Offshore wind power single pile foundation scouring depth evaluation method, system, equipment and medium

Abstract

The invention belongs to the technical field of offshore wind power, and relates to an offshore wind power single pile foundation scouring depth evaluation method, system and equipment and a medium. Comprising the following steps: acquiring historical scouring and scanning data of the wind turbine generator, and historical scouring depth data and historical wind turbine generator first-order natural vibration frequency data which are in one-to-one correspondence with the historical scouring and scanning data; acquiring parameters of the scour pit, and establishing a scour pit form model; establishing a frequency calculation model of the wind turbine generator based on the scour pit form model; historical scouring and scanning data are substituted into the frequency calculation model to obtain predicted first-order natural vibration frequency data of the wind turbine generator, and the reliability of the frequency calculation model is verified according to the historical first-order natural vibration frequency data of the wind turbine generator; and determining that the frequency calculation model is reliable, obtaining real-time first-order natural vibration frequency of the wind turbine generator, and substituting the first-order natural vibration frequency into the frequency calculation model to obtain the predicted scouring depth. According to the method, the timeliness and reliability of scouring evaluation are remarkably improved, and accurate evaluation of the foundation scouring depth is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of offshore wind power, and relates to a method, a system, a device and a medium for evaluating the scour depth of a monopile foundation for offshore wind power. Background Art

[0002] With the continuous growth of the global demand for renewable energy, offshore wind power has become an important way to develop clean energy. As a widely used foundation form in offshore wind power projects, monopile foundations have been widely applied in many offshore wind power projects due to their simple design, low construction cost and good structural stability. The monopile foundation directly drives a large-diameter steel pipe pile into the seabed, bears the vertical and horizontal loads from the wind turbine, and provides necessary support and stability for the wind turbine. However, offshore wind power projects usually face complex marine environmental conditions, including factors such as waves, tides, wind and ocean currents. The combined action of these factors makes the monopile foundation exposed to harsh natural conditions for a long time, posing certain engineering risks.

[0003] In practical applications, under the long-term load action, especially the action of ocean currents, the marine environment where the monopile foundation is located will have a significant impact on the seabed soil around the pile body. The action of ocean currents causes complex changes in the flow field around the monopile foundation, forming structures such as a horseshoe vortex in front of the pile and a wake vortex street behind the pile. These flow field distortions lead to a significant increase in the local flow velocity and a sharp rise in the bed shear stress. When these shear stresses exceed the critical incipient shear stress of the seabed soil, the surface soil particles will begin to move, forming a typical local scour pit. Over time, the depth of the scour pit will continue to increase, reducing the effective embedment depth of the monopile foundation, and further affecting the structural stability and bearing capacity.

[0004] Due to the complexity of the scour process and its significant impact on the stability of monopile foundations, the accurate prediction of scour depth has become an important issue in offshore wind power engineering. In the prior art, the commonly used scour depth prediction methods mainly rely on empirical formulas, such as the DNV code recommended formula, the HEC-18 method, etc. Although these methods have good engineering application effects and relatively simple calculation processes, they have certain limitations. First of all, empirical formulas are usually established based on experimental data under specific environmental conditions and cannot be fully applied to the complex and variable hydrodynamic conditions in actual engineering. Secondly, most of these methods only consider the influence of a single factor (such as flow velocity or wave height) and cannot fully consider the scour mechanism under the multi-directional coupling action of wind, wave and current. More importantly, empirical formulas fail to fully reflect the dynamic development characteristics of the scour process, resulting in low prediction accuracy in the long-term service stage and being unable to accurately predict the evolution trend of scour.

[0005] Therefore, existing prediction methods face significant challenges when dealing with complex marine environments and the interaction of multiple factors. To improve the prediction accuracy of the long-term stability of offshore wind turbine monopile foundations, a new evaluation method is urgently needed to more accurately and real-time grasp the foundation scour depth and take timely prevention and control measures. Summary of the Invention

[0006] The purpose of the present invention is to provide a method, system, device, and medium for evaluating the scour depth of offshore wind turbine monopile foundations to solve the problems in the prior art and achieve accurate evaluation of the foundation scour depth.

[0007] To achieve the above object, the present invention adopts the following technical solutions: In the first aspect, the present invention provides a method for evaluating the scour depth of offshore wind turbine monopile foundations, including the following steps: Obtain the historical scour survey data of the wind turbine, as well as the corresponding historical scour depth data and historical first-order natural vibration frequency data of the wind turbine; Obtain the parameters of the scour pit and establish a scour pit morphology model; Based on the scour pit morphology model, establish a frequency calculation model for the wind turbine; Substitute the historical scour survey data into the frequency calculation model to obtain the predicted first-order natural vibration frequency data of the wind turbine, and verify the reliability of the frequency calculation model according to the historical first-order natural vibration frequency data of the wind turbine; Determine that the frequency calculation model is reliable, obtain the real-time first-order natural vibration frequency of the wind turbine, and substitute it into the frequency calculation model to obtain the predicted scour depth.

[0008] Preferably, the parameters of the scour pit include the scour pit toe, the scour pit depth, and the scour pit bottom range.

[0009] Preferably, the frequency calculation model is established based on the coupling effect of the wind turbine nacelle, the tower structure, the monopile foundation, and the surrounding soil.

[0010] Preferably, the wind turbine nacelle is simplified as a concentrated mass unit, the tower structure and the monopile foundation are simulated by beam elements, and the surrounding soil is established as an equivalent stiffness distribution model according to the scour pit morphology model.

[0011] Preferably, the method for determining that the frequency calculation model is reliable is: if the difference between the predicted first-order natural vibration frequency data of the wind turbine and the historical first-order natural vibration frequency data of the wind turbine for verifying the frequency is within 0.5%, then the frequency calculation model is reliable.

[0012] Preferably, if the frequency calculation model is not reliable, adjust the stiffness of the surrounding soil until the frequency calculation model is reliable.

[0013] Preferably, the specific method for obtaining the first-order natural vibration frequency of the real-time wind turbine and substituting it into the frequency calculation model to obtain the predicted scour depth is as follows: Use the frequency calculation model to calculate the first-order natural vibration frequency of the wind turbine that has not been scoured to 0.6 times the designed pile embedment depth, and establish a functional relationship between the scour depth and the first-order natural vibration frequency of the wind turbine; obtain the first-order natural vibration frequency of the real-time wind turbine, and substitute this first-order natural vibration frequency of the real-time wind turbine into the functional relationship to obtain the predicted scour depth.

[0014] In a second aspect, the present invention provides an offshore wind power monopile foundation scour depth evaluation system, including: The first module: Obtain the historical scour survey data of the wind turbine, as well as the corresponding historical scour depth data and historical first-order natural vibration frequency data of the wind turbine for the historical scour survey data; The second module: Obtain the parameters of the scour pit and establish a scour pit morphology model; The third module: Based on the scour pit morphology model, establish a frequency calculation model for the wind turbine; The fourth module: Substitute the historical scour survey data into the frequency calculation model to obtain the predicted first-order natural vibration frequency data of the wind turbine, and verify the reliability of the frequency calculation model according to the historical first-order natural vibration frequency data of the wind turbine; The fifth module: Determine that the frequency calculation model is reliable, obtain the first-order natural vibration frequency of the real-time wind turbine, and substitute it into the frequency calculation model to obtain the predicted scour depth.

[0015] In a third aspect, the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the offshore wind power monopile foundation scour depth evaluation method are implemented.

[0016] In a fourth aspect, the present invention provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of the offshore wind power monopile foundation scour depth evaluation method are implemented.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention accurately reflects the true attenuation degree of the surrounding soil support effect through the scour pit morphology model; conducts a closed-loop verification of the frequency calculation model through historical data to ensure the prediction accuracy and engineering applicability of the model; forms a complete technical chain of "data collection - model iteration - dynamic warning" by combining the inversely calculated scour depth with the real-time monitored natural vibration frequency, significantly improving the timeliness and reliability of scour evaluation and achieving accurate evaluation of the foundation scour depth. Description of the Drawings

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0019] Figure 1 This is the multi-beam isobath map of the unit of the present invention; Figure 2 This is the frequency calculation model of the present invention; Figure 3 This is the scour pit morphology of the present invention; Figure 4 This is the function curve of the scour depth and the first natural vibration frequency of the wind turbine unit of the present invention. Detailed implementation manners

[0020] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0022] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0023] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present invention is normally placed. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present invention. In addition, terms such as "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0024] In addition, when the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and it does not mean that the structure must be completely horizontal, but it can be slightly inclined.

[0025] In the description of the embodiments of the present invention, it should also be noted that unless otherwise clearly specified and limited, when the terms "arranged", "installed", "connected", and "connected" appear, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0026] The following further describes the present invention in detail with reference to the drawings: The first object of the present invention is to provide a method for evaluating the scour depth of a monopile foundation for offshore wind power, including the following steps: Obtain the historical scour survey data of the wind turbine, as well as the historical scour depth data and the historical first-order natural vibration frequency data of the wind turbine corresponding to the historical scour survey data one by one; Obtain the parameters of the scour pit and establish a scour pit shape model; Establish a frequency calculation model of the wind turbine based on the scour pit shape model; Substitute the historical scour survey data into the frequency calculation model to obtain the predicted first-order natural vibration frequency data of the wind turbine, and verify the reliability of the frequency calculation model according to the historical first-order natural vibration frequency data of the wind turbine; Determine that the frequency calculation model is reliable, obtain the real-time first-order natural vibration frequency of the wind turbine, and substitute it into the frequency calculation model to obtain the predicted scour depth.

[0027] The present invention constructs an evaluation model based on the coupling of the scour pit shape and the structural dynamic characteristics by integrating the historical scour survey data, the measured scour depth, and the dynamic response data of the unit, breaking through the limitations of the traditional method that depends on a single empirical formula, and realizing the dynamic correlation analysis of the scour depth and the natural vibration frequency.

[0028] In the present invention, the scour pit shape model is equivalently established based on the multi-beam survey results during the operation period of the machine position, which can accurately reflect the true attenuation degree of the surrounding soil support effect; the frequency calculation model is verified in a closed loop through historical data to ensure the prediction accuracy and engineering applicability of the model; finally, the scour depth is inversely calculated by combining the real-time monitored natural vibration frequency, forming a complete technical chain of "data acquisition - model iteration - dynamic warning", significantly improving the timeliness and reliability of the scour assessment.

[0029] The parameters of the scour pit include the toe of the scour pitα , the scour pit depth H and the range of the scour pit bottom s , realizing the multi-dimensional quantitative characterization of the three-dimensional mechanical effects of the scour pit. Compared with the traditional method that only focuses on a single scour depth, the present invention reflects the shear stability of the soil mass at the scour edge through the scour toe, directly correlates the scour depth with the effective embedment length of the foundation, and reveals the weakened area of the surrounding soil support effect by the range of the scour pit bottom. The synergistic effect of the three can accurately simulate the non-linear influence of scour on the structural stiffness distribution.

[0030] The frequency calculation model is established based on the coupling effect of the wind turbine nacelle, tower structure, monopile foundation and the surrounding soil mass. Among them, the wind turbine nacelle is simplified into a lumped mass unit, the tower structure and the monopile foundation are simulated by beam elements, and the equivalent stiffness distribution model of the surrounding soil mass is established according to the scour pit morphology model. By establishing a refined coupling dynamics model, the full-dimensional mapping of the scour effect and the overall dynamic response of the unit is realized for the first time. Specifically, the wind turbine nacelle is simplified into a lumped mass unit to accurately characterize the dominant effect of the top inertial load on the frequency; the beam elements are used to simulate the tower structure and the monopile foundation to truly reflect the non-linear distribution characteristics of the structural stiffness along the height; based on the scour pit morphology, an equivalent stiffness model of the surrounding soil mass is constructed to break through the limitation of the traditional uniform soil assumption and accurately quantify the attenuation of the surrounding soil support stiffness caused by scour.

[0031] The method for determining the reliability of the frequency calculation model is as follows: if the difference between the predicted first natural vibration frequency data of the wind turbine unit and the historical first natural vibration frequency data of the wind turbine unit for verifying the frequency is within 0.5%, the frequency calculation model is reliable. If the frequency calculation model is not reliable, the stiffness of the surrounding soil mass is adjusted until the frequency calculation model is reliable. The present invention constructs an adaptive closed-loop model optimization system by establishing a quantitative verification standard with the deviation between the predicted and measured frequencies ≤ 0.5% and introducing a dynamic correction mechanism for the soil mass stiffness parameters, meeting the precise control requirements for the dynamic characteristics of the unit in harsh scenarios such as offshore wind power.

[0032] The specific method for obtaining the real-time first natural vibration frequency of the wind turbine unit and substituting it into the frequency calculation model to obtain the predicted scour depth is as follows: use the frequency calculation model to calculate the first natural vibration frequency of the wind turbine unit that has not been scoured to 0.6 times the designed pile embedment depth, establish a functional relationship between the scour depth and the first natural vibration frequency of the wind turbine unit; obtain the real-time first natural vibration frequency of the wind turbine unit, and substitute this real-time first natural vibration frequency of the wind turbine unit into the functional relationship to obtain the predicted scour depth.

[0033] Example 1 Step 1: Sort out and analyze the historical scour survey data of a wind turbine unit at a point from the operation period to the present. The scour surveys are recorded as C1, C2...C in chronological order n；The scouring depths corresponding one by one to the historical scouring survey data are H1, H2... H n , and the first-order natural vibration frequencies of the wind turbine units monitored during the corresponding surveys are f1, f2... f n .

[0034] Step 2: As shown in Figure 1 , the scouring pit shape is equivalently established based on the multi-beam survey results during the operation period of the machine position. Specifically, the parameters obtained from the multi-beam survey are: the toe of the scouring pit α , the scouring pit depth H and the range of the scouring pit bottom s . According to the above parameters, a scouring pit shape model is established, as shown in Figure 3 ; for the wind turbine unit corresponding to Step 1, based on the scouring pit shape model and based on the coupling effect of the wind turbine nacelle, tower structure, monopile foundation and the surrounding soil, a frequency calculation model is established, as shown in Figure 2 ; among them, the wind turbine nacelle is simplified as a concentrated mass unit, the tower structure and monopile foundation are simulated by beam elements, and the surrounding soil is used to establish an equivalent stiffness distribution model according to the scouring pit shape model.

[0035] Step 3: According to the frequency calculation model in Step 2, calculate the first-order natural vibration frequencies of the corresponding wind turbine units of C1, C2... C n , and record them as f 1', f 2'... f n '; Compare f 1', f 2'... f n ' with the f1, f2... f n obtained in Step 1. If the difference in the natural vibration frequencies between the two is within 0.5%, the model is verified to be reliable; if they are inconsistent, adjust the stiffness of the surrounding soil for calculation until the model is reliable.

[0036] Step 4: Use the reliable frequency calculation model to batch-calculate the first-order natural vibration frequencies of the units from no scouring to scouring reaching 0.6 times the designed buried depth of the pile, that is, η = 0~0.6 (η is the relative scouring depth, η = H / H0, H0 is the mud-in depth of the pile foundation in the case of no scouring), so as to obtain the one-to-one correspondence between the scouring depth and the first-order natural vibration frequency of the wind turbine unit, and fit the function expression f = f(η) of the first-order natural vibration frequency of the wind turbine unit and the scouring depth, as shown in Figure 4 .

[0037] Step 5: Obtain the real-time first-order natural vibration frequency of the wind turbine unit, and substitute it into f = f(η) to obtain the predicted scouring depth.

[0038] Example 2 The difference between this embodiment and Embodiment 1 is that after obtaining the predicted scouring depth, it is compared with the actual scouring depth, and the frequency calculation model is iteratively optimized.

[0039] The second object of the present invention is to provide an offshore wind power monopile foundation scouring depth evaluation system, including: The first module: obtaining the historical scouring survey data of the wind turbine, as well as the historical scouring depth data and historical wind turbine first-order natural vibration frequency data corresponding to the historical scouring survey data one by one; The second module: obtaining the parameters of the scouring pit and establishing a scouring pit shape model; The third module: establishing a frequency calculation model of the wind turbine based on the scouring pit shape model; The fourth module: substituting the historical scouring survey data into the frequency calculation model to obtain the predicted first-order natural vibration frequency data of the wind turbine, and verifying the reliability of the frequency calculation model according to the historical first-order natural vibration frequency data of the wind turbine; The fifth module: determining that the frequency calculation model is reliable, obtaining the real-time first-order natural vibration frequency of the wind turbine, and substituting it into the frequency calculation model to obtain the predicted scouring depth.

[0040] The offshore wind power monopile foundation scouring depth evaluation system of the present invention realizes accurate prediction of the scouring depth by real-time monitoring of the natural vibration frequency of the wind turbine and combining historical data with the frequency calculation model, providing a reliable early warning for the safe operation of the wind turbine; at the same time, the system replaces the traditional manual survey with automated monitoring, significantly reducing the maintenance cost and improving the detection efficiency, enabling the maintenance personnel to take remedial measures in time and effectively extending the service life of the wind turbine; in addition, based on the real-time prediction of the scouring depth by the natural vibration frequency of the wind turbine, inferring the foundation scouring depth through the natural vibration frequency of the wind turbine, a closed-loop management from monitoring and early warning to decision-making optimization is formed, comprehensively improving the safety and economy of the whole life cycle of the offshore wind power monopile foundation.

[0041] The third object of the present invention is to provide a computer device, which includes a processor and a memory. The memory is used to store a computer program, and the computer program includes program instructions. The processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, and is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function. The processor described in the embodiments of the present invention can be used for the operation of the method for evaluating the scour depth of the monopile foundation of offshore wind power.

[0042] The fourth object of the present invention is to provide a storage medium, specifically a computer-readable storage medium (Memory). The computer-readable storage medium is a memory device in the computer device and is used to store programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and, of course, the extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. And in this storage space, one or more instructions suitable for being loaded and executed by the processor are also stored. These instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. One or more instructions stored in the computer-readable storage medium can be loaded and executed by the processor to implement the corresponding steps of the method for evaluating the scour depth of the monopile foundation of offshore wind power in the above embodiments.

[0043] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) that contain computer-usable program code.

[0044] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for realizing the functions specified in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0045] These computer program instructions can 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 generate a manufactured article including instruction means, and the instruction means realizes the functions specified in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0046] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Therefore, the instructions executed on the computer or other programmable device provide steps for realizing the functions specified in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: still can modify the specific implementation manners of the present invention or make equivalent replacements, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for evaluating the scour depth of a monopile foundation for offshore wind power, characterized in that, Including the following steps: Obtain the historical scouring survey data of the wind turbine, as well as the corresponding historical scouring depth data and historical first-order natural vibration frequency data of the wind turbine for each piece of historical scouring survey data; Obtain the parameters of the scour pit and establish a scour pit shape model; Based on the scour pit shape model, establish a frequency calculation model for the wind turbine; Substitute the historical scouring survey data into the frequency calculation model to obtain the predicted first-order natural vibration frequency data of the wind turbine, and verify the reliability of the frequency calculation model according to the historical first-order natural vibration frequency data of the wind turbine; Determine that the frequency calculation model is reliable, obtain the real-time first-order natural vibration frequency of the wind turbine, and substitute it into the frequency calculation model to obtain the predicted scouring depth.

2. The method for evaluating the scour depth of a monopile foundation for offshore wind power according to claim 1, wherein The parameters of the scour pit include the scour pit toe, the scour pit depth, and the scour pit bottom range.

3. The method for evaluating the scour depth of a monopile foundation for offshore wind power according to claim 1, wherein, The frequency calculation model is established based on the coupled action of the wind turbine nacelle, the tower structure, the monopile foundation, and the surrounding soil.

4. The method for evaluating the scour depth of a monopile foundation for offshore wind power according to claim 3, wherein, The wind turbine nacelle is simplified into a concentrated mass unit, the tower structure and the monopile foundation are simulated by beam elements, and the surrounding soil is used to establish an equivalent stiffness distribution model according to the scour pit shape model.

5. The method for evaluating the scour depth of a monopile foundation for offshore wind power according to claim 3, characterized in that, The method for determining that the frequency calculation model is reliable is: if the difference between the predicted first-order natural vibration frequency data of the wind turbine and the historical first-order natural vibration frequency data for verifying the frequency is within 0.5%, then the frequency calculation model is reliable.

6. The method for evaluating the scour depth of a monopile foundation for offshore wind power according to claim 3, characterized in that, If the frequency calculation model is not reliable, adjust the stiffness of the surrounding soil until the frequency calculation model is reliable.

7. A method for evaluating the scour depth of a monopile foundation for offshore wind power according to claim 1, characterized in that, The specific method for obtaining the real-time first-order natural vibration frequency of the wind turbine and substituting it into the frequency calculation model to obtain the predicted scouring depth is as follows: Use the frequency calculation model to calculate the first-order natural vibration frequency of the wind turbine that has not been scoured to 0.6 times the designed pile embedment depth, and establish a functional relationship between the scouring depth and the first-order natural vibration frequency of the wind turbine; obtain the real-time first-order natural vibration frequency of the wind turbine, and substitute this real-time first-order natural vibration frequency of the wind turbine into the functional relationship to obtain the predicted scouring depth.

8. An evaluation system for the scour depth of a monopile foundation of an offshore wind farm, characterized in that, Applied to the method according to any one of claims 1-7, including: The first module: Obtain the historical scouring survey data of the wind turbine, as well as the corresponding historical scouring depth data and historical first-order natural vibration frequency data of the wind turbine for each piece of historical scouring survey data; The second module: Obtain the parameters of the scour pit and establish a scour pit shape model; The third module: Based on the scour pit shape model, establish a frequency calculation model for the wind turbine; The fourth module: Substitute the historical scouring survey data into the frequency calculation model to obtain the predicted first-order natural vibration frequency data of the wind turbine, and verify the reliability of the frequency calculation model according to the historical first-order natural vibration frequency data of the wind turbine; The fifth module: Determine that the frequency calculation model is reliable, obtain the real-time first-order natural vibration frequency of the wind turbine, and substitute it into the frequency calculation model to obtain the predicted scouring depth.

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1-7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the method according to any one of claims 1-7.

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