Cross-section optimization method for large-diameter hollow sandwich steel tube concrete composite single pile foundation for offshore wind power

Abstract

The present invention provides a cross-section optimization method for a large-diameter offshore wind power hollow sandwich steel tube concrete composite monopile foundation. The method comprises the following steps: firstly, cross-section parameters of the steel-concrete composite monopile foundation are digitally encoded, optimization objectives and constraints are set, a design variable range is selected, and an initial population is generated to ensure that each individual represents a different cross-section combination scheme; secondly, the fitness value of each cross-section combination scheme of the steel-concrete composite monopile foundation is calculated, and multi-objective Pareto hierarchical screening is used for evaluation; finally, a cross-section operation is performed on the selected cross-section combination schemes of the steel-concrete composite monopile foundation to generate a new cross-section combination scheme, and a small random mutation is performed on the cross-section parameters of some individuals according to a set mutation probability; and thirdly, the fitness evaluation, cross-section and mutation operations are repeated. After multiple generations of evolution, a cross-section combination scheme of the steel-concrete composite monopile foundation that meets the evaluation indicators of bending resistance and the total quality of the inner and outer steel pipes is finally obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of large-diameter offshore wind power single pile foundation structure optimization, and specifically relates to a large-diameter offshore wind power hollow sandwich steel tube concrete combined single pile foundation cross-section optimization method. Background Art

[0002] With the growing global demand for clean energy, offshore wind power has become a key development area in the renewable energy sector. However, as offshore wind power resources are reaching saturation, the potential for deep-sea wind power development has attracted significant attention. However, the complex deep-sea environment places higher demands on the performance of wind power foundation structures. Traditional monopile foundations, due to their limited design and bearing capacity, are unable to adapt to the load demands of deep-sea environments. To address this, a new type of large-diameter offshore wind power hollow sandwich steel tube concrete composite monopile foundation has been developed to improve the stability and durability of the structure and provide a more reliable support method for deep-sea wind power.

[0003] However, how to achieve economy and efficiency while meeting structural performance requirements has become a key issue in the design of this new type of monopile foundation. By rationally optimizing the cross-sectional dimensions, designers can not only significantly improve the bending resistance and overall stability of the structure, thereby more effectively resisting external forces such as ocean wind loads, but also reduce material usage and construction costs, making the design of hollow sandwich steel tube concrete composite monopile foundations more economical and sustainable. At present, there has been no research on the cross-sectional optimization of large-diameter offshore wind power hollow sandwich steel tube concrete composite monopile foundations, and further exploration and innovation are urgently needed to achieve an efficient and reliable optimization design solution. Summary of the Invention

[0004] In response to the problem that traditional single pile foundations in deepwater areas have a single structure, insufficient bending resistance and stability, and cannot meet the design and use requirements, the present invention proposes a cross-section optimization method for large-diameter offshore wind power hollow sandwich steel tube concrete combined single pile foundation, which can effectively control material usage while improving the bending resistance and stability of the foundation.

[0005] The method first digitally encodes the cross-sectional parameters of the steel-concrete composite monopile foundation, sets the optimization objectives and constraints, selects the design variable range and generates an initial population to ensure that each individual represents a different cross-sectional combination scheme; then the fitness value of each cross-sectional combination scheme of the steel-concrete composite monopile foundation is calculated and evaluated using multi-objective Pareto hierarchical screening. At the same time, combined with an adaptive selection mechanism, roulette wheel selection is used within the first 20% generations of the algorithm iteration to enhance population diversity; when the number of iterations exceeds the set number of generations, the method switches to tournament selection to focus on retaining individuals with high fitness and further promote the optimization of the population; finally, a crossover operation is performed on the selected cross-sectional combination schemes of the steel-concrete composite monopile foundation to generate a new cross-sectional combination scheme, and the cross-sectional parameters of some individuals are subjected to small random mutations with a set mutation probability; fitness evaluation, adaptive selection, crossover and mutation operations are repeated, and after multiple generations of evolution, a cross-sectional combination scheme of the steel-concrete composite monopile foundation with good bending performance and a moderate total mass of the inner and outer steel pipes is finally obtained. The present invention combines genetic algorithms to improve the bending resistance and stability of large-diameter offshore wind power hollow sandwich steel tube concrete composite single pile foundations by optimizing cross-sectional dimensions, so that the foundation can effectively control material usage while meeting engineering requirements.

[0006] The technical solution specifically adopted by the present invention to solve the technical problem is:

[0007] A cross-sectional optimization method for large-diameter offshore wind power hollow sandwich steel tube concrete composite monopile foundations is proposed. First, the cross-sectional parameters of the steel-concrete composite monopile foundation are digitally encoded, the optimization objectives and constraints are set, the design variable range is selected, and an initial population is generated to ensure that each individual represents a different cross-sectional combination scheme. Then, the fitness value of each cross-sectional combination scheme of the steel-concrete composite monopile foundation is calculated, and a multi-objective Pareto hierarchical screening is used to evaluate it. Finally, a cross-sectional operation is performed on the selected steel-concrete composite monopile foundation cross-sectional combination schemes to generate new cross-sectional combination schemes, and the cross-sectional parameters of some individuals are subjected to small random mutations according to the set mutation probability. The fitness evaluation, cross-sectional and mutation operations are repeated. After multiple generations of evolution, a cross-sectional combination scheme of the steel-concrete composite monopile foundation that meets the evaluation indicators of bending resistance and the total quality of the inner and outer steel tubes is finally obtained.

[0008] Furthermore, in the process of evaluation using multi-objective Pareto hierarchical screening, combined with the adaptive selection mechanism, roulette wheel selection is used to enhance population diversity within the first 20% generations of the algorithm iteration; when the number of iterations exceeds the set generation, it switches to tournament selection to focus on retaining high-fitness individuals and further promote population optimization; fitness evaluation, adaptive selection, crossover and mutation operations are repeated for iteration.

[0009] Furthermore, the cross-sectional parameters of the steel-concrete composite single pile foundation are digitally encoded, the optimization objectives and constraints are set, and the design variable range is selected, specifically including:

[0010] The outer diameter of the steel pipe D 外 , inner diameter of steel pipe D 内 , outer tube wall thickness t 外 , inner tube wall thickness t 内 as design variables;

[0011] The objective function of the steel-concrete composite single pile foundation is set to minimize the total mass of the inner and outer steel pipes and maximize the bending stiffness. The constraints are the basic diameter-to-thickness ratio, slenderness ratio, hollow ratio, axial compressive stability bearing capacity and bending bearing capacity:

[0012] Total mass of inner and outer steel pipes:

[0013]

[0014] L is the length of the steel pipe; ρs is the density of the steel pipe;

[0015] Bending stiffness:

[0016]

[0017] Where, E S is the elastic modulus of the steel pipe, E C is the elastic modulus of concrete;

[0018] Diameter-to-thickness ratio:

[0019]

[0020]

[0021] Where, f y is the yield strength of steel;

[0022] Slenderness ratio:

[0023]

[0024] Hollow rate:

[0025] 0.25≤η≤0.75 (7)

[0026]

[0027] Where A k is the area of ​​the hollow part, A sc is the total area of ​​the inner steel pipe and concrete;

[0028] Axial compression stability bearing capacity constraint:

[0029]

[0030] Where: N is the design value of the axial pressure, N u is the design value of the axial compressive bearing capacity of the steel tube concrete member, N0 is the design value of the axial compressive strength bearing capacity of the hollow steel tube concrete short column, is the stability factor of axially compressed members, λ sc is the slenderness ratio of the component, λ sc is the canonical slenderness ratio of the component;

[0031] Constrained by bending capacity:

[0032] M≤M u (13)

[0033] M u =γ m W sc f sc (14)

[0034]

[0035] Where: M is the design value of bending moment, M u is the design value of the axial bending bearing capacity of the steel tube concrete member, f sc is the design value of the compressive strength of the hollow steel tube concrete, γ m is the plastic development coefficient, r0 is the equivalent circle radius, r ci is the hollow radius, W sc is the section modulus of the flexural member, and θ is the hoop coefficient.

[0036] Furthermore, generating the initial population specifically includes initializing genetic algorithm parameters, including population size, maximum evolutionary generations, crossover probability, and mutation probability, to ensure the diversity and global search capability of the optimization process.

[0037] Furthermore, in the process of calculating the fitness value of each cross-section combination scheme of the steel-concrete composite single pile foundation and evaluating it using multi-objective Pareto hierarchical screening:

[0038] For each cross-section combination, the total mass and bending stiffness of the inner and outer steel tubes are calculated and standardized for all individuals. A non-dominated sorting method is used to stratify the individuals based on their combined performance in terms of total mass and bending stiffness. Individuals that fail to meet both the requirements are removed from each stratum.

[0039] For each layer of individuals, a weighted combined fitness value is calculated based on the normalized values ​​of the total mass and bending stiffness of the inner and outer steel pipes:

[0040] f(ω)=ω1·f1+ω2·(-f2) (17)

[0041] Where ω1 and ω2 are weights, ω1+ω2=1; f1 and f2 are the total mass and bending stiffness of the inner and outer steel pipes, respectively. The negative sign of f2 is added to transform both objective functions into minimization problems to facilitate the solution of the model.

[0042] Furthermore, in each generation of updates, individuals with high fitness in the top 20% of the Pareto hierarchy are prioritized to ensure the stability of the optimization direction. At the same time, to avoid premature convergence, individuals with medium and low fitness in the bottom 80% of the hierarchy are allowed to enter the next generation with a certain probability, thereby maintaining population diversity. The fitness value of each individual is returned to the population, allowing it to be adaptively selected based on fitness value in subsequent selections.

[0043] A cross-section optimization system for large-diameter offshore wind power hollow sandwich steel tube concrete composite monopile foundations, including:

[0044] The digital coding module is used to digitally encode the cross-sectional parameters of the steel-concrete composite single pile foundation, set the optimization objectives and constraints, and select the design variable range;

[0045] The iterative evolution module is used to generate the initial population to ensure that each individual represents a different cross-sectional combination scheme; the fitness value of each cross-sectional combination scheme of the steel-concrete composite monopile foundation is calculated, and a multi-objective Pareto hierarchical screening is used for evaluation; finally, a crossover operation is performed on the selected cross-sectional combination schemes of the steel-concrete composite monopile foundation to generate a new cross-sectional combination scheme, and the cross-sectional parameters of some individuals are subjected to small random mutations according to the set mutation probability; the fitness evaluation, crossover and mutation operations are repeated, and after multiple generations of evolution, a cross-sectional combination scheme of the steel-concrete composite monopile foundation that meets the evaluation indicators of bending resistance and the total quality of the internal and external steel pipes is finally obtained.

[0046] Furthermore, the iterative evolution module uses a multi-objective Pareto hierarchical screening evaluation process, combined with an adaptive selection mechanism, to use roulette wheel selection to enhance population diversity within the first 20% of the algorithm iterations; when the number of iterations exceeds the set number of generations, it switches to tournament selection to focus on retaining high-fitness individuals and further promote population optimization; and iterates by repeating fitness evaluation, adaptive selection, crossover, and mutation operations.

[0047] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the above-mentioned method for optimizing the cross-section of a large-diameter offshore wind power hollow sandwich steel tube concrete composite single pile foundation are implemented.

[0048] A non-transitory computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the above-mentioned method for optimizing the cross-section of a large-diameter offshore wind power hollow sandwich steel tube concrete combined single pile foundation.

[0049] Compared to existing technologies, the present invention and its preferred solution utilize a dual-objective optimization approach: the total mass of the inner and outer steel pipes and their flexural stiffness. This ensures that the foundation structure meets flexural performance requirements while minimizing material usage, thereby improving the overall project's economic efficiency and sustainability. Furthermore, in the preferred solution, an adaptive selection mechanism is employed, enabling flexible adjustment of the selection strategy based on the state of the population during the optimization process, maintaining population diversity at different stages and preventing premature convergence. This ensures that the algorithm maintains efficient search capabilities at all stages of progress, significantly improving the efficiency of the optimization process and the accuracy of the results. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0051] Figure 1 This is a flow chart for optimizing the cross-section of a hollow sandwich steel tube concrete combined single pile foundation according to an embodiment of the present invention;

[0052] Figure 2 Schematic diagram of cross-section optimization parameters of a hollow sandwich steel tube concrete combined single pile foundation according to an embodiment of the present invention;

[0053] Figure 3 This is a relationship diagram between the flexural stiffness and the total mass of the inner and outer steel pipes during the cross-section optimization process of the hollow sandwich steel tube concrete combined single pile foundation according to an embodiment of the present invention. DETAILED DESCRIPTION

[0054] To make the features and advantages of this patent more clearly understood, the following embodiments are specifically described in detail as follows:

[0055] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the art to which this application belongs.

[0056] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0057] like Figure 1 As shown, the present invention provides a cross-section optimization method for a large-diameter offshore wind power hollow sandwich steel tube concrete combined single pile foundation. The basic embodiment process can include the following four steps:

[0058] Step S1: Digitally encode the cross-sectional parameters of the steel-concrete composite monopile foundation, initialize the optimization algorithm parameters, select the design variable range, set the optimization target and constraints, generate the initial population, and ensure that each individual represents a different cross-sectional combination scheme;

[0059] Initialize the genetic algorithm parameters, including population size, maximum evolutionary generations, crossover probability, and mutation probability, to ensure the diversity and global search capability of the optimization process; Figure 2 As shown, select the outer diameter D of the steel pipe 外 , inner diameter of steel pipe D 内 , outer tube wall thickness t 外 , inner tube wall thickness t 内 As design variables and select the variation range:

[0060] 7m≤D 外 ≤12 m (1)

[0061] 7m≤D 内 ≤12m (2)

[0062] 0.01m≤t 外 ≤0.15m (3)

[0063] 0.01m≤t 内 ≤0.15m (4)

[0064] The objective function of the steel-concrete composite monopile foundation is to minimize the total mass of the inner and outer steel tubes and maximize the bending stiffness. The constraints are the diameter-to-thickness ratio, slenderness ratio, hollowness ratio, axial compressive stability bearing capacity, and bending bearing capacity of the foundation:

[0065] ①Total mass of inner and outer steel pipes:

[0066]

[0067] ② Bending stiffness:

[0068]

[0069] Where, E S is the elastic modulus of the steel pipe, E C is the elastic modulus of concrete;

[0070] The constraints that meet the structural requirements include the foundation's diameter-to-thickness ratio, slenderness ratio, and hollowness ratio;

[0071] ① Diameter-to-thickness ratio:

[0072]

[0073] Where, f y is the yield strength of steel;

[0074] ②Slenderness ratio:

[0075]

[0076] ③ Hollowness rate:

[0077] 0.25≤η≤0.75 (11)

[0078]

[0079] Where A k is the area of ​​the hollow part, A sc is the total area of ​​inner steel pipe and concrete

[0080] The constraints for meeting the strength requirements include the foundation's axial compressive stability and bending bearing capacity;

[0081] ①Axial compressive stability bearing capacity constraint:

[0082]

[0083]

[0084] Where: N is the design value of the axial pressure, N u is the design value of the axial compressive bearing capacity of the steel tube concrete member, N0 is the design value of the axial compressive strength bearing capacity of the hollow steel tube concrete short column, is the stability factor of axially compressed members, λ sc is the slenderness ratio of the component, λ sc is the canonical slenderness ratio of the component.

[0085] ②Constrained by bending capacity:

[0086] M≤M u (17)

[0087] M u =γ m W sc f sc (18)

[0088]

[0089] Where: M is the design value of bending moment, M u is the design value of the axial bending bearing capacity of the steel tube concrete member, f sc is the design value of the compressive strength of the hollow steel tube concrete, γ mis the plastic development coefficient, r0 is the equivalent circle radius, r ci is the hollow radius, W sc is the section modulus of the flexural member, and θ is the hoop coefficient.

[0090] Step S2: Calculate the fitness value of each cross-section combination scheme of the steel-concrete composite single pile foundation and evaluate it using multi-objective Pareto hierarchical screening. Simultaneously, in combination with an adaptive selection mechanism, roulette wheel selection is used within the first 20% of the algorithm iterations to enhance population diversity. When the number of iterations exceeds the set number of generations, tournament selection is switched to focus on retaining individuals with high fitness, further promoting population optimization.

[0091] For each cross-section combination, the total mass and bending stiffness of the inner and outer tubes are calculated and standardized for all individuals. Using a non-dominated sorting method, the individuals are stratified based on their combined performance in terms of total mass and bending stiffness. Individuals that fail to meet both the requirements are removed from each stratum.

[0092] For each layer of individuals, a weighted combined fitness value is calculated based on the normalized values ​​of the total mass and bending stiffness of the inner and outer steel pipes:

[0093] f(ω)=ω1·f1+ω2·(-f2) (21)

[0094] Where ω1 and ω2 are weights, ω1+ω2=1; f1 and f2 are the total mass and bending stiffness of the inner and outer steel pipes, respectively. The negative sign of f2 is added to transform both objective functions into minimization problems to facilitate the solution of the model.

[0095] In each generation of updates, individuals with high fitness in the top 20% of the Pareto hierarchy are prioritized to ensure the stability of the optimization direction. At the same time, to avoid premature convergence, individuals with medium and low fitness in the bottom 80% of the hierarchy are allowed to enter the next generation with a certain probability, thereby maintaining population diversity. The fitness value of each individual is returned to the population, allowing it to be adaptively selected based on its fitness value in subsequent selections. The fitness value of each individual is returned to the population, allowing it to be adaptively selected based on its fitness value in subsequent selections.

[0096] Step S3: performing a cross operation on the selected steel-concrete composite single pile foundation section combination schemes to generate a new section combination scheme, and performing a small random mutation on the section parameters of some individuals according to the set mutation probability;

[0097] Step S4: Repeat steps S2 and S3. After multiple generations of evolution, a steel-concrete composite single pile foundation section combination scheme with good bending performance and moderate total mass of inner and outer steel pipes is finally obtained.

[0098] like Figure 3 As shown in the figure, it is the Pareto frontier obtained through iterative evolution, reflecting the optimal compromise between the total mass of the inner and outer steel pipes and the bending stiffness. The horizontal axis represents the total amount of steel used in the design, and the vertical axis is the bending stiffness. The negative value is used to unify it with the optimization goal of the amount of steel used as a minimization problem. Each point in the figure represents a Pareto optimal solution, at which the optimal balance is achieved between the total mass of the inner and outer steel pipes and the bending stiffness, and it is impossible to further improve one goal without compromising the other. Through this process, the optimal choice of different cross-sectional combinations is obtained, and with reference to the single pile foundation before optimization, the cross-sectional dimensions of the hollow sandwich steel tube concrete composite single pile foundation are finally obtained as shown in Table 1.

[0099] After optimization by the present invention, the total mass of the inner and outer steel pipes of the hollow sandwich steel tube concrete combined single pile foundation remains basically unchanged, and the bending resistance of the structure is significantly improved.

[0100] Table 1 Optimized cross-sectional dimensions

[0101]

[0102] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0103] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0104] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0105] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0106] It should be noted that, unless otherwise defined, the technical or scientific terms used in the present invention should have the usual meanings understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0107] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

[0108] This patent is not limited to the above-mentioned optimal implementation method. Anyone can derive various other forms of large-diameter offshore wind power hollow sandwich steel tube concrete combined single pile foundation cross-section optimization methods based on the inspiration of this patent. All equal changes and modifications made within the scope of the patent application of this invention should be covered by this patent.

Claims

1. A cross-section optimization method for a large-diameter offshore wind power hollow sandwich steel tube concrete combined single pile foundation, characterized by: First, the cross-sectional parameters of the steel-concrete composite monopile foundation are digitally encoded, the optimization objectives and constraints are set, the design variable range is selected, and an initial population is generated to ensure that each individual represents a different cross-sectional combination scheme. The fitness value of each cross-sectional combination scheme of the steel-concrete composite monopile foundation is then calculated, and a multi-objective Pareto hierarchical screening is used to evaluate it. Finally, a crossover operation is performed on the selected cross-sectional combination schemes of the steel-concrete composite monopile foundation to generate a new cross-sectional combination scheme, and the cross-sectional parameters of some individuals are subjected to small random mutations using a set mutation probability. The fitness evaluation, crossover, and mutation operations are repeated. After multiple generations of evolution, a cross-sectional combination scheme of the steel-concrete composite monopile foundation that meets the evaluation indicators of bending resistance and the total quality of the internal and external steel pipes is finally obtained. The cross-sectional parameters of the steel-concrete composite single pile foundation are digitally encoded, the optimization objectives and constraints are set, and the design variable range is selected, specifically including: The outer diameter of the steel pipe D 外 , inner diameter of steel pipe D 内 , outer tube wall thickness t 外 , inner tube wall thickness t 内 as design variables; The objective function of the steel-concrete composite single pile foundation is set to minimize the total mass of the inner and outer steel pipes and maximize the bending stiffness. The constraints are the basic diameter-to-thickness ratio, slenderness ratio, hollow ratio, axial compressive stability bearing capacity and bending bearing capacity: Total mass of inner and outer steel pipes: L is the length of the steel pipe; ρ s is the density of the steel pipe; Bending stiffness: Where, E S is the elastic modulus of the steel pipe, E C is the elastic modulus of concrete; Diameter-to-thickness ratio: Where, f y is the yield strength of steel; Slenderness ratio: Hollow rate: 0.25≤η≤0.75 (7) Where A k is the area of ​​the hollow part, A sc is the total area of ​​the inner steel pipe and concrete; Axial compression stability bearing capacity constraint: Where: N is the design value of the axial pressure, N u is the design value of the axial compressive bearing capacity of the steel tube concrete member, N0 is the design value of the axial compressive strength bearing capacity of the hollow steel tube concrete short column, is the stability factor of axially compressed members, λ sc is the component slenderness ratio, is the regular slenderness ratio of the component; f sc is the design value of compressive strength of hollow steel tube concrete; Constrained by bending capacity: M≤M u (13) M u =γ m W sc f sc (14) Where: M is the design value of bending moment, M u is the design value of the axial bending bearing capacity of the steel tube concrete member, γ m is the plastic development coefficient, r0 is the equivalent circle radius, r ci is the hollow radius, W sc is the section modulus of the flexural member, θ is the hoop coefficient; In the process of calculating the fitness value of each cross-section combination scheme of the steel-concrete composite single pile foundation and evaluating it using multi-objective Pareto hierarchical screening: For each cross-section combination, the total mass and bending stiffness of the inner and outer steel tubes are calculated and standardized for all individuals. A non-dominated sorting method is used to stratify the individuals based on their combined performance in terms of total mass and bending stiffness. Individuals that fail to meet both the requirements are removed from each stratum. For each layer of individuals, a weighted combined fitness value is calculated based on the normalized values ​​of the total mass and bending stiffness of the inner and outer steel pipes: f(ω)=ω1·f1+ω2·(-f2) (17) Where ω1 and ω2 are weights, ω1+ω2=1; f1 and f2 are the total mass and bending stiffness of the inner and outer steel pipes, respectively. The negative sign of f2 is added to transform both objective functions into minimization problems to facilitate the solution of the model.

2. The cross-section optimization method for a large-diameter offshore wind power hollow sandwich steel tube concrete combined single pile foundation according to claim 1 is characterized by: In the process of evaluation using multi-objective Pareto hierarchical screening, combined with the adaptive selection mechanism, roulette wheel selection is used to enhance population diversity within the first 20% of the algorithm iterations; when the number of iterations exceeds the set number of generations, it switches to tournament selection to focus on retaining high-fitness individuals and further promote population optimization; fitness evaluation, adaptive selection, crossover and mutation operations are repeated for iteration.

3. The cross-section optimization method for large-diameter offshore wind power hollow sandwich steel tube concrete combined single pile foundation according to claim 1 is characterized by: The generating of the initial population specifically includes initializing the genetic algorithm parameters, including population size, maximum evolutionary generations, crossover probability and mutation probability, so as to ensure the diversity and global search capability of the optimization process.

4. The cross-section optimization method for a large-diameter offshore wind power hollow sandwich steel tube concrete combined single pile foundation according to claim 2 is characterized by: In each generation of updates, high fitness individuals in the top 20% of the Pareto hierarchy are prioritized to ensure the stability of the optimization direction. To avoid premature convergence, medium and low fitness individuals in the last 80% of the hierarchy are allowed to enter the next generation population with a certain probability, thereby maintaining population diversity. The fitness value of each individual is returned to the population for adaptive selection based on the fitness value in subsequent selections.

5. A large-diameter offshore wind power hollow sandwich steel tube concrete combined single pile foundation cross-section optimization system, used to execute the optimization method according to any one of claims 1 to 4, characterized in that: include: The digital coding module is used to digitally encode the cross-sectional parameters of the steel-concrete composite single pile foundation, set the optimization objectives and constraints, and select the design variable range; Iterative evolution module, used to generate the initial population to ensure that each individual represents a different cross-sectional combination scheme; The fitness value of each cross-section combination scheme of the steel-concrete composite single pile foundation is calculated, and multi-objective Pareto hierarchical screening is used for evaluation; finally, a cross-section combination scheme of the selected steel-concrete composite single pile foundation is cross-operated to generate a new cross-section combination scheme, and the cross-section parameters of some individuals are subjected to slight random mutations through the set mutation probability; the fitness evaluation, cross-over and mutation operations are repeated, and after multiple generations of evolution, a steel-concrete composite single pile foundation cross-section combination scheme that meets the bending performance and total quality evaluation indicators of the internal and external steel pipes is finally obtained.

6. The cross-section optimization system for large-diameter offshore wind power hollow sandwich steel tube concrete combined single pile foundation according to claim 5 is characterized by: The iterative evolution module uses a multi-objective Pareto hierarchical screening evaluation process, combined with an adaptive selection mechanism, to use roulette wheel selection to enhance population diversity within the first 20% of the algorithm iterations; when the number of iterations exceeds the set number of generations, it switches to tournament selection to focus on retaining high-fitness individuals and further promote population optimization; and iterates by repeating fitness evaluation, adaptive selection, crossover, and mutation operations.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the cross-section optimization method of a large-diameter offshore wind power hollow sandwich steel tube concrete combined single pile foundation as described in any one of claims 1 to 4 are implemented.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the cross-section optimization method of a large-diameter offshore wind power hollow sandwich steel tube concrete composite single pile foundation as described in any one of claims 1 to 4 are implemented.

Images