Pile-soil interaction considering wind power overall natural frequency acquisition method and acquisition system

Abstract

The application discloses a wind turbine overall natural vibration frequency acquisition method considering pile-soil interaction, which is based on Hamilton principle and variation method, adopts a soil high-cycle small-strain model, a Timoshenko beam and a three-dimensional displacement field simulation of soil around the pile to simulate the pile-soil interaction and acquire pile head equivalent stiffness, and optimizes a correction parameter in a natural vibration frequency analytical solution correction method through the pile head equivalent stiffness. The application considers the influence of long-term cyclic load, complex seabed geology and single pile size effect on the overall natural vibration frequency of the wind turbine, can accurately and efficiently predict the change of the overall wind turbine frequency under the action of high-cycle cyclic load, and rapidly determines a single pile size design scheme. Compared with existing commercial software, the method is more compact and has higher calculation efficiency.

Description

Technical Field

[0001] This invention relates to the fields of computer technology and marine engineering, specifically to a method and system for obtaining the overall natural frequency of wind power considering pile-soil interaction. Background Technology

[0002] Offshore wind power construction will remain a key focus of my country's new energy industry development and carbon neutrality goals for a long time, with significant development potential. The overall natural frequency of offshore wind turbines must avoid resonance caused by the overall turbine structure, wind and waves, and the rotation frequency of the turbine blades. Therefore, during the design process, the overall natural frequency of the turbine must be ensured to be between f1P and f3P. Monopile foundations have advantages such as simple fabrication, convenient construction, economical cost, and simplified design process, and are widely used in offshore wind power projects. The pile-soil interaction under the offshore wind turbine plays a crucial role in the overall modal analysis of the turbine system.

[0003] Current methods for calculating the overall natural frequency of pile foundations often simplistically treat the pile-soil interaction as the interaction between an Euler-Bernoulli beam and the Winkler foundation. This method is suitable for pile foundations with a diameter less than 1m and simple geological conditions. However, for offshore wind turbine monopile foundations with a diameter greater than 5m, factors such as long-term cyclic loading, complex seabed geology, and the size effect of the monopile must be considered. This significantly reduces the accuracy and speed of the calculation.

[0004] Therefore, the method for rapidly obtaining the overall natural frequency of wind power that comprehensively considers the pile-soil interaction proposed in this invention has great practical significance and engineering value. Summary of the Invention

[0005] This invention provides a method and system for obtaining the overall natural frequency of wind power considering pile-soil interaction, in order to solve the problems of low accuracy and low speed in the calculation of the overall natural frequency of large-diameter wind power in the prior art.

[0006] This invention provides a method for obtaining the overall natural frequency of wind power considering pile-soil interaction, comprising the following steps:

[0007] Step 1: Set the wind turbine parameters, pile parameters, soil layer characteristic data, pile top loads and boundary conditions;

[0008] Step 2: Establish a pile-soil interaction model, including a soil high-cycle cyclic small-strain model;

[0009] Step 3: Based on the parameters and boundary conditions set in Step 1 and the pile-soil interaction model established in Step 2, calculate the pile-soil interaction using Hamilton's principle, variational method, Timoshenko beam, and continuous medium element.

[0010] Step 4: Compare the pile head rotation angle in the pile-soil interaction with the set allowable value for normal operation of the wind turbine.

[0011] When the pile head rotation angle is less than or equal to the allowable value for normal operation of the wind turbine, the equivalent stiffness of the pile head is calculated by the pile head rotation angle and pile head displacement in the pile-soil interaction.

[0012] When the pile head rotation angle is greater than the allowable value for normal operation of the wind turbine, the pile foundation size is increased, and the process returns to step 2.

[0013] Step 5: Correct the equivalent stiffness of the pile head obtained in Step 4, and optimize the correction coefficient in the overall natural frequency of the wind power using the corrected equivalent stiffness of the pile head to obtain the overall natural frequency of the wind power.

[0014] Step 6: Compare the overall natural frequency of the wind power obtained in Step 5 with the natural frequency of the wind turbine.

[0015] When the absolute value of the difference between the two is less than or equal to 10% of the wind turbine's natural frequency, the pile foundation size is increased, and the process returns to step 2.

[0016] When the absolute value of the difference between the two is greater than 10% of the natural frequency of the fan, the overall natural frequency of the fan is obtained.

[0017] Furthermore, in step 2, the parameter expression for the soil high-cycle cyclic small-strain model is:

[0018]

[0019]

[0020]

[0021] In the formula, G0 (l-1) This represents the initial deformation modulus of the soil (kN / m) in the (l-1)th calculation loop. 2 ); l = 1, 2, 3, ... n; G0 (l) This represents the initial deformation modulus of the soil (kN / m) in the l-th calculation loop. 2 ), l = 1, 2, 3, ... n; A is a dimensionless coefficient related to the soil; f(e) is a function of void ratio e; OCR is the overconsolidation rate of the soil; k and m are dimensionless coefficients; K (l-1) The soil shear modulus (kN / m) in the (l-1)th calculation loop 2 );G (l-1) The soil deformation modulus (kN / m) in the (l-1)th calculation loop 2 );σ1' (l-1) The direction of the principal stress in the soil during the (l-1)th calculation loop; r pφ is the pile radius (m); w is the horizontal displacement of the pile (m); r is the radial coordinate value (m); θ is the circumferential coordinate value (rad); φ r φ θ and φ z denoted as r, θ, and z, respectively, representing the soil displacement attenuation functions; c represents the soil cohesion (kPa). ω is the internal friction angle of the soil (rad); K0 is the static earth pressure coefficient.

[0022] Furthermore, in step 3, the formula for pile-soil interaction is:

[0023] ∫M(w)δwdz+∫P(ψ)δψdz+∫Q(φ r )δφ r dz+∫R(φ θ )δφ θ dz+∫S(φ z )δφz z dz=0

[0024] In the formula, M(w) is the governing equation for calculating the horizontal displacement w of the pile; P(ψ) is the governing equation for calculating the shear angle ψ of the pile; Q(φ) is the governing equation for calculating the horizontal displacement w of the pile. r R(φ) is the governing equation for calculating the soil displacement attenuation function in the r direction; θ S(φ) is the governing equation for the soil displacement attenuation function in the θ direction; z () is the governing equation for calculating the soil displacement attenuation function in the z-direction.

[0025] Furthermore, in steps 4 and 6, the pile foundation dimensions are increased using the following formula:

[0026] D1 = D0 + K

[0027] L p1 =L p0 +K*L p0 / D0

[0028] In the formula, D0 and L p0 These are the original pile outer diameter and original pile length, respectively; D1, L p1 These represent the increased outer diameter of the pile and the increased pile length, respectively; K is the pile foundation size enlargement coefficient that can be set according to design requirements.

[0029] Furthermore, in step 5, optimizing the correction coefficient in the overall natural frequency of the wind turbine using the corrected pile head equivalent stiffness specifically involves:

[0030]

[0031]

[0032] In the formula, C L C R η is the correction factor in the formula for calculating the overall natural frequency of the wind turbine. L =K L L p 3 / (EI η );η R =K R L p / (EI η );η LR =K LR L p 2 / (EI η ); K L (kN / m), K R (kNm) and K LR (kN) represent the three spring stiffnesses at the mud surface in the pile head equivalent stiffness, respectively, for translational, rotational, and coupled effects; EI η Equivalent bending stiffness of the superstructure (kNm) 2 );L p The depth of the pile (m).

[0033] Furthermore, in step 6, when the absolute value of the difference between the two is greater than 10% of the wind turbine's natural frequency, the method further includes: obtaining the final diameter, final burial depth, final wall thickness of the pile foundation, and pile-soil interaction graph results.

[0034] The present invention also provides a system for obtaining the overall natural frequency of wind power under the pile-soil interaction, which is applicable to the above-mentioned method for obtaining the overall natural frequency of wind power under the pile-soil interaction. The system includes: a data preprocessing unit, an objective function construction unit, a calculation unit, and a result output unit.

[0035] The data preprocessing unit is connected to the objective function construction unit. The data preprocessing unit is used to set the wind turbine parameters, pile parameters, soil layer characteristic data, pile top loads and boundary conditions for the objective function construction unit.

[0036] The objective function construction unit is connected to the computation unit. The objective function construction unit is used to construct a pile-soil interaction model, including a soil high-cycle cyclic small-strain model.

[0037] The calculation unit is connected to the result output unit. The calculation unit is based on Hamilton's principle and variational method, and uses Timoshenko beam and continuous medium element theory to calculate and correct the equivalent stiffness of the pile head and the overall natural frequency of the wind turbine.

[0038] The results output unit is used to output the overall natural frequency, final diameter, final burial depth, final wall thickness of the wind turbine, and pile-soil interaction graphical results.

[0039] The beneficial effects of this invention are:

[0040] This invention introduces a high-cycle cyclic small-strain soil model into the pile-soil interaction model. Based on this model, and using Hamilton's principle and variational method, it applies Timoshenko beam and continuous medium element theory to consider the three-dimensional displacement field of the soil around the pile. This corrects the equivalent stiffness of the pile head of a large-diameter single pile under horizontal loading in multi-layered soil, and optimizes the correction parameters in the rapid acquisition method of the overall natural frequency of wind turbines under pile-soil interaction. This makes the acquisition of the equivalent stiffness of the pile head more accurate, and the natural frequency of the wind turbine calculated using the equivalent stiffness of the pile head more accurate. The optimized acquisition method of this invention improves the accuracy and speed of the calculation results while reducing the computational difficulty of the model. Comparison with existing methods such as ABAQUS, FLAC3D, and PLAXIS shows that the error of this invention can be controlled within 5%, and the calculation speed is improved by more than 50%. This invention considers the effects of long-term cyclic loading, complex seabed geology, and the size effect of single piles on the overall natural frequency of the wind turbine. It can accurately and efficiently predict the changes in the overall wind turbine frequency caused by pile-soil interaction under high-cycle cyclic loading and quickly determine the single pile size design scheme. Compared with existing commercial software, this method is more compact and has higher computational efficiency. Attached Figure Description

[0041] The features and advantages of the invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the invention in any way. In the drawings:

[0042] Figure 1 This is a flowchart of a method according to an embodiment of the present invention;

[0043] Figure 2 This is the pile-soil interaction mechanical model for a single-pile foundation of offshore wind power established in this embodiment of the invention;

[0044] Figure 3 This is the natural frequency calculation model provided in the embodiments of the present invention;

[0045] Figure 4 This is a system block diagram according to an embodiment of the present invention;

[0046] Figure 5 This is a pile-soil interaction displacement cloud diagram according to an embodiment of the present invention;

[0047] Figure 6 This is a schematic diagram illustrating the boundary conditions at the upper and lower ends of the pile in an embodiment of the present invention: the upper end has a pile cap, and the lower end is free.

[0048] Figure 7 This is a schematic diagram illustrating the boundary conditions at the upper and lower ends of the pile in an embodiment of the present invention: the upper end is free and the lower end is free.

[0049] Figure 8 This is a schematic diagram illustrating the boundary conditions at the upper and lower ends of the pile in an embodiment of the present invention: the upper end has a pile cap, and the lower end is constrained.

[0050] Figure 9 This is a schematic diagram illustrating the boundary conditions at the upper and lower ends of the pile in an embodiment of the present invention: the upper end is free and the lower end is constrained. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] The present invention will be further illustrated below with reference to specific embodiments. Those skilled in the art should understand that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Modifications to the present invention in various equivalent forms all fall within the scope defined by the appended claims.

[0053] This invention provides a method for obtaining the overall natural frequency of wind power considering pile-soil interaction, comprising the following steps:

[0054] Step 1: Set the wind turbine parameters, pile parameters, soil layer characteristic data, pile top loads and boundary conditions;

[0055] The parameters to be set include: the allowable pile head rotation angle required for normal operation of the wind turbine as specified in the design, the natural frequency of the wind turbine, and the equivalent mass m of the wind turbine and blades as a top mass block. RNAJ Equivalent elastic modulus of fuselage T Uniformly distributed mass m T Outer diameter D T Wall thickness t T A uniform cross-section member, with the equivalent outer diameter D of the connector above the pile mud surface. P Wall thickness t P Soil layer characteristic data includes the OCR value of the soil around the pile and the initial elastic modulus E. s Poisson's ratio v s Cohesion c and internal friction angle Pile parameters include elastic modulus E p Moment of inertia I p Estimated initial diameter D of the pile body (0) Estimated initial burial depth L p (0) Estimated initial wall thickness t (0) The boundary conditions of the pile include whether both ends of the pile are fixed.

[0056] As shown in Table 1 below, combined with Figure 6-9 The diagram shows the boundary conditions at both ends of a single pile:

[0057]

[0058] Table 1

[0059] In this specific embodiment, other boundary conditions include:

[0060] Constraints on each pile segment:

[0061]

[0062]

[0063]

[0064]

[0065] Step 2: Establish a pile-soil interaction model, such as... Figure 2 As shown, this includes a soil high-cycle cyclic small-strain model;

[0066] The parametric expression for the high-cycle cyclic small-strain model of soil is:

[0067]

[0068]

[0069]

[0070] In the formula, G0 (l-1) This represents the initial deformation modulus of the soil (kN / m) in the (l-1)th calculation loop. 2 ); l = 1, 2, 3, ... n; G0 (l) This represents the initial deformation modulus of the soil (kN / m) in the l-th calculation loop. 2 ), l = 1, 2, 3, ... n; A is a dimensionless coefficient related to the soil; f(e) is a function of void ratio e; OCR is the overconsolidation rate of the soil; k and m are dimensionless coefficients; K (l-1) The soil shear modulus (kN / m) in the (l-1)th calculation loop 2 );G (l-1) The soil deformation modulus (kN / m) in the (l-1)th calculation loop 2 );σ1' (l-1) The direction of the principal stress in the soil during the (l-1)th calculation loop; r pφ is the pile radius (m); w is the horizontal displacement of the pile (m); r is the radial coordinate value (m); θ is the circumferential coordinate value (rad); φ r φ θ and φ z denoted as r, θ, and z, respectively, representing the soil displacement attenuation functions; c represents the soil cohesion (kPa). ω is the internal friction angle of the soil (rad); K0 is the static earth pressure coefficient.

[0071] Step 3: Based on the parameters and boundary conditions set in Step 1 and the pile-soil interaction model established in Step 2, calculate the pile-soil interaction using Hamilton's principle, variational method, Timoshenko beam, and continuous medium element.

[0072] Based on Hamilton's principle, the total energy system L of the pile-soil system is:

[0073] L=TU T +W (8)

[0074] In the formula, T is the kinetic energy equation; U T W represents the total potential energy; W represents the work done by the external load.

[0075] in,

[0076] The kinetic energy equation T1 for the pile body is:

[0077]

[0078] In the formula, m pile For each pile element, ω represents the pile's horizontal displacement; t represents time; I represents the pile's unit mass. p ψ represents the bending inertia of the unit pile; ψ represents the shear deformation of the pile.

[0079] The soil kinetic energy equation T2 is:

[0080]

[0081] In the formula, m soil For the mass of a soil unit; I soil Let represent the bending inertia of the soil element. Under small deformation conditions calculated at the natural frequency, the inertia caused by msoil and Isoil is negligible.

[0082] The expression for the total potential energy UT1 of the pile is:

[0083]

[0084] In the formula, EPIp is the bending stiffness of the pile; Ap is the cross-sectional area of ​​the pile. If κGp is ​​set to infinity, the effect of shear deformation can be neglected.

[0085] The expression for the total potential energy UT2 of the soil is:

[0086]

[0087] In the formula, σ ij For soil stress tensor; ε ij Let i be the soil strain tensor; i, j = r, θ, z.

[0088] The work done by the external load is:

[0089]

[0090] In the above formula, the displacement of the soil around the horizontally loaded pile is assumed to be:

[0091]

[0092] In the formula φ r , φθ and φ z Let be the soil displacement attenuation functions in the r, θ, and z directions, respectively. All three are dimensionless functions and are functions of r.

[0093] φ r φ θ and φ z The boundary conditions of a function can be defined as:

[0094]

[0095]

[0096]

[0097] Substituting equations (1)-(17) into equation (8), and using the variational principle, we obtain the expression for pile-soil interaction:

[0098] ∫M(w)δwdz+∫P(ψ)δψdz+∫Q(φ r )δφ r dz+∫R(φ θ )δφ θ dz+∫S(φ z )δφ z dz = 0 (18)

[0099] In the formula, M(w), P(ψ), Q(φ) r ), R(φ θ ) and S(φ z ) respectively containing δ(w), δ(ψ), δ(φ) r ), δ(φ θ ) and δ(φ zA polynomial of ). According to the variational method, if and only if M(w) = 0, P(ψ) = 0, Q(φ) = 0. r )=0、R(φ θ )=0 and S(φ z When ) = 0, δ(ψ), δ(w), and δ(φ) simultaneously satisfy the condition. r ), δ(φ θ ) and δ(φ z The equation holds true for all quantities when ψ, w, and φ are infinitesimal. From this, we can further derive the following: r φ θ φ z The relational expression.

[0100] Step 4: Compare the pile head rotation angle in the pile-soil interaction with the set allowable value for normal operation of the wind turbine.

[0101] When the pile head rotation angle is less than or equal to the allowable value for normal operation of the wind turbine, the equivalent stiffness of the pile head is calculated by the pile head rotation angle and pile head displacement in the pile-soil interaction.

[0102] When the pile head rotation angle is greater than the allowable value for normal operation of the wind turbine, the pile foundation size is increased, and the process returns to step 2. The pile-soil interaction model is then reconstructed using the increased pile foundation size.

[0103] Step 5: Perform conventional correction on the equivalent stiffness of the pile head obtained in Step 4, and optimize the correction coefficient in the overall natural frequency of the wind power using the corrected equivalent stiffness of the pile head to obtain the overall natural frequency of the wind power.

[0104] like Figure 3 As shown, the formula for calculating the overall natural frequency of wind power is:

[0105] f0 = C L C R f FB (19)

[0106] In the formula, f FB The natural frequency of the wind turbine when it is fixed at the base of the tower is calculated using the following formula:

[0107]

[0108] In the formula: E T For the equivalent elastic modulus of the fuselage, m T For the uniformly distributed mass of the tower, D T For the outer diameter of the tower, t T C is the tower wall thickness; MP =(1 / (1+(1+ρ)) 3 )λ-λ) 0.5 ; λ = L s / L T ρ = E T IT / (E p I p ); α varies depending on the type of tower, and here we take α = 33 / 140.

[0109] C R and C L The expression is:

[0110]

[0111]

[0112] In the formula, C L C R η is the correction factor in the formula for calculating the overall natural frequency of the wind turbine. L =K L L p 3 / (EI η );η R =K R L p / (EI η );η LR =K LR L p 2 / (EI η ); K L (kN / m), K R (kNm) and K LR (kN) represent the three spring stiffnesses at the mud surface in the pile head equivalent stiffness, respectively, for translational, rotational, and coupled effects; EI η Equivalent bending stiffness of the superstructure (kNm) 2 );L p The depth of the pile (m).

[0113] Step 6: Compare the overall natural frequency of the wind power obtained in Step 5 with the natural frequency of the wind turbine.

[0114] When the absolute value of the difference between the two is less than or equal to 10% of the wind turbine's natural frequency, the pile foundation size is increased, and the process returns to step 2.

[0115] When the absolute value of the difference between the two values ​​is greater than 10% of the wind turbine's natural frequency, the overall natural frequency of the wind turbine is obtained. Simultaneously, the final diameter D of the pile foundation can be output as an image based on the pile-soil interaction model. (n) Final burial depth L p (n) Final wall thickness t (n) And the graphical results of pile-soil interaction.

[0116] In this embodiment of the invention, w(z), h(z), and v(z) are known, and the pile bending moment (M) and pile shear force (F) are known. s Both the axial force (Q) and the axial force (Q) can be calculated using the following formula:

[0117] Flexible piles:

[0118]

[0119]

[0120]

[0121] Semi-rigid piles:

[0122]

[0123]

[0124]

[0125] like Figure 4 As shown in the figure, a wind power overall natural frequency acquisition system considering pile-soil interaction is also provided in a specific embodiment of the present invention, including: a data preprocessing unit 210, an objective function construction unit 220, a calculation unit 230 and a result output unit 240.

[0126] Data preprocessing unit 210; used to collect wind turbine and pile parameters, soil layer characteristic data, and various loads on the pile top. Wind turbine parameters include: the allowable pile head rotation angle required for normal operation of the wind turbine as specified in the design, the natural frequency of the wind turbine, and the equivalent mass m of the wind turbine and blades at the top. RNAJ Equivalent elastic modulus of fuselage T Uniformly distributed mass m T Outer diameter D T Wall thickness t T A uniform cross-section member, with the equivalent outer diameter D of the connector above the pile mud surface. P Wall thickness t P The soil layer characteristic data includes the OCR value of the soil around the pile and the initial elastic modulus E. s Poisson's ratio v s Cohesion c and internal friction angle The pile parameters include the elastic modulus E. p Moment of inertia I p Estimated initial diameter D of the pile body (0) Estimated initial burial depth L p (0) Estimated initial wall thickness t (0) The boundary conditions of the pile body include whether both ends of the pile are fixed or free.

[0127] Objective function construction unit 220: Establish the calculation model of the interaction between the upper wind turbine, pile and soil, and the mechanical model of the high-cycle cyclic small strain model of the multi-layer soil around the pile;

[0128] Calculation Unit 230: Based on Hamilton's principle and variational method, it uses Timoshenko beam and continuous medium element theory to consider the three-dimensional displacement field of the soil around the pile, calculates the interaction between a large-diameter single pile and soil under horizontal load in multi-layer soil, corrects the expression for pile head stiffness in the analytical solution of natural frequency, and quickly calculates the overall natural frequency of the wind turbine considering pile-soil interaction; it then compares and judges the result with the allowable pile head rotation angle and the natural frequency of the wind turbine, and quickly adjusts the pile foundation size design scheme.

[0129] Result Output Unit 240: Based on the known displacements of each pile segment node, calculates the pile body response, and outputs the corresponding natural frequency value and the final pile diameter D based on the command. (n) Final burial depth L p (n) Final wall thickness t (n) And the graphical results of pile-soil interaction.

[0130] Specifically, a wind turbine from an offshore wind farm in southeastern coastal my country is used for calculation and analysis. The wind turbine is a Shanghai Electric SWT-4.0-130 unit, with a tower height of 86m and a tower upper diameter D. T It is 3.1m long, with a lower diameter D. P The tower is 5.5m long, with a wall thickness of 0.06m, an elastic modulus of 210GPa, a mass of 269,750kg, and a concentrated mass at the top of the tower. RNAJ The effective bending stiffness EI of the foundation superstructure is 243,000 kg. η 658.455 GNm 2 The substructure uses large-diameter monopile foundations, with each pile made of steel pipe and having an elastic modulus of 210 GPa. The height from the connection node to the mud surface is 16.2 m. When the foundation is considered consolidated, and the mud surface is assumed to be the fixed end, the overall natural frequency f of the wind turbine is... FB The measured frequency f0 is 0.325Hz, while the actual measured f0 is 0.388Hz. The physical parameters of the soil layer where the pile foundation is located are shown in Table 2, which lists the relevant soil parameters for the site. The results obtained using this invention are shown in Table 3, which lists the calculation results of this invention.

[0131] As shown in Table 3, the f0 calculated by this invention is 0.317Hz, while the API specification calculation result is 0.288Hz. The former is very close to the measured result of 0.325Hz, indicating that the calculation using this invention is accurate and reliable.

[0132] The final diameter D of the pile foundation derived in this invention (n) The final wall thickness is 6.1m, and the final wall thickness is t. (n)The final burial depth is 0.07m, and the final burial depth is L. p (n) It is 44m.

[0133] like Figure 5 As shown, the calculation time for the horizontal displacement of the pile body derived by this invention is within 10 seconds. The comparison results with existing ABAQUS, FLAC3D and PLAXIS show that the error of this invention can be controlled within 5%, and the calculation speed is improved by more than 50%.

[0134]

[0135] Table 2

[0136]

[0137] Table 3

[0138] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for obtaining the overall natural frequency of wind power considering pile-soil interaction, characterized in that, Includes the following steps: Step 1: Set the wind turbine parameters, pile parameters, soil layer characteristic data, pile top loads and boundary conditions; Step 2: Establish a pile-soil interaction model, which includes a high-cycle cyclic small-strain model for the soil. The parameter expression for the high-cycle cyclic small-strain model for the soil is as follows: ； ； ； In the formula, G0 (l-1) This represents the initial deformation modulus of the soil in the (l-1)th calculation loop; l = 1, 2, 3, ..., n; G0 (l) In the l-th calculation loop, the initial deformation modulus of the soil is represented by l = 1, 2, 3, ..., n; A is a dimensionless coefficient related to the soil; f(e) is a function of the void ratio e; OCR is the overconsolidation rate of the soil; k and m are dimensionless coefficients; K (l-1) G represents the soil shear modulus in the (l-1)th calculation loop. (l-1) σ1' is the soil deformation modulus in the (l-1)th calculation loop. (l-1) The direction of the principal stress in the soil during the (l-1)th calculation loop is: w = (w - r) / (θ - φ) = (r ... r ϕ θ and ϕ z φ represents the soil displacement attenuation function in the r, θ, and z directions, respectively; c represents the soil cohesion; φ represents the soil internal friction angle; and K0 represents the static earth pressure coefficient. Step 3: Based on the parameters and boundary conditions set in Step 1 and the pile-soil interaction model established in Step 2, calculate the pile-soil interaction using Hamilton's principle, variational method, Timoshenko beam, and continuous medium element. The formula for pile-soil interaction is: ； In the formula, M(w) is the governing equation for calculating the horizontal displacement w of the pile; P(ψ) is the governing equation for calculating the shear angle ψ of the pile; Q(ϕ) r R(ϕ) is the governing equation for calculating the soil displacement attenuation function in the r direction; θ S(ϕ) is the governing equation for the soil displacement attenuation function in the θ direction; z The equation is the governing equation for calculating the soil displacement attenuation function in the z-direction. Step 4: Compare the pile head rotation angle in the pile-soil interaction with the set allowable value for normal operation of the wind turbine. When the pile head rotation angle is less than or equal to the allowable value for normal operation of the wind turbine, the equivalent stiffness of the pile head is calculated by the pile head rotation angle and pile head displacement in the pile-soil interaction. When the pile head rotation angle is greater than the allowable value for normal operation of the wind turbine, the pile foundation size is increased, and the process returns to step 2. Step 5: Correct the equivalent stiffness of the pile head obtained in Step 4, and optimize the correction coefficient in the overall natural frequency of the wind power using the corrected equivalent stiffness of the pile head to obtain the overall natural frequency of the wind power. Step 6: Compare the overall natural frequency of the wind power obtained in Step 5 with the natural frequency of the wind turbine. When the absolute value of the difference between the two is less than or equal to 10% of the wind turbine's natural frequency, the pile foundation size is increased, and the process returns to step 2. When the absolute value of the difference between the two is greater than 10% of the natural frequency of the fan, the overall natural frequency of the fan is obtained.

2. The method for obtaining the overall natural frequency of wind power considering pile-soil interaction as described in claim 1, characterized in that, In steps 4 and 6, the pile foundation dimensions are increased using the following formula: D1 = D0 + K; L p1 = L p0 +K* L p0 / D0; In the formula, D0 and L p0 These are the original pile outer diameter and original pile length, respectively; D1, L p1 These represent the increased outer diameter of the pile and the increased pile length, respectively; K is the pile foundation size enlargement coefficient that can be set according to design requirements.

3. The method for obtaining the overall natural frequency of wind power considering pile-soil interaction as described in claim 1, characterized in that, In the formula for increasing the pile foundation size, K is set to 0.

5.

4. The method for obtaining the overall natural frequency of wind power considering pile-soil interaction as described in claim 1, characterized in that, In step 5, the optimization of the correction coefficient in the overall natural frequency of the wind turbine using the corrected pile head equivalent stiffness is specifically as follows: ； ； In the formula, C L C R This is a correction factor in the formula for calculating the overall natural frequency of the wind turbine. η L =K L L p 3 / (EI η );η R =K R L p / (EI η );η LR =K LR L p 2 / (EI η ); K L K R and K LR These are the three types of spring stiffness at the mud surface in the equivalent stiffness of the pile head, representing translational, rotational, and coupled effects; EI η Equivalent bending stiffness of the superstructure based on the foundation; L p This refers to the depth of the pile.

5. The method for obtaining the overall natural frequency of wind power considering pile-soil interaction as described in claim 1 or 2, characterized in that, In step 6, when the absolute value of the difference between the two is greater than 10% of the wind turbine's natural frequency, the method further includes: obtaining the final diameter of the pile foundation, the estimated initial burial depth, the estimated initial wall thickness, and the pile-soil interaction diagram results.

6. A system for obtaining the overall natural frequency of wind power generation based on pile-soil interaction, applicable to the method for obtaining the overall natural frequency of wind power generation based on pile-soil interaction as described in any one of claims 1-5, characterized in that, The wind power overall natural frequency acquisition system based on the pile-soil interaction includes: a data preprocessing unit, an objective function construction unit, a calculation unit, and a result output unit; The data preprocessing unit is connected to the objective function construction unit. The data preprocessing unit is used to set the wind turbine parameters, pile parameters, soil layer characteristic data, pile top loads and boundary conditions for the objective function construction unit. The objective function construction unit is connected to the computation unit. The objective function construction unit is used to construct a pile-soil interaction model, including a soil high-cycle cyclic small-strain model. The calculation unit is connected to the result output unit. The calculation unit is based on Hamilton's principle and variational method, and uses Timoshenko beam and continuous medium element theory to calculate and correct the equivalent stiffness of the pile head and the overall natural frequency of the wind turbine. The output unit is used to output the overall natural frequency of the wind turbine, the final diameter of the pile foundation, the estimated initial burial depth, the estimated initial wall thickness, and the pile-soil interaction diagram results.

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