Space prestressed concrete filled steel tube large-diameter single-pile foundation of offshore wind turbine

Abstract

The invention provides an offshore wind turbine space prestressed concrete filled steel tube large-diameter single pile foundation which comprises a pile top transition section and a main body structure. A main body structure comprises a steel pipe pile outer wall and space prestress steel pipe concrete columns, the space prestress steel pipe concrete columns are arranged on the inner side of the steel pipe pile outer wall from top to bottom, and the multiple space prestress steel pipe concrete columns are arranged on the inner side of the steel pipe pile outer wall in the circumferential direction; the top section of the outer wall of the steel pipe pile is not provided with a space prestress steel pipe concrete column and is combined into the pile top transition section, and a conical ground breaker is arranged at the bottom end of the space prestress steel pipe concrete column. The device can be effectively applied to deep water with the depth of 50 meters. The integral flexural rigidity and local stability of the single-pile foundation are improved, the steel consumption and self weight of the structure are effectively reduced, and the single-pile foundation has more advantages in the aspects of transportation, construction and installation and has high economic value.

Description

Technical Field

[0001] The invention relates to the technical field of offshore wind power generation equipment, and in particular to a large-diameter single pile foundation of a spatial prestressed steel tube concrete for an offshore wind turbine. Background Art

[0002] As a new type of renewable clean energy that can be developed sustainably and does not occupy land resources, offshore wind power has been rapidly developed. The wind turbine foundation structure is an important part of the offshore wind turbine support system. It is responsible for effectively transmitting the wind load on the wind turbine and the waves, currents, berthing forces, and impact forces borne by the foundation to the foundation soil to ensure the stability and safety of the entire wind turbine. Among them, the single pile foundation has been widely used in offshore wind farms due to its simple structure, simple construction process, short construction period, good economy, and small sea area. Its market share is as high as 65%.

[0003] At present, offshore wind power monopile foundation mainly adopts all-steel structure, which is only suitable for sea areas with a water depth of about 30 meters. In deep water conditions, the bending stiffness and natural frequency of all-steel monopile foundation are small, which cannot meet the design requirements. And because the lateral stiffness of the steel pipe pile wall is small, the pile wall is prone to local buckling under extreme conditions such as typhoons. In addition, with the popularization of large-capacity wind turbines, the diameter and wall thickness of all-steel monopile foundations will increase significantly, and the amount of steel used and its own weight will continue to rise, which exceeds the current processing, manufacturing, offshore transportation and installation capabilities. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned all-steel structure type single pile foundation and provide a large-diameter single pile foundation of offshore wind turbine space prestressed steel tube concrete. The combination of space prestressed steel tube concrete columns and large-diameter steel pipe piles improves the overall bending stiffness and local stability of the single pile foundation, while effectively reducing the amount of structural steel and deadweight, and can be effectively applied in deep water conditions.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A spatial prestressed steel tube concrete large diameter single pile foundation for offshore wind turbines, characterized in that: it comprises a pile top transition section and a main structure of the spatial prestressed steel tube concrete large diameter single pile foundation; the main structure comprises an outer wall of a steel tube pile and a spatial prestressed steel tube concrete column, the spatial prestressed steel tube concrete column is arranged from top to bottom on the inner side of the outer wall of the steel tube pile, and a plurality of spatial prestressed steel tube concrete columns are arranged along the circumferential direction on the inner side of the outer wall of the steel tube pile; The top section of the outer wall of the steel pipe pile is not provided with a spatial prestressed steel pipe concrete column but is combined into a pile top transition section, the pile top transition section includes a connecting transition structure located at the top, the pile top transition section includes a mechanical transition structure located between the connecting transition structure and the top of the spatial prestressed steel pipe concrete column and connected to the spatial prestressed steel pipe concrete column and the inner side of the top section of the outer wall of the steel pipe pile; The spatial prestressed steel tube concrete column comprises a spatial prestressed steel tube concrete column steel pipe welded to the inner side of the outer wall of a steel pipe pile, the steel pipe of the spatial prestressed steel tube concrete column is filled with prestressed ultra-high performance concrete, a cover plate is arranged at the end of the spatial prestressed steel tube concrete column steel pipe; a conical earth breaker is arranged at the bottom end of the spatial prestressed steel tube concrete column.

[0006] On the basis of adopting the above technical solutions, the present invention may also adopt the following further technical solutions, or use these further technical solutions in combination: The pile top transition section includes a T-type pile top flange, a plurality of rounded L-shaped ribs, an annular reinforcement rib and the top section of the outer wall of the steel pipe pile; the lower end of the T-type pile top flange is welded to the top end of the outer wall of the steel pipe pile as the connection transition structure, the annular reinforcement rib is welded to the inner side of the top section and to the top end of the spatial prestressed steel tube concrete column, a plurality of the rounded L-shaped ribs are arranged along the circumferential direction of the annular reinforcement ribs, and the right-angled side surfaces and bottom surfaces of the rounded L-shaped ribs are respectively welded to the top section and the upper contact surface of the annular reinforcement ribs to form the mechanical transition structure.

[0007] The cross-sectional diameter of the T-type pile top flange is the same as that of the top end of the steel pipe pile outer wall, the lower end of the T-type pile top flange is connected to the top end of the steel pipe pile outer wall by double-sided bevel full penetration welding, the outer diameter of the annular reinforcing rib is the same as the inner diameter of the top section, the outer side surface of the annular reinforcing rib is connected to the inner contact surface of the top section by double-sided bevel full penetration welding, the right-angled side surface of the rounded L-shaped rib is connected to the inner contact surface of the steel pipe pile outer wall by double-sided bevel full penetration welding, and the right-angled bottom surface of the rounded L-shaped rib is connected to the upper contact surface of the annular reinforcing rib by double-sided bevel full penetration welding.

[0008] The rounded L-shaped rib plate is provided between the top of each spatial prestressed steel tube concrete column and the connecting transition structure.

[0009] A conical earth breaker is arranged at the lower end of each spatial prestressed steel tube concrete column.

[0010] The conical breaker is a solid steel cone, the top surface of the steel conical breaker is the same as the lower end surface of the spatial prestressed steel tube concrete column or the top of the steel conical breaker smoothly transitions to the lower end of the spatial prestressed steel tube concrete column, and the outer edge of the contact surface between the top of the steel conical breaker and the lower end of the spatial prestressed steel tube concrete column is connected by spot welding.

[0011] The main structure of the spatial prestressed steel tube concrete large-diameter single pile foundation contains a variable diameter section, the diameter-to-thickness ratio of the outer wall of the steel tube pile is about 300-600, the inner surface of the outer wall of the steel tube pile is roughened, and the axis of the spatial prestressed steel tube concrete column is parallel to the generatrix of the outer wall of the steel tube pile.

[0012] The ultra-high performance concrete adopts steel fiber concrete.

[0013] The diameter-to-thickness ratio of the spatial prestressed steel tube concrete column steel tube is about 50-90, the inner surface of the spatial prestressed steel tube concrete column steel tube is roughened, the volume percentage of the steel fiber content of the ultra-high performance concrete is 1%-5%, and the spatial prepressure is 3-8MPa.

[0014] The outer edges of the contact surfaces of the spatial prestressed steel tube concrete column steel tube and the outer wall of the steel tube pile are connected by spot welding at fixed intervals along the height direction.

[0015] Due to the adoption of the technical solution of the present invention, the present invention effectively integrates the circumferentially arranged spatial prestressed steel tube concrete columns into the single pile foundation, and the overall force performance and mechanical conduction performance of the single pile foundation of the present invention are good, and the in-situ construction can still be carried out according to the traditional single pile foundation, and can be effectively used in deep water up to 50 meters deep. The present invention not only improves the overall bending stiffness and local stability of the single pile foundation (including improving the lateral bending stiffness, ultimate bending bearing capacity, local buckling bearing capacity, and structural natural frequency and natural frequency), but also effectively reduces the amount of steel used and the deadweight of the structure, which is more advantageous in transportation, construction and installation, and has greater economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a longitudinal cross-sectional view of an embodiment of the present invention; Figure 2 is a transverse cross-sectional view of the pile top flange connection transition section of an embodiment of the present invention, that is, Figure 1 AA section view; Figure 3 is a cross-sectional view of the main structure of an embodiment of the present invention, that is, Figure 1 BB cross-sectional view. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the technical solution of the present invention, the preferred implementation scheme of the present invention is described below in conjunction with specific embodiments. However, it should be understood that the drawings are only for illustrative purposes and cannot be understood as limiting the present invention. In order to better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationship described in the drawings is only for illustrative purposes and cannot be understood as limiting the present invention.

[0018] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0019] like Figures 1 to 3 As shown, the present invention provides a spatial prestressed steel tube concrete large diameter single pile foundation for offshore wind turbines, comprising a pile top transition section 1 and a main structure 2 of the spatial prestressed steel tube concrete large diameter single pile foundation; the main structure 2 comprises a steel tube pile outer wall 21 and a spatial prestressed steel tube concrete column 22, the spatial prestressed steel tube concrete column 22 being arranged from top to bottom on the inner side of the steel tube pile outer wall 21, and a plurality of spatial prestressed steel tube concrete columns 22 being arranged along the circumferential direction on the inner side of the steel tube pile outer wall 21.

[0020] The top section of the outer wall 21 of the steel pipe pile is not provided with a spatial prestressed steel pipe concrete column 22 but is integrated into the pile top transition section 1, thereby improving the overall force bearing performance and mechanical conduction performance of the single pile foundation. The pile top transition section 1 includes a connecting transition structure located at the top, and the pile top transition section 1 also includes a mechanical transition structure located between the connecting transition structure and the top of the spatial prestressed steel pipe concrete column 22 and connected to the spatial prestressed steel pipe concrete column 22 and the inner side of the top section of the outer wall of the steel pipe pile.

[0021] The spatial prestressed steel tube concrete column 22 includes a spatial prestressed steel tube concrete column steel pipe 222 welded to the inner side of the outer wall of the steel pipe pile, the spatial prestressed steel tube concrete column steel pipe is filled with prestressed ultra-high performance concrete 221, and a cover plate 223 is arranged at the end of the spatial prestressed steel tube concrete column steel pipe; a conical earth breaker 3 is arranged at the bottom end of the spatial prestressed steel tube concrete column 22.

[0022] The pile top transition section 1 includes a T-type pile top flange 11, a plurality of rounded L-shaped ribs 12, an annular reinforcing rib 13 and the top section of the outer wall of the steel pipe pile. The T-type pile top flange 11 serves as the connection transition structure, including a top flange for connecting to an offshore wind turbine tower. Below the top flange of the T-type pile top flange 11 is a connecting cylinder, which is welded to the top of the outer wall 21 of the steel pipe pile. The annular reinforcing rib 13 is welded to the inner side of the top section and to the top of the spatial prestressed steel tube concrete column. The plurality of rounded L-shaped ribs 12 are arranged along the circumferential direction of the annular reinforcing ribs. The right-angled side surfaces and bottom surfaces of the rounded L-shaped ribs 12 are respectively welded to the inner side of the top section and the upper contact surface of the annular reinforcing rib 13 to form the mechanical transition structure. A specific implementation method is further described in detail below: The connecting cylinder of the T-type pile top flange 11 and the top cross-sectional diameter of the steel pipe pile outer wall 21 are both about 9.5m. The connecting cylinder of the T-type pile top flange 11 and the steel pipe pile outer wall 21 are connected by double-sided bevel full penetration welding. In this example, the annular reinforcing rib 13 has a plate thickness of about 90 mm, a ring width of about 900 mm, and an outer diameter of the ring of about 9.5 m. The outer diameter of the annular reinforcing rib 13 is the same as the inner diameter of the steel pipe pile outer wall 21. The outer side surface of the annular reinforcing rib 13 and the inner contact surface of the steel pipe pile outer wall 21 are connected by double-sided bevel full penetration welding. The rounded L-shaped rib 12 has a plate thickness of about 60 mm and a right angle side length of about 900 mm. mm, the rounded L-shaped ribs 12 are located above the annular reinforcing ribs 13, and are arranged in 24 rows at equal intervals along the inner side of the outer wall 21 of the steel pipe pile, with an interval angle of about 15°. The rounded L-shaped ribs 12 are provided between the top of each spatial prestressed steel tube concrete column 22 and the connecting transition structure. The right-angled side surface of the rounded L-shaped ribs 12 and the inner contact surface of the outer wall 21 of the steel pipe pile are connected by double-sided bevel full penetration welding, and the right-angled bottom surface of the rounded L-shaped ribs 12 and the upper contact surface of the annular reinforcing ribs 13 are connected by double-sided bevel full penetration welding. The annular reinforcing ribs are tightly attached to the top of the spatial prestressed steel tube concrete column, and are welded to the cover plate 223 at the top of the spatial prestressed steel tube concrete column by spot welding.

[0023] The diameter-to-thickness ratio of the outer wall 21 of the steel pipe pile is about 450-550, the outer diameter is about 9.5-10.5m, the wall thickness is about 20mm, and the pile length is about 120m. The inner surface of the outer wall 21 of the steel pipe pile is roughened. The axis of the spatial prestressed steel tube concrete column 22 is parallel to the generatrix of the outer wall 21 of the steel pipe pile. The spatial prestressed steel tube concrete column 22 is arranged in 24 rows at equal intervals along the inner side of the outer wall 21 of the steel pipe pile at an interval angle of about 15°. The rounded L-shaped ribs 12 are circumferentially distributed directly above the corresponding spatial prestressed steel tube concrete column 22. The main structure of the spatial prestressed steel tube concrete large-diameter single pile foundation contains a variable diameter section 23, the length of which is about 30m, and the outer diameter increases by about 1m from top to bottom (about 15% increase).

[0024] The ultra-high performance concrete 221 filled in the steel tube 222 of the spatial prestressed steel tube concrete column adopts steel fiber concrete. Steel fiber is a preferred embodiment of ultra-high performance concrete in the present invention. Ultra-high performance concrete can also use other metal or non-metallic fibers, or use a variety of fibers mixed and added. In this embodiment, the diameter-to-thickness ratio of the steel tube 222 of the spatial prestressed steel tube concrete column is about 70, the diameter is about 0.9 m, the inner surface of the steel tube 222 of the spatial prestressed steel tube concrete column is roughened, the steel fiber content of the ultra-high performance concrete 221 is about 1.5%, the uniaxial tensile strength is about 14MPa, the residual uniaxial tensile strength under 1.5‰ strain is greater than 12MPa, and the spatial prestress is about 7MPa. The end cover plate 223 of the steel tube of the spatial prestressed steel tube concrete column is reserved with one grouting port and one exhaust port, and the grouting port and the exhaust port are both closed after the grouting is completed.

[0025] In this embodiment, the outer edges of the contact surfaces between the outer side of the spatial prestressed steel tube concrete column steel tube 222 and the inner side of the steel tube pile outer wall 21 are connected by fixed interval spot welding 224 along the height direction. The spatial prestressed steel tube concrete column steel tube 222 is preferably a steel tube segment with a cross section in the shape of a fan with a central angle between 220-300°. The segment is welded to the steel tube pile outer wall 21 to form a closed steel tube, which not only saves more materials but also has good space utilization.

[0026] A conical breaker 3 is arranged at the lower end of each spatial prestressed steel tube concrete column 22. The conical breaker 3 is a solid steel cone. The top surface of the conical breaker 3 is the same as the outer contour of the cover plate 223 at the lower end of the steel tube of the spatial prestressed steel tube concrete column. The height of the conical breaker 3 is about 1m. The outer edge of the contact surface between the top surface of the conical breaker 3 and the cover plate 223 at the lower end of the steel tube of the spatial prestressed steel tube concrete column is connected by spot welding.

[0027] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A large-diameter single pile foundation of spatial prestressed steel tube concrete for offshore wind turbines, characterized in that: It includes a pile top transition section and the main structure of the spatial prestressed steel tube concrete large-diameter single pile foundation; the main structure includes the outer wall of the steel tube pile and the spatial prestressed steel tube concrete column, the spatial prestressed steel tube concrete column is arranged from top to bottom on the inner side of the outer wall of the steel tube pile, and a plurality of spatial prestressed steel tube concrete columns are arranged along the circumferential direction on the inner side of the outer wall of the steel tube pile; The top section of the outer wall of the steel pipe pile is not provided with a spatial prestressed steel pipe concrete column but is combined into a pile top transition section, the pile top transition section includes a connecting transition structure located at the top, the pile top transition section includes a mechanical transition structure located between the connecting transition structure and the top of the spatial prestressed steel pipe concrete column and connected to the spatial prestressed steel pipe concrete column and the inner side of the top section of the outer wall of the steel pipe pile; The spatial prestressed steel tube concrete column comprises a spatial prestressed steel tube concrete column steel pipe welded to the inner side of the outer wall of a steel pipe pile, the steel pipe of the spatial prestressed steel tube concrete column is filled with prestressed ultra-high performance concrete, a cover plate is arranged at the end of the spatial prestressed steel tube concrete column steel pipe; a conical earth breaker is arranged at the bottom end of the spatial prestressed steel tube concrete column.

2. The large-diameter single pile foundation of spatial prestressed steel tube concrete for offshore wind turbines according to claim 1 is characterized by: The pile top transition section includes a T-type pile top flange, a plurality of rounded L-shaped ribs, an annular reinforcement rib and the top section of the outer wall of the steel pipe pile; the lower end of the T-type pile top flange is welded to the top end of the outer wall of the steel pipe pile as the connection transition structure, the annular reinforcement rib is welded to the inner side of the top section and to the top end of the spatial prestressed steel tube concrete column, a plurality of the rounded L-shaped ribs are arranged along the circumferential direction of the annular reinforcement ribs, and the right-angled side surfaces and bottom surfaces of the rounded L-shaped ribs are respectively welded to the top section and the upper contact surface of the annular reinforcement ribs to form the mechanical transition structure.

3. The large-diameter single pile foundation of spatial prestressed steel tube concrete for offshore wind turbines according to claim 2 is characterized by: The cross-sectional diameter of the T-type pile top flange is the same as that of the top end of the steel pipe pile outer wall, the lower end of the T-type pile top flange is connected to the top end of the steel pipe pile outer wall by double-sided bevel full penetration welding, the outer diameter of the annular reinforcing rib is the same as the inner diameter of the top section, the outer side surface of the annular reinforcing rib is connected to the inner contact surface of the top section by double-sided bevel full penetration welding, the right-angled side surface of the rounded L-shaped rib is connected to the inner contact surface of the steel pipe pile outer wall by double-sided bevel full penetration welding, and the right-angled bottom surface of the rounded L-shaped rib is connected to the upper contact surface of the annular reinforcing rib by double-sided bevel full penetration welding.

4. The large-diameter single pile foundation of spatial prestressed steel tube concrete for offshore wind turbines according to claim 2 is characterized by: The rounded L-shaped rib plate is provided between the top of each spatial prestressed steel tube concrete column and the connecting transition structure.

5. The large-diameter single pile foundation of spatial prestressed steel tube concrete for offshore wind turbines according to claim 1 is characterized by: A conical earth breaker is arranged at the lower end of each spatial prestressed steel tube concrete column.

6. The large-diameter single pile foundation of spatial prestressed steel tube concrete for offshore wind turbines according to claim 1 or 5, characterized in that: The conical breaker is a solid steel cone, the top surface of the steel conical breaker is the same as the lower end surface of the spatial prestressed steel tube concrete column or the top of the steel conical breaker smoothly transitions to the lower end of the spatial prestressed steel tube concrete column, and the outer edge of the contact surface between the top of the steel conical breaker and the lower end of the spatial prestressed steel tube concrete column is connected by spot welding.

7. The large-diameter single pile foundation of spatial prestressed steel tube concrete for offshore wind turbines according to claim 1 is characterized by: The main structure of the spatial prestressed steel tube concrete large-diameter single pile foundation contains a variable diameter section, the diameter-to-thickness ratio of the outer wall of the steel tube pile is about 300-600, the inner surface of the outer wall of the steel tube pile is roughened, and the axis of the spatial prestressed steel tube concrete column is parallel to the generatrix of the outer wall of the steel tube pile.

8. The large-diameter single pile foundation of spatial prestressed steel tube concrete for offshore wind turbines according to claim 1 is characterized by: The ultra-high performance concrete adopts steel fiber concrete.

9. The large-diameter single pile foundation of spatial prestressed steel tube concrete for offshore wind turbines according to claim 8, characterized in that: The diameter-to-thickness ratio of the spatial prestressed steel tube concrete column steel tube is about 50-90, the inner surface of the spatial prestressed steel tube concrete column steel tube is roughened, the volume percentage of the steel fiber content of the ultra-high performance concrete is 1%-5%, and the spatial prepressure is 3-8MPa.

10. The large-diameter single pile foundation of spatial prestressed steel tube concrete for offshore wind turbines according to claim 1, characterized in that: The outer edges of the contact surfaces of the spatial prestressed steel tube concrete column steel tube and the outer wall of the steel tube pile are connected by spot welding at fixed intervals along the height direction.

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