Connection device of floating body and tower in offshore wind power generation facility, and construction method of offshore wind power generation facility

Abstract

[Problem] To provide a connection device with which it is possible to stably and efficiently connect an upper structure to a floating body. [Solution] The connection device 48 is composed of: a floating body-side connection device 49 provided at the upper end of a floating body 4; and a tower-side connection device 50 provided at the lower end of a tower 6. The floating body-side connection device 49 has at least two introduction tubes 54, 55 embedded on the upper surface side of a bottom plate 51, and the tower-side connection device 50 has a plurality of introduction pins 59, 60 provided on the lower surface side of a top plate 56 in correspondence to the introduction tubes 54, 55. The introduction tubes 54, 55 are constituted by engagement tube parts 54A, 55B in which elliptical through-holes are formed, and funnel parts 54B, 55B, and the introduction pins 59, 60 have elliptical cross sections so as to correspond to the elliptical through-holes. A connection flange 53 of the floating body-side connection device 49 and a connection flange 58 of the tower-side connection device 50 are fastened by a bolt and nut member 62 while the corresponding introduction tubes 54, 55 and the introduction pins 59, 60 are engaged with each other.

Description

Connection device between a floating body and a tower in an offshore wind power generation facility and construction method of the offshore wind power generation facility

[0001] The present invention relates to a connection device between a floating body and a tower in an offshore wind power generation facility and a construction method of the offshore wind power generation facility.

[0002] Conventionally, mainly power generation methods such as hydraulic power, thermal power, and nuclear power generation have been adopted. In recent years, however, wind power generation that generates electricity by utilizing natural wind has attracted attention from the viewpoints of environmental protection and effective utilization of natural energy. This wind power generation facility includes an onshore installation type and an offshore (mainly sea) installation type. In the case of Japan, which is surrounded by mountains along the coast, there are few plains where stable winds can be expected in the coastal areas. On the other hand, Japan is surrounded by the sea on all sides, and has advantages such as easily obtaining winds suitable for power generation at sea and having few installation restrictions. Therefore, in recent years, various types of offshore wind power generation facilities and floating body structures have been proposed.

[0003] The floating body structure is roughly classified into a barge type floating body that floats the floating body on the water surface, a semi-submersible type that sinks the lower part of the floating body below the water surface and floats it in a semi-submerged state, and a spar type that floats in a standing state like a fishing float.

[0004] Regarding the spar type floating body, the applicant proposed in Patent Document 1 below an offshore wind power generation facility comprising a floating body, a mooring cable, a tower, a nacelle installed at the top of the tower, and a plurality of wind turbine blades. The floating body includes a lower concrete floating body structure portion (hereinafter referred to as a concrete floating body portion) in which a plurality of precast cylindrical bodies made of concrete are stacked in the height direction and each precast cylindrical body is tightly connected by PC steel materials to achieve integration, and an upper steel floating body structure portion (hereinafter referred to as a steel floating body portion) continuously provided above the lower concrete floating body structure portion. The offshore wind power generation facility having a spar type floating body structure (hereinafter referred to as a spar type offshore wind power generation facility).

[0005] As shown in Figure 29, the method for constructing the floating body of the aforementioned spar-type offshore wind power generation facility involves, at a shipyard, manufacturing steel rings by dividing the steel floating body into predetermined weight units, and then welding these steel rings together to complete the steel floating body. This steel floating body is then loaded onto a barge and transported by barge to the on-site manufacturing yard, where it is unloaded (lifted onto land) at the quay using a large crane vessel of the 1300-ton class. On the other hand, the concrete floating body is manufactured at the concrete manufacturer's factory by dividing one ring into multiple circumferential sections for the convenience of truck transport, transporting these divided rings by truck to the on-site manufacturing yard, where they are joined circumferentially, and then further connecting each ring longitudinally using PC steel to complete the concrete floating body. Finally, the steel floating body and the concrete floating body are joined together using a large crane vessel of the 1300-ton class to complete the floating body.

[0006] Japanese Patent Publication No. 5274329, Japanese Unexamined Patent Publication No. 2012-201219

[0007] When constructing a spar-type offshore wind power generation facility at sea, it is desirable to install the superstructure, consisting of a tower, nacelle, and blades, while the spar-type floating body is floating on the sea, in a calm bay. However, since the draft (the part below the waterline) of the spar-type floating body is generally 70m or more, and the water depth in bays is generally shallower, construction in a bay is difficult. Therefore, as shown in Figure 30, the installation of the superstructure has been carried out in the deep waters outside the bay using a large crane ship (large crane vessel) 70 (see Patent Document 2).

[0008] However, the process of connecting the superstructure, which was lifted by the crane ship 70, to the floating body while it was adrift on the open sea required careful attention and safety precautions, as both the floating body and the crane ship 70 were constantly moving, making it a time-consuming and laborious task. Therefore, a method for stably and efficiently connecting the superstructure to the floating body was desired.

[0009] Therefore, the main objective of the present invention is to provide a connection device between a floating body and a tower for stably and efficiently connecting the superstructure to the floating body, and to provide a method for constructing an offshore wind power generation facility using the connection device.

[0010] To solve the above problems, the present invention according to claim 1 provides a connection device between a floating body and a tower in an offshore wind power generation facility comprising a spar-type floating body, mooring ropes, a tower, a nacelle and a plurality of blades installed at the top of the tower, wherein the connection device comprises a floating body-side connection device provided at the upper end of the floating body and a tower-side connection device provided at the lower end of the tower, the floating body-side connection device comprises a bottom plate, a peripheral wall rising from the entire periphery of the bottom plate, and a connecting flange extending inward horizontally from the upper end of the peripheral wall and having bolt holes formed at predetermined intervals around its entire circumference, and has at least two introduction pipes planted on the upper surface side of the bottom plate, the tower-side connection device comprises a top plate, a peripheral wall hanging down from the entire periphery of the top plate, and a connecting flange extending inward horizontally from the lower end of the peripheral wall and having bolt holes formed at predetermined intervals around its entire circumference, and has a plurality of introduction pins provided on the lower surface side of the top plate corresponding to the introduction pipes. The invention provides a connection device for connecting a floating body and a tower in an offshore wind power generation facility, characterized in that the introduction pipe is composed of an engagement pipe section having an elliptical through-hole and a funnel section extending from the upper part of the engagement pipe section, the introduction pin has an elliptical cross-section corresponding to the elliptical through-hole, the heights of the introduction pipe and the introduction pin are different on one side of each other, and the connecting flange of the floating body side connection device and the connecting flange of the tower side connection device are superimposed on each other with the corresponding introduction pipe and introduction pin engaged and fastened together with bolts and nuts.

[0011] In the invention described in claim 1 above, a connecting device is provided at the connection point between the floating body and the tower. The connecting device consists of a floating body-side connecting device provided at the upper end of the floating body and a tower-side connecting device provided at the lower end of the tower. The floating body-side connecting device consists of a base plate, a peripheral wall rising from the entire periphery of the base plate, and a connecting flange extending horizontally inward from the upper end of the peripheral wall and having bolt holes formed at predetermined intervals around its entire circumference, and has at least two introduction pipes embedded on the upper surface side of the base plate. The tower-side connecting device consists of a top plate, a peripheral wall hanging down from the entire periphery of the top plate, and a connecting flange extending horizontally inward from the lower end of the peripheral wall and having bolt holes formed at predetermined intervals around its entire circumference, and has a structure having a plurality of introduction pins provided on the lower surface side of the top plate corresponding to the introduction pipes.

[0012] The introduction pipe consists of an engaging pipe section with an elliptical through-hole and a funnel section extending from the upper part of the engaging pipe section. The introduction pin has an elliptical cross-section corresponding to the elliptical through-hole, and the introduction pipe and introduction pin are at different heights on one side of each other. The connecting flange of the floating body-side connecting device and the connecting flange of the tower-side connecting device are superimposed on each other when the corresponding introduction pipe and introduction pin are engaged, and fastened together with bolts and nuts.

[0013] In other words, the present invention provides a connection device consisting of a floating body-side connection device provided at the upper end of the floating body and a tower-side connection device provided at the lower end of the tower, and these connection devices are equipped with a guidance mechanism for connecting the tower to the floating body. The guidance mechanism consists of an introduction pipe provided at the floating body-side connection device and an introduction pin provided at the tower-side connection device. The introduction pipe is composed of an engagement pipe section with an elliptical through-hole and a funnel section extending from the upper part of the engagement pipe section, and the introduction pin has an elliptical cross-section to correspond to the elliptical through-hole. Since the heights of the introduction pipe and introduction pin are different on one side of each, when one set of introduction pipe and introduction pin is fitted together first, the fitting structure of the elliptical shapes (the engagement pipe section with an elliptical through-hole and the introduction pin with an elliptical cross-section) allows the other introduction pipe and introduction pin to fit together tightly and smoothly, making it possible to stably and efficiently connect the superstructure (tower side) to the floating body.

[0014] As part of the present invention according to claim 2, a connection device between a floating body and a tower in an offshore wind power generation facility according to claim 1 is provided, wherein the introduction pipe has multiple radially arranged protrusions on the inner surface of the funnel portion.

[0015] The invention described in claim 2 above is characterized in that, after engaging the introduction pin with the introduction tube, multiple radial projections are formed on the inner surface of the funnel portion in order to smoothly guide the introduction pin to the engagement tube portion located in the center of the introduction tube.

[0016] The present invention according to claim 3 is a method for constructing an offshore wind power generation facility as described in either claim 1 or 2, comprising: a first step of assembling the superstructure of the offshore wind power generation facility, consisting of a tower, nacelle, and blades, on an assembly frame in a sea area or quay selected as a calm area with relatively calm waves; a second step of lifting the superstructure assembled on the assembly frame in one piece with a crane ship and transporting it to the construction site of the offshore wind power generation facility; a third step of assembling a floating body at a quay, transporting the completed floating body to the construction site of the offshore wind power generation facility, and, once the floating body is floating on the sea, attaching mooring lines to hold the floating body in an upright position; A method for constructing an offshore wind power generation facility is provided, characterized in that, when completing the offshore wind power generation facility by connecting the superstructure to the upper part of the floating body while the superstructure is lifted by the crane ship, one of the introduction pins of the tower-side connection device provided at the lower end of the tower is engaged with the funnel portion of the corresponding introduction pipe of the floating-side connection device provided at the upper end of the floating body, the tower is then lowered so that the introduction pin of the tower-side connection device is fitted into the engagement pipe portion of the introduction pipe of the floating-side connection device, while the introduction pin of the other tower-side connection device is fitted into the engagement pipe portion of the introduction pipe of the floating-side connection device, thereby joining the tower-side connection device to the floating-side connection device, and the connecting flange of the tower-side connection device and the connecting flange of the floating-side connection device are fastened with bolts and nuts.

[0017] The invention described in claim 3 above provides a specific method for constructing an offshore wind power generation facility using the aforementioned connecting device.

[0018] First, the superstructure of the offshore wind power generation equipment, consisting of the tower, nacelle, and blades, is assembled on an assembly frame in a calm sea area or quay selected as a relatively calm zone (Step 1). Next, the superstructure assembled on the assembly frame is lifted in one piece by a crane ship and transported to the construction site of the offshore wind power generation equipment (Step 2).

[0019] On the other hand, after assembling the floating structure at the quay, the completed floating structure is transported to the construction site of the offshore wind power generation facility by, for example, a semi-submersible spud barge, and once the floating structure is floated offshore, mooring lines are attached to hold the floating structure upright (third step). This third step is a separate process from the first and second steps, and may be performed before or after the first and second steps. It may also be performed concurrently.

[0020] Then, in order to complete the offshore wind power generation facility by connecting the superstructure to the upper part of the floating body while it is still lifted by the crane ship, one of the introduction pins of the tower-side connection device provided at the lower end of the tower is engaged with the funnel portion of the corresponding introduction pipe of the floating-side connection device provided at the upper end of the floating body. Then, the tower is lowered so that the introduction pin of the tower-side connection device is fitted into the engagement pipe portion of the introduction pipe of the floating-side connection device, while the introduction pin of the other tower-side connection device is fitted into the engagement pipe portion of the introduction pipe of the floating-side connection device, thereby joining the tower-side connection device to the floating-side connection device, and the connecting flange of the tower-side connection device and the connecting flange of the floating-side connection device are fastened with bolts and nuts (fourth step). By following the above steps 1 to 4, it becomes possible to construct the offshore wind power generation facility stably and efficiently.

[0021] As part of the present invention according to claim 4, a method for constructing a spar-type offshore wind power generation facility according to claim 1 is provided, using an SEP-type barge, a monopile foundation, a jacket foundation, or a caisson foundation as the assembly frame.

[0022] The invention described in claim 4 above provides a specific example of an assembly frame. Specifically, an SEP-type barge, a monopile foundation, a jacket foundation, or a caisson foundation can be used as the assembly frame.

[0023] As described in detail above, the present invention provides a connection device between a floating body and a tower in an offshore wind power generation facility, and a method for constructing an offshore wind power generation facility using the connection device, thereby enabling a stable and efficient connection of the superstructure to the floating body.

[0024] This is an overall view of the spar-type offshore wind power generation facility 1. This is a longitudinal cross-sectional view of the floating body 4. This shows the precast cylindrical body 15, (A) is a longitudinal cross-sectional view, (B) is a plan view (viewed by arrow BB), and (C) is a bottom view (viewed by arrow CC). These are diagrams (A) and (B) showing the fastening procedure for the precast cylindrical bodies 15. This is an enlarged longitudinal cross-sectional view showing the boundary between the concrete floating body section 4A and the steel floating body section 4B. This shows the semi-submersible crane ship 2 used for the one-stop construction of the superstructure 12, (A) is a side view and (B) is a plan view thereof. This is a plan view showing another example of the movable counterweight device 3. This is a plan view showing yet another example of the movable counterweight device 3. This is the construction procedure (part 1) for the spar-type offshore wind power generation facility 1. This is the construction procedure (part 2) for the spar-type offshore wind power generation facility 1. This is the construction procedure (part 3) for the spar-type offshore wind power generation facility 1. This is the construction procedure (4) for the spar-type offshore wind power generation facility 1. This is the construction procedure (5) for the spar-type offshore wind power generation facility 1. This is the construction procedure (6) for the spar-type offshore wind power generation facility 1. This is the construction procedure (7) for the spar-type offshore wind power generation facility 1. This is the construction procedure (8) for the spar-type offshore wind power generation facility 1. This is the construction procedure (9) for the spar-type offshore wind power generation facility 1. This is the construction procedure (10) for the spar-type offshore wind power generation facility 1. This is an enlarged cross-sectional view showing the connection device 48 between the floating body 4 and the tower 6. This shows the floating body side connection device 49, (A) is a cross-sectional view and (B) is a plan view. This shows the tower side connection device 50, (A) is a cross-sectional view and (B) is a bottom view. These are diagrams (A) to (D) showing the connection procedure between the floating body 4 and the tower 6 by the connection device 49. This figure shows the range of motion of the tower 6 when a pair of inlet pipes 54 and inlet pins 59 are engaged. This is a plan view and an enlarged view of the main part showing a state in which a projection 61 is formed on the inner surface of the funnel portion of the inlet pipe 54 (55). These are connection procedure diagrams (A) to (C) showing modified examples of the floating body side connection device 49 and the tower side connection device 50. This is an assembly procedure diagram of the superstructure showing another example of the assembly frame 13. This is an assembly procedure diagram of the superstructure showing another example of the assembly frame 13. This is an assembly procedure diagram of the superstructure showing another example of the assembly frame 13. This is a flowchart showing a conventional floating body construction method. This is a diagram of the one-stop construction procedure using a large crane ship 70 in Patent Document 2.

[0025] Embodiments of the present invention will be described in detail below with reference to the drawings.

[0026] [Spar-type offshore wind power generation facility 1] First, we will describe spar-type offshore wind power generation facility 1 in detail based on Figures 1 to 5.

[0027] The aforementioned spar-type offshore wind power generation facility 1 is, in detail as shown in Figure 1, composed of a spar-type cylindrical floating body 4, mooring ropes 10, a tower 6, and a wind turbine 7 consisting of a nacelle 8 and a plurality of blades 9, 9... installed at the top of the tower 6.

[0028] As shown in Figure 2, the floating body 4 consists of a concrete floating body section 4A, which is formed by stacking multiple precast cylindrical concrete bodies 15, 15... in the height direction and fastening each precast cylindrical body 15, 15... together with PC steel members 19 to create a unified structure, and a steel floating body section 4B which is connected to the upper side of the concrete floating body section 4A.

[0029] The hollow portion of the floating body 4 can be filled with or discharged ballast material such as water, gravel, fine aggregate or coarse aggregate, or metal particles, and the buoyancy (draft) can be adjusted. The filling and discharge of ballast material can be done by employing the fluid transport method previously proposed by the applicant in Japanese Patent Application Publication No. 2012-201217.

[0030] The concrete floating section 4A is composed of precast cylindrical concrete bodies 15, 15... As shown in Figure 3, the precast cylindrical bodies 15 are circular precast members with the same cross-section in the axial direction, and each is manufactured using the same mold, or hollow precast members manufactured by centrifugal molding are used.

[0031] Within the wall surface, in addition to the reinforcing bars 20, sheaths 21, 21... are embedded at appropriate intervals in the circumferential direction for inserting PC steel members 19. The lower ends of these sheaths 21, 21... have enlarged diameter sections 21a to allow insertion of couplers for connecting the PC steel members 19, and the upper parts have box-shaped cutouts 22 for fitting anchor plates. Multiple hanging brackets 23 are also provided on the upper surface.

[0032] To fasten the precast cylindrical bodies 15 together, as shown in Figure 4(A), the precast cylindrical bodies 15, 15 are stacked by inserting the PC steel members 19, 19... extending upward from the lower precast cylindrical body 15 into the sheaths 21, 21..., then the anchor plate 24 is fitted into the box-shaped section 22, and tension is introduced into the PC steel members 19 using the nut member 25 to integrate them. In addition, grout material is injected into the sheath 21 through the grout injection hole 27. The hole 24a formed in the anchor plate 24 is a grout injection confirmation hole, and the filling of the grout material is completed when the grout material is discharged from this confirmation hole.

[0033] Next, as shown in Figure 4(B), the couplers 26 are screwed onto the protruding parts of the PC steel members 19, and the upper PC steel members 19, 19... are connected. Then, the PC steel members 19, 19... are inserted into the sheaths 21, 21... of the upper precast cylindrical body 15 and stacked, and the procedure for fixing the PC steel members 19 in the manner described above is repeated sequentially to stack the structures in the height direction. At this time, an adhesive 28 such as epoxy resin or a sealant is applied to the joint surface between the lower precast cylindrical body 15 and the upper precast cylindrical body 15 to ensure watertightness and to join the joint surfaces.

[0034] The steel floating section 4B is composed of a steel cylindrical body 17 located on the lower side and a steel cylindrical body 18 located on the upper side. The lower part of the steel cylindrical body 17 has the same outer diameter as the precast cylindrical body 15, and as shown in Figure 5, it is connected to the precast cylindrical body 15 by bolts or welding (bolt fastening in the illustrated example). The upper part of the steel cylindrical body 17 has a truncated cone shape with a gradually narrowing diameter.

[0035] The upper steel cylindrical body 18 is a cylindrical body with an outer diameter that is continuous with the upper outer diameter of the lower steel cylindrical body 17, and is connected to the lower steel cylindrical body 17 by bolts or welding (bolt fastening in the illustrated example). These steel cylindrical bodies 17 and 18 are composed of steel rings divided into predetermined weight units, and each steel ring is integrated by welding in the circumferential direction.

[0036] On the other hand, the tower 6 is made of steel, concrete, or PRC (prestressed reinforced concrete), but it is preferable to use one made of steel to reduce the total weight. The outer diameter of the tower 6 and the outer diameter of the upper steel cylindrical body 18 are almost the same, and the outer shape is continuous in the vertical direction without any steps or other differences.

[0037] As shown in Figure 1, the mooring point P of the mooring rope 10 to the floating body 4 is set below the sea surface and higher than the center of gravity G of the floating body 4. Therefore, it is possible to prevent ships from coming into contact with the mooring rope 10. In addition, a resistance moment is generated at the mooring point P, centered on the center of gravity G of the floating body 4, to prevent the floating body 4 from tilting too much, thereby enabling the tilting posture of the tower 6 to be properly maintained.

[0038] On the other hand, the nacelle 8 is a device equipped with a generator that converts the rotation of the wind turbine 7 into electricity, a controller that can automatically change the angle of the blades 9, and other such components.

[0039] [Regarding the semi-submersible crane vessel 2] Before detailing the construction method of the spar-type offshore wind power generation facility 1, we will detail the semi-submersible crane vessel 2 used when constructing the superstructure 12, consisting of the tower 6, nacelle 8, and blades 9, in a single unit, based on Figures 6 to 8.

[0040] As shown in Figure 6, the semi-submersible crane ship 2 is a semi-submersible floating body 11 which is composed of a plurality of columns 31, 31... that serve as buoyancy bodies and connecting members 33, 33... that connect them, and a crane 5 is mounted on the deck surface of the semi-submersible floating body 11.

[0041] The semi-submersible float 11 comprises a plurality of columns 31, 31..., which serve as buoyancy bodies, with three columns 31, 31... in the illustrated example. These columns 31 are cylindrical hollow structures, and the float base 30 of the semi-submersible float 11 is constructed by arranging these columns 31, 31... at the vertices of a polygon in a plan view, for example, and then connecting these columns 1031, 31... with connecting members 33, 33....

[0042] On the upper surface of the floating body base 30, a deck main body 38 is provided, and a cantilever-shaped overhanging deck portion 37 is continuously provided on one end side from this deck main body 38. Further, a movable counterweight deck portion 39 is provided on the opposite side of the overhanging deck portion 37 across the deck main body 38. On the lower surface side of the overhanging deck portion 37, a frame structure 34 is arranged in a cantilever shape for structural reinforcement. Similarly, for the movable counterweight deck portion 39, frame structures 35 and 36 are arranged in a cantilever shape on the lower surface side of the deck for structural reinforcement. The deck main body 38 has a shape in which the width gradually decreases as it goes to the left side of the drawing, and the overhanging deck portion 37 has a shape that protrudes bar-shaped from the leading edge of the deck main body 38 and is on the bow side. The movable counterweight deck portion 39 is a space provided to secure the movement range of the weight and is on the stern side. Note that the deck main body 38 and the movable counterweight deck portion 39 have a stepped structure because they have an overlap of the deck, but they may also be flush.

[0043] The crane 5 is provided on the upper surface of the deck main body 38 of the semi-submersible floating body 11, at a position near the overhanging deck portion 37. The installation position of the crane 5 is directly above the column 31, and the load from the crane 5 is directly transmitted to the column 31. As the crane 5, a fixed type is desirable, but in some cases, it is also possible to mount a movable crane on the deck main body 38. In any case, it is necessary to have a lifting capacity and a lifting height capable of installing the tower 6, nacelle 8, and blade 9 of the offshore wind power generation facility. Also, when adopting a tower crane, it becomes easily possible to secure a desired lifting height by a self-elevating structure.

[0044] At the tip of the overhanging deck portion 37, a tower gripping device 40 for integrally fixing the tower of the offshore wind power generation facility to the semi-submersible crane ship 2 is provided. The tower gripping device 40 is an openable and closable gripper mechanism.

[0045] On the upper surface of the deck 39 for the mobile counterweight, a mobile counterweight device 3 is provided. As shown in, for example, FIG. 6(B), this mobile counterweight device 3 is made movable in any direction by providing a traveling part on the lower surface of the weight 42, and winches 41A to 41D are respectively arranged at the four corners. Wires 43a to 43d drawn out from the winches 41A to 41D are respectively connected to the corners of the weight 42, and the weight 42 is moved and controlled to a predetermined position by operating the winches 41A to 41D. In this mobile counterweight device 3, the weight 42 can be moved to an arbitrary position within the plane in the X and Y directions in plan view. It is desirable that the control of each of the winches 41A to 41D be performed by coordinated control under computer control (not shown).

[0046] As shown in the drawing, the weight 42 has a box-shaped structure and it is possible to adjust the weight by putting ballast materials such as slag aggregates inside, or by combining and putting in steel materials or the like when the weight is insufficient.

[0047] Regarding the winch 41, as shown in FIG. 7, winches 41A to 41C can be respectively arranged at three corners in three directions at the vertices of a substantially equilateral triangle, and wires 43a to 43c drawn out from the winches 41A to 41C can be respectively connected to the weight 42, and the weight 42 can be moved and controlled to a predetermined position by operating the winches 41A to 41C. Also, briefly, as shown in FIG. 8, winches 41A and 41B can be arranged at the front and rear parts straddling the weight 42, wires 43a and 43b drawn out from the winches 41A and 41B can be connected to the weight 42, and the weight 42 can be moved and controlled to a predetermined position in the Y direction by operating the winches 41A and 41B. In this case, it is desirable to provide moving guides 44, 44 on both side parts of the weight 42 so that the weight 42 can only move in the Y direction.

[0048] As shown in FIG. 6, it is desirable to provide fin stabilizers 32, 32 in the diving part of the semi-submersible floating body 11 to enhance the stability against waves.

[0049] According to the semi-submersible crane vessel 2, since it is equipped with the movable counterweight device 3, it is possible to suppress swaying when lifting heavy objects and perform work stably.

[0050] [Construction Method of Spar-Type Offshore Wind Power Generation Facility 1] Next, the construction method of the spar-type offshore wind power generation facility 1 using the semi-submersible crane ship 2 will be described in detail with reference to Figures 9 to 21.

[0051] <Step 1> As shown in Figure 9, once the SEP barge 14 with a crane is docked at the quay yard, the tower 6, nacelle 8 and blades 9, 9... are loaded onto the SEP barge 14 using the crane 45. The SEP barge 14 with a crane is equipped with vertically extending, movable legs (hereinafter also referred to as "lifting legs") at three or four locations on the barge, and is equipped with a hydraulic jack system that drives these lifting legs up and down. The lifting legs can be lowered downwards to support their lower ends on the seabed, and by continuing to lower the lifting legs, the barge can be raised above the sea surface. The crane 45 is integrally mounted on the barge, allowing cargo to be loaded and unloaded onto the barge.

[0052] Next, as shown in Figure 10, an assembly platform 13 is set up in a sea area selected as a relatively calm area with gentle waves. This assembly platform 13 is a platform for assembling the superstructure 12 of the offshore wind power generation facility 1, which consists of a tower 6, a nacelle 8, and blades 9. In the illustrated example, a SEP-type barge 46 is used as the assembly platform 13. The SEP-type barge 46 is a barge equipped with vertically extending, movable legs (elevating legs) at three or four locations on the barge, and as shown in Figure 10, the barge can be stably held by resting the elevating legs on the seabed. In the illustrated example, a semi-submersible spud barge 46 (with elevating legs), which will be described later, is used as a substitute for the SEP-type barge.

[0053] For assembly, the crane-equipped SEP barge 14 is positioned alongside the assembly frame 13, and the lifting legs are lowered to position the barge above sea level. The tower 6, nacelle 8, and blade 9 are then assembled on the assembly frame 13 in that order to complete the superstructure 12.

[0054] <Second Step> In the next second step, as shown in Figure 11, the aforementioned semi-submersible crane ship 2 is moored alongside the SEP-type barge 46, and the assembled superstructure 12 is lifted by the crane 5. At this time, the lower end of the tower 6 is held by the tower gripping device 40 to prevent the swaying of the superstructure 12 as much as possible. Also, since the superstructure 12 is quite heavy at this time, the weight 42 of the movable counterweight device 3 is moved to the rear to stabilize the ship's hull, which has been swaying forward due to this lifting load, in a horizontal position.

[0055] Once the superstructure 12 is lifted by the semi-submersible crane vessel 2, the semi-submersible crane vessel 2 is transported by the towboat 47 to the construction site of the spar-type offshore wind power generation facility 1, as shown in Figure 12.

[0056] <Step 3> This third step is a separate process from steps 1 and 2, and may be performed before or after steps 1 and 2. It may also be performed concurrently.

[0057] The third step involves assembling the entire floating structure 4 at the quay, then transporting the completed floating structure 4 to the construction site of the spar-type offshore wind power generation equipment 1 by a semi-submersible spud barge 46, and once the floating structure 4 is floated offshore, attaching mooring ropes to hold the floating structure 4 in an upright position.

[0058] Specifically, the floating structure 4 is first completed in the quay yard. As for the method of constructing the floating structure, the method described in Japanese Patent Publication No. 2018-173011, proposed by the present applicant, can be suitably adopted.

[0059] The floating structure construction method involves defining and setting up a steel ring connecting yard A, a concrete ring fabrication yard B, and a concrete ring connecting yard C in the quay yard, as shown in Figure 13.

[0060] In the steel ring connecting yard A, a first bridge crane 50 is provided so as to be able to travel in a certain direction, and rotating frames 52, 52... are installed at appropriate intervals in the direction of travel of the first bridge crane, and a movable tent 56 is provided so as to be able to move in the direction of travel of the first bridge crane. In the concrete ring manufacturing yard B, a movable tent 57 is provided and a complete set of concrete ring manufacturing equipment is installed. In the concrete ring connecting yard C, a second bridge crane 55 is provided so as to be able to travel in a certain direction, and a movable tent 58 is provided so as to be able to move in the direction of travel of the second bridge crane.

[0061] The method for constructing a spar-type offshore wind power generation facility consists of two steps: first, installing steel rings 51, 51... sequentially on the rotating frames 52, 52... using the first bridge crane 50, covering the surroundings with a movable tent 56 as needed, and connecting the steel rings 51, 51... by welding them in the circumferential direction while rotating them around their axis to complete the steel floating body section 53B; and second, once the steel floating body section 53B has been moved to the concrete ring connecting yard C and installed in a predetermined position, transporting the concrete rings 54 manufactured in the concrete ring manufacturing yard B sequentially to the concrete ring connecting yard C, covering the surroundings with a movable tent 58 as needed, connecting the concrete rings 54 to the steel floating body section 53B using the second bridge crane 55, and completing the floating body 53 by fastening and integrating them with PC steel materials. Once the floating body 4 is completed in this manner, as shown in Figure 14, it is moved sideways at the quay and loaded onto the semi-submersible spud barge 46 (roll-on). This semi-submersible spud barge 46 is a barge whose draft can be adjusted to a semi-submersible state by adjusting the ballast water. After rolling the cargo onto the barge while adjusting the ballast, the cargo can be floated offshore by adjusting the ballast water to make it semi-submersible. Therefore, once the floating body 4 is transported to the construction site, it becomes possible to float and launch the floating body 4 on the sea surface in a semi-submersible state without the need for a crane.

[0062] Once the semi-submersible spud barge 46 is towed by the tugboat 47 to the construction site of the spar-type offshore wind power generation facility 1, as shown in Figure 15, the floating body 4 is launched and floated on the surface of the sea by making the semi-submersible spud barge 46 semi-submersible (roll-off). Then, the floating body 4 is uprighted by pouring ballast water into it, and placed in a vertical position.

[0063] When the floating body 4 is in a vertical position, it is desirable to attach mooring ropes 10, 10... to it to ensure the stability of the floating body 4, as shown in Figure 16.

[0064] <Step 4> In Step 4, as shown in Figures 17 and 18, the spar-type offshore wind power generation facility 1 is completed by connecting the upper structure 12, which is lifted by the semi-submersible crane ship 2, to the upper part of the floating body 4.

[0065] [Connection of the superstructure 12 to the floating body 4] In order to stably and efficiently perform the work of connecting the lower end of the superstructure 12, or more precisely the lower end of the tower 6, to the upper end of the floating body 4, a connecting device 48 for connecting them is provided, as shown in Figure 19, in this embodiment.

[0066] As shown in Figure 19, the connecting device 48 consists of a floating-side connecting device 49 provided at the upper end of the floating body 4 and a tower-side connecting device 50 provided at the lower end of the tower 6. The floating-side connecting device 49 and the tower-side connecting device 50 are connected to each other, thereby connecting the superstructure 12 to the floating body 4.

[0067] The floating body side connecting device 49 is, in detail as shown in Figure 20, composed of a bottom plate 51, a peripheral wall 52 rising from the entire periphery of the bottom plate 51, and a connecting flange 53 extending horizontally inward from the upper end of the peripheral wall 52 and having bolt holes (not shown) formed at predetermined intervals around its entire circumference, and is equipped with at least two introduction pipes 54, 55 embedded on the upper surface side of the bottom plate 51.

[0068] The planar external shape of the floating body side connecting device 49 is circular with the same outer diameter as the steel cylindrical body 18 of the floating body 4, and an opening 51a is formed in the center of the bottom plate 51 for loading and unloading ballast. The introduction pipes 54 and 55 consist of an engaging pipe section 54A (55A) with an elliptical through hole 54c (55c) formed therein, and a funnel section 55B (55B) extending from the upper part of the engaging pipe section 54A (55A). Furthermore, these introduction pipes 54 and 55 have different heights from each other. That is, if the height of introduction pipe 54 is h1 and the height of introduction pipe 55 is h2, then as shown in the figure, the relationship is h1 > h2. In addition, in the funnel sections 54B and 55B of the introduction pipes 54 and 55, as shown in Figure 24, multiple radial projections 61, 61... may be provided on the inner surface of the funnel sections 54B and 55B. The protrusions 61, 61... allow the introduction pin 59 (60) to be smoothly guided to the engagement pipe portion 54A (55A) located in the center of the introduction pipe 54 (55).

[0069] On the other hand, the tower-side connection device 50, as shown in detail in Figure 21, consists of a top plate 56, a peripheral wall 57 hanging down from the entire periphery of the top plate 56, and a connecting flange 58 extending horizontally inward from the lower end of the peripheral wall 57, with bolt holes (not shown) formed at predetermined intervals around its entire circumference. The top plate 56 is also provided with a plurality of introduction pins 59, 60 on its lower surface corresponding to the introduction pipes 54, 55. The planar external shape of the tower-side connection device 50 is circular, with the same outer diameter as the tower 6, and an opening 56a may be formed in the center of the top plate 56 for purposes such as loading and unloading ballast. The introduction pins 59, 60 have an elliptical cross-section to correspond to the elliptical through-holes 54c (55c) of the introduction pipes 54, 55, and have the same height dimension.

[0070] The elliptical dimensions of the introduction pins 59 and 60 are slightly smaller than the elliptical through-holes 54c (55c) of the engaging pipe section 54A (55A). In this case, as shown in Figure 23, when the introduction pin 59 is initially engaged with the elliptical through-hole 54c of the introduction pipe 54, it is desirable to have a dimensional difference (play) such that the other introduction pin 60 can only move within a range S that fits within the range of the funnel section 55B of the introduction pipe 55. That is, once the leading introduction pin 59 is engaged with the elliptical through-hole 54c of the introduction pipe 54, the trailing introduction pin 60 can be easily inserted into the funnel section 55B of the introduction pipe 55. By limiting its range of motion to the range of the introduction pipe 55 (funnel section 55B), the introduction pin 60 and the introduction pipe 55 can be easily fitted together.

[0071] With the corresponding introduction pipes 54 and 55 and introduction pins 59 and 60 engaged, the connecting flange 53 of the floating body-side connecting device 49 and the connecting flange 58 of the tower-side connecting device 50 are superimposed on each other and fastened together by bolt and nut members 62 provided in each through hole.

[0072] When connecting the upper structure 12 to the upper part of the floating body 4 while it is being lifted by the semi-submersible crane ship 2, as shown in Figure 22, if one of the introduction pins 59, 60 of the tower-side connecting device 50 provided at the lower end of the tower 6 (the introduction pin 59 corresponding to the higher introduction pipe 54) is engaged with the funnel portion 54B of the corresponding introduction pipe 54 of the floating body-side connecting device 49 provided at the upper end of the floating body 4 (Figure 22(A)), then the tower The tower-side connector 50 is joined to the floating-side connector 49 by lowering the -6 and inserting the introduction pin 59 of the tower-side connector 50 into the engaging pipe portion 54A of the introduction pipe 54 of the floating-side connector 49, while inserting the other introduction pin 60 of the tower-side connector 50 into the engaging pipe portion 55A of the introduction pipe 55 of the floating-side connector 49, and fastening the connecting flange 58 of the tower-side connector 50 and the connecting flange 53 of the floating-side connector 49 with a bolt and nut member 62.

[0073] By the way, in the above example configuration, the height dimensions of the inlet pipes 54 and 55 are made different from each other, but as shown in Figure 25, the height dimensions of the inlet pipes 54 and 55 may be the same, and the height dimensions of the inlet pins 59 and 60 may be made different from each other. In the illustrated example, the height dimension of the inlet pin 59 is set higher than that of the inlet pin 60. Then, as shown in Figure 25, if one of the introduction pins 59 and 60 of the tower-side connection device 50 provided at the lower end of the tower 6 (the higher introduction pin 59) is engaged with the funnel portion 54B of the corresponding introduction pipe 54 of the floating body-side connection device 49 provided at the upper end of the floating body 4, the tower 6 is then lowered to insert the introduction pin 59 of the tower-side connection device 50 into the engaging pipe portion 54A of the introduction pipe 54 of the floating body-side connection device 49, while inserting the other introduction pin 60 of the tower-side connection device 50 into the engaging pipe portion 55A of the introduction pipe 55 of the floating body-side connection device 49, thereby joining the tower-side connection device 50 to the floating body-side connection device 49.

[0074] [Other examples of configurations] (1) In the above example of configuration, a semi-submersible crane ship 2 was used as a crane ship for the simultaneous construction of the superstructure 12 of the spar-type offshore wind power generation facility 1, but a large crane ship may also be used, or a crane ship equipped with a movable counterweight device 3 may be used.

[0075] (2) In the above example, a SEP-type barge (semi-submersible spud barge) 46 was used as the assembly frame 13, but as shown in Figure 26, a monopile foundation 63 may be used as the assembly frame 13, or as shown in Figure 27, a jacket foundation 64 may be used as the assembly frame 13. Furthermore, as shown in Figure 28, a caisson foundation 65 may be used as the assembly frame 13.

[0076] (3) The above example of configuration is for a spar-type floating structure in which the floating body 4 consists of a concrete floating section 4A and a steel floating section 4B connected to the upper side of the concrete floating section 4A. However, the same procedure can be used to construct a spar-type floating structure in which the floating body 4 consists only of a concrete floating section 4A in which multiple layers of concrete rings 15, 15... are stacked and each concrete ring 15, 15... is fastened together with PC steel members 19 to form a unified structure. Of course, the same applies to any other floating structure.

[0077] (4) In the above example, the assembly of the superstructure 12 of the offshore wind power generation facility 1 was carried out in a sea area selected as a calm area with relatively gentle waves, but in some cases the assembly of the superstructure 12 may be carried out on a quay.

[0078] 1...Spar-type offshore wind power generation equipment, 2...Semi-submersible crane ship, 3...Mobile counterweight device, 4...Floating body, 4A...Concrete floating body section, 4B...Steel floating body section, 5・45...Crane, 6...Tower, 7...Wind turbine, 8...Nacelle, 9...Blade, 10...Mooring rope, 11...SEP barge with crane, 12...Superstructure, 13...Assembly frame, 15・16...Precast cylindrical body (concrete ring), 19...PC steel material, 46 ...Semi-submersible spud barge, 48...connecting device, 49...floating body side connecting device, 50...tower side connecting device, 51...bottom plate, 52...peripheral wall, 53...connecting flange, 54・55...inlet pipe, 54A・55A...engaging pipe section, 54B・55B...funnel section, 56...top plate, 57...peripheral wall, 58...connecting flange, 59・60...inlet pin, 61...projection, 62...bolt and nut component, 63...monopile foundation, 64...jacket foundation, 65...caisson foundation

Claims

1. A connection device between a floating body and a tower in an offshore wind power generation facility comprising a spar-type floating body, mooring ropes, a tower, a nacelle and multiple blades installed at the top of the tower, wherein the connection device comprises a floating body-side connection device provided at the upper end of the floating body and a tower-side connection device provided at the lower end of the tower, the floating body-side connection device comprises a bottom plate, a peripheral wall rising from the entire periphery of the bottom plate, and a connecting flange extending inward horizontally from the upper end of the peripheral wall and having bolt holes formed at predetermined intervals around its entire circumference, and has at least two inlet pipes embedded on the upper surface side of the bottom plate, the tower-side connection device comprises a top plate, a peripheral wall hanging down from the entire periphery of the top plate, and a connecting flange extending inward horizontally from the lower end of the peripheral wall and having bolt holes formed at predetermined intervals around its entire circumference, and has a plurality of inlet pins provided on the lower surface side of the top plate corresponding to the inlet pipes, The connection device for connecting a floating body and a tower in an offshore wind power generation facility is characterized in that the introduction pipe is composed of an engagement pipe section having an elliptical through-hole and a funnel section extending from the upper part of the engagement pipe section, the introduction pin has an elliptical cross-section corresponding to the elliptical through-hole, the heights of the introduction pipe and the introduction pin are different on one side of each other, and the connecting flange of the floating body side connection device and the connecting flange of the tower side connection device are superimposed on each other with the corresponding introduction pipe and introduction pin engaged and fastened together with bolts and nuts.

2. The connection device between a floating body and a tower in an offshore wind power generation facility according to claim 1, wherein the introduction pipe has multiple radially arranged protrusions on the inner surface of the funnel portion.

3. A method for constructing an offshore wind power generation facility according to either claim 1 or 2, comprising: a first step of assembling the superstructure of the offshore wind power generation facility, consisting of a tower, nacelle, and blades, on an assembly frame in a sea area or quay selected as a calm area with relatively calm waves; a second step of lifting the superstructure assembled on the assembly frame in one piece with a crane ship and transporting it to the construction site of the offshore wind power generation facility; a third step of assembling a floating body at a quay, transporting the completed floating body to the construction site of the offshore wind power generation facility, and, once the floating body is floating on the sea, attaching mooring lines to hold the floating body in an upright position; A method for constructing an offshore wind power generation facility, characterized in that, in order to complete the offshore wind power generation facility by connecting the superstructure to the upper part of the floating body while the superstructure is lifted by the crane ship, one of the introduction pins of the tower-side connection device provided at the lower end of the tower is engaged with the funnel portion of the corresponding introduction pipe of the floating-side connection device provided at the upper end of the floating body, the tower is then lowered so that the introduction pin of the tower-side connection device is fitted into the engagement pipe portion of the introduction pipe of the floating-side connection device, while the introduction pin of the other tower-side connection device is fitted into the engagement pipe portion of the introduction pipe of the floating-side connection device, thereby joining the tower-side connection device to the floating-side connection device, and the connecting flange of the tower-side connection device and the connecting flange of the floating-side connection device are fastened with bolts and nuts.

4. The method for constructing an offshore wind power generation facility according to claim 3, wherein the assembly platform is an SEP type barge, a monopile foundation, a jacket foundation, or a caisson foundation.

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