Numerical simulation method and system for dynamic pile driving in cohesionless soil

Abstract

The present invention relates to the field of geotechnical mechanics, and more particularly to a numerical simulation method and system for dynamic piling in cohesionless soil. The method comprises: obtaining a generalized dynamic piling model and a cohesionless soil sample of a target study area; determining hypoplastic model parameters of the cohesionless soil and linear elastic model parameters of the pile; and based on the hypoplastic model parameters of the cohesionless soil and the linear elastic model parameters of the pile, using a pre-established numerical model to call a preset VUMAT subroutine to simulate the large deformation of the soil and the dynamic changes of pore water pressure during the dynamic piling process, thereby obtaining simulated piling results. The preset VUMAT subroutine is obtained by using an improved CEL method. Thus, the problems of complex models, numerous parameters, and difficulty in solving the problem in the related technical solution process are solved, thereby reducing the model complexity and solution difficulty.

Description

Technical Field

[0001] The present invention relates to the technical field of dynamic piling, and in particular to a numerical simulation method and system suitable for dynamic piling in cohesive-free soil. Background Art

[0002] Dynamic piling is a construction technique that uses mechanical dynamic loads (such as vibration or impact) to drive precast piles into the ground. The principle is to use dynamic loads to disrupt the soil structure surrounding the pile, reducing the resistance between the pile and the soil, thereby allowing the pile to sink smoothly. This technique has the advantages of wide applicability, high construction efficiency, and low environmental pollution, making it widely adopted in construction projects. Historically, dynamic piling was primarily used in soft clayey soils, which have relatively low resistance and require less mechanical properties. In recent years, with the advancement of piling equipment, the application of this technique in harder sandy soils has rapidly developed. Sandy soil, as a typical non-cohesive granular material, has weak inter-particle cohesion, high permeability, and low compressibility. When subjected to strong dynamic loads in a saturated state, it is prone to liquefaction and a sharp decrease in strength. However, theoretical models and calculation methods for dynamic piling developed for soft clayey soils have shown significant limitations when applied to non-cohesive soils. For example, they fail to fully account for the effects of soil particle rearrangement on density and permeability, and they struggle to simulate the accumulation and dissipation of pore water pressure. Therefore, there is an urgent need for a new method that can be used to deeply study and analyze the pile-soil interaction mechanism and the comprehensive influence of various parameters of dynamic piling in cohesionless soil.

[0003] In related technologies, traditional analytical methods have difficulty constructing accurate and solvable mathematical models to solve key state variables such as stress, strain, and pore water pressure in cohesionless soils due to the difficulty in solving dynamic piling problems. Consequently, numerical methods are widely used in solving these problems. Finite element methods, with their mature computational methods and abundant software resources, are the most commonly used approach to address the problem of hard sandy soil layers with weak inter-particle cohesion, high permeability, and low compressibility. These layers are prone to liquefaction and a sharp drop in strength when subjected to intense dynamic loads in a saturated state.

[0004] However, when using the finite element method to model and analyze the process of dynamic pile driving in cohesionless soil, there are some difficulties that need to be solved urgently: (1) The elastic-plastic model is the mainstream constitutive model of geotechnical bodies today. The geotechnical material models provided in commercial finite element software are mostly based on the elastic-plastic theory, such as the Mohr-Columb model, the Cam-Clay model, the Modified Cam-Clay model, the Drucker-Prage model, etc. There are some shortcomings when applying the elastic-plastic model to cohesionless soil. For example, the elastic-plastic theory decomposes deformation into elastic and plastic parts and assumes the existence of a yield surface. When the stress state is on the yield surface, the material reaches its yield point and begins to transform into plastic deformation. However, under deviatoric stress loading conditions, cohesionless soil usually does not show a typical yield point, making it difficult to define its elastic deformation area; during unloading, its deformation is not completely reversible. In addition, the elastic-plastic theory only uses plastic volume strain as a hardening parameter to determine the plastic strain, and cannot consider the volume expansion and softening characteristics caused by shear. Moreover, the elastic-plastic model is generally based on statics theory, ignoring the loading and unloading process and the motion state of the soil during the construction phase, and directly solving the failure state of the soil through static limit equilibrium analysis. Therefore, there are certain limitations when using the elastic-plastic model embedded in commercial finite element software to describe the mechanical response of non-cohesive soil during dynamic pile driving. (2) In the finite element method, the soil around the pile will undergo large displacement during the process of pile driving into the soil, generating large nonlinear strains, which is a typical large soil deformation problem. When using traditional finite element methods to simulate this process, it is easy to cause mesh distortion and distortion, resulting in non-convergence of the calculation. The main reasons are as follows: First, the finite element method is based on the continuum medium assumption, which assumes that material particles are continuous and void-free in space and always maintain the shape of a continuum during deformation. Therefore, the grid unit cannot be broken, making it difficult to simulate the actual situation of piles (especially flat-end piles) being driven into the soil; second, the material movement in the finite element method is based on the Lagrangian description, and the nodes of the grid unit (Lagrangian unit) are bound to the material. When the material undergoes large deformation, it is easy to cause grid distortion and distortion, resulting in calculation termination. (3) The coupled Euler-Lagrangian (CEL) method was introduced into the large deformation analysis of geotechnical engineering. This method uses Lagrangian units to simulate small deformation materials (such as piles) and Euler units to simulate large deformation materials (such as soil), so that the motion domains based on Lagrangian description and Euler description can coexist and interact in a finite element model. The CEL method can effectively simulate the static pressure process of piles and solve the grid quality and convergence problems caused by large deformation of soil. However, the dynamic piling process is more complicated. Under strong dynamic loads, non-cohesive soil undergoes liquefaction, which involves the rearrangement and displacement of soil particles and dynamic changes in pore water pressure.The Euler unit in the CEL method is essentially a fluid unit, which makes it difficult to simulate the flow of pore fluid in solid particles and the interaction between the two, making it impossible to effectively perform water-mechanical coupling analysis, which needs to be solved urgently. Summary of the Invention

[0005] The present invention provides a numerical simulation method and system suitable for dynamic piling in cohesionless soil, so as to solve the problems of complex models, numerous parameters and difficult solutions in the solution process of related technologies, and reduce the model complexity and solution difficulty.

[0006] The first aspect of the present invention provides a numerical simulation method suitable for dynamic piling in cohesionless soil, wherein the method includes: obtaining a generalized dynamic piling model and a cohesionless soil sample in a target study area; determining the subplastic model parameters of the cohesionless soil and the linear elastic model parameters of the pile, and based on the subplastic model parameters of the cohesionless soil and the linear elastic model parameters of the pile, using a pre-established numerical model to call a preset VUMAT subroutine to simulate the large deformation of the soil and the dynamic changes of pore water pressure during the dynamic piling process to obtain simulated piling results, wherein the preset VUMAT subroutine is written by an improved CEL method.

[0007] Furthermore, in some embodiments, after obtaining the simulated piling results, the method further includes: acquiring piling monitoring data of the target study area; and verifying the simulated piling results based on the piling monitoring data, so as to perform accuracy analysis on the numerical model according to the verification results.

[0008] Furthermore, in some embodiments, obtaining a generalized model of dynamic piling in the target study area includes: obtaining the site stratigraphic conditions, groundwater conditions and the occurrence state of cohesionless soil in the target study area, and obtaining geological condition analysis results based on the site stratigraphic conditions, the groundwater conditions and the occurrence state of the cohesionless soil; determining pile foundation design parameters based on the geological condition analysis results, wherein the pile foundation design parameters include pile type size, material properties, piling equipment and loading parameters; obtaining piling monitoring data of the target study area, and obtaining the generalized model of dynamic piling based on the geological condition analysis results, the pile foundation design parameters and the piling monitoring data.

[0009] Furthermore, in some embodiments, based on the hypoplastic model parameters of the cohesionless soil and the linear elastic model parameters of the pile, the preset VUMAT subroutine is used to simulate the large deformation of the soil and the dynamic changes of the pore water pressure during the dynamic pile driving process to obtain the soil behavior simulation results, including: constructing a Niemunis-Herle hypoplastic model based on the hypoplastic model parameters of the cohesionless soil, and embedding the VUMAT subroutine of the Niemunis-Herle hypoplastic model into the preset ABAQUS software to obtain the mechanical behavior simulation results of the cohesionless soil; based on the preset Darcy's law, rewriting the preset pore fluid mass balance equation, and replacing the temperature in the preset thermal energy balance equation according to the excess pore fluid pressure of the rewritten pore fluid mass balance equation, and based on the replacement The improved CEL method is determined by combining the heat conduction transfer process in the thermal-displacement coupling analysis program to simulate the diffusion of pore fluid in the soil skeleton and perform related stress analysis, wherein the preset Darcy's law is used to describe the flow of pore fluid between the soil skeletons, and the preset heat balance equation is set in the thermal-displacement coupling analysis program; the preset VUMAT subroutine is determined according to the improved CEL method, and based on the subplastic model parameters of the cohesionless soil and the linear elastic model parameters of the pile, the preset VUMAT subroutine is called by using a pre-established numerical model to simulate the soil behavior of the large deformation of the soil and the dynamic change of the pore water pressure during the dynamic piling process, and the simulated piling result is obtained in combination with the mechanical behavior simulation result of the cohesionless soil.

[0010] Furthermore, in some embodiments, before using the pre-established numerical model to call the preset VUMAT subroutine to simulate the soil behavior of the large deformation of the soil and the dynamic changes of the pore water pressure during the dynamic piling process, it also includes: based on the generalized dynamic piling model, three-dimensional geometric modeling of the pile and the soil is performed to obtain the modeled pile and the modeled soil; based on the preset Lagrangian unit and the preset Euler unit, the improved CEL method is used to mesh the modeled pile and the modeled soil to obtain meshing results; boundary conditions and pile-soil contact characteristics are determined according to the soil behavior simulation results, and the pre-established numerical model is constructed based on the meshing results, the boundary conditions and the pile-soil contact characteristics.

[0011] The numerical simulation method for dynamic piling in cohesionless soil, provided by an embodiment of the present invention, can accurately simulate the process of pile driving into soil under dynamic loads (such as vibration or impact), the mechanical behavior of cohesionless soil, and the dynamic changes in pore water pressure, thereby enabling modeling and analysis of the dynamic piling process in cohesionless soil. This method addresses the complex models, numerous parameters, and difficulty in solving the problem encountered in related techniques, reducing both model complexity and solution difficulty.

[0012] The second aspect of the present invention provides a numerical simulation system suitable for dynamic piling in cohesionless soil, wherein the device includes: an acquisition module for acquiring a generalized dynamic piling model and a cohesionless soil sample of a target study area; a data processing module for determining the subplastic model parameters of the cohesionless soil and the linear elastic model parameters of the pile, and based on the subplastic model parameters of the cohesionless soil and the linear elastic model parameters of the pile, using a pre-established numerical model to call a preset VUMAT subroutine to simulate the soil behavior of the large deformation of the soil and the dynamic changes of pore water pressure during the dynamic piling process, to obtain a simulated piling result, wherein the preset VUMAT subroutine is written by the improved CEL method.

[0013] Furthermore, in some embodiments, after obtaining the simulated piling results, the data processing module is also used to: obtain piling monitoring data of the target study area; and verify the simulated piling results based on the piling monitoring data, so as to perform accuracy analysis on the numerical model according to the verification results.

[0014] Furthermore, in some embodiments, the acquisition module is specifically used to: obtain the site stratigraphic conditions, groundwater conditions and the occurrence state of non-cohesion soil in the target study area, and obtain geological condition analysis results based on the site stratigraphic conditions, the groundwater conditions and the occurrence state of the non-cohesion soil; determine pile foundation design parameters based on the geological condition analysis results, wherein the pile foundation design parameters include pile type size, material properties, pile driving equipment and loading parameters; obtain pile driving monitoring data of the target study area, and obtain the dynamic pile driving generalization model based on the geological condition analysis results, the pile foundation design parameters and the pile driving monitoring data.

[0015] Furthermore, in some embodiments, the data processing module is specifically used to: construct a Niemunis-Herle hypoplastic model based on the hypoplastic model parameters of the cohesionless soil, and embed the VUMAT subroutine of the Niemunis-Herle hypoplastic model into the preset ABAQUS software to obtain the mechanical behavior simulation results of the cohesionless soil; based on the preset Darcy's law, rewrite the preset pore fluid mass balance equation, and replace the temperature in the preset thermal energy balance equation according to the super pore fluid pressure of the rewritten pore fluid mass balance equation, and based on the replaced thermal energy balance equation, simulate the pore fluid in the heat conduction transfer process in the thermal-displacement coupling analysis program. Diffusion in the soil skeleton and related stress analysis are performed to determine the improved CEL method in combination with the analysis results, wherein the preset Darcy's law is used to describe the flow of pore fluid between the soil skeletons, and the preset thermal energy balance equation is set in the thermal-displacement coupling analysis program; the preset VUMAT subroutine is determined according to the improved CEL method, and based on the subplastic model parameters of the cohesionless soil and the linear elastic model parameters of the pile, the preset VUMAT subroutine is called using a pre-established numerical model to simulate the soil behavior of the large deformation of the soil and the dynamic change of pore water pressure during the dynamic piling process, and the simulated piling result is obtained in combination with the mechanical behavior simulation result of the cohesionless soil.

[0016] Furthermore, in some embodiments, before using the pre-established numerical model to call the preset VUMAT subroutine to simulate the soil behavior results of the large deformation of the soil and the dynamic changes of pore water pressure during the dynamic piling process, the data processing module is also used to: based on the generalized dynamic piling model, perform three-dimensional geometric modeling of the piles and soil to obtain the modeled piles and the modeled soil; based on the preset Lagrangian unit and the preset Euler unit, use the improved CEL method to mesh the modeled piles and the modeled soil to obtain meshing results; determine the boundary conditions and pile-soil contact characteristics, and construct the pre-established numerical model based on the meshing results, the boundary conditions and the pile-soil contact characteristics.

[0017] The numerical simulation system for dynamic piling in cohesionless soils provided by the present invention can accurately simulate the process of pile driving into soil under dynamic loads (such as vibration or impact), the mechanical behavior of cohesionless soil, and the dynamic changes in pore water pressure, thereby enabling modeling and analysis of the dynamic piling process in cohesionless soils. This system addresses the complex models, numerous parameters, and difficulty in solving the problems encountered in related solutions, reducing both model complexity and solution difficulty.

[0018] Therefore, the numerical simulation method for dynamic piling in cohesionless soil according to the embodiment of the present invention has the following beneficial effects:

[0019] (1) By embedding the Niemunis-Herle hypoplastic model developed for cohesionless granular materials into the ABAQUS software, the embodiment of the present invention can accurately simulate the mechanical properties of cohesionless soil under dynamic loads, such as particle rearrangement, displacement, inelasticity, dilatancy, softening and liquefaction, thereby overcoming the limitations of the elastoplastic model and improving the accuracy and reliability of the simulation results.

[0020] (2) The embodiment of the present invention enables the Euler element in the CEL method to effectively simulate the diffusion of pore fluid in the soil skeleton and perform related stress analysis, successfully solving the problem that the Euler element is difficult to characterize the accumulation and dissipation of pore water pressure when simulating large deformation soils, thereby realizing water-mechanical coupling analysis.

[0021] (3) The embodiment of the present invention improves the CEL method and embeds it into ABAQUS software, thereby solving the shortcomings of the Euler unit in simulating the diffusion of pore fluid in the soil skeleton and related stress analysis. It can accurately reflect the accumulation and dissipation of pore water pressure in large deformation soil during dynamic pile driving, and improves the applicability of the CEL method in large deformation analysis of geotechnical engineering.

[0022] (4) The embodiments of the present invention solve the limitations of the elastic-plastic model, the mesh problem caused by large soil deformation, and the problem that the CEL method is not applicable to water-mechanical coupling analysis. It can effectively simulate the physical phenomena in the dynamic pile driving process and fill the gap in numerical technology in the field of dynamic pile driving.

[0023] (5) The embodiments of the present invention can accurately simulate the process of pile driving into soil under dynamic load, the mechanical behavior of cohesionless soil, and the dynamic changes of pore water pressure, etc., and effectively solve the problems of traditional analytical methods in solving problems related to dynamic pile driving, such as complex models, numerous parameters, and difficulty in solving them.

[0024] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0026] Figure 1 A flow chart of a numerical simulation method for dynamic piling in cohesionless soil provided according to an embodiment of the present invention;

[0027] Figure 2 A schematic diagram of a technical route for secondary development based on a VUMAT subroutine according to a specific embodiment of the present invention;

[0028] Figure 3 A flow chart of a numerical simulation method provided according to a specific embodiment of the present invention;

[0029] Figure 4 Schematic diagram of a numerical simulation system for dynamic piling in cohesionless soil according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0031] The following describes, with reference to the accompanying drawings, a numerical simulation method and system for dynamic piling in cohesionless soil according to an embodiment of the present invention. To address the problems mentioned in the background art above, such as complex models, numerous parameters, and difficulty solving the related art solutions, the present invention provides a numerical simulation method for dynamic piling in cohesionless soil. This method accurately simulates the process of pile driving into soil under dynamic loads (such as vibration or impact), the mechanical behavior of cohesionless soil, and the dynamic changes in pore water pressure. This method enables modeling and analysis of the dynamic piling process in cohesionless soil, resolving the problems of complex models, numerous parameters, and difficulty solving the related art solutions. This method fills a gap in numerical technology in the field of dynamic piling, providing a new technical approach for the design and construction of dynamic piling projects.

[0032] Specifically, Figure 1 This is a flow chart of a numerical simulation method for dynamic piling in cohesionless soil provided according to an embodiment of the present invention.

[0033] like Figure 1 As shown in FIG, the numerical simulation method for dynamic piling in cohesionless soil includes the following steps:

[0034] In step S101, a generalized dynamic piling model and cohesionless soil samples of the target study area are obtained.

[0035] Furthermore, in some embodiments, obtaining a generalized model of dynamic piling in the target study area includes: obtaining site stratigraphic conditions, groundwater conditions, and the occurrence state of cohesionless soil in the target study area, and obtaining geological condition analysis results based on the site stratigraphic conditions, groundwater conditions, and the occurrence state of cohesionless soil; determining pile foundation design parameters based on the geological condition analysis results, wherein the pile foundation design parameters include pile type and size, material properties, piling equipment, and loading parameters; obtaining piling monitoring data in the target study area, and obtaining a generalized model of dynamic piling based on the geological condition analysis results, pile foundation design parameters, and piling monitoring data.

[0036] The target study area's geological conditions include the type and thickness of each stratum, groundwater conditions include the type and depth of each aquifer, and the occurrence state of cohesionless soil includes its density and saturation. Furthermore, pile dimensions include length and cross-sectional dimensions, material properties include density, elastic modulus, and Poisson's ratio, and the piling equipment can be either a vibratory hammer or an impact hammer. Loading parameters include action frequency and peak load. Pile monitoring data includes driving depth and pore water pressure. By comprehensively considering the influence of these factors, a generalized dynamic piling model was developed.

[0037] In step S102, the hypoplastic model parameters of the cohesionless soil and the linear elastic model parameters of the pile are determined, and based on the hypoplastic model parameters of the cohesionless soil and the linear elastic model parameters of the pile, the preset VUMAT subroutine is called by the pre-established numerical model to simulate the soil behavior of the large deformation of the soil and the dynamic change of the pore water pressure during the dynamic piling process to obtain the simulated piling results, wherein the preset VUMAT subroutine is written by the improved CEL method.

[0038] The material model parameters can be determined by soil sample collection and testing and construction data review. Specifically, soil sample collection and testing can be done by taking cohesiveless soil samples from the study area, conducting indoor geotechnical tests, and determining the subplastic model parameters of cohesiveless soil, including density ρ, critical friction angle φ c , particle hardness h s , index n, upper limit porosity ratio e at zero pressure i0 , critical porosity ratio e at zero pressure c0 , the lower limit porosity ratio e under zero pressure d0 , exponents α and β, maximum intergranular strain R, stiffness factor m R and m T , exponential β r and χ. Construction data includes density ρ, elastic modulus E s and Poisson's ratio μ.

[0039] Further, Figure 2The following is a schematic diagram of a technical route for secondary development based on a VUMAT subroutine according to a specific embodiment of the present invention. Figure 2 As shown, simulation is achieved through secondary development based on the VUMAT subroutine, including secondary development of the Niemunis-Herle hypoplastic model VUMAT. This involves writing a VUMAT subroutine for the Niemunis-Herle hypoplastic model and embedding it into ABAQUS software to simulate the mechanical behavior of cohesionless soil. The CEL method is improved based on the up-form saturated soil dynamic equation. Darcy's law is used to describe the flow of pore fluid within the soil skeleton. Based on the pore fluid mass balance equation proposed by Zienkiewicz, the temperature in the thermal energy balance equation in the ABAQUS / Explicit thermal-displacement coupling analysis program is replaced with the excess pore fluid pressure in the pore fluid mass balance equation. The diffusion of pore fluid in the soil skeleton is simulated through the heat conduction transfer process in the thermal-displacement coupling analysis program, and related stress analysis is performed. The relevant control equations are modified to determine the constants required for the model. The secondary development of VUMAT, an improved CEL method, is to write a VUMAT subroutine of the improved CEL method and embed it into ABAQUS software to simulate the large deformation of soil and the dynamic changes of pore water pressure during dynamic piling.

[0040] It should be noted that ABAQUS is a finite element software with a rich variety of unit types, material models and analysis processes. It can simulate single parts and complex systems in many fields such as solid mechanics and fluid mechanics, support modeling and analysis of multi-physics field coupling, and provide secondary development interfaces to meet the specific needs of users. In addition, during the simulation process, the simulation of pile driving and soil behavior is carried out simultaneously, and pile driving causes changes in soil behavior.

[0041] Furthermore, in some embodiments, before using a pre-established numerical model to call a preset VUMAT subroutine to perform soil behavior simulation results on the large deformation of the soil and the dynamic changes of pore water pressure during the dynamic piling process, it also includes: based on the generalized model of dynamic piling, three-dimensional geometric modeling of the piles and soil to obtain modeled piles and modeled soil; based on the preset Lagrangian unit and the preset Euler unit, using the improved CEL method, meshing the modeled piles and modeled soil to obtain meshing results; determining the boundary conditions and pile-soil contact characteristics according to the soil behavior simulation results, and constructing the pre-established numerical model based on the meshing results, boundary conditions and pile-soil contact characteristics.

[0042] Among them, based on the generalized model of dynamic piling, the piles and soil are three-dimensionally modeled. The CEL method is used to simulate the piles using Lagrangian elements and the soil using Euler elements, and the piles and soil are meshed. The boundary conditions affect the predicted range of influence of dynamic piling, including stress and drainage conditions. The pile-soil contact characteristics include appropriate contact models and friction coefficients. Based on the generalized model of dynamic piling, the pile loading mode and analysis steps, including loading form, frequency, force, etc., are set to simulate the actual dynamic piling construction process, and the above-mentioned VUMAT subroutine is called at each time increment and each integration point.

[0043] Furthermore, in some embodiments, after obtaining the simulated piling results, the method further includes: obtaining piling monitoring data of the target study area; and verifying the simulated piling results based on the piling monitoring data, so as to perform accuracy analysis on the numerical model according to the verification results.

[0044] The numerical model can be verified based on the layout of on-site construction monitoring points and monitoring data (such as driving depth and pore water pressure) to ensure its accuracy and reliability. Numerical calculation results, such as soil porosity, excess pore water pressure, effective stress, and pile stress and strain, can be output on demand. By varying the values ​​of key parameters based on the pile foundation design and construction plan, the physical phenomena during dynamic piling and the combined impact of parameter changes on the process can be studied and analyzed.

[0045] In order to enable relevant practitioners in this field to better understand the numerical simulation method for dynamic piling in non-cohesive soil according to an embodiment of the present invention, it is described below with reference to specific embodiments.

[0046] It should be noted that this example uses Larsen steel sheet pile construction as an example. The site's strata are primarily composed of sandy soil, which is considered cohesive-free. To ensure smooth installation of the steel sheet piles, a vibrating pile driver was used as the primary construction equipment.

[0047] Figure 3 A flow chart of a numerical simulation method provided according to a specific embodiment of the present invention is shown as follows: Figure 3 As shown, this embodiment includes the following steps:

[0048] In step S301 , the dynamic pile driving model is generalized.

[0049] For example, the embodiments of the present invention can clarify, by consulting the geotechnical engineering investigation report, that the strata on the site in the study area are mainly fine sand, sandy silt, and silty clay, of which the depth of approximately 0-4 m is a plain fill layer, 4-16 m is a fine sand layer, and 16-20 m is a silty clay layer; within the exploration depth range, the groundwater level is revealed to be approximately 4.15-16.00 m deep, and the aquifer is a fine sand layer, indicating that the soil layer is in a saturated state; through the standard penetration test, the N value of the fine sand is approximately 30, indicating that the soil layer is in a relatively dense state.

[0050] Furthermore, the embodiment of the present invention can clarify that the Larsen steel sheet pile has a U-shape, a pile length of 12 m, a cross-sectional dimension of 400 mm in width, 170 mm in height, 15.5 mm in thickness, and an area of ​​96.99 cm² by consulting the pile foundation design and construction plan; the linear elastic model parameters of the steel are a density of 7.85 g / cm³, an elastic modulus of 2.06×108 kPa, and a Poisson's ratio of 0.3; the vibratory pile driver used outputs a high-frequency vibration load with a vibration frequency of 47 Hz, an excitation force peak of 580 kN, and a target piling depth of 12 m.

[0051] Furthermore, the embodiment of the present invention can clarify the layout of the on-site pore water pressure gauges by consulting the construction monitoring report: a total of two pore water pressure gauges are buried, 15.5 cm from the pile axis, at depths of 3 m and 9 m, respectively. The monitoring data of the pore water pressure gauges, as well as the steel sheet pile advancement process (pile driving depth and time required for each stage) and the final pile driving depth (11.5 m) are recorded.

[0052] In step S302 , material model parameters are determined.

[0053] Specifically, the embodiment of the present invention can take fine sand samples to carry out indoor geotechnical tests. The maximum porosity ratio is determined by relative density test. e max , minimum porosity ratio e min and relative density D r (60%), further determine the upper limit porosity ratio under zero pressure e i0 , critical porosity ratio at zero pressure e c0 , lower limit porosity ratio at zero pressure e d0 ( e i0 / e max ≈1.2, e c0 ≈ e max , ed0 ≈ e min ); Determination of critical friction angle by triaxial compression test φ c ,index α ; Determine particle hardness by confined or triaxial compression testing h s and index n; the index is determined by cyclic loading test β r and χ , the value range is 0.2≤ β r <1 and 1< χ ≤10; usually, the index β , maximum intergranular strain R, stiffness factor m R and m T is considered as a constant, where β The value is 1, and the value of R is 1×10 -4 、 m R and m T The values ​​are 2 and 5 respectively. The parameters of the hypoplastic model are shown in Table 1.

[0054] Table 1

[0055]

[0056] In step S303, secondary development is performed based on the VUMAT subroutine.

[0057] Specifically, the embodiment of the present invention obtains a constitutive model of the hypoplastic critical state based on the general form of the hypoplastic model that can consider the deviatoric stress critical state surface:

[0058]

[0059]

[0060] in, , , .

[0061] Furthermore, considering the stiffness change of granular materials under small strain conditions, the general form of the Niemunis-Herle hypoplastic model is obtained as follows:

[0062]

[0063]

[0064] in, ρ is a state variable, when ρ =1:

[0065]

[0066] When 0< ρ <1 hour:

[0067]

[0068] in, is the Jaumann stress rate tensor; is the densogenic factor; is the pressure factor; is the upper limit porosity ratio under mean stress; is the critical void ratio at mean stress; is the lower limit void ratio under mean stress; D is the strain rate tensor; L and N represent the stress rate components of linear and nonlinear strain rate, respectively; yes The bias part is , ; ψ Stress state related parameters, through and The norm of establishes the relationship; is the stiffness tensor; R is the maximum intergranular strain; is the hypoplastic tensor; is the intergranular strain tensor; yes direction; m R and m T are the stiffness factors when the strain path changes by 180° and 90°, m R > m T >1; is a weighting factor used for smoothing. The VUMAT subroutine for the Niemunis-Herle hypoplastic model was developed based on the VUMAT subroutine interface and programming framework provided by ABAQUS. During development, the state variables were defined strictly according to the interface requirements, and the specified data structure and transfer mechanism were followed to pass the updated stresses and state variables to the ABAQUS main program in the correct data format.

[0069] Furthermore, in some embodiments, based on the hypoplastic model parameters of cohesionless soil and the linear elastic model parameters of piles, a preset VUMAT subroutine is used to simulate the large deformation of soil and the dynamic changes of pore water pressure during dynamic piling to obtain soil behavior simulation results, including: constructing a Niemunis-Herle hypoplastic model based on the hypoplastic model parameters of cohesionless soil, and embedding the VUMAT subroutine of the Niemunis-Herle hypoplastic model into the preset ABAQUS software to obtain mechanical behavior simulation results of cohesionless soil; rewriting the preset pore fluid mass balance equation based on the preset Darcy's law, and replacing the temperature in the preset thermal energy balance equation according to the excess pore fluid pressure of the rewritten pore fluid mass balance equation, Based on the replaced thermal energy balance equation, the diffusion of pore fluid in the soil skeleton is simulated through the heat conduction transfer process in the thermal-displacement coupling analysis program and related stress analysis is performed to determine the improved CEL method in combination with the analysis results, wherein the preset Darcy's law is used to describe the flow of pore fluid between the soil skeletons, and the preset thermal energy balance equation is set in the thermal-displacement coupling analysis program; the preset VUMAT subroutine is determined according to the improved CEL method, and based on the subplastic model parameters of cohesionless soil and the linear elastic model parameters of the pile, the preset VUMAT subroutine is called using the pre-established numerical model to simulate the soil behavior of the large deformation of the soil and the dynamic changes of the pore water pressure during the dynamic piling process, and the simulated piling results are obtained in combination with the mechanical behavior simulation results of cohesionless soil.

[0070] For example, the default Darcy's law is used to describe the flow of pore fluid between the soil skeleton. According to the pore fluid mass balance equation proposed by Zienkiewicz based on the up-form saturated soil dynamic equation:

[0071]

[0072] When the relative acceleration between the pore fluid and the soil skeleton is neglected, the pore fluid mass balance equation can be rewritten as:

[0073]

[0074] Let the pore fluid pressure gradient , pore fluid pressure rate , we can get:

[0075]

[0076] in, u s is the soil skeleton displacement; p f is the pore fluid pressure; is the pore fluid pressure rate; and are the velocities of the soil skeleton and pore fluid, respectively; and are the accelerations of the soil skeleton and pore fluid, respectively; is the pore fluid volume fraction; is the pore fluid bulk modulus; is the permeability of saturated soil, where is the hydraulic conductivity; is the pore fluid specific gravity; is the dynamic viscosity of the pore fluid; b is the gravity; is the pore fluid density.

[0077] Furthermore, the thermal energy balance equation in the ABAQUS / Explicit thermal-displacement coupled analysis program is

[0078]

[0079] in, ρ is the total density; c is the specific heat; is the rate of temperature change; θ It is the temperature; is the thermal conductivity; is the internal heat production. θ Replaced by the excess pore fluid pressure in the pore fluid mass balance equation , three matches are identified:

[0080]

[0081]

[0082]

[0083] Furthermore, the diffusion of pore fluid in the soil skeleton is simulated by the heat conduction transfer process in the thermal-displacement coupling analysis program and the related stress analysis is performed. The relevant control equations are modified and the constants required for the model are determined as follows:

[0084] ,

[0085] The VUMAT subroutine for the improved CEL method was developed based on the VUMAT subroutine interface and programming framework provided by ABAQUS. During development, the state variables were defined strictly according to the interface requirements, and the specified data structure and transfer mechanism were followed. The updated stresses and state variables were passed to the ABAQUS main program in the correct data format.

[0086] It should be noted that the saturation of fine sand in this specific embodiment is about 0.995, and the saturation density is about 2.2×10 - 3 kg / m 3 , pore water volume fraction is about 0.33, at which point the pore water bulk modulus About 30 MPa; assuming the pore water density =1, pore water dynamic viscosity 1.006×10 -6 m 2 / s, permeability of fine sand 1×10 -4 Pa, calculation constant c 5.64×10 -6 ,constant 1×10 -4 In the ABAQUS / Explicit thermal-displacement coupled analysis program, the constant c Set to 5.64×10 -6 , the constant Set to 1×10 -4 .

[0087] Furthermore, embodiments of the present invention can model the Larsen steel sheet piles according to their actual dimensions, based on the pile foundation design and construction plan. The CEL method is used to simulate the pile using Lagrangian elements, with the element type being C3D8R. Based on the geotechnical engineering survey report, the site strata are generalized as a single fine sand layer. The horizontal distance between the soil boundary and the pile is set to 20 times the pile width, or 8 meters, and the vertical height is set to twice the pile length, or 24 meters, to eliminate the impact of the finite cutoff boundary on the simulation results. The soil is simulated using Euler elements, with the element type being EC3D8RT. The pile and soil elements are meshed, and the pile bottom is set to be located on the soil surface.

[0088] Furthermore, the vertical displacement of the bottom of the soil and the horizontal displacement of the side of the soil are restricted to zero; by improving the CEL method, the temperature in the numerical model is θ Replaced by excess pore fluid pressure , set the temperature boundary condition of the soil boundary to 0 to make it permeable and transform it into a drainage boundary; set the top and bottom boundaries of the soil as drainage boundaries, and set the side boundaries as undrained boundaries to simulate soil consolidation and other phenomena.

[0089] Furthermore, the pile-soil contact in ABAQUS / Explicit is modeled using General contact. The tangential behavior of the pile-soil interface is simulated using the Coulomb friction criterion, while the normal behavior is simulated using hard contact. Under partially drained conditions, the friction force is calculated based on the effective stress method; generally, the difference between the total stress and the effective stress is approximately two times. Therefore, the friction coefficient under partially drained conditions is reduced to 0.125.

[0090] Furthermore, based on the pile foundation design and construction plan, two analysis steps were set up. The first step was initial geostress equilibrium: a gravity load was applied to the soil to simulate the initial geostress state of the fine sand layer. The second step was vibration piling simulation: a force control method was used to simulate the actual vibration piling process, constraining the horizontal displacement of the pile. A vibration frequency of 47 Hz and a peak excitation force of 500 kN were applied to the top of the pile until the pile was driven to a depth of 11.5 m.

[0091] In step S304 , a numerical model is constructed.

[0092] Specifically, the embodiment of the present invention can use a linear elastic model to simulate the mechanical behavior of the pile and input relevant model parameters; use the Niemunis-Herle hypoplastic model to simulate the mechanical behavior of the pile and input relevant model parameters; determine the relative density of fine sand based on indoor geotechnical tests D r The initial porosity ratio is 60%. e 0 is 0.513, and the initial porosity is set to e 0 is set to 0.513, and the maximum intergranular strain R is set to 0.0001. In the Property module of ABAQUS / Explicit, execute the "Create Material" command; in the pop-up Edit Material window: execute the "Depvar" command and set the number of state variables to 35; execute the "User Material" command to enter the relevant parameters of the hypoplastic model; execute the "Conductivity" and "Specific Heat" commands to define the specific heat respectively. c and thermal conductivity Next, in the Job module, follow these steps: Open the Edit Job window; Execute the "General" command and enter the file path of the VUMAT subroutine in the User subroutine file field. Alternatively, you can call the VUMAT subroutine in an INP file to execute the numerical simulation method.

[0093] In step S305 , a verification analysis is performed on the model.

[0094] Specifically, the embodiment of the present invention can improve the CEL method, and the node temperature NT11 can reflect the excess pore water pressure Based on the layout of monitoring points during on-site construction, the excess pore water pressure curve at the corresponding locations after the vibration piling process is extracted. A good fit between the numerical simulation values ​​and the site monitoring values ​​proves the accuracy and reliability of the constructed model. The numerical calculation results, such as soil porosity, excess pore water pressure, effective stress, and pile stress and strain, are output as needed. Based on the pile foundation design and construction plan, the values ​​of key parameters are varied to study and analyze the physical phenomena during dynamic piling and the comprehensive impact of various parameter changes on the dynamic piling process.

[0095] Thus, the numerical simulation process of dynamic pile driving in cohesionless soil based on the secondary development of ABAQUS software was completed.

[0096] The numerical simulation method for dynamic piling in cohesionless soil, provided by an embodiment of the present invention, can accurately simulate the process of pile driving into soil under dynamic loads (such as vibration or impact), the mechanical behavior of cohesionless soil, and the dynamic changes in pore water pressure, thereby enabling modeling and analysis of the dynamic piling process in cohesionless soil. This method addresses the complex models, numerous parameters, and difficulty in solving the problem encountered in related techniques, reducing both model complexity and solution difficulty.

[0097] Next, a numerical simulation system for dynamic piling in cohesionless soil proposed in an embodiment of the present invention will be described with reference to the accompanying drawings.

[0098] Figure 4 Schematic diagram of a numerical simulation system for dynamic piling in cohesionless soil according to an embodiment of the present invention.

[0099] like Figure 4 As shown, the numerical simulation system 10 suitable for dynamic piling in cohesionless soil includes: an acquisition module 100 and a data processing module 200.

[0100] Among them, the acquisition module 100 is used to obtain the generalized model of dynamic piling and cohesionless soil samples in the target study area; the data processing module 200 is used to determine the subplastic model parameters of cohesionless soil and the linear elastic model parameters of piles, and based on the subplastic model parameters of cohesionless soil and the linear elastic model parameters of piles, use the pre-established numerical model to call the preset VUMAT subroutine to simulate the soil behavior of large deformation and dynamic changes of pore water pressure during dynamic piling, and obtain simulated piling results. Among them, the preset VUMAT subroutine is written by the improved CEL method.

[0101] Furthermore, in some embodiments, after obtaining the simulated piling results, the data processing module 200 is also used to: obtain piling monitoring data of the target study area; and verify the simulated piling results based on the piling monitoring data, so as to perform accuracy analysis on the numerical model according to the verification results.

[0102] Furthermore, in some embodiments, the acquisition module 100 is specifically used to: obtain the site stratigraphic conditions, groundwater conditions and the occurrence state of non-cohesion soil in the target study area, and obtain geological condition analysis results based on the site stratigraphic conditions, groundwater conditions and the occurrence state of non-cohesion soil; determine pile foundation design parameters based on the geological condition analysis results, wherein the pile foundation design parameters include pile type size, material properties, pile driving equipment and loading parameters; obtain pile driving monitoring data in the target study area, and obtain a dynamic pile driving generalization model based on the geological condition analysis results, pile foundation design parameters and pile driving monitoring data.

[0103] Furthermore, in some embodiments, the data processing module 200 is specifically used to: construct a Niemunis-Herle hypoplastic model based on the hypoplastic model parameters of cohesionless soil, and embed the VUMAT subroutine of the Niemunis-Herle hypoplastic model into the preset ABAQUS software to obtain the mechanical behavior simulation results of the cohesionless soil; based on the preset Darcy's law, rewrite the preset pore fluid mass balance equation, and replace the temperature in the preset thermal energy balance equation according to the super pore fluid pressure of the rewritten pore fluid mass balance equation, and based on the replaced thermal energy balance equation, analyze the heat conduction transfer process in the thermal-displacement coupling analysis program. The diffusion of pore fluid in the soil skeleton is simulated and related stress analysis is performed to determine the improved CEL method based on the analysis results. The preset Darcy's law is used to describe the flow of pore fluid between the soil skeleton, and the preset thermal energy balance equation is set in the thermal-displacement coupling analysis program. The preset VUMAT subroutine is determined according to the improved CEL method, and based on the hypoplastic model parameters of cohesionless soil and the linear elastic model parameters of the pile, the preset VUMAT subroutine is called using the pre-established numerical model to simulate the soil behavior of large deformation and dynamic changes in pore water pressure during dynamic piling. The simulated piling results are obtained in combination with the mechanical behavior simulation results of cohesionless soil.

[0104] Furthermore, in some embodiments, before using a pre-established numerical model to call a preset VUMAT subroutine to perform soil behavior simulation results on the large deformation of soil and the dynamic changes of pore water pressure during dynamic piling, the data processing module 200 is also used to: perform three-dimensional geometric modeling of piles and soil based on a generalized dynamic piling model to obtain modeled piles and modeled soil; based on a preset Lagrangian unit and a preset Euler unit, use an improved CEL method to mesh the modeled piles and modeled soil to obtain meshing results; determine boundary conditions and pile-soil contact characteristics according to the soil behavior simulation results, and construct a pre-established numerical model based on the meshing results, boundary conditions and pile-soil contact characteristics.

[0105] It should be noted that the above explanation of the embodiment of the numerical simulation method for dynamic pile driving in non-cohesive soil is also applicable to the numerical simulation device for dynamic pile driving in non-cohesive soil in this embodiment, and will not be repeated here.

[0106] The numerical simulation system for dynamic piling in cohesionless soils provided by the present invention can accurately simulate the process of pile driving into soil under dynamic loads (such as vibration or impact), the mechanical behavior of cohesionless soil, and the dynamic changes in pore water pressure, thereby enabling modeling and analysis of the dynamic piling process in cohesionless soils. This system addresses the complex models, numerous parameters, and difficulty in solving the problems encountered in related solutions, reducing both model complexity and solution difficulty.

[0107] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0108] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "N" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0109] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing a custom logical function or step of a process, and the scope of the preferred embodiments of the invention includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of the invention pertain.

[0110] It should be understood that various components of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiment, the N steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having logic gate circuits for implementing logical functions on data signals, an application-specific integrated circuit having suitable combinational logic gate circuits, a programmable gate array (PGA), a field-programmable gate array (FPGA), etc.

[0111] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

Claims

1. A numerical simulation method for dynamic piling in cohesionless soil, characterized in that: The following steps are involved: Obtain a generalized dynamic pile driving model and cohesionless soil samples for the target study area; Determining hypoplastic model parameters of the cohesionless soil and linear elastic model parameters of the pile, and based on the hypoplastic model parameters of the cohesionless soil and the linear elastic model parameters of the pile, using a pre-established numerical model to call a preset VUMAT subroutine to simulate soil behavior during a dynamic pile driving process, with respect to large deformation of the soil and dynamic changes in pore water pressure, to obtain simulated pile driving results, wherein the preset VUMAT subroutine is written using an improved CEL method; Among them, based on the hypoplastic model parameters of the cohesionless soil and the linear elastic model parameters of the pile, the preset VUMAT subroutine is used to simulate the large deformation of the soil and the dynamic change of the pore water pressure during the dynamic pile driving process to obtain the soil behavior simulation results, including: based on the hypoplastic model parameters of the cohesionless soil, a Niemunis-Herle hypoplastic model is constructed, and the VUMAT subroutine of the Niemunis-Herle hypoplastic model is embedded in the preset ABAQUS software to obtain the mechanical behavior simulation results of the cohesionless soil; based on the preset Darcy's law, the preset pore fluid mass balance equation is rewritten, and the temperature in the preset thermal energy balance equation is replaced according to the super pore fluid pressure of the rewritten pore fluid mass balance equation, and based on the replaced thermal energy The improved CEL method is determined by combining the analysis results of the heat conduction transfer process in the thermal-displacement coupling analysis program to simulate the diffusion of pore fluid in the soil skeleton and perform related stress analysis, wherein the preset Darcy's law is used to describe the flow of pore fluid between the soil skeletons, and the preset thermal energy balance equation is set in the thermal-displacement coupling analysis program; the preset VUMAT subroutine is determined according to the improved CEL method, and based on the subplastic model parameters of the cohesionless soil and the linear elastic model parameters of the pile, the preset VUMAT subroutine is called by using a pre-established numerical model to simulate the soil behavior of the large deformation of the soil and the dynamic change of the pore water pressure during the dynamic piling process, and the simulated piling result is obtained in combination with the mechanical behavior simulation result of the cohesionless soil.

2. The method according to claim 1, characterized in that After obtaining the simulated piling result, the method further includes: Acquiring piling monitoring data of the target study area; The simulated piling results are verified based on the piling monitoring data, so as to analyze the accuracy of the numerical model according to the verification results.

3. The method according to claim 1, characterized in that The method of obtaining a generalized dynamic piling model for a target research area includes: Obtaining the site stratigraphic conditions, groundwater conditions, and occurrence state of cohesionless soil in the target study area, and obtaining geological condition analysis results based on the site stratigraphic conditions, groundwater conditions, and occurrence state of the cohesionless soil; Determining pile foundation design parameters based on the geological condition analysis results, wherein the pile foundation design parameters include pile size, material properties, piling equipment, and loading parameters; The piling monitoring data of the target research area is obtained, and the dynamic piling generalization model is obtained according to the geological condition analysis results, the pile foundation design parameters and the piling monitoring data.

4. The method according to claim 1, wherein Before using the pre-established numerical model to call the preset VUMAT subroutine to simulate the soil behavior results of the large deformation of the soil and the dynamic change of the pore water pressure during the dynamic pile driving process, the method further includes: Based on the generalized model of dynamic piling, three-dimensional geometric modeling of piles and soil is performed to obtain modeled piles and modeled soil; Based on the preset Lagrangian unit and the preset Euler unit, the improved CEL method is used to mesh the modeled pile and the modeled soil to obtain a meshing result; Boundary conditions and pile-soil contact characteristics are determined, and the pre-established numerical model is constructed based on the meshing result, the boundary conditions and the pile-soil contact characteristics.

5. A numerical simulation system for dynamic piling in cohesionless soil, characterized in that: include: Acquisition module, used to obtain the generalized dynamic pile driving model and cohesionless soil samples of the target study area; a data processing module for determining hypoplastic model parameters of the cohesionless soil and linear elastic model parameters of the pile, and based on the hypoplastic model parameters of the cohesionless soil and the linear elastic model parameters of the pile, using a pre-established numerical model to call a preset VUMAT subroutine to simulate soil behavior with respect to large deformation of the soil and dynamic changes in pore water pressure during dynamic piling, thereby obtaining simulated piling results, wherein the preset VUMAT subroutine is written using an improved CEL method; Among them, the data processing module is specifically used to: construct a Niemunis-Herle hypoplastic model based on the hypoplastic model parameters of the cohesionless soil, and embed the VUMAT subroutine of the Niemunis-Herle hypoplastic model into the preset ABAQUS software to obtain the mechanical behavior simulation results of the cohesionless soil; based on the preset Darcy's law, rewrite the preset pore fluid mass balance equation, and replace the temperature in the preset thermal energy balance equation according to the super pore fluid pressure of the rewritten pore fluid mass balance equation, and based on the replaced thermal energy balance equation, simulate the pore fluid in the soil skeleton through the heat conduction transfer process in the thermal-displacement coupling analysis program. Diffusion and related stress analysis are performed to determine the improved CEL method in combination with the analysis results, wherein the preset Darcy's law is used to describe the flow of pore fluid between the soil skeleton, and the preset thermal energy balance equation is set in the thermal-displacement coupling analysis program; the preset VUMAT subroutine is determined according to the improved CEL method, and based on the subplastic model parameters of the cohesionless soil and the linear elastic model parameters of the pile, the preset VUMAT subroutine is called using a pre-established numerical model to simulate the soil behavior of the large deformation of the soil and the dynamic change of the pore water pressure during the dynamic piling process, and the simulated piling result is obtained in combination with the mechanical behavior simulation result of the cohesionless soil.

6. The system according to claim 5, characterized in that After obtaining the simulated piling result, the data processing module is further used to: Acquiring piling monitoring data of the target study area; The simulated piling results are verified based on the piling monitoring data, so as to analyze the accuracy of the numerical model according to the verification results.

7. The system according to claim 5, characterized in that The acquisition module is specifically used for: Obtaining the site stratigraphic conditions, groundwater conditions, and occurrence state of cohesionless soil in the target study area, and obtaining geological condition analysis results based on the site stratigraphic conditions, groundwater conditions, and occurrence state of the cohesionless soil; Determining pile foundation design parameters based on the geological condition analysis results, wherein the pile foundation design parameters include pile size, material properties, piling equipment, and loading parameters; The piling monitoring data of the target research area is obtained, and the dynamic piling generalization model is obtained according to the geological condition analysis results, the pile foundation design parameters and the piling monitoring data.

8. The system according to claim 5, characterized in that Before using the pre-established numerical model to call the preset VUMAT subroutine to simulate the soil behavior of the large deformation of the soil and the dynamic change of the pore water pressure during the dynamic pile driving process, the data processing module is further used to: Based on the generalized model of dynamic piling, three-dimensional geometric modeling of piles and soil is performed to obtain modeled piles and modeled soil; Based on the preset Lagrangian unit and the preset Euler unit, the improved CEL method is used to mesh the modeled pile and the modeled soil to obtain a meshing result; Boundary conditions and pile-soil contact characteristics are determined, and the pre-established numerical model is constructed based on the meshing result, the boundary conditions and the pile-soil contact characteristics.

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