
The method for constructing a foundation structure for offshore wind power generation according to claim 10, further comprising: A method of constructing a foundation structure for offshore wind power generation, comprising:
A step of directly setting the foundation on the seabed by towing the outer shell to which the transition piece is fixed and transporting it to the site, immersing the outer shell in the seabed, and filling the outer shell with concrete or sand. When,
Step b of fixing one end of the ground anchor to the seabed,
Step c of fixing the other end of the ground anchor to the direct foundation,
A step d of installing a substructure of an offshore wind power generation in which a windmill tower is installed on the upper part directly on the foundation;
A method for constructing a foundation structure for offshore wind power generation, comprising: 12. A sheath pipe is embedded in the direct foundation, the concrete or sand is filled into the outside of the sheath pipe, and the ground anchor is inserted into the sheath pipe and fixed to the ground. Alternatively, the method for constructing the foundation structure for offshore wind power generation according to claim 12.

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