Offshore wind power concrete filled steel tube single pile foundation and construction method thereof

Abstract

The invention discloses an offshore wind power concrete filled steel tube single pile foundation and a construction method thereof. The offshore wind power concrete filled steel tube single pile foundation comprises a pile pipe and an annular reinforced concrete lining layer. The outer wall of the pile pipe is an integral steel pipe, an inner cavity penetrating through the two ends is formed in the pile pipe, and the pile pipe comprises a lower pile body and an upper pile body, and when the lower pile body is sunk to a designed depth, the lower pile body is embedded in a seabed, and the upper pile body is soaked in water. Concrete is poured into the inner cavity to form an annular reinforced concrete lining layer, and the outer wall of the annular reinforced concrete lining layer is connected with the inner wall of the upper pile body to jointly form a composite bearing structure. A plurality of wing plates are arranged around the periphery of the lower pile body at intervals, and through rigidity transition between the wing plates and the lower pile body, the structural strength and the horizontal resistance of a soil body are improved. The annular reinforced concrete lining layer is arranged on the upper pile body, and the wing plates are arranged on the lower pile body, so that the vibration frequency and the fatigue resistance of the single-pile foundation are effectively improved, meanwhile, the foundation structure is simplified, the manufacturing cost and the construction difficulty are reduced, and the single-pile foundation is suitable for deep and far sea large megawatt wind turbine foundation construction.

Description

Technical Field

[0001] This invention relates to the field of wind power generation technology, and in particular to a steel pipe concrete monopile foundation for offshore wind power and its construction method. Background Technology

[0002] With the increasing global demand for clean energy, offshore wind power, as an important component of renewable energy, is gradually developing towards larger capacities. Currently, the mainstream foundation types for offshore wind turbines mainly include monopile foundations and jacket foundations.

[0003] Traditional monopile foundations have long dominated in shallow water areas due to their advantages such as simple structure, convenient installation, strong site adaptability, and low unit construction cost. However, with the increasing demand for wind turbine capacity, wind turbine foundations need to be installed at deeper underwater locations, and traditional monopile foundations are unable to meet the higher standards of stiffness and fatigue requirements.

[0004] Although jacket foundations can meet the performance requirements of deep-sea megawatt wind turbines, their structure is complex, the installation process is complicated, and the overall cost is high. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, one of the objectives of this invention is to provide a steel-concrete monopile foundation for offshore wind power and its construction method, which enables the monopile foundation to meet higher standards of stiffness and fatigue requirements.

[0006] The second objective of this invention is to provide a steel-concrete monopile foundation for offshore wind power and its construction method, which not only meets the performance requirements of large-megawatt wind turbines in deep-sea areas, but also reduces its own cost.

[0007] The objective of this invention is achieved by the following technical solution: a steel-concrete monopile foundation for offshore wind power, comprising: a pile pipe and a ring-shaped reinforced concrete inner lining;

[0008] The outer wall of the pile pipe is an integral steel pipe with an inner cavity that extends through both ends of the pile pipe. The pile pipe includes a lower pile body and an upper pile body connected sequentially along the length of the pile pipe. The lower pile body is used to be buried in the seabed, and the upper pile body is used to be immersed in the water above the seabed.

[0009] The annular reinforced concrete lining is located inside the cavity, and the outer wall of the annular reinforced concrete lining is connected to the inner wall of the upper pile body to jointly form a composite load-bearing structure.

[0010] Furthermore, the inner wall of the upper pile body is provided with a first alignment mark for being above sea level, and the inner wall of the upper pile body is provided with a second alignment mark for being flush with the seabed surface.

[0011] Furthermore, the annular reinforced concrete lining includes a shear-resistant connection structure and annular concrete. The periphery of the shear-resistant connection structure abuts against the inner wall of the upper pile body, and the annular concrete covers the outside of the shear-resistant connection structure. The annular concrete extends horizontally around the inner cavity and abuts against the inner wall of the upper pile body.

[0012] Furthermore, the shear-resistant connection structure extends horizontally around the inner cavity to form a ring structure.

[0013] Furthermore, the shear-resistant connection structure is a steel cage.

[0014] Furthermore, the offshore wind power steel pipe concrete monopile foundation also includes multiple wing plates. One side of the wing plate is connected to the outer wall of the lower pile body, and the other side of the wing plate extends in a direction away from the axis of the lower pile body. The multiple wing plates are distributed at intervals around the periphery of the lower pile body, and the wing plates are used to embed into the seabed.

[0015] Furthermore, the wing plate is a polygonal plate structure.

[0016] A construction method for a steel-concrete monopile foundation for offshore wind power includes the following steps:

[0017] The pile pipe pre-installed with the shear-resistant connection structure is driven into the seabed, and the lower pile body is hammered until it is buried in the seabed, while the upper pile body is immersed in the water above the seabed, and the top of the upper pile body is exposed above the horizontal plane.

[0018] Drain the water from the inner cavity;

[0019] The annular bottom template is lowered into the inner cavity and fixed to the inner wall of the upper pile body;

[0020] The annular inner template (or the template that has already been installed) is lowered into the inner cavity, and the bottom of the annular inner template abuts against the inner outer edge of the annular bottom template. The annular inner template is placed extending upward in the vertical direction to form a concrete pouring space between the inner wall of the upper pile body, the annular bottom template and the annular inner template.

[0021] A concrete mixture is poured into the concrete pouring space until the poured concrete mixture and the shear-resistant connection structure solidify to form the annular reinforced concrete lining.

[0022] Furthermore, the template includes a temporary template or a permanent template; the step of pouring concrete mixture in the concrete pouring space until the poured concrete mixture and the shear-resistant connection structure solidify to form the annular reinforced concrete lining includes: when a temporary template is used, the temporary template is removed after the annular reinforced concrete lining has solidified; when a permanent template is used, the permanent template is retained in the cavity.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1. Specifically, a ring-shaped reinforced concrete liner is located in the upper part of the inner cavity. The ring-shaped reinforced concrete liner is formed by on-site casting. The outer wall of the ring-shaped reinforced concrete liner is bonded to the inner wall of the upper pile body through natural adhesion or partial interlocking, thus forming a composite load-bearing structure together with the upper pile body. Compared to a structure consisting only of the upper pile body wall thickness, this composite load-bearing structure increases the moment of inertia of the cross-section, thereby improving the bending strength of the upper pile body and the vibration frequency of the system. Under load (including before and after the installation of the tower and wind turbine), the upper pile body and the ring-shaped reinforced concrete liner share the load and deform collaboratively. The outer wall of the upper pile body deforms under external loads. During deformation, the upper pile body circumferentially compresses the ring-shaped reinforced concrete liner. The ring-shaped reinforced concrete liner provides continuous circumferential support to the inner wall of the upper pile body, suppressing the stress and deformation of the upper pile body in the compressive stress zone, thereby improving the load-bearing capacity of the upper pile body. Meanwhile, under the action of cyclic wind and wave loads, the composite interface between the upper pile body and the annular reinforced concrete lining layer redistributes the load through a shear force transfer mechanism (such as shear keys), so that the fatigue stress amplitude originally concentrated on the inner wall of the upper pile body is dispersed to the annular concrete lining layer, thereby reducing the stress concentration of the pile pipe bearing part (upper pile body) and thus meeting the fatigue requirements.

[0025] 2. After the composite load-bearing structure undergoes bending deformation, the overturning moment generated by the upper pile is transferred to the lower pile. The lower pile resists the overturning moment by anchoring to the seabed soil and distributing the load to the surrounding soil, thus completing the unloading. By setting wing plates, the structural strength of the lower pile and its interaction force with the surrounding soil can be increased, improving the horizontal bearing capacity and overturning resistance of the lower pile, and forming a transition in the cross-sectional stiffness between the upper and lower piles. This allows the monopile foundation to meet higher standards of stiffness and fatigue requirements, making it suitable for wind turbine installation in deeper waters. Furthermore, for existing monopile foundations that require reinforcement or modification, a ring-shaped reinforced concrete lining can be directly poured into the inner cavity of the original pile tube to extend its service life. Compared to the option of completely demolishing and replacing the entire monopile foundation, this significantly reduces modification costs.

[0026] 3. In terms of manufacturing cost, compared with the jacket foundation, the monopile foundation structure described in this application is simple. It only requires a single steel pipe and a local ring-shaped reinforced concrete lining to achieve the load-bearing function. The amount of steel required is less, the requirements for hoisting tools are low, and no node processing or grouting connection process is required during manufacturing, thereby reducing the cost.

[0027] 4. In terms of construction, the monopile foundation of this application adopts a single large-diameter steel pipe pile for one-time pile driving. It only requires driving the pile pipe into the seabed to the design depth by hammering. After the pile is driven, a ring of concrete is poured into the inner cavity of the upper pile. Compared with the construction method of jacket foundation, it eliminates the need for complex procedures such as underwater leveling, jacket installation, and grouting connection, shortens the offshore operation time, and has relatively lower requirements for construction vessels and equipment, thereby reducing construction costs. Attached Figure Description

[0028] Figure 1 This is a structural schematic diagram of a steel-concrete monopile foundation for offshore wind power according to the present invention, wherein: the square represents the seabed;

[0029] Figure 2 for Figure 1 The cross-sectional view shown here, where the dashed line represents the sea level.

[0030] In the diagram: 1. Pile pipe; 11. Inner cavity; 12. Lower pile body; 13. Upper pile body; 2. Annular reinforced concrete inner lining; 21. Shear connection structure; 22. Annular concrete; 3. First alignment mark; 4. Second alignment mark; 5. Wing plate. Detailed Implementation

[0031] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0032] It should be noted that when an element is described as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is described as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] like Figure 1 and Figure 2 As shown, a preferred embodiment of the present invention provides a steel-concrete monopile foundation for offshore wind power, comprising: a pile pipe 1 and a ring-shaped reinforced concrete inner lining 2.

[0035] The outer wall of the pile pipe 1 is a single steel pipe. Depending on the depth and topography of the construction water area, structural steel or pipeline steel of different yield strengths can be used to meet load-bearing requirements. Furthermore, since the pile pipe 1 needs to be immersed in seawater for extended periods, an anti-corrosion coating (such as epoxy coating or thermally sprayed zinc-aluminum coating) needs to be applied to the outer wall of the pile pipe 1 to extend its service life. Based on the presence of an inner cavity 11, which extends through both ends of the pile pipe 1, it facilitates the discharge of mud and seawater from the top of the inner cavity 11 during pile driving, preventing the "air cushion effect" caused by the inner cavity 11 being closed and hindering pile driving, thus ensuring pile driving efficiency. After emptying the inner cavity 11, an operating channel is provided for the subsequent construction of the annular reinforced concrete lining layer 2. The pile pipe 1 includes a lower pile body 12 and an upper pile body 13 connected sequentially along the length of the pile pipe 1. The lower pile body 12 and the upper pile body 13 are integrally formed. The length is set according to the sea conditions (e.g., seawater depth, seabed soil hardness) of the wind turbine's location. The lower pile 12 is used to be buried in the seabed, and the upper pile 13 is used to be immersed in the water above the seabed. Specifically, before pile driving, a stabilizing platform needs to be pre-established at the designated wind turbine location. Then, the pile pipe 1 is inserted into the stabilizing platform as a whole, and the pile gripper of the stabilizing platform clamps the outer wall of the pile pipe 1. The stabilizing platform monitors the inclination of the pile pipe 1 in real time and actively straightens the pile pipe 1 when it is tilted, thereby ensuring the verticality and stability of the pile pipe 1 during the subsequent penetration construction. Afterward, the construction personnel use a pile hammer to gradually drive the pile pipe 1 to the design depth, so that the lower pile 12 is submerged below the seabed surface, thereby anchoring the pile pipe 1 as a whole to the seabed, supporting the upper pile 13, and immersing the upper pile 13 in the seawater above the seabed to bear the impact load of seawater, as well as the working load and wind load generated after the wind turbine and tower are installed.

[0036] The annular reinforced concrete liner 2 is disposed within the inner cavity 11, and the outer wall of the annular reinforced concrete liner 2 is connected to the inner wall of the upper pile body 13 to jointly form a composite load-bearing structure. As a preferred design, the axial length of the annular reinforced concrete liner 2 should be equal to or slightly less than the length of the upper pile body 13 to ensure the composite load-bearing structure covers seawater depth. Specifically, the annular reinforced concrete liner 2 is disposed at the upper part of the inner cavity 11 and is formed by on-site casting. The outer wall of the annular reinforced concrete liner 2 is bonded to the inner wall of the upper pile body 13 through natural adhesion or partial interlocking, thus forming a composite load-bearing structure together with the upper pile body 13. Compared to a structure consisting only of the wall thickness of the upper pile body 13, this composite load-bearing structure increases the moment of inertia of the cross-section, thereby improving the structural strength and system frequency of the upper pile body 13.

[0037] Under load (including before and after the installation of the tower and wind turbine), the upper pile body 13 and the annular reinforced concrete liner 2 share the load and deform together. The outer wall of the upper pile body 13 deforms under external loads. During the deformation process, the upper pile body 13 circumferentially compresses the annular reinforced concrete liner 2. The annular reinforced concrete liner 2 forms a continuous circumferential support for the inner wall of the upper pile body 13, suppressing the stress and deformation of the upper pile body 13 in the compressive stress zone, thereby improving the load-bearing capacity of the upper pile body 13. At the same time, under cyclic loads, the composite interface between the upper pile body 13 and the annular reinforced concrete liner 2 redistributes the load through a shear force transfer mechanism (e.g., shear keys), dispersing the fatigue stress amplitude originally concentrated on the inner wall of the upper pile body 13 to be borne by the annular concrete liner 22. This reduces the stress concentration in the load-bearing part of the pile pipe 1 (upper pile body 13), thereby meeting fatigue requirements.

[0038] After the composite load-bearing structure undergoes bending deformation, the overturning moment generated by the upper pile 13 is transferred to the lower pile 12. The lower pile 12 resists the overturning moment by anchoring to the seabed soil and distributing the load to the surrounding soil, thus completing the unloading. This allows the monopile foundation to meet higher standards of stiffness and fatigue requirements, making it suitable for wind turbine installations in deeper waters. Furthermore, for existing monopile foundations that require reinforcement or modification, a ring-shaped reinforced concrete lining layer 2 can be directly poured into the inner cavity 11 of the original pile pipe 1 to extend its service life. Compared to the option of completely demolishing and replacing the entire monopile foundation, this significantly reduces modification costs.

[0039] In terms of manufacturing cost, compared with the jacket foundation, the monopile foundation structure described in this application is simple. It only requires a single steel pipe and a local ring-shaped reinforced concrete inner lining 2 to achieve the load-bearing function. The amount of steel required is less, and no node processing or grouting connection process is required during manufacturing, thereby reducing construction costs.

[0040] Preferably, the inner wall of the upper pile body 13 is provided with a first alignment mark 3 for being above sea level, and the inner wall of the upper pile body 13 is provided with a second alignment mark 4 for being flush with the seabed surface. The first alignment mark 3 and the second alignment mark 4 can be implemented in various forms: for example, pre-processed color segments, reflective patches, or positioning rods with scales inside the upper pile body 13; the first alignment mark 3 and the second alignment mark 4 have two functions: firstly, as a reference point when the pile tube 1 is driven into the ground: when the lower pile body 12 is driven into the design depth, the second alignment mark 4 should be flush with the seabed surface. In other words, if the second alignment mark 4 is observed to be flush with the seabed surface, it can be determined that the lower pile body 12 has been driven into the design depth; secondly, to play a positioning role in setting the annular reinforced concrete inner lining layer 2: ensuring that the lower end face of the annular reinforced concrete inner lining layer 2 is flush with the seabed surface and the upper end face of the annular reinforced concrete inner lining layer 2 is higher than the sea level, so that the composite bearing structure covers the upper pile body 13 section within the seawater depth range, thereby improving the structural strength and system stiffness of the pile tube 1.

[0041] Preferably, the annular reinforced concrete liner 2 includes a shear connection structure 21 and annular concrete 22. The shear connection structure 21 is a rigid structure pre-processed on the inner wall of the upper pile body 13. The outer periphery of the shear connection structure 21 abuts against the inner wall of the upper pile body 13 to bear the load on the outer wall of the upper pile body 13. The annular concrete 22 covers the shear connection structure 21 and fills to form the main body of the annular reinforced concrete liner 2. The annular concrete 22 extends horizontally around the inner cavity 11 and abuts against the inner wall of the upper pile body 13 so that the annular concrete 22 circumferentially supports the upper pile body 13. After the annular concrete 22 solidifies and is cured, it forms the annular reinforced concrete liner 2. It should be noted that the shear connection structure 21 here does not simply refer to the shear key in the engineering context. The shear connection structure 21 should be interpreted in a broad sense. Here, the shear connection structure 21 should be understood as including all structures that resist shear forces after being combined with the inner wall of the annular concrete 22 and the upper pile body 13.

[0042] Preferably, the shear-resistant connection structure 21 extends horizontally around the inner cavity 11 to form a ring structure. As one specific embodiment, the shear-resistant connection structure 21 can be implemented using multiple shear keys, which are distributed circumferentially around the axis of the inner cavity 11. The outer periphery of each shear key abuts against the inner wall of the upper pile body 13 to circumferentially transfer the interfacial shear stress.

[0043] Preferably, the shear-resistant connection structure 21 is a reinforcing cage. The advantages of using a reinforcing cage are: on the one hand, after the reinforcing cage is combined with the annular concrete 22 and the inner wall of the upper pile body 13, it can transmit and resist the interfacial shear stress, realizing the basic function of the shear-resistant connection structure 21; on the other hand, the reinforcing cage can serve as a supporting skeleton for the annular concrete 22, improving the compressive strength and plastic deformation capacity of the concrete, and enhancing the overall strength of the annular reinforced concrete lining layer 2.

[0044] Preferably, the offshore wind power steel-concrete monopile foundation further includes multiple flanges 5. One side of each flange 5 is connected to the outer wall of the lower pile body 12, and the other side of each flange 5 extends away from the axis of the lower pile body 12. Multiple flanges 5 are distributed at intervals around the periphery of the lower pile body 12, and the flanges 5 are used to embed into the seabed. It is understood that when the bearing capacity or stiffness of the seabed soil is insufficient, flanges 5 need to be added. The horizontal projected area of ​​the flanges 5 expands the contact area between the lower pile body 12 and the soil, distributing the load of the lower pile body 12 to a larger area of ​​soil, thereby improving the overturning resistance of the lower pile body 12. It is also understood that when the structural strength of the lower pile body 12 is insufficient, the flanges 5 can be used to increase the structural strength of the pile, optimize the stiffness transition from the upper pile body to the lower pile body, and thus improve the fatigue life of the lower pile body 12. The wing plate 5 is welded to the outer wall of the lower pile body 12 and can be driven into the design depth along with the lower pile body 12. The specific parameters of the wing plate 5 (e.g., wing plate 5 length, wing plate 5 depth, wing plate 5 quantity) and the depth of penetration into the mud can be determined comprehensively through engineering analysis based on the specific site geological conditions, marine environmental load, and wind turbine capacity requirements. At this time, the pile gripper on the pile stabilization platform needs to be modified accordingly, and guide grooves corresponding to the position of the wing plate 5 need to be added to ensure that the wing plate 5 can pass smoothly through the pile gripper and ensure the smooth progress of the pile driving process.

[0045] Preferably, the wing plate 5 is a polygonal plate structure. Under normal circumstances, the wing plate 5 adopts a rectangular plate structure; however, under certain special working conditions, the wing plate 5 may adopt a triangular plate structure, a trapezoidal structure, or an irregular structure to improve the stress state of the lower pile body 12 and increase the horizontal resistance of the single pile foundation.

[0046] like Figures 1 to 2 As shown, a construction method for a steel-concrete monopile foundation for offshore wind power includes the following steps:

[0047] The pile pipe 1, pre-installed with the shear connection structure 21, is driven into the seabed and hammered until the lower pile body 12 is buried in the seabed, and the upper pile body 13 is immersed in the water above the seabed, with the top of the upper pile body 13 exposed above the horizontal plane; at this time, the second alignment mark 4 is flush with the seabed surface, and the first alignment mark 3 is slightly higher than the sea level.

[0048] The water inside the inner cavity 11 is drained; and the mud and sand generated during the sedimentation process are also removed from the inner cavity 11 to keep the inner cavity 11 clean.

[0049] The annular bottom template is lowered into the inner cavity 11 and fixed to the inner wall of the upper pile body 13. The annular bottom template is engaged with the positioning structure of the upper pile body 13 by fasteners (e.g., positioning holes or positioning pins). The top surface of the annular bottom template is attached to the bottom of the shear-resistant connection structure 21 to prevent the annular concrete 22 from leaking downwards. The template can also be pre-assembled in the factory to reduce on-site installation procedures.

[0050] The annular inner template (or an already installed template) is lowered into the inner cavity 11, with the bottom of the annular inner template abutting against the inner outer edge of the annular bottom template to form a cylindrical template; the annular inner template is placed vertically upward to form a concrete pouring space between the inner wall of the upper pile body 13, the annular bottom template, and the annular inner template; considering the complexity of offshore formwork removal construction, a permanent template can be set in the inner cavity 11 in advance, which does not need to be removed.

[0051] A concrete mixture is poured into the concrete pouring space until it solidifies with the shear-resistant connection structure 21 to form the annular reinforced concrete lining layer 2. During the formation of the annular reinforced concrete lining layer 2, it needs to be cured to ensure its molding quality.

[0052] At the construction level, the monopile foundation of this application adopts a single large-diameter steel pipe pile for one-time pile driving construction. It only requires driving the pile pipe 1 into the seabed to the design depth by hammering. After the pile is driven, annular concrete 22 is poured into the inner cavity 11 of the upper pile body 13. Compared with the construction method of jacket foundation, it eliminates the need for complex procedures such as underwater leveling, jacket installation and grouting connection, shortens the offshore operation time, and has relatively lower requirements for construction vessels and equipment, thereby reducing construction costs.

[0053] Preferably, the process of pouring concrete mixture within the concrete pouring space until the poured concrete mixture and the shear-resistant connection structure 21 solidify to form the annular reinforced concrete inner lining layer 2 includes: removing the annular bottom formwork before fixing it to the concrete mixture; and removing the annular inner formwork before fixing it to the concrete mixture. If temporary formwork is used, it can be removed and reused after the concrete curing is completed.

[0054] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0055] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0056] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in this application, and these should all be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A type of offshore wind turbine steel-concrete monopile foundation, characterized in that, include: The pile pipe (1) has an outer wall made of integral steel pipe and an inner cavity (11) that extends through both ends of the pile pipe (1). The pile pipe (1) includes a lower pile body (12) and an upper pile body (13) connected sequentially along the length of the pile pipe (1). The lower pile body (12) is used to be buried in the seabed, and the upper pile body (13) is used to be immersed in the water above the seabed. A ring-shaped reinforced concrete inner lining (2) is provided in the inner cavity (11). The outer wall of the ring-shaped reinforced concrete inner lining (2) is connected to the inner wall of the upper pile body (13) to jointly form a composite load-bearing structure.

2. The offshore wind power steel-concrete monopile foundation according to claim 1, characterized in that: The inner wall of the upper pile body (13) is provided with a first alignment mark (3) for being above sea level, and the inner wall of the upper pile body (13) is provided with a second alignment mark (4) for being flush with the seabed surface.

3. The offshore wind power steel-concrete monopile foundation according to claim 1, characterized in that: The annular reinforced concrete lining (2) includes a shear connection structure (21) and an annular concrete (22). The periphery of the shear connection structure (21) abuts against the inner wall of the upper pile body (13). The annular concrete (22) covers the outside of the shear connection structure (21). The annular concrete (22) extends horizontally around the inner cavity (11) and abuts against the inner wall of the upper pile body (13).

4. A steel-concrete monopile foundation for offshore wind power according to claim 3, characterized in that: The shear-resistant connection structure (21) extends horizontally around the inner cavity (11) and forms a ring structure.

5. A steel-concrete monopile foundation for offshore wind power according to claim 3, characterized in that: The shear-resistant connection structure (21) is a steel cage.

6. A steel-concrete monopile foundation for offshore wind power according to claim 2, characterized in that: The offshore wind power steel pipe concrete monopile foundation also includes multiple wing plates (5). One side of the wing plate (5) is connected to the outer wall of the lower pile body (12), and the other side of the wing plate (5) extends in a direction away from the axis of the lower pile body (12). The multiple wing plates (5) are distributed at intervals around the periphery of the lower pile body (12), and the wing plates (5) are used to embed into the seabed.

7. A steel-concrete monopile foundation for offshore wind power according to claim 6, characterized in that: The wing plate (5) has a polygonal plate-like structure.

8. A construction method for an offshore wind turbine steel-concrete monopile foundation, comprising the offshore wind turbine steel-concrete monopile foundation as described in any one of claims 1-7, characterized in that, Includes the following steps: The pile pipe (1) pre-installed with the shear connection structure (21) is driven into the seabed and hammered until the lower pile body (12) is buried in the seabed, and the upper pile body (13) is immersed in the water above the seabed, and the top of the upper pile body (13) is exposed above the horizontal plane. Drain the water from the inner cavity (11); The annular bottom template is lowered into the inner cavity (11) and fixed to the inner wall of the upper pile body (13); The annular inner template (or the pre-installed template) is lowered into the inner cavity (11), and the bottom of the annular inner template abuts against the inner outer edge of the annular bottom template, and the annular inner template is placed extending upward in the vertical direction to form a concrete pouring space between the inner wall of the upper pile body (13), the annular bottom template and the annular inner template. A concrete mixture is poured into the concrete pouring space until the poured concrete mixture and the shear-resistant connection structure (21) solidify into the annular reinforced concrete lining (2).

9. A construction method for a steel-concrete monopile foundation for offshore wind power according to claim 8, characterized in that: The template includes a temporary template or a permanent template; the step of pouring concrete mixture in the concrete pouring space until the poured concrete mixture and the shear-resistant connection structure (21) solidify to form the annular reinforced concrete lining (2) includes: when a temporary template is used, the temporary template is removed after the annular reinforced concrete lining (2) solidifies; when a permanent template is used, the permanent template is retained in the inner cavity (11).

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