A method for evaluating horizontal bearing response of a large-diameter single pile-bar composite foundation of an offshore wind turbine on soft soil

Abstract

The application provides a soft soil foundation offshore wind turbine large-diameter single pile-bar composite foundation horizontal bearing response evaluation method, including the following steps: S1, determining the geometric size parameters of the composite foundation; S2, measuring the shear strain required for the single shear of the foundation soil unit to reach failure, and fitting to obtain the shape parameters of the normalized stress-strain curve of the soil unit; S3, measuring the shear strength distribution of the seabed with depth; S4, measuring the roughness of the interface between the composite foundation and the soil; S5, calculating the depth z of the influence range area of the shallow barrel of the composite foundation b ; S6, simplifying the interaction between the composite foundation and the soil into a Winkler beam-spring model and establishing a model control equation; S7, calculating the concentrated rotating soil spring M b -θ b curve at the mud surface; S8, calculating the horizontal soil spring p-y curve outside the barrel influence depth; and S9, solving the Winkler beam-spring model control equation of the composite foundation to obtain the horizontal bearing response of the foundation. The application innovatively proposes a large-diameter single pile-bar composite foundation bearing performance analysis model, which has important engineering practical significance.

Description

Technical Field

[0001] This invention belongs to the field of offshore wind power technology and relates to a method for evaluating the horizontal bearing capacity response of a large-diameter monopile-bucket composite foundation for offshore wind turbines on soft soil foundations. Background Technology

[0002] Developing offshore wind power is an inevitable choice. Currently, monopile foundations with a diameter exceeding 5m are the most widely used foundation type in the domestic and international offshore wind power field due to their simple structure and high construction efficiency. However, as offshore wind power gradually moves towards deep-sea and large-capacity turbines, the harsh marine engineering environment and the increased wind, wave, and current forces on large-capacity wind turbines make the foundation stress more severe and complex. Furthermore, in the southeastern waters of my country, the seabed soft soil layer is deep (usually exceeding 30 meters), and the shallow soil has poor mechanical properties (undrained shear strength less than 30 kPa). Under these conditions, conventional monopile foundations cannot meet the overall structural stiffness requirements for normal turbine operation. Infinitely increasing pile diameter and length to improve stiffness and bearing capacity would exceed domestic capabilities in steel structure fabrication, large-diameter monopile transportation, and pile driving equipment and construction, or lead to exorbitant costs due to equipment shortages. Therefore, developing composite foundations for deep-sea soft soil foundations to improve the bearing capacity of traditional monopile foundations is an effective way to solve these problems.

[0003] In recent years, large-diameter monopile-bucket composite foundations have emerged as a fundamental type of innovative design and have been practically applied in offshore wind power projects. These foundations combine large-diameter monopile foundations with suction-type bucket foundations, fully utilizing the resistance of the shallow soil surrounding the piles through the bucket shape to improve the overall stiffness and horizontal bearing capacity of the foundation. This composite foundation provides an effective solution for the foundation design of wind turbines in deep water, large-capacity units, and soft soil foundations. However, as an emerging foundation type, related design methods and analysis models for large-diameter monopile-bucket composite foundations are still lacking. The assessment of their horizontal bearing response in engineering design can only rely on three-dimensional finite element simulation, which is complex and cumbersome, inefficient, and requires highly skilled engineers. Therefore, establishing a method for assessing the horizontal bearing response of large-diameter monopile-bucket composite foundations for offshore wind turbines in soft soil foundations, and achieving rapid and accurate assessment of the composite foundation's bearing capacity, has significant practical engineering value. Summary of the Invention

[0004] The purpose of this invention is to propose a method for evaluating the horizontal bearing capacity response of large-diameter monopile-bucket composite foundations for offshore wind turbines on soft soil foundations, filling the current gap in design methods and analysis models for monopile-bucket composite foundations, and enabling rapid and accurate evaluation of the bearing capacity of monopile-bucket composite foundations in engineering design.

[0005] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0006] A method for evaluating the horizontal bearing capacity response of a large-diameter monopile-bucket composite foundation for offshore wind turbines on soft soil foundations, characterized by the following steps:

[0007] S1. Determine the geometric parameters of the large-diameter monopile-bucket composite foundation, including: monopile diameter d, monopile penetration depth L, shallow bucket diameter D, and bucket penetration depth H.

[0008] S2, The soil shear strain γ required to reach failure under single shear mode of the foundation soil element was measured. f Then, the normalized stress-strain curve of the soil element under single shear was fitted to obtain the shape parameter β of the stress-strain curve of the soil element.

[0009] S3, measured undrained shear strength s of soft soil seabed u Distribution with depth includes: soil strength s at the seabed surface u0 The rate of change of intensity with depth, k;

[0010] At this point, the shear strength distribution of the seabed soil can be expressed as: s u =s u0 +kz, where z is the depth of the soil below the mud surface;

[0011] S4. Measure the roughness α of the interface between the large-diameter single pile-bucket composite foundation and the soil.

[0012] S5. Calculate the depth z of the influence zone of the bucket body in a large-diameter monopile-bucket composite foundation. b ;

[0013] S6. The interaction between the large-diameter single-pile-bucket composite foundation and the soil is simplified into a horizontally loaded Winkler beam-spring model. In the model, the soil resistance contribution within the influence zone of the shallow bucket of the composite foundation is represented by a concentrated rotating soil spring (M) acting at the mud surface. b -θ b Curve, where M b Let θ be the soil resistance bending moment. b The contribution of soil resistance outside the influence zone depth is characterized by the basic horizontal rotation angle, and the distributed horizontal soil spring (py curve, where p is the horizontal soil resistance and y is the basic horizontal displacement) is used to characterize it. Based on beam bending theory and micro-element analysis method, the governing equations of the Winkler beam-spring model of large-diameter single pile-bucket composite foundation under horizontal load are established according to the force balance.

[0014] S7. Calculate the concentrated rotating soil spring M at the mud surface location (z=0). b -θ b curve;

[0015] S8. Calculate the depth outside the influence of the shallow barrel (z = z) b-L) Distributed horizontal soil spring py curve;

[0016] S9, Based on concentrated rotational soil spring M b -θ b The curves and distributed horizontal soil spring py curves were used to solve the governing equations of the Winkler beam-spring model for horizontally loaded large-diameter monopile-bucket composite foundations using the finite difference method. Finally, the horizontal bearing response (displacement, pile bending moment distribution, etc.) of large-diameter monopile-bucket composite foundations under different load magnitudes were obtained.

[0017] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0018] As a preferred embodiment of the present invention, the normalized stress-strain curve of a single shear soil element is fitted by the following formula:

[0019]

[0020] In the formula, τ is the shear stress, and s u_ele γ is the shear strength of the soil element, and γ is the shear strain. f β represents the soil shear strain required to reach failure under the single shear mode of the soil element, and β is the shape parameter of the stress-strain curve of the fitted soil element.

[0021] As a preferred embodiment of the present invention: the depth z of the influence zone of the large-diameter monopile-bucket composite foundation barrel body b Calculate using the following formula:

[0022]

[0023] In the formula, H is the depth of the shallow barrel into the soil, and D is the diameter of the shallow barrel.

[0024] As a preferred embodiment of the present invention: a concentrated rotating soil spring M is located at the mud surface position (z=0). b -θ b The curve is calculated using the following formula:

[0025]

[0026] In the formula, M b To concentrate the bending moment of the rotating soil spring soil resistance, θ b Where D is the horizontal turning angle of the base mud surface, H is the diameter of the shallow bucket, and γ is the depth of the shallow bucket into the soil. f M represents the soil shear strain required to reach failure in the single shear mode of the foundation soil element. b_ult The concentrated rotational soil spring ultimate soil resistance bending moment is calculated using the following formula:

[0027]

[0028] In the formula, D is the diameter of the shallow barrel, H is the depth of the shallow barrel embedded in the soil, k is the rate of change of soil shear strength with depth, and s u0 s represents the shear strength of the soil at the seabed surface. ub It is the shear strength of the soil at the depth of the foundation bucket.

[0029] As a preferred technical solution of the present invention: the shallow barrel body affects the depth outside (z=z) b -L) The distributed horizontal soil spring py curve is calculated using the following formula:

[0030]

[0031] In the formula, p is the horizontal soil resistance, y is the foundation horizontal displacement, and s is the horizontal displacement. u The distribution of undrained shear strength in soft soil seabed, where d is the diameter of a single pile, and γ f β represents the soil shear strain required to reach failure under the single shear mode of the foundation soil element, β is the shape parameter of the stress-strain curve of the soil element, and α is the roughness of the interface between the large-diameter single pile-bucket composite foundation and the soil.

[0032] In a second aspect of the present invention, a non-transitory computer-readable storage medium is provided having a computer program stored thereon, characterized in that, when executed by a processor, the computer program implements the steps of the above-described method for evaluating the horizontal bearing capacity response of large-diameter monopile-bucket composite foundations for offshore wind turbines on soft soil foundations.

[0033] According to a third aspect of the present invention, an electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the program to implement the steps of the above-described method for evaluating the horizontal bearing capacity response of a large-diameter monopile-bucket composite foundation for offshore wind turbines on soft soil foundations.

[0034] The method for evaluating the horizontal bearing capacity response of large-diameter monopile-bucket composite foundations for offshore wind turbines on soft soil foundations provided by this invention has the following beneficial effects:

[0035] 1) This invention innovatively proposes a method for evaluating the bearing capacity of large-diameter monopile-bucket composite foundations that meets engineering practicality. It can quickly and accurately predict the horizontal bearing capacity of the foundation without the need for three-dimensional finite element simulation, which has important engineering practical significance.

[0036] 2) This invention starts from the failure mode of the soil around the foundation, fully considers the enhancement effect of shallow bucket on the bearing capacity of traditional single pile foundation, and also considers the basic mechanical properties of the foundation soil. It is applicable to soft soil foundations with different mechanical properties, and further improves the accuracy of the bearing capacity assessment of large-diameter single pile-bucket composite foundation.

[0037] 3) This invention can provide key technical support and necessary analysis methods for the design of large-diameter monopile-bucket composite foundations for offshore wind turbines on soft soil foundations. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the large-diameter monopile-bucket composite foundation structure of the present invention.

[0039] Figure 2 This is a schematic diagram of fitting the normalized stress-strain curve of the soil element under single shear in this invention.

[0040] Figure 3 This is a schematic diagram showing the depth of the influence zone of the large-diameter monopile-bucket composite foundation barrel of the present invention.

[0041] Figure 4 This invention presents a Winkler beam-spring action model for the horizontal loading of a large-diameter monopile-bucket composite foundation and soil interaction.

[0042] Figure 5 M is a concentrated rotating soil spring at a typical mud surface location. b -θ b curve.

[0043] Figure 6 The Py curves are typical of horizontal soil springs at different depths.

[0044] Figure 7 This invention provides a comparison of the calculated load-displacement response results of a large-diameter monopile-bucket composite foundation with experimental measurements.

[0045] Figure 8 This invention provides a comparison of the calculated and experimentally measured results of the turning moment distribution of large-diameter single-pile-bucket composite foundations. Detailed implementation method:

[0046] A method for evaluating the horizontal bearing capacity response of a large-diameter monopile-bucket composite foundation for offshore wind turbines on soft soil foundations includes the following steps:

[0047] S1. Determine the geometrical parameters of the large-diameter monopile-bucket composite foundation, including: monopile diameter d, monopile embedment depth L, shallow bucket diameter D, and bucket embedment depth H, such as... Figure 1 As shown;

[0048] S2. In-situ soil samples were taken from the foundation soil to conduct indoor single-shear tests on soil elements. The shear strain γ required for the soil element to reach failure (i.e., the shear stress remains basically stable while the shear strain continues to develop) under the single-shear shear mode was measured. f The normalized stress-strain curve of the soil element under single shear is fitted using the following formula to obtain the shape parameter β of the stress-strain curve of the soil element, as follows: Figure 2 As shown;

[0049]

[0050] In the formula, τ is the shear stress, and s u_ele Let γ be the shear strength of the soil element, and γ be the shear strain. f β is the soil shear strain required to reach failure under the single shear mode of the foundation soil element, and β is the shape parameter of the fitted soil element stress-strain curve.

[0051] S3, measured undrained shear strength s of soft soil seabed u Distribution with depth includes: soil strength s at the seabed surface u0 The rate of change of strength with depth, k; the distribution of shear strength of seabed soil can be expressed as: s u =s u0 +kz, where z is the depth of the soil below the mud surface; at this point, the shear strength s of the soil at the depth of the composite foundation bucket. ub It can be calculated using the following formula:

[0052] s ub =s u0 +kH (2)

[0053] In the formula, H is the depth of the shallow barrel embedded in the soil.

[0054] S4. Measure the roughness α of the interface between the large-diameter single pile-bucket composite foundation and the soil.

[0055] S5. Calculate the depth z of the influence zone of the bucket body in a large-diameter monopile-bucket composite foundation. b The affected area is a circular damage surface caused by the rotation of the shallow barrel, such as... Figure 3 As shown, the depth of the affected area can be calculated using the following formula:

[0056]

[0057] In the formula, H is the depth of the shallow barrel into the soil, and D is the diameter of the shallow barrel.

[0058] S6. The interaction between the large-diameter monopile-bucket composite foundation and the soil is simplified to a horizontally loaded Winkler beam-spring model, such as... Figure 4 As shown. The large-diameter monopile is simplified to a Winkler elastic foundation beam. The soil resistance contribution within the shallow barrel influence zone is characterized by a concentrated rotating soil spring acting at the mud surface. The mechanical response characteristics of this concentrated rotating soil spring are represented by M... b -θ b The curve represents M, where M b Let θ be the soil resistance bending moment. bThe horizontal rotation angle of the foundation mud surface is used; the contribution of the soil resistance outside the shallow bucket body's influence depth is characterized by distributed horizontal soil springs, and the mechanical response characteristics of these horizontal soil springs are represented by the py curve, where p is the horizontal soil resistance and y is the foundation horizontal displacement; based on beam bending theory and micro-element analysis method, according to the force balance, the governing equations of the Winkler beam-spring model for horizontally loaded large-diameter single-pile-bucket composite foundation are established, as shown in the following equation:

[0059]

[0060] In the formula, E p For the elastic modulus of a single pile, I p Let y be the moment of inertia of a single pile section, y be the horizontal displacement of a single pile, and k be the moment of inertia of a single pile section. θ To concentrate the rotational soil spring stiffness, k at the mud surface θ =M b / θ b k x For the stiffness of the horizontal soil spring, according to k x =p / y calculation.

[0061] S7. Calculate the concentrated rotating soil spring M at the mud surface location (z=0). b -θ b Curve. Based on the shallow bucket failure mode, considering the self-similarity between the soil shear mechanical response and the bucket bearing response, M b -θ b The curve can be calculated using the following formula:

[0062]

[0063] In the formula, M b To concentrate the bending moment of the rotating soil spring soil resistance, θ b Where D is the horizontal turning angle of the base mud surface, H is the diameter of the shallow bucket, and γ is the depth of the shallow bucket into the soil. f M represents the soil shear strain required to reach failure in the single shear mode of the foundation soil element. b_ult The concentrated rotational soil spring ultimate soil resistance bending moment can be calculated using the following formula:

[0064]

[0065] In the formula, D is the diameter of the shallow barrel, H is the depth of the shallow barrel embedded in the soil, k is the rate of change of soil shear strength with depth, and s u0 s represents the shear strength of the soil at the seabed surface. ub The shear strength of the soil at the depth of the foundation bucket is calculated according to formula (2).

[0066] S8. Calculate the depth outside the influence of the shallow barrel (z = z) b-L) Distributed horizontal soil spring py curve. Within this depth range, the failure mode of the soil around the pile mainly exhibits full-flow failure due to flow around the pile, while the soil elements primarily bear single shear failure. Considering the consistency of the shear mode and the self-similarity between the soil shear mechanical response and the py curve in the full-flow zone, the py curve can be calculated using the following formula.

[0067]

[0068] In the formula, p is the horizontal soil resistance, y is the foundation horizontal displacement, and s is the horizontal displacement. u The distribution of undrained shear strength in soft soil seabed, where d is the diameter of a single pile, and γ f β represents the soil shear strain required to reach failure under the single shear mode of the foundation soil element, β is the shape parameter of the stress-strain curve of the soil element, and α is the roughness of the interface between the large-diameter single pile-bucket composite foundation and the soil.

[0069] S9, Based on concentrated rotational soil spring M b -θ b The curve and the distributed horizontal soil spring py curve, combined with equations (5)-(7), use the finite difference method to solve the control equation (equation (4)) of the Winkler beam-spring model of the large-diameter single pile-bucket composite foundation under horizontal load, and finally the horizontal bearing response of the large-diameter single pile-bucket composite foundation under different loads can be obtained.

[0070] Example:

[0071] The foundation of an offshore wind farm in a southeastern sea area of ​​my country adopts a large-diameter monopile-bucket composite foundation. The monopile diameter is 4m, the pile depth is 60m, and the shallow bucket diameter is 12m with a depth of 10m. The seabed foundation consists of soft clay soil. The undrained shear strength of the soil at the mud surface is 1kPa, and the shear strength varies with depth by 1.54kPa / m. The roughness of the pile-soil interface is 1. Soil element tests were conducted on seabed soil samples. The shear strain required for failure under single shear mode was measured to be 10%, and the shape parameter of the fitted soil element stress-strain curve was 2.2. A horizontal load was applied at a depth of 8m above the mud surface of the foundation. The horizontal bearing capacity of the large-diameter monopile-bucket composite foundation under this condition was calculated.

[0072] A method for evaluating the horizontal bearing capacity response of a large-diameter monopile-bucket composite foundation for offshore wind turbines on soft soil foundations, the implementation steps of which are as follows:

[0073] S1. Determine the geometric dimensions of the large-diameter monopile-bucket composite foundation, where the monopile diameter d = 4m, the monopile penetration depth L = 60m, the shallow bucket diameter D = 12m, and the bucket penetration depth H = 10m.

[0074] S2. In-situ soil samples were taken from the foundation soil to conduct indoor single-shear tests on soil elements. The shear strain γ required for the soil element to reach failure (i.e., the shear stress remains basically stable while the shear strain continues to develop) under single-shear shear mode was measured. f =10%; The following formula is used to fit the normalized stress-strain curve of the soil element under single shear, resulting in the shape parameter β = 2.2 of the soil element stress-strain curve. Figure 2 As shown.

[0075]

[0076] In the formula, τ is the shear stress, and s u_ele Let γ be the shear strength of the soil element, and γ be the shear strain. f The soil shear strain required to reach failure under the single shear shear mode of the foundation soil unit.

[0077] S3, measured undrained shear strength s of soft soil seabed u Distribution with depth, where: soil strength s at the seabed surface u0 =1 kPa, strength variation rate with depth k = 1.54 kPa / m; the shear strength distribution of seabed soil can be expressed as: s u =s u0 +kz=1+1.54z, where z is the depth of the soil below the mud surface; at this point, the shear strength s of the soil at the depth of the composite foundation bucket is... ub It can be calculated using the following formula:

[0078] s ub =s u0 +kH=1+1.54×10=16.4kPa

[0079] In the formula, H is the depth of the shallow barrel embedded in the soil.

[0080] S4. The roughness of the interface between the large-diameter single pile-bucket composite foundation and the soil was measured to be α = 1.

[0081] S5. Calculate the depth z of the influence zone of the bucket body in a large-diameter monopile-bucket composite foundation. b :

[0082]

[0083] In the formula, H is the depth of the shallow barrel into the soil, and D is the diameter of the shallow barrel.

[0084] S6. The interaction between the large-diameter monopile-bucket composite foundation and the soil is simplified to a horizontally loaded Winkler beam-spring model, such as... Figure 4As shown. The large-diameter monopile is simplified to a Winkler elastic foundation beam. The soil resistance contribution within the shallow barrel influence zone is characterized by a concentrated rotating soil spring acting at the mud surface. The mechanical response characteristics of this concentrated rotating soil spring are represented by M... b -θ b The curve represents M, where M b Let θ be the soil resistance bending moment. b The horizontal rotation angle of the foundation mud surface is used; the contribution of the soil resistance outside the shallow bucket body's influence depth is characterized by distributed horizontal soil springs, and the mechanical response characteristics of these horizontal soil springs are represented by the py curve, where p is the horizontal soil resistance and y is the foundation horizontal displacement; based on beam bending theory and micro-element analysis method, according to the force balance, the governing equations of the Winkler beam-spring model for horizontally loaded large-diameter single-pile-bucket composite foundation are established, as shown in the following equation:

[0085]

[0086] In the formula, E p For the elastic modulus of a single pile, I p Let y be the moment of inertia of a single pile section, y be the horizontal displacement of a single pile, and k be the moment of inertia of a single pile section. θ To concentrate the rotational soil spring stiffness, k at the mud surface θ =M b / θ b k x For the stiffness of the horizontal soil spring, according to k x =p / y calculation.

[0087] S7. The concentrated rotating soil spring M at the mud surface location (z=0) is calculated using the following formula. b -θ b curve:

[0088]

[0089] In the formula, M b To concentrate the bending moment of the rotating soil spring soil resistance, θ b Where D is the horizontal turning angle of the base mud surface, H is the diameter of the shallow bucket, and γ is the depth of the shallow bucket into the soil. f M represents the soil shear strain required to reach failure in the single shear mode of the foundation soil element. b_ult The concentrated rotational soil spring ultimate soil resistance bending moment can be calculated using the following formula:

[0090]

[0091] The concentrated rotating soil spring M at the mud surface position (z=0) calculated according to the above formula is... b -θ b Curves Figure 5 As shown.

[0092] S6. The depth of influence of the shallow barrel is calculated using the following formula (z = z). b -L) Distributed horizontal soil spring py curve:

[0093]

[0094] In the formula, p is the horizontal soil resistance, y is the foundation horizontal displacement, and s is the horizontal displacement. u The distribution of undrained shear strength in soft soil seabed, where d is the diameter of a single pile, and γ f β represents the soil shear strain required to reach failure under the single shear mode of the foundation soil element, β is the shape parameter of the stress-strain curve of the soil element, and α is the roughness of the interface between the large-diameter single pile-bucket composite foundation and the soil.

[0095] The typical distributed horizontal soil spring py curves at different depths calculated using the above formula are as follows: Figure 6 As shown.

[0096] S8. Based on the above-obtained concentrated rotating soil spring M b -θ b The curves and distributed horizontal soil spring py curves are used to solve the governing equations of the Winkler beam-spring model for horizontally loaded large-diameter monopile-bucket composite foundations using the finite difference method. This allows for the determination of the horizontal bearing response of the large-diameter monopile-bucket composite foundation under different load magnitudes, including the load-displacement response at the loading point and the pile bending moment distribution under different load magnitudes, as shown below. Figure 7 and Figure 8 As shown.

[0097] In addition, the load-displacement response and pile bending moment distribution at the loading point of the large-diameter single-pile-bucket composite foundation, obtained from experimental measurements, were also plotted on [the following graphs / plots]. Figure 7 and Figure 8 For comparison, the data in the figure shows that the results calculated using the method provided by this invention are in good agreement with the experimental results, verifying the effectiveness and accuracy of the method provided by this invention.

[0098] From the above description of the embodiments, those skilled in the art will clearly understand that the facilities of the present invention can be implemented using software plus necessary general-purpose hardware platforms. Embodiments of the present invention can be implemented using existing processors, or by dedicated processors used for this or other purposes for suitable systems, or by hardwired systems. Embodiments of the present invention also include non-transitory computer-readable storage media, comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon; such machine-readable media can be any available medium accessible by a general-purpose or special-purpose computer or other machine with a processor. For example, such machine-readable media can include RAM, ROM, EPROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other medium that can be used to carry or store the required program code in the form of machine-executable instructions or data structures and is accessible by a general-purpose or special-purpose computer or other machine with a processor. When information is transmitted or provided to a machine via a network or other communication connection (hardwired, wireless, or a combination of hardwired and wireless), that connection is also considered a machine-readable medium.

[0099] The above are merely embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for evaluating the horizontal bearing capacity response of a large-diameter monopile-bucket composite foundation for offshore wind turbines on soft soil foundations, characterized in that: The method includes the following steps: S1. Determine the geometric dimensions of the large-diameter monopile-bucket composite foundation, including: monopile diameter d, monopile penetration depth L, shallow bucket diameter D, and bucket penetration depth H. S2, The soil shear strain γ required to reach failure under single shear mode of the foundation soil element was measured. f By fitting the normalized stress-strain curve of a single shear soil element, the shape parameter β of the stress-strain curve of the soil element is obtained. S3, measured undrained shear strength s of soft soil seabed u Distribution with depth includes: soil strength s at the seabed surface u0 The rate of change of intensity with depth, k; The shear strength distribution of seabed soil is expressed as: s u = s u0 +kz, where z is the depth of the soil below the mud surface; S4. Measure the roughness α of the interface between the large-diameter single pile-bucket composite foundation and the soil. S5. Calculate the depth z of the influence zone of the bucket body in a large-diameter monopile-bucket composite foundation. b ; S6. The interaction between the large-diameter single-pile-bucket composite foundation and the soil is simplified into a horizontally loaded Winkler beam-spring action model. In the model, the soil resistance contribution within the influence zone of the shallow bucket of the composite foundation is represented by a concentrated rotating soil spring acting at the mud surface, and its mechanical response is represented by M... b -θ b The curve represents M, where M b Let θ be the soil resistance bending moment. b The basic horizontal rotation angle is used; the contribution of soil resistance outside the influence zone depth is characterized by distributed horizontal soil springs, and its mechanical response is represented by the py curve, where p is the horizontal soil resistance and y is the basic horizontal displacement; based on beam bending theory and micro-element analysis method, according to the force balance, the governing equation of the Winkler beam-spring model of horizontal load on large-diameter single pile-bucket composite foundation is established. S7, Calculate the concentrated rotating soil spring M at the mud surface location. b -θ b curve; S8. Calculate the py curve of the distributed horizontal soil spring outside the influence depth of the shallow barrel. S9, Based on concentrated rotational soil spring M b -θ b The curves and distributed horizontal soil spring py curves are used to solve the governing equations of the Winkler beam-spring model for horizontally loaded large-diameter monopile-bucket composite foundations using the finite difference method. Finally, the horizontal bearing response of large-diameter monopile-bucket composite foundations under different load magnitudes is obtained, including displacement and pile bending moment distribution.

2. The method for evaluating the horizontal bearing capacity response of a large-diameter monopile-bucket composite foundation for offshore wind turbines on soft soil foundations according to claim 1, characterized in that: Concentrated rotation of soil spring M at mud surface location b -θ b The curve is calculated using the following formula: In the formula, M b To concentrate the bending moment of the rotating soil spring soil resistance, θ b Where D is the horizontal turning angle of the base mud surface, H is the diameter of the shallow bucket, and γ is the depth of the shallow bucket into the soil. f M represents the soil shear strain required to reach failure in the single shear mode of the foundation soil element. b_ult The concentrated rotational soil spring ultimate soil resistance bending moment can be calculated using the following formula: In the formula, D is the diameter of the shallow barrel, H is the depth of the shallow barrel embedded in the soil, k is the rate of change of soil shear strength with depth, and s u0 s represents the shear strength of the soil at the seabed surface. ub It is the shear strength of the soil at the depth of the foundation bucket.

3. The method for evaluating the horizontal bearing capacity response of a large-diameter monopile-bucket composite foundation for offshore wind turbines on soft soil foundations according to claim 1, characterized in that: The py curve of the distributed horizontal soil spring outside the influence depth of the shallow barrel is calculated using the following formula: In the formula, p is the horizontal soil resistance, y is the foundation horizontal displacement, and s is the horizontal displacement. u The distribution of undrained shear strength in soft soil seabed, where d is the diameter of a single pile, and γ f β represents the soil shear strain required to reach failure under the single shear mode of the foundation soil element, β is the shape parameter of the stress-strain curve of the soil element, and α is the roughness of the interface between the large-diameter single pile-bucket composite foundation and the soil.

4. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the method for evaluating the horizontal bearing capacity response of a large-diameter monopile-bucket composite foundation for offshore wind turbines on soft soil foundations as described in claim 3.

5. An electronic 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 program, it implements the steps of the method for evaluating the horizontal bearing capacity response of a large-diameter monopile-bucket composite foundation for offshore wind turbines on soft soil foundations as described in claim 3.

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