An assembled offshore wind power floating foundation and a construction method thereof

Abstract

The application discloses an assembled offshore wind power floating foundation, which comprises a main column, three floating cylinders, three groups of water conveying corridors, connecting components and three groups of reinforcing trusses; a concrete ballast tank is arranged at the bottom of the main column; the three floating cylinders are arranged at equal distances around the main column; the three groups of water conveying corridors are arranged at equal distances around the main column, and the two ends of the water conveying corridors are connected with the main column and the floating cylinders through the connecting components, so that the floating cylinders and the main column are connected internally; one group of the reinforcing trusses is connected between every two adjacent floating cylinders. The main column is composed of multiple steel cylinder segments which are connected vertically through high-strength bolt flanges; the application aims to overcome the existing defects and provide an assembled offshore wind power floating foundation and a construction method, so that the offshore operation time is greatly reduced, and the batch manufacturing and installation of large-scale wind farms are suitable.

Description

Technical Field

[0001] This invention relates to a prefabricated floating foundation for offshore wind power and its construction method. Background Technology

[0002] As offshore wind power expands into deeper waters, the advantages of floating foundations are becoming increasingly apparent, and they are poised to become the mainstream technology in the future.

[0003] Existing floating foundations mainly include single-column, semi-submersible, and tension leg types. They suffer from a lack of modular and mass production design. Traditional floating foundation components are typically welded together at the factory before towing, making efficient modular manufacturing and rapid on-site assembly difficult. The highly customized nature of each component cannot meet the demands of large-scale mass production, resulting in high manufacturing costs and long construction cycles.

[0004] Therefore, a prefabricated floating foundation for offshore wind power and its construction method are proposed to address the above problems. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing methods by providing a prefabricated floating foundation for offshore wind power and a construction method that significantly reduces offshore operation time and is suitable for mass production and installation in large-scale wind farms.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a prefabricated floating foundation for offshore wind power, comprising: The main column has a concrete ballast tank at its bottom. Three pontoons are arranged at equal intervals around the main column; Three sets of water conveyance channels are arranged at equal intervals around the main column. The two ends of the water conveyance channels are connected to the main column and the pontoon through connecting components, so that the pontoon and the main column can be connected internally. Three sets of reinforcing trusses, with one set of reinforcing trusses connecting each pair of adjacent pontoons.

[0007] Preferably, the main column is composed of multiple steel cylindrical sections connected vertically by high-strength bolts and flanges; The concrete ballast tank is filled with concrete and forms a steel-concrete composite structure with the main column through shear connectors.

[0008] Preferably, all three pontoons are steel-structured empty-cell structures.

[0009] Preferably, the water conveyance corridor is a box-section beam made of high-strength concrete; the water conveyance corridor is provided with a hollow channel and a reserved hole inside, the hollow channel connects the main column and the pontoon, and the reserved hole is filled with prestressed steel strands and grouting.

[0010] Preferably, the connecting component includes a steel end plate and an anchor plate; the anchor plate is pre-embedded at the end of the water conveyance channel, the steel end plate is welded and fixed to the pre-embedded steel plates on the main column and the pontoon, and the prestressed steel strands passing through the reserved channel are tensioned to connect the steel end plate and the anchor plate, thereby realizing the anchoring of the end of the water conveyance channel.

[0011] Preferably, a replaceable sacrificial anode is provided on the outer side of the steel end plate.

[0012] Preferably, the three sets of reinforcing trusses and the three sets of pontoons cooperate to form an equilateral triangular closed-loop force-bearing structure.

[0013] A construction method for a prefabricated floating foundation for offshore wind power includes the following steps: Step 1: Standardized prefabrication of main columns, pontoons, water conveyance channels, connecting components and reinforcing trusses is completed in the prefabrication plant to achieve mass production prefabrication of each structural component in sections and blocks, ensuring the dimensional accuracy and quality of the components upon delivery. Step 2: The prefabricated steel cylinder sections are transported to the dock or near-shore assembly site and vertically assembled into the main column structure by connecting with high-strength flange bolts or welding. Then, a concrete ballast tank is poured at the bottom of the main column, and the concrete is tightly bonded to the steel cylinder wall by shear connectors to form a steel-concrete composite counterweight structure. Step 3: The three prefabricated pontoons are hoisted to the preset assembly positions in sequence, so that the three pontoons surround the main column to complete the initial positioning and leveling of the pontoons; Step four: hoist the precast concrete water conveyance channel and weld the steel end plates of the connecting components to the embedded steel plates on the main columns and pontoons respectively; insert prestressed steel strands into the reserved ducts of the water conveyance channel and tension and anchor the prestressed steel strands so that the ends of the water conveyance channel are anchored to the anchor plates; after the tensioning is completed, grout the reserved ducts to form an integral bond between the prestressed steel strands and the concrete structure, ensuring that the water conveyance channel is under long-term pressure and stress. Step 5: Install the three sets of reinforcing trusses between each pair of adjacent pontoons. Secure the ends of the reinforcing trusses to the pontoons by welding or bolting to form an equilateral triangular closed-loop force system, thereby improving the overall torsional stiffness of the foundation. Step 6: Using the hollow channel inside the water conveyance corridor as the ballast water flow channel, connect the ballast water pump inside the main column with each buoy ballast tank, and conduct water commissioning on the overall ballast water system. Adjust the buoyancy of the foundation by injecting water into each compartment so that the foundation reaches the designed draft and equilibrium state. Step 7: Use tugboats to tow the assembled and debugged floating foundation to the offshore turbine location. After completing the on-site mooring system connection and fixation, carry out the installation of the wind turbine tower and the wind turbine main unit in sequence to complete the overall wind power foundation construction.

[0014] Compared with existing technologies, the advantages of this invention are as follows: This prefabricated floating foundation for offshore wind power and its construction method involve setting up a main column, three pontoons, three sets of water conveyance channels, connecting components, and three sets of reinforcing trusses. The main column has a concrete ballast tank at its base. The three pontoons are arranged equidistantly around the main column. The three sets of water conveyance channels are also arranged equidistantly around the main column, with both ends connected to the main column and pontoons via connecting components, achieving internal communication between the pontoons and the main column. Each pair of adjacent pontoons is connected by one set of reinforcing trusses. This achieves full prefabrication, facilitating mass production. The main column is a steel cylindrical structure with a concrete ballast tank at its base, the pontoons are empty steel structures, and the water conveyance channels, connecting components, and reinforcing trusses all adopt a modular design. All components can be mass-produced in a factory and quickly assembled on-site using prestressed steel strands and connecting components, significantly reducing offshore operation time and making it suitable for the mass manufacturing and installation of large-scale wind farms. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the prefabricated floating foundation for offshore wind power according to the present invention; Figure 2 This is a cross-sectional schematic diagram of the water conveyance corridor of the present invention; Figure 3 This is a schematic diagram of the connecting component of the present invention.

[0016] In the diagram: 1. Main column; 2. Floating pontoon; 3. Water conveyance channel; 4. Connecting components; 5. Reinforcing truss. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figure 1-3As shown, a prefabricated floating foundation for offshore wind power includes a main column 1, three pontoons 2, three sets of water conveyance channels 3, connecting components 4, and three sets of reinforcing trusses 5. A concrete ballast tank is provided at the bottom of the main column 1. The three pontoons 2 are arranged at equal intervals around the main column 1. The three sets of water conveyance channels 3 are arranged at equal intervals around the main column 1. The two ends of the water conveyance channels 3 are connected to the main column 1 and the pontoons 2 through the connecting components 4, so as to realize the internal communication between the pontoons 2 and the main column 1. Each set of reinforcing trusses 5 is connected between every two adjacent pontoons 2.

[0019] Specifically, the main column 1 is composed of multiple steel cylindrical sections connected vertically by high-strength bolts and flanges; the concrete ballast tank is filled with concrete and forms a steel-concrete composite structure with the main column 1 through shear connectors.

[0020] Specifically, all three pontoons 2 are steel-structured empty structures.

[0021] Specifically, the water conveyance corridor 3 is a box-section beam made of high-strength concrete precast; the water conveyance corridor 3 has a hollow channel and a reserved hole inside. The hollow channel connects the main column 1 and the pontoon 2. The reserved hole is filled with prestressed steel strands and grouting.

[0022] Specifically, the water conveyance channel 3 has a dual function. On the one hand, it serves as a structural load-bearing component, connecting the main column 1 and the pontoons 2, transmitting bending moments and shear forces. On the other hand, its internal hollow channels act as ballast water regulation pipelines, connecting the ballast water pump in the main column 1 and the ballast tanks of each pontoon 2, used to regulate the buoyancy and center of gravity of the foundation. The water conveyance channel 3 has pre-reserved channels for prestressed steel strands to pass through. After the prestressed steel strands are inserted into the pre-reserved channels, tensioning is performed, and after tensioning, the pre-reserved channels are grouted.

[0023] Specifically, the connecting component 4 includes a steel end plate and an anchor plate; the anchor plate is pre-embedded at the end of the water conveyance channel 3, and the steel end plate is welded and fixed to the pre-embedded steel plates on the main column 1 and the float 2. The prestressed steel strands running through the reserved ducts are tensioned to connect the steel end plate and the anchor plate, thereby achieving anchoring at the end of the water conveyance channel 3. A replaceable sacrificial anode is provided on the outside of the steel end plate.

[0024] During installation, the water conveyance channel 3 is hoisted into place, and the steel end plates are welded to the pre-embedded steel plates on the main column 1 or the pontoon 2. Then, the prestressed steel strands are tensioned, and the ends of the water conveyance channel 3 are anchored to the connecting member 4. By applying prestress to the water conveyance channel 3, it is kept under pressure during service, effectively controlling the development of cracks. After the prestressing is completed, the reserved ducts are grouted to achieve full-section bonding between the prestressed tendons and the concrete structure.

[0025] Specifically, the three sets of reinforcing trusses 5 and the three sets of pontoons 2 work together to form an equilateral triangular closed-loop load-bearing structure. The reinforcing trusses 5 are used to resist the out-of-plane torque generated by oblique waves or asymmetric wind loads, and directly transfer the out-of-plane load between the two pontoons 2, significantly enhancing the torsional stiffness of the overall structure and the fatigue resistance of the connection nodes.

[0026] A construction method for a prefabricated floating foundation for offshore wind power includes the following steps: Step 1: In the prefabrication plant, the standardized prefabrication of the main column 1, pontoon 2, water conveyance corridor 3, connecting components 4 and reinforcing truss 5 is completed respectively, so as to realize the mass production and prefabrication of each structural component in sections and blocks, and ensure the dimensional accuracy and quality of the components. Step 2: The prefabricated steel cylinder sections are transported to the dock or near-shore assembly site and vertically assembled into the main column 1 structure by connecting with high-strength flange bolts or welding. Then, a concrete ballast tank is poured at the bottom of the main column 1 and the concrete is tightly bonded to the steel cylinder wall by shear connectors to form a steel-concrete composite counterweight structure. Step 3: The three prefabricated pontoons 2 are hoisted to the preset assembly positions in sequence, so that the three pontoons 2 surround the main column 1, and the pontoons 2 are initially positioned and leveled. Step four: hoist the precast concrete water conveyance channel 3, and weld and fix the steel end plates of the connecting component 4 to the embedded steel plates on the main column 1 and the float 2 respectively; insert prestressed steel strands into the reserved ducts of the water conveyance channel 3, and tension and anchor the prestressed steel strands so that the ends of the water conveyance channel 3 are anchored to the anchor plate; after the tensioning is completed, grout the reserved ducts to form an integral bond between the prestressed steel strands and the concrete structure, ensuring that the water conveyance channel 3 is under long-term pressure and stress. Step 5: Install the three sets of reinforcing trusses 5 between each pair of adjacent pontoons 2. Secure the ends of the reinforcing trusses 5 to the pontoons 2 by welding or bolting to form an equilateral triangular closed-loop force system and improve the overall torsional stiffness of the foundation. Step 6: Using the hollow channel inside the water conveyance corridor 3 as the ballast water flow channel, connect the ballast water pump inside the main column 1 with the ballast tanks of each float 2, and conduct water commissioning on the overall ballast water system. Adjust the buoyancy of the foundation by injecting water into each compartment so that the foundation reaches the design draft and equilibrium state. Step 7: Use tugboats to tow the assembled and debugged floating foundation to the offshore turbine location. After completing the on-site mooring system connection and fixation, carry out the installation of the wind turbine tower and the wind turbine main unit in sequence to complete the overall wind power foundation construction.

[0027] This prefabricated floating foundation and construction method for offshore wind power utilizes a main column 1, three pontoons 2, three sets of water conveyance channels 3, connecting components 4, and three sets of reinforcing trusses 5. The main column 1 has a concrete ballast tank at its base. The three pontoons 2 are equidistantly arranged around the main column 1. The three sets of water conveyance channels 3 are also equidistantly arranged around the main column 1, with both ends of the channels connected to the main column 1 and pontoons 2 via connecting components 4, enabling internal communication between the pontoons 2 and the main column 1. Each pair of adjacent pontoons 2 is connected by a reinforcing truss 5. This method achieves full prefabrication, facilitating mass production. The main column is a steel cylindrical structure with a concrete ballast tank at its base, the pontoons are empty steel structures, and the water conveyance channels, connecting components, and reinforcing trusses all employ modular design. All components can be mass-produced in the factory and quickly assembled on-site using prestressed steel strands and connecting components, significantly reducing offshore operation time and making it suitable for large-scale wind farm mass manufacturing and installation.

[0028] Connecting components are used as a transition, with one end connected to the steel structure (column or pontoon) and the other end anchored to the concrete water conveyance channel through prestressed steel strands, forming a reliable force transmission path and avoiding stress concentration and fatigue problems caused by direct welding of concrete and steel or simple bolt connection.

[0029] By applying prestress to the water conveyance channel, the concrete structure remains under compression during service, effectively controlling the generation and propagation of cracks and significantly improving the structure's durability and service life in a marine corrosive environment. Grouting the pre-reserved ducts after tensioning provides full-section bond protection for the prestressing tendons, further enhancing durability.

[0030] The water conveyance corridor not only serves as a key load-bearing component connecting the main column and the pontoon, but its internal cavity also acts as a ballast water conveyance channel, eliminating the need for additional pipelines. It has a compact structure and low cost.

[0031] The low center of gravity is provided by the ballast tank at the bottom of the main column, and the large waterline area is provided by the surrounding buoys, which achieves excellent roll and pitch suppression effect and is suitable for various sea areas.

[0032] By setting independent reinforcing trusses between adjacent pontoons, the out-of-plane torque generated by oblique waves or asymmetric wind loads can be effectively resisted, significantly improving the torsional stiffness and fatigue resistance of the overall structure.

[0033] The sacrificial anodes set on the outside of the steel end plate provide cathodic protection for the steel end plate and weld; the prestressed ducts are filled with grout after tensioning to form a long-term anti-corrosion barrier for the prestressed tendons.

[0034] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A prefabricated floating foundation for offshore wind power, characterized in that, include: Main column (1), the bottom of which is provided with a concrete ballast tank; Three pontoons (2) are arranged at equal intervals around the main column (1); Three sets of water conveyance channels (3) are arranged at equal distances around the main column (1). The two ends of the water conveyance channel (3) are connected to the main column (1) and the pontoon (2) through connecting components (4) to realize the internal communication between the pontoon (2) and the main column (1). Three sets of reinforcing trusses (5), with one set of reinforcing trusses (5) connecting each two adjacent floats (2).

2. The prefabricated floating foundation for offshore wind power according to claim 1, characterized in that, The main column (1) is composed of multiple steel cylindrical sections connected vertically by high-strength bolt flanges; The concrete ballast tank is filled with concrete and forms a steel-concrete composite structure with the main column (1) through shear connectors.

3. The prefabricated floating foundation for offshore wind power according to claim 1, characterized in that, All three pontoons (2) are steel-structured empty structures.

4. The prefabricated floating foundation for offshore wind power according to claim 1, characterized in that, The water conveyance corridor (3) is a box-section beam made of high-strength concrete precast; the water conveyance corridor (3) is provided with a hollow channel and a reserved hole inside. The hollow channel connects the main column (1) and the pontoon (2). The reserved hole is filled with prestressed steel strands and grouting.

5. The prefabricated floating foundation for offshore wind power according to claim 4, characterized in that, The connecting component (4) includes a steel end plate and an anchor plate; the anchor plate is pre-embedded at the end of the water conveyance channel (3), the steel end plate is welded and fixed to the pre-embedded steel plates on the main column (1) and the float (2), and the prestressed steel strands passing through the reserved channel are tensioned to connect the steel end plate and the anchor plate to realize the anchoring of the end of the water conveyance channel (3).

6. The prefabricated floating foundation for offshore wind power according to claim 5, characterized in that, A replaceable sacrificial anode is provided on the outer side of the steel end plate.

7. The prefabricated floating foundation for offshore wind power according to claim 1, characterized in that, The three sets of reinforcing trusses (5) and the three sets of pontoons (2) work together to form an equilateral triangular closed-loop force structure.

8. A construction method for a prefabricated floating foundation for offshore wind power as described in claim 1, characterized in that, Includes the following steps: Step 1: In the prefabrication plant, the standardized prefabrication of the main column (1), pontoon (2), water conveyance corridor (3), connecting components (4) and reinforcing truss (5) is completed respectively, so as to realize the segmented and block-based mass production prefabrication of each structural component and ensure the dimensional accuracy and quality of the components. Step 2: The prefabricated steel cylinder sections are transported to the dock or near-shore assembly site and vertically assembled into the main column (1) structure by connecting with flange high-strength bolts or welding. Then, a concrete ballast tank is poured at the bottom of the main column (1) and the concrete is tightly bonded to the steel cylinder wall by shear connectors to form a steel-concrete composite counterweight structure. Step 3: The three prefabricated pontoons (2) are hoisted to the preset assembly position in sequence, so that the three pontoons (2) surround the main column (1) to complete the initial positioning and leveling of the pontoons (2); Step 4: Hoist the precast concrete water conveyance corridor (3), and weld and fix the steel end plates of the connecting components (4) to the pre-embedded steel plates on the main column (1) and the pontoon (2) respectively; insert prestressed steel strands into the reserved ducts of the water conveyance corridor (3), and tension and anchor the prestressed steel strands so that the end of the water conveyance corridor (3) is anchored to the anchor plate; after the tensioning construction is completed, grout the reserved ducts to form an integral bond between the prestressed steel strands and the concrete structure, so that the water conveyance corridor (3) is in a state of pressure and stress for a long time; Step 5: Install the three sets of reinforcing trusses (5) between each pair of adjacent pontoons (2), and fix the two ends of the reinforcing trusses (5) to the pontoons (2) by welding or bolting to form an equilateral triangular closed-loop force system, thereby improving the overall torsional stiffness of the foundation. Step 6: Using the hollow channel inside the water conveyance corridor (3) as the ballast water flow channel, connect the ballast water pump inside the main column (1) with each buoy (2) ballast tank, and conduct water commissioning on the overall ballast water system. Adjust the foundation floating state by injecting water into each compartment so that the foundation reaches the designed draft and balance state. Step 7: Use tugboats to tow the assembled and debugged floating foundation to the offshore turbine location. After completing the on-site mooring system connection and fixation, carry out the installation of the wind turbine tower and the wind turbine main unit in sequence to complete the overall wind power foundation construction.

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