A calculation method and device for the bearing capacity envelope of a skirt foundation in marine clay
By introducing the regularization mechanism of Cosserat continuum theory and the Drucker-Prager constitutive model on the ABAQUS platform, the grid dependence problem of skirting base in marine clay is solved, and efficient and accurate bearing capacity calculation is achieved.
Patent Information
- Application Number
- CN202510467668.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-15
- Publication Date
- 2025-08-05
- Estimated Expiration
- 2045-04-15
AI Technical Summary
The existing method of scaffolding basic bearing capacity analysis has grid dependence and calculation instability when simulating saturated marine clay, and it is difficult to achieve efficient and accurate bearing capacity calculations in complex working conditions.
ABAQUS's UEL subprogram interface is adopted to realize the regularization mechanism of Cosserat continuum theory through FORTRAN code, introduce rotational freedom and internal length parameters, combine with Drucker-Prager constitutive model, establish a two-dimensional plane strain model for the skirting base, and apply loads by side rubbing method, extract the ultimate bending moment and horizontal bearing capacity, and draw the bearing capacity envelope.
It effectively avoids grid dependence, improves the accuracy and stability of bearing capacity calculation, accurately describes the elastic-plastic behavior of saturated marine clay, and improves the calculation accuracy.
Smart Images
Figure CN119989832B_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of bearing capacity calculation of skirt plate foundations, and in particular to a method and device for calculating the bearing capacity envelope of skirt plate foundations in marine clay. Background Art
[0002] The bearing capacity of skirt slab foundations is affected by a variety of factors, including soil type, soil physical and mechanical properties, foundation geometry (such as depth-to-diameter ratio), load application mode, and changes in the foundation's surrounding environment. Therefore, accurate numerical simulation and analysis of the bearing capacity of skirt slab foundations is an effective means of addressing these complex influencing factors.
[0003] Saturated marine clay is a special type of soil. Its complex mechanical behaviors such as nonlinearity and strain localization make it difficult for traditional numerical calculation methods to accurately simulate. Although the Mohr-Coulomb criterion can effectively describe the strength of the soil, it has a strong grid dependence when considering the strain localization phenomenon, resulting in unstable and inaccurate calculation results. In order to solve this problem, researchers have tried to introduce the Cosserat continuum theory. The Cosserat continuum theory introduces the microstructural effects of the material. By introducing rotational degrees of freedom and length scale parameters, it can effectively describe and simulate the non-local behavior of the soil, especially showing good results in strain localization, plastic failure and foundation bearing capacity analysis.
[0004] However, existing methods for analyzing the bearing capacity of skirt slab foundations based on Cosserat continuum theory still face certain technical bottlenecks. While some studies have employed Cosserat continuum theory for skirt slab foundation analysis, most have focused on simple two-dimensional or three-dimensional models and are limited to static analysis. Further research is needed to improve numerical solution capabilities, refine theoretical models, and achieve efficient calculations under complex conditions. Summary of the Invention
[0005] The purpose of this application is to overcome the defects in the above-mentioned prior art and provide a method and device for calculating the bearing capacity envelope of a skirt foundation in marine clay.
[0006] This application provides a method for calculating the bearing capacity envelope of a skirt foundation in marine clay, including:
[0007] Through the UEL subroutine interface of ABAQUS, a FORTRAN code was used to implement the regularization mechanism of Cosserat's continuum theory. The regularization mechanism includes the introduction of rotational degrees of freedom and internal length parameters, and the establishment of a Drucker-Prager constitutive model that matches the Mohr-Coulomb criterion to simulate the elastic-plastic behavior of saturated marine clay.
[0008] A two-dimensional plane strain model of the skirt foundation with different depth-to-diameter ratios is established in ABAQUS, an inp file is exported after meshing, and the inp file is modified to embed custom elements, Cosserat material parameters, and virtual element connection settings;
[0009] The side rub method is used to apply rotation load and horizontal displacement load to the two-dimensional plane strain model in the modified inp file. After solving with ABAQUS, the ultimate bending moment and horizontal bearing capacity are extracted, and the bearing capacity envelope is drawn.
[0010] Optionally, the regularization mechanism is implemented based on the strain-displacement relationship and equilibrium equation of a two-dimensional Cosserat continuum, which is expressed as:
[0011] ;
[0012] ;
[0013] Where ε is the Cosserat strain tensor, L is the differential operator matrix, u is the displacement vector, σ is the Cosserat stress tensor, and f is the body force vector;
[0014] The differential operator matrix L is defined as:
[0015] ;
[0016] in, represents the positive strain in the x direction, represents the positive strain in the y direction;
[0017] For ε, which is defined as the sum of linear elastic strain and plastic strain, its isotropic elastic modulus matrix is satisfy:
[0018] ;
[0019] Where, λ=2Gν / (1-2ν), G is the shear modulus, ν is the Poisson's ratio, is the Cosserat shear modulus.
[0020] Optionally, establishing a Drucker-Prager constitutive model that matches the Mohr-Coulomb criterion includes: establishing a Drucker-Prager constitutive model that matches the Mohr-Coulomb criterion based on an equivalent relationship between the Drucker-Prager criterion and the Mohr-Coulomb criterion under two-dimensional plane strain conditions.
[0021] Optionally, it also includes:
[0022] According to the custom field variable output requirements, a cloud map containing Cosserat rotational degrees of freedom, plastic strain localization area and stress vector is generated in the ABAQUS result file.
[0023] Optionally, a two-dimensional plane strain model of the skirt foundation with different depth-to-diameter ratios is established in ABAQUS, including:
[0024] According to the dimensional requirements of depth-to-diameter ratio H / D=0.2, 0.5, and 1.0, a two-dimensional plane strain model with a soil domain size of 10B×3B was established;
[0025] The mesh around the skirt foundation is refined, and the mesh element type is an eight-node plane strain quadrilateral element. A fixed constraint is applied to the bottom boundary, and a horizontal displacement constraint is applied to the lateral boundary.
[0026] Optionally, applying a lateral rubbing method to the modified inp file to apply a rotational load and a horizontal displacement load includes:
[0027] Apply a rotation load with an angle increment of Δθ = 0.001 rad until the failure state θmax = 0.1 rad is reached;
[0028] Apply horizontal displacement loads in stages at the extreme rotation angle, with a displacement increment of Δu=0.01B, until the calculation fails to converge.
[0029] Optionally, after solving the problem in ABAQUS, the ultimate bending moment and horizontal bearing capacity are extracted and the bearing capacity envelope is drawn, including:
[0030] According to the ODB result file of ABAQUS, the integral value of the base reaction under each load step is extracted, the horizontal bearing capacity Hult and bending moment Mult are calculated, and the VHM three-dimensional envelope is generated by data fitting.
[0031] Optionally, the value range of the internal length parameter is 0.1m≤lc≤1.0m, and lc=2d50 is satisfied according to the average diameter d50 of soil particles.
[0032] The present application also provides a device for calculating the bearing capacity envelope of a skirt foundation in marine clay, comprising:
[0033] The regularization modeling module is configured to implement the regularization mechanism of Cosserat continuum theory using FORTRAN code through the UEL subroutine interface of ABAQUS. It includes: a rotational degree of freedom embedding unit, which is used to add a microscopic rotation component about the z-axis to the nodal degrees of freedom; an internal length parameter loading unit, which stores and associates the mapping relationship between the internal length parameter and the average diameter of the soil particles; and a differential operator matrix generator, which generates a 7×3-dimensional differential operator matrix according to the formula;
[0034] The DP-MC constitutive module is configured to establish a Drucker-Prager constitutive model that matches the Mohr-Coulomb criterion. It includes: a parameter converter that converts the input cohesion c and friction angle into DP-MC coefficients; a yield surface calculation unit that updates the yield surface in real time;
[0035] The model building module is configured to generate and pre-process finite element model data, including: a depth-to-diameter ratio parameterized modeling unit that automatically adjusts the model geometry based on the depth-to-diameter ratio; an intelligent mesh generator that performs local meshing on the area surrounding the skirt base; and an inp file editor that writes Cosserat material parameters into the inp file.
[0036] The calculation execution module is configured to drive the ABAQUS solver to perform load-bearing capacity analysis, including: a side-scrubbing loading controller that applies loads in stages according to rotation increments and displacement increments; a regularized convergence monitor that triggers mesh adaptive reconstruction when the node rotation wz>0.1rad;
[0037] The visualization output module is configured to generate engineering analysis results, including: an envelope plotter that fits the extracted Hult-Mult data into a three-dimensional envelope surface; and a strain localization cloud map generator that displays the κxz and κyz curvature distribution in the form of a heat map.
[0038] Optionally, the regularized modeling module uses FORTRAN code to implement the regularization mechanism of Cosserat continuum theory, which is expressed as:
[0039] ;
[0040] ;
[0041] Where ε is the Cosserat strain tensor, L is the differential operator matrix, u is the displacement vector, σ is the Cosserat stress tensor, and f is the body force vector;
[0042] The differential operator matrix L is defined as:
[0043] ;
[0044] in, represents the positive strain in the x direction, represents the positive strain in the y direction;
[0045] For ε, which is defined as the sum of linear elastic strain and plastic strain, its isotropic elastic modulus matrix is satisfy:
[0046] ;
[0047] Where, λ=2Gν / (1-2ν), G is the shear modulus, ν is the Poisson's ratio, is the Cosserat shear modulus.
[0048] The beneficial effects of this application are:
[0049] The present application provides a method for calculating the bearing capacity envelope of a skirt foundation in marine clay, comprising: implementing a regularization mechanism of the Cosserat continuum theory through the UEL subroutine interface of ABAQUS using FORTRAN code programming, wherein the regularization mechanism includes introducing rotational degrees of freedom and internal length parameters, and establishing a Drucker-Prager constitutive model that matches the Moore-Coulomb criterion to simulate the elastic-plastic behavior of saturated marine clay; establishing a two-dimensional plane strain model of the skirt foundation containing different depth-to-diameter ratios in the ABAQUS, exporting an inp file after meshing, and modifying the inp file to embed custom units, Cosserat material parameters, and virtual unit connection settings; applying rotational loads and horizontal displacement loads to the two-dimensional plane strain model in the modified inp file using the side rub method, extracting the ultimate bending moment and horizontal bearing capacity after solving with ABAQUS, and drawing the bearing capacity envelope. This application solves the problems of local strain and numerical instability caused by meshing in traditional numerical methods by introducing the regularization mechanism of Cosserat continuum theory; utilizes the non-local effect of Cosserat continuum theory to effectively avoid the common mesh dependence problem in traditional finite element methods; combines the Drucker-Prager constitutive model and Cosserat continuum theory to accurately describe the elastic-plastic behavior of saturated marine clay, thereby improving the accuracy of bearing capacity calculation. BRIEF DESCRIPTION OF THE DRAWINGS
[0050] Figure 1 This is a schematic diagram of the calculation process of the bearing capacity envelope of the skirt foundation in marine clay in this application;
[0051] Figure 2 This is a schematic diagram of the mesh division and boundary conditions of the skirt foundation in this application;
[0052] Figure 3 is a schematic diagram of the deformed grid in this application;
[0053] Figure 4 This is a schematic diagram comparing the envelope of the skirt plate foundation bearing capacity in this application;
[0054] Figure 5 Schematic diagram of the deviation of different internal length parameters lc in this application. DETAILED DESCRIPTION
[0055] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, the embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.
[0056] Please refer to Figure 1 As shown, the present application provides a method for calculating the bearing capacity envelope of a skirt foundation in marine clay, comprising:
[0057] S101. Using the UEL subroutine interface of ABAQUS, FORTRAN code is used to implement the regularization mechanism of Cosserat's continuum theory. The regularization mechanism includes the introduction of rotational degrees of freedom and internal length parameters, and the establishment of a Drucker-Prager constitutive model that matches the Mohr-Coulomb criterion to simulate the elastic-plastic behavior of saturated marine clay.
[0058] Constructing regularization mechanism and elastic-plastic constitutive model:
[0059] The UEL subroutine interface provided by ABAQUS was developed using FORTRAN code. The regularization mechanism of Cosserat's continuum theory was introduced into the matrix to be solved, and the constitutive model was programmed as the Drucker-Prager criterion that matches the Mohr-Coulomb criterion to simulate the elastic-plastic behavior of saturated marine soil.
[0060] Develop visualization modules to customize variable output.
[0061] Furthermore, by introducing the regularization mechanism of the rotational degree of freedom and the internal length parameter lc, the strain-displacement relationship and equilibrium equation of the two-dimensional Cosserat continuum are:
[0062] ;
[0063] ;
[0064] Where ε is the Cosserat strain tensor, L is the differential operator matrix, u is the displacement vector, σ is the Cosserat stress tensor, and f is the body force vector;
[0065] The differential operator matrix L is defined as:
[0066] ;
[0067] in, represents the positive strain in the x direction, represents the positive strain in the y direction;
[0068] For ε, a linear elastic strain is assumed and plastic strain The sum of the isotropic elastic modulus matrix is for:
[0069] ;
[0070] Where, λ=2Gν / (1-2ν), G is the shear modulus, ν is the Poisson's ratio, is the Cosserat shear modulus.
[0071] is the Lame constant, and its relationship with the shear modulus and Poisson's ratio satisfies the equation:
[0072] ;
[0073] The shear strain in a two-dimensional Cosserat continuum can be expressed as:
[0074] ;
[0075] in, is the asymmetric Cosserat shear strain component, is the displacement gradient component, is the microscopic rotational degree of freedom around the z-axis.
[0076] By selecting reasonable values for the coefficients and in the Drucker-Prager yield criterion (DP criterion) under two-dimensional plane strain conditions, the DP yield criterion and the Mohr-Coulomb yield criterion (MC criterion) can be made highly consistent when calculating rock and soil strength-related problems, that is, a DP criterion matching the MC criterion (DP-MC criterion) can be obtained.
[0077] Under two-dimensional plane strain conditions, the yield surface equation of DP-MC is expressed as
[0078] ;
[0079] Where:
[0080] ;
[0081] ;
[0082] ;
[0083] ;
[0084] ;
[0085] Where q is the deviatoric stress, is the hydrostatic pressure, is the friction angle related parameter, is the cohesion-related parameter, is the soil friction angle, and c is the cohesion.
[0086] S102, establishing a two-dimensional plane strain model of the skirt foundation with different aspect ratios in ABAQUS, exporting an inp file after meshing, and modifying the inp file to embed custom units, Cosserat material parameters, and virtual unit connection settings;
[0087] An analytical model of the skirt foundation was created in Abaqus, including varying depth-to-diameter ratios to simulate the effects of size. After meshing and establishing the relevant element and node sets, an inp file containing various model parameters was exported for calculation.
[0088] Modify the inp file, add custom units and material parameter settings, and add virtual units to achieve connection with the developed solver part.
[0089] Take the rigid skirt foundation located in a homogeneous marine saturated clay as an example:
[0090] The eight-node plane strain quadrilateral element was used in the calculation. To avoid the influence of boundary effect, the size of the soil domain was set to 10BX3B (B=3m).
[0091] In this numerical simulation, the depth-to-diameter ratios are 0.2, 0.5, and 1.0 to simulate the influence of foundation size effect on bearing capacity.
[0092] Horizontal constraints are imposed on the vertical boundaries of the soil domain, fixed constraints are imposed on the bottom boundary, and the top boundary is free.
[0093] like Figure 2 As shown in the figure, in order to improve the calculation accuracy, the mesh in a certain range near the anchor plate is refined. The basic mesh division and boundary conditions of the skirt plate with a depth-to-diameter ratio of 1.0 are shown.
[0094] For undrained conditions, the same material parameters are used and the soil Poisson's ratio is , friction angle and expansion angle , cohesion , directly use the undrained shear strength of the soil, and the elastic modulus is taken as , and it is assumed that the skirt base is rigid, that is, it is considered that it does not deform during the drawing process.
[0095] The interface between the foundation and the soil is rough and binds the foundation to the soil.
[0096] S103. Apply rotational load and horizontal displacement load to the two-dimensional plane strain model in the modified inp file using the side rub method, extract the ultimate bending moment and horizontal bearing capacity after solving through ABAQUS, and draw the bearing capacity envelope.
[0097] Use the side rub method and displacement loading method to set different rotation angles and displacements.
[0098] Submit the inp file and the programmed FOR program in the job module of the ABAQUS platform for calculation. After the calculation is completed, open the odB result file, extract the calculation results of the skirt plate foundation bearing capacity, organize the data, and draw the envelope line.
[0099] like Figure 3 As shown in the figure, the deformed mesh diagram obtained greatly improves the mesh distortion, improves the mesh quality and overcomes the mesh dependence compared with the classical finite element method.
[0100] like Figure 4 As shown, the bearing capacity envelopes of skirt plate foundations with different depth-to-diameter ratios are sorted out. This application ensures the accuracy of the bearing capacity envelopes while leveraging the advantages of the Cosserat continuum.
[0101] like Figure 5 As shown in the figure, the influence of different values of the regularization mechanism of the internal length parameter on the bearing capacity envelope is analyzed, and the deviation comparison of the internal length parameter lc is obtained, which reveals the change law of the envelope shape and ultimate bearing capacity with different lc values.
[0102] The present application also provides a device for calculating the bearing capacity envelope of a skirt foundation in marine clay, comprising:
[0103] The regularization modeling module is configured to implement the regularization mechanism of Cosserat continuum theory using FORTRAN code through the UEL subroutine interface of ABAQUS. It includes: a rotational degree of freedom embedding unit, which is used to add a microscopic rotation component about the z-axis to the nodal degrees of freedom; an internal length parameter loading unit, which stores and associates the mapping relationship between the internal length parameter and the average diameter of the soil particles; and a differential operator matrix generator, which generates a 7×3-dimensional differential operator matrix according to the formula;
[0104] The DP-MC constitutive module is configured to establish a Drucker-Prager constitutive model that matches the Mohr-Coulomb criterion. It includes: a parameter converter that converts the input cohesion c and friction angle into DP-MC coefficients; a yield surface calculation unit that updates the yield surface in real time;
[0105] The model building module is configured to generate and pre-process finite element model data, including: a depth-to-diameter ratio parameterized modeling unit that automatically adjusts the model geometry based on the depth-to-diameter ratio; an intelligent mesh generator that performs local meshing on the area surrounding the skirt base; and an inp file editor that writes Cosserat material parameters into the inp file.
[0106] The calculation execution module is configured to drive the ABAQUS solver to perform load-bearing capacity analysis, including: a side-scrubbing loading controller that applies loads in stages according to rotation increments and displacement increments; a regularized convergence monitor that triggers mesh adaptive reconstruction when the node rotation wz>0.1rad;
[0107] The visualization output module is configured to generate engineering analysis results, including: an envelope plotter that fits the extracted Hult-Mult data into a three-dimensional envelope surface; and a strain localization cloud map generator that displays the κxz and κyz curvature distribution in the form of a heat map.
[0108] Furthermore, the regularized modeling module uses FORTRAN code to implement the regularization mechanism of Cosserat continuum theory, which is expressed as:
[0109] ;
[0110] ;
[0111] Where ε is the Cosserat strain tensor, L is the differential operator matrix, u is the displacement vector, σ is the Cosserat stress tensor, and f is the body force vector;
[0112] The differential operator matrix L is defined as:
[0113] ;
[0114] in, represents the positive strain in the x direction, represents the positive strain in the y direction;
[0115] For ε, which is defined as the sum of linear elastic strain and plastic strain, its isotropic elastic modulus matrix is satisfy:
[0116] ;
[0117] Where, λ=2Gν / (1-2ν), G is the shear modulus, ν is the Poisson's ratio, is the Cosserat shear modulus.
[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. A method for calculating the bearing capacity envelope of a skirt foundation in marine clay, characterized in that: include: Through the UEL subroutine interface of ABAQUS, a FORTRAN code was used to implement the regularization mechanism of Cosserat's continuum theory. The regularization mechanism includes the introduction of rotational degrees of freedom and internal length parameters, and the establishment of a Drucker-Prager constitutive model that matches the Mohr-Coulomb criterion to simulate the elastic-plastic behavior of saturated marine clay. A two-dimensional plane strain model of a skirt foundation with different aspect ratios including 0.2, 0.5, and 1.0 is established in ABAQUS, an inp file is exported after meshing, and the inp file is modified to embed custom units, Cosserat material parameters, and virtual unit connection settings, wherein the virtual unit is used to visualize the calculation results of the custom units; The side rub method is used to apply angular load and horizontal displacement load to the two-dimensional plane strain model in the modified inp file. After solving with ABAQUS, the ultimate bending moment and horizontal bearing capacity are extracted, the bearing capacity envelope is drawn, and the envelope change when the internal length parameter takes different values is analyzed. The internal length parameter takes a value of 0.01 to 0.1 times the model height.
2. The method for calculating the bearing capacity envelope of a skirt foundation in marine clay according to claim 1, characterized in that: The regularization mechanism is implemented based on the strain-displacement relationship and equilibrium equation of the two-dimensional Cosserat continuum, which is expressed as: ； ； Where ε is the Cosserat strain tensor, L is the differential operator matrix, u is the displacement vector, σ is the Cosserat stress tensor, and f is the body force vector; The differential operator matrix L is defined as: ； in, represents the positive strain in the x direction, represents the positive strain in the y direction; For ε, which is defined as the sum of linear elastic strain and plastic strain, its isotropic elastic modulus matrix is satisfy: ； Where, λ=2Gν / (1-2ν), G is the shear modulus, ν is the Poisson's ratio, is the Cosserat shear modulus.
3. The method for calculating the bearing capacity envelope of a skirt foundation in marine clay according to claim 1, characterized in that: A Drucker-Prager constitutive model matching the Mohr-Coulomb criterion is established, including: establishing a Drucker-Prager constitutive model matching the Mohr-Coulomb criterion based on the equivalent relationship between the Drucker-Prager criterion and the Mohr-Coulomb criterion under two-dimensional plane strain conditions.
4. The method for calculating the bearing capacity envelope of a skirt foundation in marine clay according to claim 1, characterized in that: Also includes: According to the custom field variable output requirements, a cloud map containing Cosserat rotational degrees of freedom, plastic strain localization area and stress vector is generated in the ABAQUS result file.
5. The method for calculating the bearing capacity envelope of a skirt foundation in marine clay according to claim 1, characterized in that: A two-dimensional plane strain model of the skirt foundation with different depth-to-diameter ratios is established in ABAQUS, including: According to the dimensional requirements of depth-to-diameter ratio H / D=0.2, 0.5, and 1.0, a two-dimensional plane strain model with a soil domain size of 10B×3B was established; The mesh around the skirt foundation is refined, and the mesh element type is an eight-node plane strain quadrilateral element. A fixed constraint is applied to the bottom boundary, and a horizontal displacement constraint is applied to the lateral boundary.
6. The method for calculating the bearing capacity envelope of a skirt foundation in marine clay according to claim 1, characterized in that: The lateral rubbing method is used to apply rotation load and horizontal displacement load to the two-dimensional plane strain model in the modified inp file, including: Apply a rotation load with an angle increment of Δθ = 0.001 rad until the failure state θmax = 0.1 rad is reached; Apply horizontal displacement loads in stages at the extreme rotation angle, with a displacement increment of Δu=0.01B, until the calculation fails to converge.
7. The method for calculating the bearing capacity envelope of a skirt foundation in marine clay according to claim 1, characterized in that: After solving the problem in ABAQUS, the ultimate bending moment and horizontal bearing capacity are extracted and the bearing capacity envelope is drawn, including: According to the ODB result file of ABAQUS, the integral value of the base reaction under each load step is extracted, the horizontal bearing capacity Hult and bending moment Mult are calculated, and the VHM three-dimensional envelope is generated by data fitting.
8. The method for calculating the bearing capacity envelope of a skirt foundation in marine clay according to claim 2, characterized in that: The value range of the internal length parameter is 0.1m≤lc≤1.0m, and according to the average diameter d50 of soil particles, lc=2d50 is satisfied.
9. A device for calculating the bearing capacity envelope of a skirt foundation in marine clay, characterized in that: include: The regularization modeling module is configured to implement the regularization mechanism of Cosserat continuum theory using FORTRAN code through the UEL subroutine interface of ABAQUS. It includes: a rotational degree of freedom embedding unit, which is used to add a microscopic rotation component about the z-axis to the nodal degrees of freedom; an internal length parameter loading unit, which stores and associates the mapping relationship between the internal length parameter and the average diameter of the soil particles; and a differential operator matrix generator, which generates a 7×3-dimensional differential operator matrix according to the formula; The DP-MC constitutive module is configured to establish a Drucker-Prager constitutive model that matches the Mohr-Coulomb criterion. It includes: a parameter converter that converts the input cohesion c and friction angle into DP-MC coefficients; a yield surface calculation unit that updates the yield surface in real time; A model building module is configured to generate and pre-process finite element model data, including: a depth-to-diameter ratio parameterized modeling unit that automatically adjusts the model geometry based on the depth-to-diameter ratio, including 0.2, 0.5, and 1.0; an intelligent mesh generator that performs local meshing on the area surrounding the skirt base; and an inp file editor that writes Cosserat material parameters into the inp file. The calculation execution module is configured to drive the ABAQUS solver to perform load-bearing capacity analysis, including: a side-scrubbing loading controller that applies loads in stages according to rotation increments and displacement increments; a regularized convergence monitor that triggers mesh adaptive reconstruction when the node rotation wz>0.1rad; A visualization output module is configured to generate engineering analysis results, including an envelope plotter that fits the extracted Hult-Mult data into a three-dimensional envelope surface; a strain localization cloud map generator that displays the κxz and κyz curvature distribution in the form of a heat map and analyzes the envelope changes for different values of the internal length parameter, where the internal length parameter takes a value between 0.01 and 0.1 times the model height.
10. The device for calculating the bearing capacity envelope of a skirt foundation in marine clay according to claim 9, characterized in that: The regularization modeling module uses FORTRAN code to implement the regularization mechanism of Cosserat continuum theory, which is expressed as: ； ； Where ε is the Cosserat strain tensor, L is the differential operator matrix, u is the displacement vector, σ is the Cosserat stress tensor, and f is the body force vector; The differential operator matrix L is defined as: ； in, represents the positive strain in the x direction, represents the positive strain in the y direction; For ε, which is defined as the sum of linear elastic strain and plastic strain, its isotropic elastic modulus matrix is satisfy: ； Where, λ=2Gν / (1-2ν), G is the shear modulus, ν is the Poisson's ratio, is the Cosserat shear modulus.