An efficient method and device for establishing soil resistance model around offshore wind power piles

Abstract

The present invention belongs to the technical field of computer algorithm models. Specifically, it is an efficient algorithm and device for the soil resistance model around offshore wind power piles. The method uses CPT or SPT data collected on site to obtain the corresponding soil layer parameters, and uses a simplified calculation method derived from the variational method based on the three-dimensional displacement attenuation function assumption to quickly determine the various spring parameters. The pile-soil interaction objective function is established based on the Kinetic energy conservation, thereby quickly and accurately calculating the pile body response of the offshore wind power single pile foundation under the combined load. The pile-soil interaction models are: a three-spring model is used for flexible piles, and a six-spring model is used for semi-rigid piles and rigid piles. The algorithm simultaneously considers the offshore wind power single pile-soil interaction under the combined action of vertical and horizontal loads and overturning moments. The algorithm is more compact and has higher computational efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of computer algorithm models, and in particular, relates to an efficient offshore wind power pile surrounding soil resistance model algorithm and device. Background Art

[0002] The investment and construction of offshore wind power are developing rapidly and have great room for development.

[0003] While monopile foundations have been widely used, they have also brought many problems. During normal operation of wind turbines, monopile foundations must withstand the vertical and horizontal loads and overturning moments transmitted from the superstructure. Existing design specifications mainly consider the effects of horizontal loads and often ignore the influence of vertical loads. However, existing research results have shown that vertical loads can have a significant impact on the horizontal bearing capacity of piles. To this end, an efficient and accurate calculation and implementation method for offshore wind power monopile-soil interaction under the combined effects of vertical and horizontal loads and overturning moments is proposed, which has great practical significance and engineering value. Summary of the Invention

[0004] The purpose of the present invention is to provide an efficient algorithm and device for the soil resistance model around offshore wind turbine piles. The algorithm aims to quickly determine the pile body based on known external loads and pile body parameters, as well as soil layer parameters converted from existing CPT or SPT data, thereby providing rapid guidance for the design of offshore wind turbine single pile foundations.

[0005] The specific technical solutions adopted in the present invention are as follows:

[0006] An efficient soil resistance model algorithm for offshore wind turbine piles utilizes field-collected CPT or SPT data to obtain soil parameters. A simplified calculation method based on the assumption of a three-dimensional displacement attenuation function and derived from the calculus of variations is used to rapidly determine the various spring parameters. A pile-soil interaction expression is established based on the Kinetic principle of energy conservation, enabling rapid and accurate calculation of the pile response of offshore wind turbine single-pile foundations under combined loads. The pile-soil interaction model uses a three-spring model for flexible piles and a six-spring model for semi-rigid and rigid piles.

[0007] Among them, by introducing a simplified formula of the variational method based on the assumption of a three-dimensional displacement attenuation function, the distributed springs of each pile segment are calculated, and the pile-soil interaction objective function is established based on Kinetic energy conservation.

[0008] Specifically, the method includes the following steps:

[0009] Step 1: Collect characteristic data of each soil layer, pile body parameters and various loads on the pile top;

[0010] Step 2: Use the Kinetic energy conservation principle to construct the pile-soil interaction objective function:

[0011] Among them, the Kinetic energy conservation principle is used to construct the pile-soil interaction objective function, and the pile deformation energy storage U E The objective function is:

[0012] Flexible piles:

[0013]

[0014] Semi-rigid piles:

[0015]

[0016] Rigid piles:

[0017] U E =0

[0018] Among them, E p is the elastic modulus of the pile body, I p is the moment of inertia of the pile body, ψ is the cross-sectional rotation angle caused by pure bending, κ is the shear deformation coefficient, w is the horizontal displacement of the axial moment of the beam element, G p is the shear stiffness of the pile body, A p is the cross-sectional area of the pile body, and h is the settlement of the pile body;

[0019] The work done by the soil resistance around the pile in the Kinetic energy principle is U S The objective function is:

[0020] Flexible piles:

[0021]

[0022] Semi-rigid piles and rigid piles:

[0023]

[0024] Among them, τ is the vertical soil resistance of the pile body, p is the horizontal soil resistance of the pile body, m is the additional bending moment of the pile body, Q b is the end resistance, F b is the pile tip shear force, M b is the bending moment at the pile tip;

[0025] In the kinetic energy principle, the objective function of the work W done by the load at the two end nodes of a pile segment (i) is: Flexible pile:

[0026] W=P i-1 h i-1 +F i-1 (w i-1 +v i-1 )+M i-1 θi-1 +P i h i +F i (w i +v i )+M i θ i

[0027] Semi-rigid piles:

[0028] W=P i-1 (h i-1 +w i-1 φ z (r p ))+F i-1 (w i-1 +v i-1 )+M i-1 θ i-1 +P i (h i +w i φ z (r p ))+F i (w i +v i )+M i θ i

[0029] Rigid piles:

[0030] W=P i-1 (h0+(w0-θ0z i-1 )φ z (r p ))+F i-1 (w0-θ0z i-1 +v0)+M i-1 θ0+P i (h0+(w0-θ0z i )φ z (r p ))+F i (w0-θ0z i +v0)+M i θ0

[0031] Where: W represents the work done by all loads at the two end nodes (i-1 and i) of a certain pile segment (i), i is the pile segment number (i = 1, 2, 3, ..., n), P i-1 is the axial load at the (i-1) node (kN), F i-1 is the tangential load at the (i-1) node (kN), M i-1 is the moment at the (i-1) node (kNm), P i is the axial load at node (i) (kN), Fi is the tangential load at node (i) (kN), M i is the moment at node (i) (kNm), h i-1 is the axial displacement at the (i-1) node caused by the vertical load P0 at the pile top (m), w i-1 is the tangential displacement (m) at the (i-1) node caused by the horizontal load F0 on the pile top, v i-1 is the tangential displacement at the (i-1) node caused by the vertical load P0 at the pile top (m), θ i-1 is the rotation angle at the (i-1) node (rad), h i is the axial displacement (m) at the node (i) caused by the vertical load P0, w i is the tangential displacement (m) at node (i) caused by the horizontal load F0, v i is the tangential displacement (m) at node (i) caused by the vertical load P0, θ i is the rotation angle at node (i) (rad), h0 is the settlement of pile top (m), w0 is the horizontal displacement of pile top (m), θ0 is the rotation angle at pile top (rad), φ r (r p ) is the value of the vertical displacement attenuation function at the pile-soil interface caused by the horizontal load and moment at the pile top in the variational method system based on the three-dimensional displacement attenuation function assumption;

[0032] Step 3: Using the minimum energy principle and the calculus of variations, a simplified calculation method for each soil resistance is obtained. Using a three-spring or six-spring model, the soil resistance objective function is constructed:

[0033] The simplified calculation method derived from the calculus of variations and the assumption of a three-dimensional displacement attenuation function is used to quickly determine the expressions of various spring parameters:

[0034]

[0035]

[0036] Where: k is the initial compression stiffness of each soil layer; T is the initial shear stiffness of each soil layer; Gs is the initial shear modulus of each soil layer (kPa); λs is the initial compression modulus of each soil layer (kPa); Pu is the ultimate horizontal soil resistance; Mu is the ultimate additional moment; Fbu is the ultimate horizontal shear force at the pile end (kN / m); Mb is the ultimate resistance moment at the pile end (kNm).

[0037] Step 4: After adding other boundary constraints, an efficient soil resistance model algorithm for offshore wind turbine piles is obtained;

[0038] Step 5: By knowing the displacement of each pile segment node, calculate the internal force response of the pile body, combine it with the instructions, and output the corresponding graphical results.

[0039] The present invention also discloses an efficient offshore wind power pile surrounding soil resistance model device, comprising a data preprocessing unit, an objective function construction unit, a constraint construction unit and a result output unit;

[0040] The data preprocessing unit is used to collect characteristic data of each soil layer, pile body parameters and various loads on the pile top. The characteristic data of each soil layer includes all parameters measured by CPT and SPT;

[0041] The objective function construction unit quickly determines the various spring parameters by adopting a simplified calculation method derived from the calculus of variations based on the assumption of a three-dimensional displacement attenuation function, and establishes the pile-soil interaction objective function based on the Kinetic energy conservation principle. The pile-soil interaction objective function includes the pile body deformation energy storage objective function U E , the objective function of the work done by the soil resistance around the pile U S and the work done by the node loads at both ends of the pile segment, W;

[0042] The constraint construction unit constructs the boundary constraints of the pile-soil interaction by introducing the constraint boundary conditions of the pile top and pile end and the continuity conditions of each node of the pile body, integrates the unit matrices of each pile segment into an overall square matrix, and finally solves the displacements of the pile body; the result output unit calculates the internal force response of the pile body by knowing the displacement of each node of the pile segment, and outputs the corresponding graphical results in combination with the instructions.

[0043] Beneficial effects of the present invention: The present invention calculates the distributed springs of each pile segment by introducing a simplified formula of the variational method based on the assumption of a three-dimensional displacement attenuation function, and constructs a simple objective function of the soil resistance around the pile based on the Kinetic energy conservation, which not only improves the accuracy and speed of the calculation results, but also reduces the calculation difficulty of the model; the comparison results with the existing ABAQUS, FLAC3D and PLAXIS show that the accuracy of the prediction of various soil resistances of the pile body of the non-invasive load monitoring mixed integer programming model constructed by the construction method of the present invention reaches more than 95%, and the calculation speed is increased by more than 60%. It can be seen that the soil resistance model algorithm around offshore wind power piles constructed by the present invention can be used to calculate the interaction between offshore wind power single piles and soil under the combined action of vertical, horizontal loads and overturning moments, and the results are more efficient and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a flow chart of the efficient offshore wind power pile surrounding soil resistance model algorithm in the present invention.

[0045] Figure 2 This is a three-spring model diagram of the efficient offshore wind power pile surrounding soil resistance model algorithm in the present invention.

[0046] Figure 3This is a six-spring model diagram of the efficient offshore wind power pile surrounding soil resistance model algorithm in the present invention.

[0047] Figure 4 This is a comparison chart of the results of different calculation methods and actual measurements in the horizontal test in an embodiment of the present invention.

[0048] Figure 5 1 is a comparison chart of the results of different calculation methods and actual measurements in the vertical compressive static load test in an embodiment of the present invention.

[0049] Figure 6 1 is a comparison chart of the results of different calculation methods and actual measurements in the vertical compressive static load test in an embodiment of the present invention.

[0050] Figure 7 A structural block diagram of a device for constructing an efficient algorithm for the soil resistance model of offshore wind power piles provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0051] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The embodiments are only used to explain the present invention and do not limit the scope of protection of the present invention.

[0052] The present invention discloses an efficient offshore wind power pile surrounding soil resistance model algorithm. By introducing a simplified variational method based on the assumption of a three-dimensional displacement attenuation function, the algorithm calculates the distributed springs of each pile segment and constructs a concise pile surrounding soil resistance objective function based on Kinetic energy conservation. This improves the accuracy and speed of the calculation results and reduces the calculation difficulty of the model. Comparison results with existing ABAQUS, FLAC3D and PLAXIS show that the non-invasive load monitoring mixed integer programming model constructed using the construction method of the present invention has an accuracy of over 95% in predicting various soil resistances of the pile body and an improvement of over 60% in calculation speed.

[0053] Figure 1 The present invention provides a flowchart of an efficient algorithm for the soil resistance model of offshore wind power piles.

[0054] like Figure 1 As shown, the embodiment of the present invention provides an efficient offshore wind power pile surrounding soil resistance model algorithm, including:

[0055] Step 1: Collect characteristic data of each soil layer, pile body parameters and various loads on the pile top;

[0056] Step 2: Using the Kinetic energy conservation principle, construct the pile-soil interaction objective function;

[0057] Step 3: Using the minimum energy principle and the calculus of variations, a simplified calculation method for each soil resistance is obtained, and a soil resistance objective function is constructed using a three-spring or six-spring model.

[0058] Step 4: After adding other boundary constraints, an efficient soil resistance model algorithm for offshore wind turbine piles is obtained;

[0059] Step 5: By knowing the displacement of each pile segment node, calculate the internal force response of the pile body, combine it with the instructions, and output the corresponding graphical results.

[0060] In step 1, the data preprocessing unit is used to collect characteristic data of each soil layer, pile body parameters and various loads on the pile top. The soil layer characteristic data includes all parameters measured by CPT or SPT.

[0061] In the embodiment of the present invention, the CPT or SPT measured data needs to be converted into the soil elastic modulus E by the methods in Table 1 and Table 2 respectively. s and Poisson's ratio v s .

[0062] Table 1 Conversion relationship between CPT data and elastic modulus

[0063]

[0064]

[0065] Table 2 Conversion relationship between SPT data and elastic modulus

[0066]

[0067] Step 2: Establish the pile-soil interaction objective function based on the Kinetic energy conservation principle.

[0068] In the embodiment of the present invention, the pile deformation energy storage U in the Kinetic energy principle E The objective function is: Flexible pile:

[0069]

[0070] Semi-rigid piles:

[0071]

[0072] Rigid piles:

[0073] U E =0 (3)

[0074] Among them, E p is the elastic modulus of the pile body, I pis the moment of inertia of the pile body, ψ is the cross-sectional rotation angle caused by pure bending, κ is the shear deformation coefficient, w is the horizontal displacement of the axial moment of the beam element, G p is the shear stiffness of the pile body, A p is the cross-sectional area of the pile body, and h is the settlement of the pile body.

[0075] Kinetic energy principle: the work done by the soil resistance around the pile U S The objective function is:

[0076] Flexible pile (three-spring model):

[0077]

[0078] Semi-rigid piles and rigid piles (six-spring model):

[0079]

[0080] Among them, τ is the vertical soil resistance of the pile body, p is the horizontal soil resistance of the pile body, m is the additional bending moment of the pile body, Q b is the end resistance, F b is the pile tip shear force, M b is the bending moment at the pile end.

[0081] In the kinetic energy principle, the objective function of the work W done by the load at both ends of a pile segment (i) is:

[0082] Flexible piles:

[0083] W=P i-1 h i-1 +F i-1 (w i-1 +v i-1 )+M i-1 θ i-1 +P i h i +F i (w i +v i )+M i θ i

[0084] Semi-rigid piles:

[0085] W=P i-1 (h i-1 +w i-1 φ z (r p ))+F i-1 (w i-1 +v i-1 )+M i-1 θ i-1 +P i (h i+w i φ z (r p ))+F i (w i +v i )+M i θ i

[0086] Rigid piles:

[0087] W=P i-1 (h0+(w0-θ0z i-1 )φ z (r p ))+F i-1 (w0-θ0z i-1 +v0)+M i-1 θ0+P i (h0+(w0-θ0z i )φ z (r p ))+F i (w0-θ0z i +v0)+M i θ0

[0088] Where: W represents the work done by all loads at the two end nodes (i-1 and i) of a certain pile segment (i), i is the pile segment number (i = 1, 2, 3, ..., n), P i-1 is the axial load at the (i-1) node (kN), F i-1 is the tangential load at the (i-1) node (kN), M i-1 is the moment at the (i-1) node (kNm), P i is the axial load at node (i) (kN), F i is the tangential load at node (i) (kN), M i is the moment at node (i) (kNm), h i-1 is the axial displacement at the (i-1) node caused by the vertical load P0 at the pile top (m), w i-1 is the tangential displacement (m) at the (i-1) node caused by the horizontal load F0 on the pile top, v i-1 is the tangential displacement at the (i-1) node caused by the vertical load P0 at the pile top (m), θ i-1 is the rotation angle at the (i-1) node (rad), h i is the axial displacement (m) at the node (i) caused by the vertical load P0, w i is the tangential displacement (m) at node (i) caused by the horizontal load F0, v i is the tangential displacement (m) at node (i) caused by the vertical load P0, θ iis the rotation angle at node (i) (rad), h0 is the settlement of pile top (m), w0 is the horizontal displacement of pile top (m), θ0 is the rotation angle at pile top (rad), φ r (r p ) is the value of the vertical displacement attenuation function at the pile-soil interface caused by the horizontal load and moment at the pile top in the variational method system based on the three-dimensional displacement attenuation function assumption.

[0089] Step three: quickly determine the various spring parameters by using a simplified calculation method based on the three-dimensional displacement attenuation function assumption and variational method.

[0090] In the embodiment of the present invention, a four-spring model ( Figure 2 ), and the six-spring model is used for semi-rigid piles and rigid piles ( Figure 3 ).

[0091] In an embodiment of the present invention, a simplified calculation method based on the assumption of a three-dimensional displacement attenuation function and derived by the calculus of variations is used to quickly determine the expressions of various spring parameters:

[0092]

[0093] The calculation methods of the initial spring stiffness k and shear stiffness T in the flexible pile are:

[0094]

[0095]

[0096] The calculation methods for the initial spring stiffness k and shear stiffness T in semi-rigid piles or rigid piles are shown in Table 3:

[0097] Table 3 Calculation method of initial stiffness k and shear stiffness T

[0098]

[0099] Where L0 is the cantilever length for applying horizontal force, L p is the pile length, D is the outer diameter of the pile, D ref =1m.

[0100] Step 4: By introducing the constraint boundary conditions of the pile top and pile end and the continuity conditions of each node of the pile body, the boundary constraints of the pile-soil interaction are constructed, and the unit matrices of each pile segment are integrated into an overall square matrix, and finally the displacements of the pile body are solved.

[0101] In this embodiment of the present invention, other constraints include:

[0102] Constraints for each pile segment:

[0103]

[0104]

[0105] The boundary conditions at the upper and lower ends of the flexible pile are shown in Table 4:

[0106] Table 4 Boundary conditions of flexible piles and corresponding combination formulas

[0107]

[0108] The boundary conditions at the upper and lower ends of the rigid pile are shown in Table 5:

[0109] Table 5 Boundary conditions of rigid piles and corresponding combination formulas

[0110]

[0111]

[0112] Step 5: By knowing the displacement of each pile segment node, calculate the internal force response of the pile body, combine it with the instructions, and output the corresponding graphical results.

[0113] In the embodiment of the present invention, w(z), h(z) and v(z) are known, and the pile bending moment (M), pile shear force (S) and axial force (Q) can be calculated by the following formulas:

[0114] Flexible piles:

[0115]

[0116]

[0117] Semi-rigid piles:

[0118]

[0119] In summary, the embodiment of the present invention provides an efficient soil resistance model algorithm for offshore wind power piles. By introducing a simplified formula of the variational method based on the assumption of a three-dimensional displacement attenuation function, the distributed springs of each pile segment are calculated. Based on the Kinetic energy conservation, a simple soil resistance objective function for piles is constructed, which not only improves the accuracy and speed of the calculation results, but also reduces the calculation difficulty of the model. The comparison results with the existing ABAQUS, FLAC3D and PLAXIS show that the accuracy of the prediction of various soil resistances of the pile body calculated by the present invention reaches more than 95%, and the calculation speed is increased by more than 60%. It can be seen that the soil resistance model algorithm for offshore wind power piles constructed by the present invention can be used to calculate the interaction between offshore wind power single piles and soil under the combined action of vertical, horizontal loads and overturning moments, and the results are more efficient and accurate.

[0120] The feasibility of the model constructed by the present invention is demonstrated through specific examples below.

[0121] A typical steel pipe flexible test pile at an offshore wind farm was subjected to vertical compression and pullout tests and horizontal load tests, and the results were compared with those obtained using FLAC3D and the calculations presented in this paper. The test pile site is located in Quaternary soils, representing typical alluvial, marine, and estuarine-terrestrial sedimentary deposits. The primary soil layer is composed of silt interbedded with silty sand. The relevant parameters of the test pile are shown in Table 6, and relevant parameters obtained from geological surveys are listed in Table 7.

[0122] The piles were 2m in diameter steel pipe piles, with the anchor piles and reference piles serving as engineering piles after the tests were completed. The test plan involved first conducting static compression and pullout tests on the test piles using the anchor pile method, followed three days later by a horizontal load test on the original piles. To measure pile strain, distributed optical fibers were installed in the test piles. During the vertical static compression test, four anchor piles provided the reaction force, and the top of the test pile was subjected to a free, unconstrained boundary condition. The loading scheme began at 6000 kN and progressed in 3000 kN increments to 18000 kN. At the 6000 kN level, the corresponding displacement at the loading point was 5.54 mm, and at the mud surface, it was 5.12 mm. During the vertical static pullout test, the top of the pile was free and unconstrained, with an upward pull of 3.10 mm at the 2000 kN level. During the horizontal static load test, the top of the pile remained free and unconstrained, and loading was performed using the top-thrust method, with the anchor piles providing the test reaction force. When the load reaches 100kN, the mud surface displacement is 7.59mm.

[0123] When adopting the present invention to calculate, the soil domain length and width are taken as 15 times of the pile diameter, the soil height is taken as 2 times of the pile length, and the grid is divided into a small unit of 0.1×0.1×0.1m. The soil elastic modulus and Poisson's ratio derived from geological survey data are listed in Table 8. Two oblique loads are applied to the pile top, one is 100kN for the horizontal component and 6000kN for the vertical component, and the other is 100kN for the horizontal component and -2000kN for the vertical component (vertically upward). When adopting FLAC3D modeling calculation, the pile-soil model is completely consistent with that calculated by the variational method.

[0124] The results calculated by the present invention are compared with the pile body response under the inclined load obtained by FLAC3D simulation and the measured data to verify the accuracy of the present invention. The calculation conditions are shown in Table 9, and the comparison results are listed in Figure 4 middle.

[0125] Figure 4 (a)-(b) respectively show the horizontal displacement and bending moment distribution diagrams of the pile body when the load is 100kN in the horizontal static load test. The measured value, variation calculation value and FLAC3D calculation value at the mud surface are 7.59mm, 6.60mm and 6.60mm, respectively. Figure 4The comparison results show that the distribution of pile horizontal displacement and bending moment calculated by the variational method is basically consistent with the pile horizontal response results under the combined load of FLAC3D, and is in good agreement with the measured results. Figure 5 Figures (a) and (b) show the pile compression and axial force distribution diagrams for the vertical compressive test at a load of 6000 kN. The distribution of the measured pile compression along the pile length is given only for the mud surface and within 6 m below. The measured value, the variational calculated value, and the FLAC3D calculated value at the mud surface are 5.23 mm, 5.23 mm, and 5.54 mm, respectively. Figure 5 The comparison results show that the distribution of vertical compression and axial force of the pile body calculated by the variational method is basically consistent with the horizontal response results of the pile body under the action of FLAC3D combined loads, and are in good agreement with the measured results. Figure 6 The pile compression and axial force distribution diagrams for a vertical pull-out test at a load of 2000kN are given, but the distribution of the measured pile compression along the pile length is not given. The measured values at the mud surface, the variational calculated values, and the FLAC3D calculated values are 1.53mm, 1.56mm, and 1.67mm, respectively. In summary, the present invention can well simulate the bearing characteristics of a single offshore wind power pile foundation under combined loads. The present invention has an extremely fast calculation speed and can provide a good solution for engineering design prediction to a large extent.

[0126] Table 6 Test pile related parameters

[0127]

[0128] Table 7 Soil layer related parameters

[0129]

[0130] Table 8 Required soil layer related parameters

[0131]

[0132] Table 9 Load simulation conditions

[0133]

[0134] Figure 7 This is a structural block diagram of a device for constructing an efficient offshore wind turbine pile surrounding soil resistance model algorithm provided by an embodiment of the present invention. For ease of explanation, only the parts related to the embodiment of the present invention are shown in the figure, which are described in detail as follows:

[0135] See also Figure 7 The device for constructing an efficient offshore wind power pile surrounding soil resistance model algorithm provided by an embodiment of the present invention includes a data preprocessing unit 210, an objective function construction unit 220, a constraint construction unit 230 and a result output unit 240.

[0136] The data preprocessing unit 210 is used to collect characteristic data of each soil layer, pile body parameters and pile top loads. The soil layer characteristic data includes all parameters measured by CPT and SPT.

[0137] The objective function construction unit 220 quickly determines the various spring parameters by adopting a simplified calculation method derived from the calculus of variations based on the assumption of a three-dimensional displacement attenuation function, and establishes the pile-soil interaction objective function based on the Kinetic energy conservation principle. The pile-soil interaction objective function includes the pile deformation energy storage objective function U E , the objective function of the soil resistance work around the pile US and the load work W at the nodes at both ends of the pile segment;

[0138] The constraint construction unit 230 constructs the pile-soil interaction boundary constraints by introducing the pile top and pile end constraint boundary conditions and the continuity conditions of each node of the pile body, integrates the unit matrices of each pile segment into an overall square matrix, and finally solves the various displacements of the pile body; and

[0139] The result output unit 240 calculates the internal force response of the pile body by knowing the displacement of each pile segment node, and outputs the corresponding graphical results in combination with the instructions.

[0140] It should be understood that, although the various steps in the flow chart of each embodiment of the present invention are shown in sequence according to the indication of the arrows, these steps are not necessarily performed in sequence according to the order indicated by the arrows. Unless otherwise specified herein, the execution of these steps is not strictly limited in order, and these steps can be performed in other orders. Moreover, at least a portion of the steps in each embodiment may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these sub-steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0141] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. An efficient method for establishing a soil resistance model around offshore wind power piles, characterized in that: The corresponding soil layer parameters are obtained using CPT or SPT data collected on site. A simplified calculation method based on the three-dimensional displacement attenuation function assumption and the variational method is used to quickly determine the various spring parameters. The pile-soil interaction objective function is established based on the Kinetic energy conservation principle. This allows for the rapid and accurate calculation of the pile body response of the offshore wind turbine single pile foundation under combined loads. The pile-soil interaction models are: a four-spring model for flexible piles and a six-spring model for semi-rigid and rigid piles. The specific steps include: Step 1: Collect characteristic data of each soil layer, pile body parameters and various loads on the pile top; Step 2: Using the Kinetic energy conservation principle, construct the pile-soil interaction objective function; Step 3: Using the minimum energy principle and the calculus of variations, a simplified calculation method for each soil resistance is obtained, and a soil resistance objective function is constructed using a three-spring or six-spring model. Step 4: After adding other boundary constraints, an efficient soil resistance model algorithm for offshore wind turbine piles is obtained; Step 5: By knowing the displacement of each pile segment node, calculate the internal force response of the pile body, combine the instructions, and output the corresponding graphical results; In step 2, the Kinetic energy conservation principle is used to construct the pile-soil interaction objective function, and the pile deformation energy storage U E The objective function is: Flexible piles: Semi-rigid piles: Rigid piles: U E ＝0 Among them, E p is the elastic modulus of the pile body, I p is the moment of inertia of the pile body, ψ is the cross-sectional rotation angle caused by pure bending, κ is the shear deformation coefficient, w is the horizontal displacement of the axial moment of the beam element, G p is the shear stiffness of the pile body, A p is the cross-sectional area of the pile body, and h is the settlement of the pile body.

2. The method for establishing an efficient soil resistance model for offshore wind power piles according to claim 1 is characterized in that: In the step 2, the work done by the soil resistance around the pile in the Kinetic energy principle is U S The objective function is: Flexible pile: Semi-rigid piles and rigid piles: Among them, τ is the vertical soil resistance of the pile body, p is the horizontal soil resistance of the pile body, m is the additional bending moment of the pile body, Q b is the end resistance, F b is the pile tip shear force, M b is the bending moment at the pile end.

3. The method for establishing an efficient soil resistance model around offshore wind power piles according to claim 2 is characterized in that: In step 2, the objective function of the work W of the load at both ends of a pile segment (i) in the Kinetic energy principle is: Flexible piles: W=P i-1 h i-1 +F i-1 (w i-1 +v i-1 )+M i-1 θ i-1 +P i h i +F i (w i +v i )+M i θ i Semi-rigid piles: W=P i-1 (h i-1 +w i-1 φ z (r p ))+F i-1 (w i-1 +v i-1 )+M i-1 θ i-1 +P i (h i +w i φ z (r p ))+F i (w i +v i )+M i θ i Rigid piles: W=P i-1 (h0+(w0-θ0z i-1 )φ z (r p ))+F i-1 (w0-θ0z i-1 +v0)+M i-1 θ0+P i (h0+(w0-θ0z i )φ z (r p )) +F i (w0-θ0z i +v0)+M i θ0 Where: W represents the work done by all loads at the two end nodes (i-1 and i) of a certain pile segment (i), i is the pile segment number i = 1, 2, 3, ..., n, P i-1 is the axial load at the (i-1) node, F i-1 is the tangential load at the (i-1) node, M i-1 is the moment at the (i-1) node, P i is the axial load at node (i), F i is the tangential load at node (i), M i is the moment at node (i), h i-1 is the axial displacement at the (i-1) node caused by the vertical load P0 on the pile top, w i-1 is the tangential displacement at the (i-1) node caused by the horizontal load F0 on the pile top, v i-1 is the tangential displacement at the (i-1) node caused by the vertical load P0 on the pile top, θ i-1 is the rotation angle at the (i-1) node, h i is the axial displacement at node (i) caused by the vertical load P0, w i is the tangential displacement at node (i) caused by the horizontal load F0, v i is the tangential displacement at node (i) caused by the vertical load P0, θ i is the rotation angle at node (i), h0 is the pile top settlement, w0 is the horizontal displacement of the pile top, θ0 is the pile top rotation angle, φ r (r p ) is the value of the vertical displacement attenuation function at the pile-soil interface caused by the horizontal load and moment at the pile top in the variational method system based on the three-dimensional displacement attenuation function assumption.

4. The method for establishing an efficient soil resistance model around offshore wind power piles according to claim 3 is characterized in that: In step 3, a simplified calculation method based on the assumption of a three-dimensional displacement attenuation function and derived by the calculus of variations is used to quickly determine the expressions of various spring parameters: Where: k is the initial compression stiffness of each soil layer; T is the initial shear stiffness of each soil layer; G s is the initial shear modulus of each soil layer; s is the initial compression modulus of each soil layer; P u is the ultimate horizontal soil resistance; M u is the limit additional torque; F bu is the ultimate horizontal shear force at the pile tip; M b is the ultimate resistance moment of the pile tip.

5. An efficient offshore wind power pile surrounding soil resistance device, the device using the model established by the efficient offshore wind power pile surrounding soil resistance model establishment method according to claim 4, characterized in that: It includes data preprocessing unit, objective function building unit, constraint building unit and result output unit; The data preprocessing unit is used to collect characteristic data of each soil layer, pile body parameters and various loads on the pile top. The characteristic data of each soil layer includes all parameters measured by CPT and SPT; The objective function construction unit quickly determines the various spring parameters by adopting a simplified calculation method derived from the three-dimensional displacement attenuation function assumption and the variational method, and establishes the pile-soil interaction objective function based on the Kinetic energy conservation principle. The pile-soil interaction objective function includes the pile body deformation energy storage objective function U E , the objective function of the work done by the soil resistance around the pile U S and the work done by the node loads at both ends of the pile segment, W; The constraint construction unit constructs the pile-soil interaction boundary constraints by introducing the pile top and pile end constraint boundary conditions and the continuity conditions of each node of the pile body, integrates the unit matrices of each pile segment into an overall square matrix, and finally solves the various displacements of the pile body; The result output unit calculates the internal force response of the pile body by knowing the displacement of each pile segment node, and outputs the corresponding graphic results in combination with the instructions.

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