Prefabricated joint structure of offshore wind power jacket and construction method of prefabricated joint structure

Abstract

The invention provides an offshore wind power jacket prefabricated joint structure and a construction method thereof. The offshore wind power jacket prefabricated joint structure comprises a main pipe, a branch pipe, a main pipe connecting part and a branch pipe connecting part. The main pipe comprises a main pipe outer steel pipe and a main pipe inner steel pipe which are coaxially sleeved; concrete is filled between the main pipe outer steel pipe and the main pipe inner steel pipe to form a main pipe concrete interlayer; the branch pipe comprises a branch pipe outer steel pipe and a branch pipe inner steel pipe which are coaxially sleeved, and concrete is filled between the branch pipe outer steel pipe and the branch pipe inner steel pipe to form a branch pipe concrete interlayer; one end of the branch pipe is connected to the side wall of the main pipe, and the other end of the branch pipe is connected with the jacket inclined strut through the branch pipe connecting part; a first grouting partition plate and a second grouting partition plate are connected between the main pipe outer steel pipe and the main pipe inner steel pipe. A third grouting partition plate is connected between the branch pipe outer steel pipe and the branch pipe inner steel pipe. The anti-fatigue performance of the joint is improved, the influence of stress concentration is weakened, and then the stability and durability of the jacket foundation are enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore wind power, and in particular to a prefabricated node structure of an offshore wind power conductor frame and a construction method thereof. Background Art

[0002] In recent years, my country's offshore wind power industry has entered a stage of large-scale development, becoming a key growth driver of the new energy system. While offshore wind power project development in my country is primarily concentrated in coastal waters, as offshore wind resource development approaches saturation, the trend is inevitable for offshore wind power to move from offshore to deep-sea locations. Among various offshore wind turbine foundation structures, jacket foundations, with their superior structural stiffness, outstanding anti-overturning performance, gentle response to hydrodynamic loads, and mature technology, have become the preferred foundation for deep-sea wind turbines.

[0003] Compared to nearshore waters, deep-sea structural engineering faces even more severe challenges related to hydrodynamic coupling. Jacket foundations are subject to a combination of superstructure loads and environmental loads, primarily wave and current loads. Due to their complex geometrical characteristics, jacket joints become weak points of stress concentration. Under multiaxial alternating stress cycles, they are prone to significant plastic deformation, which in turn affects the stability of the jacket foundation. Therefore, localized reinforcement of these joints has become a key research topic for deep-sea offshore wind turbine jacket foundations.

[0004] Concrete-filled steel tube (CFST) components are composite structures in which concrete is filled inside a steel tube, allowing the core concrete and the steel tube to function together. The steel tube and concrete share common loads, allowing the tensile strength of the steel tube and the compressive strength of the concrete within the component to be fully utilized. As a variable-section form of CFST components, hollow sandwich CFST components consist of two concentrically placed steel tubes and a concrete core. Compared to traditional CFST components, the inner steel tube of hollow sandwich CFST components avoids the adverse effects of concrete shrinkage and creep on component performance in larger CFST components, resulting in higher load-bearing capacity, ductility, and seismic and impact resistance. This structural design also significantly reduces the deadweight of the structure, thereby improving component hoisting efficiency and construction feasibility during construction. This design holds broad application prospects in deep-sea structural engineering.

[0005] Prefabricated installation technology, through modular prefabrication and segmented transportation, overcomes the limitations of complex deep-sea conditions that limit the overall lifting of large structures, effectively reducing the risks and operational difficulties of offshore construction. However, the application of prefabricated structures in deep-sea offshore wind power is still in its exploratory stages and faces numerous challenges that need to be overcome.

[0006] Chinese utility model patent application number CN202223135175.2 proposes a pure steel tube jacket node. Composed of main legs and diagonal braces, it is configured as an integrated structure, simplifying construction and eliminating the need to increase the thickness of the joint to meet weld fatigue strength requirements, thus saving material. However, it must be noted that pure steel tube nodes exhibit higher load-bearing performance than hollow sandwich steel tube concrete-filled nodes.

[0007] Chinese invention patent application number CN202411314909.4 proposes a prefabricated offshore wind turbine jacket foundation and its construction method. By pouring concrete into the core of the joints, the joints' load-bearing capacity is improved, preventing premature yielding under external forces. However, during the jacket assembly process, the connectors must be welded. This increases the difficulty and risk of welding for jacket foundations in deep-sea areas, while also making it difficult to ensure weld consistency and reliability, which in turn affects the stability of the jacket's overall structure. Summary of the Invention

[0008] To address the shortcomings of the existing technology, the first objective of the present invention is to provide a prefabricated node structure for offshore wind turbine jackets. This invention improves the fatigue resistance of the nodes, mitigates the effects of stress concentration, and thereby enhances the stability and durability of the jacket foundation. It also reduces the difficulty of deep-sea jacket foundation assembly and improves construction efficiency.

[0009] In a first aspect, the present invention provides a prefabricated node structure of an offshore wind power conductor frame, comprising a main pipe, a branch pipe, a main pipe connecting portion and a branch pipe connecting portion; the main pipe comprises a coaxially sleeved main pipe outer steel pipe and a main pipe inner steel pipe, and concrete is filled between the main pipe outer steel pipe and the main pipe inner steel pipe to form a main pipe concrete sandwich; the branch pipe comprises a coaxially sleeved branch pipe outer steel pipe and a branch pipe inner steel pipe, and concrete is filled between the branch pipe outer steel pipe and the branch pipe inner steel pipe to form a branch pipe concrete sandwich; the two ends of the main pipe are respectively connected to the conductor frame main legs through the main pipe connecting portion, one end of the branch pipe is connected to the side wall of the main pipe, and the other end is connected to the conductor frame diagonal brace through the branch pipe connecting portion; a first grouting baffle and a second grouting baffle are connected between the main pipe outer steel pipe and the main pipe inner steel pipe, and the first grouting baffle and the second grouting baffle are respectively located at the two end faces of the main pipe; a third grouting baffle is connected between the branch pipe outer steel pipe and the branch pipe inner steel pipe, and the third grouting baffle is located at the end face of the branch pipe away from the main pipe.

[0010] As a preferred solution, several layers of bolt structures are connected between the main pipe connection portion and the main leg of the jacket; each layer of the bolt structure includes a plurality of single-side bolts, and the plurality of single-side bolts are arranged at intervals along the circumferential direction.

[0011] As a preferred solution, several layers of bolt structures are connected between the branch pipe connection portion and the conductor frame diagonal brace; each layer of the bolt structure includes a plurality of single-sided bolts, and the plurality of single-sided bolts are arranged at intervals along the circumferential direction.

[0012] As a preferred solution, the single-sided bolts are all configured as expansion type single-sided bolts, which include a nut, a washer, a screw, a sleeve and an expansion cone head; the expansion cone head is provided at one end of the screw, and the sleeve is sleeved on the outside, and the nut is provided at the other end and the washer is sleeved on the outside.

[0013] As a preferred solution, the main leg of the jacket is provided with a plurality of first unilateral bolt holes, the main pipe connection portion is correspondingly provided with a plurality of third unilateral bolt holes, and unilateral bolts are passed between the first unilateral bolt holes and the third unilateral bolt holes.

[0014] As a preferred solution, the conductor frame diagonal support is provided with a plurality of second unilateral bolt holes, the branch pipe connecting portion is correspondingly provided with a plurality of fourth unilateral bolt holes, and unilateral bolts are passed between the second unilateral bolt holes and the fourth unilateral bolt holes.

[0015] As a preferred solution, several layers of stud structures are provided on the inner wall of the main pipe outer steel pipe, the inner wall of the branch pipe outer steel pipe, the outer wall of the main pipe inner steel pipe and the outer wall of the branch pipe inner steel pipe. Each layer of the stud structure includes multiple studs, and the multiple studs are arranged at intervals along the circumferential direction. The studs are fixed on the steel pipe walls where they are located and do not contact the adjacent steel pipe walls.

[0016] As a preferred solution, the several layers of stud structures on the inner wall of the main pipe outer steel pipe and the outer wall of the main pipe inner steel pipe are staggered, and the several layers of stud structures on the inner wall of the branch pipe outer steel pipe and the outer wall of the branch pipe inner steel pipe are also staggered to avoid mutual interference.

[0017] As a preferred solution, a plurality of grouting holes are arranged circumferentially at intervals on the first grouting baffle and the third grouting baffle; the first grouting baffle and the second grouting baffle are flush with the end faces of the main outer steel pipe and the main inner steel pipe, and are welded to them; the third grouting baffle is flush with the end faces of the branch outer steel pipe and the branch inner steel pipe, and are welded to them; the first grouting baffle, the second grouting baffle and the third grouting baffle are not removed after the grouting is completed.

[0018] In a second aspect, a second object of the present invention is to provide a construction method for the above-mentioned prefabricated node structure of the offshore wind turbine jacket, the construction method comprising the following steps: Step S1: Prefabricate the node structure according to claim 1 in a factory, specifically comprising the following sub-steps: Step S1.1: A first single-sided bolt hole is formed on the jacket main leg, and a second single-sided bolt hole is formed on the jacket diagonal brace; a third single-sided bolt hole is formed on the main pipe connection portion, and a fourth single-sided bolt hole is formed on the branch pipe connection portion; a first grouting hole is formed on the first grouting partition; and a second grouting hole is formed on the third grouting partition; Step S1.2: Installing a plurality of layers of studs on the inner wall of the main pipe outer steel pipe, the inner wall of the branch pipe outer steel pipe, the outer wall of the main pipe inner steel pipe, and the outer wall of the branch pipe inner steel pipe; Step S1.3: Coaxially sleeve the main pipe outer steel pipe and the main pipe inner steel pipe, and the branch pipe outer steel pipe and the branch pipe inner steel pipe; weld the branch pipe inner steel pipe and the branch pipe outer steel pipe to the main pipe outer steel pipe in sequence; Step S1.4: Install the first grouting baffle and the second grouting baffle on both end faces of the main pipe, and weld them to the outer steel pipe and the inner steel pipe of the main pipe respectively; install the third grouting baffle on the end face of the branch pipe away from the main pipe, and weld them to the outer steel pipe and the inner steel pipe of the branch pipe; Step S1.5: Weld the main pipe connection portion to the end of the main pipe outer steel pipe, and weld the branch pipe connection portion to the end of the branch pipe outer steel pipe; Step S1.6: Pour concrete between the outer steel pipe of the main pipe and the inner steel pipe of the main pipe through the first grouting hole formed on the first grouting partition to form a sandwich concrete structure; and pour concrete between the outer steel pipe of the branch pipe and the inner steel pipe of the branch pipe through the second grouting hole formed on the third grouting partition to form a sandwich concrete structure. Step S2: transporting the prefabricated node structure to the offshore construction site by barging or floating for assembly, which specifically includes: Step S2.1: Coaxially sleeve the main pipe connection portion and the jacket main leg, and adjust them so that the first single-side bolt hole and the third single-side bolt hole are concentrically aligned; Step S2.2: Insert a single-side bolt from the outside of the main pipe connection. Tighten the nut so that the screw drives the expansion cone head back. The sleeve expands outward and squeezes the bolt hole wall, generating radial pressure and friction, achieving high-strength anchoring between the main pipe connection and the jacket leg. Step S2.3: Coaxially sleeve the branch pipe connection part and the jacket brace, adjust until the second single-sided bolt hole is concentrically aligned with the fourth single-sided bolt hole, insert the single-sided bolt and repeat the tightening steps of step S2.2 to achieve high-strength anchoring between the branch pipe connection part and the jacket brace.

[0019] The beneficial effects provided by the present invention are: The main pipe and branch pipe of the present invention adopt a coaxial outer steel pipe and inner steel pipe, and the interlayer is filled with concrete. Compared with traditional steel nodes, it has significant advantages in improving the mechanical properties of the nodes, reducing stress concentration, and improving fatigue resistance.

[0020] The present invention is prefabricated in a factory and transported to an offshore construction site by barging or floating for assembly. Advanced production equipment and strict quality inspection methods can be used to ensure the mechanical properties and fatigue resistance of the nodes.

[0021] The present invention adopts single-sided bolts to connect the jacket main legs and diagonal braces, which can effectively shorten the installation time and improve the construction efficiency. It is suitable for the rapid installation of jacket foundations in deep sea areas.

[0022] The present invention realizes modular assembly of offshore wind turbine jacket foundations, thereby reducing the full life cycle cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A schematic diagram of the overall effect of applying the prefabricated node structure of an offshore wind turbine jacket provided by an embodiment of the present invention to an offshore wind turbine jacket foundation; Figure 2 A schematic diagram of the three-dimensional structure of a prefabricated node structure of an offshore wind turbine jacket provided by an embodiment of the present invention; Figure 3 A cross-sectional view of a prefabricated node structure for an offshore wind turbine jacket provided by an embodiment of the present invention; Figure 4 A perspective view of the main pipes and branch pipes of a prefabricated node structure of an offshore wind power jacket provided by an embodiment of the present invention; Figure 5 A schematic structural diagram of a single-sided bolt provided in an embodiment of the present invention.

[0025] Figure markings: 1-main pipe, 101-main pipe outer steel pipe, 102-main pipe concrete interlayer, 103-main pipe inner steel pipe, 2-branch pipe, 201-branch pipe outer steel pipe, 202-branch pipe concrete interlayer, 203-branch pipe inner steel pipe, 3-jacket main leg, 301-first single-sided bolt hole, 4-jacket diagonal brace, 401-second single-sided bolt hole, 5-main pipe connection part, 501-third single-sided bolt hole, 6-branch pipe connection part, 601-fourth single-sided bolt hole, 7-single-sided bolt, 701-nut, 702-washer, 703-screw, 704-sleeve, 705-expansion cone head, 8-first grouting partition, 801-first grouting hole, 9-second grouting partition, 10-third grouting partition, 1001-second grouting hole, 11-bolt. DETAILED DESCRIPTION

[0026] To help those skilled in the art better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples. However, it should be understood that the drawings are for illustrative purposes only and are not to be construed as limiting the present invention. To better illustrate the present embodiments, certain components in the drawings may be omitted, enlarged, or reduced, and do not represent the dimensions of actual products. It is understandable that certain well-known structures and their descriptions may be omitted from the drawings. The positional relationships depicted in the drawings are for illustrative purposes only and are not to be construed as limiting the present invention.

[0027] The present invention will be further described below with reference to the accompanying drawings and examples, but they are not intended to limit the present invention.

[0028] like Figures 1 to 4 As shown, a prefabricated node structure for an offshore wind turbine jacket includes a main pipe 1, branch pipes 2, a main pipe connection portion 5, and a branch pipe connection portion 6. The main pipe 1 is connected to the jacket main leg 3 via the main pipe connection portion 5 using single-sided bolts 7; the branch pipe 2 is connected to the jacket brace 4 via the branch pipe connection portion 6 using single-sided bolts 7.

[0029] like Figure 3-4 As shown, the main pipe 1 comprises a coaxially sleeved outer steel pipe 101 and an inner steel pipe 103, with concrete filled between them to form a main concrete sandwich 102. The branch pipe 2 comprises a coaxially sleeved outer steel pipe 201 and an inner steel pipe 203, with concrete filled between them to form a branch concrete sandwich 202. Both the main pipe 1 and the branch pipe 2 are hollow sandwich concrete-filled steel tubular components, offering significant advantages in improving joint mechanical properties, reducing stress concentration, and enhancing fatigue resistance.

[0030] The two ends of the main pipe 1 are respectively connected to the main legs 3 of the jacket through the main pipe connecting part 5, one end of the branch pipe 2 is welded to the side wall of the main pipe 1, and the other end is connected to the jacket diagonal support 4 through the branch pipe connecting part 6; a first grouting baffle 8 and a second grouting baffle 9 are connected between the main pipe outer steel pipe 101 and the main pipe inner steel pipe 103, and the first grouting baffle 8 and the second grouting baffle 9 are respectively located at the two end faces of the main pipe 1; a third grouting baffle 10 is connected between the branch pipe outer steel pipe 201 and the branch pipe inner steel pipe 203, and the third grouting baffle 10 is located at the end face of the branch pipe 2 away from the main pipe 1.

[0031] Several layers of stud structures are provided on the inner wall of the main outer steel pipe 101, the inner wall of the branch outer steel pipe 201, the outer wall of the main inner steel pipe 103 and the outer wall of the branch inner steel pipe 203. Each layer of the stud structure includes a plurality of studs 11. The plurality of studs 11 are arranged at intervals along the circumferential direction. Through bidirectional mechanical anchoring, the interlayer concrete and the inner and outer steel pipes are forced to deform cooperatively, thereby suppressing interface slip and effectively transmitting shear force. The studs 11 are all fixed on the steel pipe wall where they are located and do not contact the adjacent steel pipe walls.

[0032] The multiple layers of stud structures on the inner wall of the main outer steel pipe 101 and the outer wall of the main inner steel pipe 103 are staggered, and the multiple layers of stud structures on the inner wall of the branch outer steel pipe 201 and the outer wall of the branch inner steel pipe 203 are also staggered to avoid mutual interference.

[0033] Multiple grouting holes are arranged circumferentially on the first grouting partition 8 and the third grouting partition 10. Specifically, the first grouting partition 8 has eight first grouting holes 801 spaced circumferentially, the second grouting partition 9 has no grouting holes, and the third grouting partition 10 has four second grouting holes 1001 spaced circumferentially.

[0034] The first grouting baffle 8 and the second grouting baffle 9 are both flush with the end faces of the main outer steel pipe 101 and the main inner steel pipe 103 and are welded thereto; the third grouting baffle 10 is flush with the end faces of the branch outer steel pipe 201 and the branch inner steel pipe 203 and is welded thereto.

[0035] The first grouting diaphragm 8, the second grouting diaphragm 9 and the third grouting diaphragm 10 are not removed after the grouting is completed, so as to strengthen the restraint effect on the main pipe concrete interlayer 102 and the branch pipe concrete interlayer 202, thereby enhancing the overall stiffness and bearing performance of the jacket prefabricated node.

[0036] The main pipe outer steel pipe 101 and the main pipe connecting portion 5 , as well as the branch pipe outer steel pipe 201 and the branch pipe connecting portion 6 are all connected by welding.

[0037] The main pipe connection 5 is connected to the jacket main leg 3 by a five-layer bolt structure, arranged at equal intervals. Each layer of bolt structure includes five single-sided bolts 7, which are spaced apart along the circumference. The branch pipe connection 6 is connected to the jacket brace 4 by a five-layer bolt structure, which includes multiple single-sided bolts 7, which are spaced apart along the circumference.

[0038] like Figure 5As shown, the single-sided bolts 7 are expansion-type, comprising a nut 701, a washer 702, a screw 703, a sleeve 704, and an expansion cone 705. The expansion cone 705 is mounted on one end of the screw 703, with the sleeve 704 sleeved on the outside. The nut 701 is mounted on the other end, with the washer 702 sleeved on the outside. The single-sided bolts 7 achieve reliable anchoring between the prefabricated jacket node structure and the jacket main legs 3 and jacket braces 4 through internal expansion, providing superior seismic performance and convenient installation.

[0039] By adopting unilateral bolts 7, efficient and convenient assembly between the jacket prefabricated node structure and the jacket main legs 3 and jacket diagonal braces 4 is achieved. This not only effectively avoids safety hazards such as increased weld defect rate and post-weld residual stress concentration under deep-sea wet working conditions, but also significantly shortens the offshore operation window period through standardized prefabricated nodes and assembly processes, realizes modular assembly of offshore wind turbine jacket foundations, and reduces the cost of the entire life cycle.

[0040] Specifically, the jacket main leg 3 is provided with a plurality of first unilateral bolt holes 301; the jacket diagonal brace 4 is provided with a plurality of second unilateral bolt holes 401; the main pipe connection portion 5 is provided with a third unilateral bolt hole 501; and the branch pipe connection portion 6 is provided with a fourth unilateral bolt hole 601. The first unilateral bolt holes 301 and the third unilateral bolt holes 501 are matched in number; the second unilateral bolt holes 401 and the fourth unilateral bolt holes 601 are matched in number. The jacket main leg 3 and the main pipe connection portion 5 are connected using unilateral bolts 7 through the first unilateral bolt holes 301 and the third unilateral bolt holes 501; and the jacket diagonal brace 4 and the branch pipe connection portion 6 are connected using unilateral bolts 7 through the second unilateral bolt holes 401 and the fourth unilateral bolt holes 601.

[0041] It should be noted that in the present invention, the form of the prefabricated node structure of the conductor rack is not limited to the K-type node, but can also be a Y-type node, a T-type node, a double-plane K-type node, etc.; the size, material and connection method of the prefabricated node can be adjusted according to actual working conditions.

[0042] The present invention also provides a construction method for a prefabricated node structure of an offshore wind power conductor frame, the construction method comprising the following steps: Step S1: Prefabricate the node structure according to claim 1 in a factory, specifically comprising the following sub-steps: Step S1.1: A first unilateral bolt hole 301 is formed on the jacket main leg 3, and a second unilateral bolt hole 401 is formed on the jacket brace 4; a third unilateral bolt hole 501 is formed on the main pipe connection portion 5, and a fourth unilateral bolt hole 601 is formed on the branch pipe connection portion 6; a first grouting hole 801 is formed on the first grouting partition 8; and a second grouting hole 1001 is formed on the third grouting partition. Step S1.2: Arrange several layers of studs 11 on the inner wall of the main outer steel pipe 101 , the inner wall of the branch outer steel pipe 201 , the outer wall of the main inner steel pipe 103 , and the outer wall of the branch inner steel pipe 203 ; Step S1.3: Coaxially sleeve the main outer steel pipe 101 and the main inner steel pipe 103, and the branch outer steel pipe 201 and the branch inner steel pipe 203; weld the branch inner steel pipe 203 and the branch outer steel pipe 201 to the main outer steel pipe 101 in sequence; Step S1.4: Install the first grouting baffle 8 and the second grouting baffle 9 on both end faces of the main pipe 1, and weld them to the main pipe outer steel pipe 101 and the main pipe inner steel pipe 103. Install the third grouting baffle 10 on the end face of the branch pipe 2 away from the main pipe 1, and weld them to the branch pipe outer steel pipe 201 and the branch pipe inner steel pipe 203. Step S1.5: Weld the main pipe connection portion 5 to the end of the main pipe outer steel pipe 101, and weld the branch pipe connection portion 6 to the end of the branch pipe outer steel pipe 201; Step S1.6: Concrete is poured between the main outer steel pipe 101 and the main inner steel pipe 103 through the first grouting hole 801 formed in the first grouting diaphragm 8 to form a sandwich concrete structure. Concrete is poured between the branch outer steel pipe 201 and the branch inner steel pipe 203 through the second grouting hole 1001 formed in the third grouting diaphragm 10 to form a sandwich concrete structure. Step S2: transporting the prefabricated node structure to the offshore construction site by barging or floating for assembly, which specifically includes: Step S2.1: Coaxially sleeve the main pipe connection portion 5 and the jacket main leg 3, and adjust them so that the first single-side bolt hole 301 and the third single-side bolt hole 501 are concentrically aligned; Step S2.2: Insert a single-side bolt 7 from the outside of the main pipe connection 5. Tighten the nut 701 so that the screw 703 pulls the expansion cone 705 back. The sleeve 704 expands outward and squeezes the bolt hole wall, creating radial pressure and friction, achieving high-strength anchoring between the main pipe connection 5 and the jacket leg 3. Step S2.3: Coaxially sleeve the branch pipe connection part 6 and the jacket brace 4, adjust until the second unilateral bolt hole 401 is concentrically aligned with the fourth unilateral bolt hole 601, insert the unilateral bolt 7 and repeat the tightening steps of step S2.2 to achieve high-strength anchoring between the branch pipe connection part 6 and the jacket brace 4.

[0043] According to the description and drawings of the present invention, those skilled in the art can easily manufacture or use the offshore wind power conduit prefabricated node structure and construction method of the present invention, and can produce the positive effects described in the present invention.

[0044] Unless otherwise specified, in the present invention, if there are terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" indicating orientation or positional relationships, they are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the orientation or positional relationship in the present invention are only used for illustrative purposes and cannot be understood as limiting the present invention. For those skilled in the art, the specific meanings of the above terms can be understood in conjunction with the accompanying drawings and according to specific circumstances.

[0045] Unless otherwise specified or limited, the terms "disposed," "connected," and "connected" in this disclosure should be interpreted broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediary, or internal connections between two components. Those skilled in the art will understand the specific meanings of these terms in this disclosure based on the specific circumstances.

[0046] 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 scope of protection of the present invention.

Claims

1. A prefabricated node structure for an offshore wind turbine jacket, characterized by: It includes a main pipe, a branch pipe, a main pipe connecting part and a branch pipe connecting part; the main pipe includes a coaxially sleeved main pipe outer steel pipe and a main pipe inner steel pipe, and concrete is filled between the main pipe outer steel pipe and the main pipe inner steel pipe to form a main pipe concrete sandwich; the branch pipe includes a coaxially sleeved branch pipe outer steel pipe and a branch pipe inner steel pipe, and concrete is filled between the branch pipe outer steel pipe and the branch pipe inner steel pipe to form a branch pipe concrete sandwich; the two ends of the main pipe are respectively connected to the main legs of the conductor frame through the main pipe connecting part, one end of the branch pipe is connected to the side wall of the main pipe, and the other end is connected to the conductor frame diagonal brace through the branch pipe connecting part; a first grouting partition and a second grouting partition are connected between the main pipe outer steel pipe and the main pipe inner steel pipe, and the first grouting partition and the second grouting partition are respectively located at the two end faces of the main pipe; a third grouting partition is connected between the branch pipe outer steel pipe and the branch pipe inner steel pipe, and the third grouting partition is located at the end face of the branch pipe away from the main pipe.

2. The prefabricated node structure of the offshore wind power jacket according to claim 1 is characterized in that: Several layers of bolt structures are connected between the main pipe connection portion and the main leg of the jacket; each layer of the bolt structure includes a plurality of single-side bolts, and the plurality of single-side bolts are arranged at intervals along the circumferential direction.

3. The prefabricated node structure of the offshore wind power jacket according to claim 1 is characterized in that: Several layers of bolt structures are connected between the branch pipe connection portion and the conductor frame diagonal brace; each layer of the bolt structure includes a plurality of single-side bolts, and the plurality of single-side bolts are arranged at intervals along the circumferential direction.

4. The prefabricated node structure for an offshore wind turbine jacket according to any one of claims 2 or 3, characterized in that: The single-sided bolts are all configured as expansion type single-sided bolts, which include a nut, a washer, a screw, a sleeve and an expansion cone head; the expansion cone head is set at one end of the screw, and the sleeve is sleeved on the outside, and the nut is set at the other end and the washer is sleeved on the outside.

5. The offshore wind power jacket prefabricated node structure according to claim 2, characterized in that: The main leg of the jacket is provided with a plurality of first unilateral bolt holes, and the main pipe connecting portion is correspondingly provided with a plurality of third unilateral bolt holes, and unilateral bolts are passed through the first unilateral bolt holes and the third unilateral bolt holes.

6. The offshore wind power jacket prefabricated node structure according to claim 3, characterized in that: The pipe frame diagonal support is provided with a plurality of second unilateral bolt holes, and the branch pipe connecting portion is correspondingly provided with a plurality of fourth unilateral bolt holes, and unilateral bolts are passed through the second unilateral bolt holes and the fourth unilateral bolt holes.

7. The offshore wind power jacket prefabricated node structure according to claim 1, characterized in that: Several layers of stud structures are provided on the inner wall of the main pipe outer steel pipe, the inner wall of the branch pipe outer steel pipe, the outer wall of the main pipe inner steel pipe and the outer wall of the branch pipe inner steel pipe. Each layer of the stud structure includes multiple studs, and the multiple studs are arranged at intervals along the circumferential direction. The studs are fixed on the steel pipe wall where they are located and do not contact the adjacent steel pipe walls.

8. The offshore wind power jacket prefabricated node structure according to claim 7, characterized in that: The multiple layers of stud structures on the inner wall of the main pipe outer steel pipe and the outer wall of the main pipe inner steel pipe are staggered, and the multiple layers of stud structures on the inner wall of the branch pipe outer steel pipe and the outer wall of the branch pipe inner steel pipe are also staggered to avoid mutual interference.

9. The offshore wind power jacket prefabricated node structure according to claim 1, characterized in that: The first grouting baffle and the third grouting baffle are both provided with a plurality of grouting holes arranged at intervals in the circumferential direction; the first grouting baffle and the second grouting baffle are both flush with the end faces of the main pipe outer steel pipe and the main pipe inner steel pipe, and are welded to them; the third grouting baffle is flush with the end faces of the branch pipe outer steel pipe and the branch pipe inner steel pipe, and are welded to them; the first grouting baffle, the second grouting baffle and the third grouting baffle are not removed after the grouting is completed.

10. A construction method for a prefabricated node structure of an offshore wind turbine jacket as claimed in claim 1, the construction method comprising the following steps: Step S1: Prefabricate the node structure according to claim 1 in a factory, specifically comprising the following sub-steps: Step S1.1: A first single-sided bolt hole is formed on the jacket main leg, and a second single-sided bolt hole is formed on the jacket diagonal brace; a third single-sided bolt hole is formed on the main pipe connection portion, and a fourth single-sided bolt hole is formed on the branch pipe connection portion; a first grouting hole is formed on the first grouting partition; and a second grouting hole is formed on the third grouting partition; Step S1.2: Installing a plurality of layers of studs on the inner wall of the main pipe outer steel pipe, the inner wall of the branch pipe outer steel pipe, the outer wall of the main pipe inner steel pipe, and the outer wall of the branch pipe inner steel pipe; Step S1.3: Coaxially sleeve the main pipe outer steel pipe and the main pipe inner steel pipe, and the branch pipe outer steel pipe and the branch pipe inner steel pipe; weld the branch pipe inner steel pipe and the branch pipe outer steel pipe to the main pipe outer steel pipe in sequence; Step S1.4: Install the first grouting baffle and the second grouting baffle on both end faces of the main pipe, and weld them to the outer steel pipe and the inner steel pipe of the main pipe respectively; install the third grouting baffle on the end face of the branch pipe away from the main pipe, and weld them to the outer steel pipe and the inner steel pipe of the branch pipe; Step S1.5: Weld the main pipe connection portion to the end of the main pipe outer steel pipe, and weld the branch pipe connection portion to the end of the branch pipe outer steel pipe; Step S1.6: Pour concrete between the outer steel pipe of the main pipe and the inner steel pipe of the main pipe through the first grouting hole formed on the first grouting partition to form a sandwich concrete structure; and pour concrete between the outer steel pipe of the branch pipe and the inner steel pipe of the branch pipe through the second grouting hole formed on the third grouting partition to form a sandwich concrete structure. Step S2: transporting the prefabricated node structure to the offshore construction site by barging or floating for assembly, which specifically includes: Step S2.1: Coaxially sleeve the main pipe connection portion and the jacket main leg, and adjust them so that the first single-side bolt hole and the third single-side bolt hole are concentrically aligned; Step S2.2: Insert a single-side bolt from the outside of the main pipe connection. Tighten the nut so that the screw drives the expansion cone head back. The sleeve expands outward and squeezes the bolt hole wall, generating radial pressure and friction, achieving high-strength anchoring between the main pipe connection and the jacket leg. Step S2.3: Coaxially sleeve the branch pipe connection part and the jacket brace, adjust until the second single-sided bolt hole is concentrically aligned with the fourth single-sided bolt hole, insert the single-sided bolt and repeat the tightening steps of step S2.2 to achieve high-strength anchoring between the branch pipe connection part and the jacket brace.

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