A three-dimensional finite element simulation method for constructing the rheological characteristics of the lithosphere

Abstract

This application relates to the field of geophysics and discloses a three-dimensional finite element simulation method for constructing the rheological characteristics of the lithosphere, including the following steps: S1, creating a three-dimensional mathematical model, which is based on geophysical data and uses the WGS84 coordinate system as the reference coordinate system; S2, dividing blocks and layers according to the geological data of the study area; S3, performing finite element mesh division on the model; S4, loading the rheological properties of the lithosphere into the model; S5, applying dynamic analysis to simulate the deformation of the lithosphere and the surface deformation field. By using finite element analysis tools and geological data including topography, geological structure, and fault information, the present invention can create a highly accurate three-dimensional geological model. This improvement in accuracy makes the simulation results more reliable, thus enabling more accurate prediction of geological activities such as earthquakes and the behavior of crustal deformation.

Description

Technical Field

[0001] The present invention relates to the field of geophysical technologies, and specifically to a three-dimensional finite element simulation method for constructing the rheological characteristics of the lithosphere. Background Art

[0002] The lithosphere of the Earth includes the crust and the upper mantle, and is a complex dynamic system. Its deformation and flow behavior have a profound impact on the changes in the Earth's surface environment and internal structure. The dynamic behavior of the lithosphere is not only related to geological disasters such as earthquakes and volcanic activities, but also affects the circulation of crustal materials and the distribution of energy resources. Therefore, the study of its mechanical behavior is of great significance for understanding the geodynamic process and predicting related geological events.

[0003] Traditional lithosphere research methods focus on field geological surveys and laboratory rock mechanics tests. Although these methods can provide intuitive rock behavior data, they are often limited in spatial and temporal scales. To overcome these limitations, scientists use numerical simulation techniques to study the mechanical behavior of the lithosphere. Finite element analysis (FEA), as a powerful numerical simulation tool, is widely used in engineering and scientific research to simulate the behavior of complex systems.

[0004] The finite element method is a technique for solving continuum mechanics problems by dividing the mesh and applying the variational principle. It divides complex physical problems into smaller, manageable units, and the physical behavior within each unit can be described by simple mathematical equations. The core of this method is that it can transform a continuum problem with infinite degrees of freedom into a discrete problem with finite degrees of freedom, and thus solve it through mathematical and computational means.

[0005] In the study of the lithosphere, the finite element method allows researchers to establish detailed geological models, including various geological structures such as faults, layered sequences, and different types of rocks. By performing dynamic analysis on these models, the actual situation of rocks in nature, such as their response when subjected to geological forces (such as earthquakes or tectonic stresses), can be simulated.

[0006] In order to further improve the accuracy of simulation and the breadth of application, the present invention proposes a three-dimensional finite element simulation method that combines the rheological characteristics of the lithosphere. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the present invention provides a three-dimensional finite element simulation method for constructing the rheological characteristics of the lithosphere, which not only considers the elastic and viscoelastic properties of rocks, but also can simulate complex geological structures and dynamic behaviors, such as fault activities and interlayer slips. By establishing a reasonable mathematical and geometric model and making a detailed regional division according to the actual geological structure, this method can define unique rheological characteristics for each region, thus more accurately reflecting the dynamic process of the lithosphere in the simulation.

[0008] To achieve the above objectives, the present invention is realized through the following technical solutions: A three-dimensional finite element simulation method for constructing the rheological characteristics of the lithosphere, comprising the following steps:

[0009] Create a three-dimensional mathematical model, the three-dimensional mathematical model is based on geophysical data, and the WGS84 coordinate system is used as the reference coordinate system;

[0010] Divide the blocks and layers according to the geological data of the study area;

[0011] Perform finite element mesh division on the model;

[0012] Load the rheological characteristics of the lithosphere for the model;

[0013] Apply dynamic analysis to simulate the deformation of the lithosphere and the surface deformation field.

[0014] Preferably, the step of creating the three-dimensional mathematical model includes using topographic and geological structure data to model the three-dimensional model, and converting the longitude and latitude coordinates of the three-dimensional model into a plane coordinate system through Gauss projection.

[0015] Preferably, the step of dividing the blocks and layers according to the geological data of the study area includes using the Crust1.0 global crust model to obtain the elastic properties and the depth information of the lower layer of the structure of the geological blocks and layers, and dividing different layers of the upper sedimentary layer, the lower sedimentary layer, the upper crust and the lower crust based on these data.

[0016] Preferably, the step of performing finite element mesh division on the model includes using the Gmsh software to mesh each geological block and layer of the three-dimensional model through tetrahedral mesh elements, and evaluating the quality of the generated mesh to ensure the uniformity and applicability of the mesh.

[0017] Preferably, in the step of loading the rheological characteristics of the lithosphere for the model, it includes loading elastic and viscoelastic material properties for different blocks of the model, adding boundary conditions to the outer boundary of the model, and adding motion characteristics to the faults.

[0018] Preferably, the step of applying kinetic analysis to simulate the deformation of the lithosphere and the surface deformation field is carried out in the PyLith software. By constructing a time-based kinetic analysis, transient and periodic loads caused by geological events are considered, and the dynamic response triggered by seismic events is included in the simulation.

[0019] Preferably, the step of applying kinetic analysis to simulate the deformation of the lithosphere and the surface deformation field further includes configuring a time-dependent slip rate function for a specific fault in PyLith, which quantitatively describes the slip rate and the slip start time of the fault based on geological and seismic data.

[0020] Preferably, the kinetic analysis in the step of applying kinetic analysis to simulate the deformation of the lithosphere and the surface deformation field further includes considering the overall and local stability of the model, as well as the response of the model to complex loading conditions.

[0021] Preferably, the method further includes: using surface deformation data to determine the displacement and stress conditions of the outer boundary of the model, and applying these data to the four boundaries of the model to simulate the dynamic behavior of the crust.

[0022] The present invention also provides a three-dimensional finite element simulation device for constructing the rheological characteristics of the lithosphere, which is used to implement the method, including:

[0023] An input module, configured to receive three-dimensional mathematical model data based on geophysical data, where the model data includes topographic and geological structure information using the WGS84 coordinate system as the reference coordinate system;

[0024] A processing module, configured to:

[0025] Based on the received three-dimensional mathematical model data, perform the division of geological blocks and layers, and use a global crust model such as Crust1.0 to determine the properties of each geological layer;

[0026] Perform finite element mesh generation on the model, including meshing using tetrahedral mesh elements and evaluating the mesh quality;

[0027] Load the rheological characteristics of the lithosphere into the model, including loading elastic and viscoelastic material properties for different blocks of the model, adding boundary conditions to the outer boundary of the model, and adding motion characteristics to the faults;

[0028] A kinetic analysis module, configured to perform kinetic analysis using software. The analysis module simulates the deformation of the lithosphere and the surface deformation field according to the principle of virtual displacement, including considering transient and periodic loads caused by geological events, and including the dynamic response triggered by seismic events in the simulation;

[0029] An output module, configured to output simulation results, including a three-dimensional visual representation of the lithospheric deformation and the surface deformation field.

[0030] The present invention provides a three-dimensional finite element simulation method for constructing the rheological characteristics of the lithosphere. It has the following beneficial effects:

[0031] 1. By using finite element analysis tools and geological data including topography, geological structure, and fault information, the present invention can create a highly accurate three-dimensional geological model. This improvement in accuracy makes the simulation results more reliable, enabling more accurate prediction of geological activities such as earthquakes and crustal deformation behavior.

[0032] 2. This method combines various geological data and complex rheological characteristics (such as elastic and viscoelastic behaviors), providing a powerful tool for geologists to study the dynamic changes of the lithosphere. By simulating geological processes under different geological conditions, scientists can better understand the mechanisms of crustal movement and plate tectonics.

[0033] 3. Using the simulation method of the present invention, the impacts that may be caused by earthquakes and other geological events can be predicted, thus helping the government and relevant agencies to optimize disaster prevention and response strategies. This can not only reduce the impact of natural disasters but also enhance people's sense of security.

[0034] 4. By accurately simulating the geological structure and the behavior of the lithosphere, this method can help mining and petroleum engineers better understand the potential resource distribution, thereby making more informed drilling and extraction decisions. This helps to optimize resource extraction and utilization and reduce environmental impacts. Brief Description of the Drawings

[0035] Figure 1 It is a schematic flow chart of the method of the present invention;

[0036] Figure 2 It is a schematic diagram of a three-dimensional complete block in the study area of an embodiment of the present invention;

[0037] Figure 3 It is a schematic diagram of a three-dimensional fault model in the study area of an embodiment of the present invention;

[0038] Figure 4 It is a schematic diagram of the structure after fault plate division in the study area of an embodiment of the present invention;

[0039] Figure 5 It is a schematic diagram of the structure after layer division in the study area of an embodiment of the present invention;

[0040] Figure 6 It is a schematic diagram of grid division in the study area of an embodiment of the present invention;

[0041] Figure 7Schematic diagram for evaluating the model grid of the study area in the embodiment of the present invention;

[0042] Figure 8 Schematic diagram of the boundary conditions after difference in the study area in the embodiment of the present invention;

[0043] Figure 9 Schematic diagram of the fault slip function in the study area in the embodiment of the present invention;

[0044] Figure 10 Schematic diagram of the device structure of the present invention.

[0045] Among them, 10 is the input module; 20 is the processing module; 30 is the dynamic analysis module; 40 is the output module. Detailed implementation manners

[0046] Next, in conjunction with the accompanying drawings of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0047] Please refer to the attached Figure 1 - attached Figure 9 , the present invention provides a three-dimensional finite element simulation method for constructing the rheological characteristics of the lithosphere, aiming to simulate the deformation and dynamic behavior of the lithosphere on the geological time scale through numerical simulation technology. The method of the present invention utilizes finite element analysis (FEA) technology, which can provide detailed insights into the deformation of the crust and upper mantle, and is of great significance for the prevention of geological disasters and the development of geological resources.

[0048] Specifically, the method includes the following steps:

[0049] S1. Create a three-dimensional mathematical model

[0050] In this step, first, a detailed three-dimensional mathematical model is created based on geophysical data (such as topography, geological structure, and geological history data). The WGS84 global positioning system coordinate system is used as the reference to ensure the global consistency and accurate docking of the data. Through the Gaussian projection or other suitable map projection methods, the geophysical data is converted from geographic coordinates into a more convenient Cartesian coordinate system for calculation. This step is the basis for establishing an accurate model and provides a solid starting point for subsequent analysis.

[0051] In step S1 of a preferred embodiment of the present invention, a three-dimensional mathematical model based on geophysical data is created, and the detailed steps are as follows:

[0052] S1a. Select and set the coordinate system

[0053] In the first step of creating a three-dimensional mathematical model, the WGS84 coordinate system is used as the reference coordinate system. This global positioning system coordinate system provides a unified reference for geophysical data, ensuring that data from all over the world can be accurately corresponded.

[0054] S1b. Coordinate transformation and projection processing

[0055] Perform projection processing on the longitude and latitude data in the WGS84 coordinate system and convert them into distance units (such as meters) that are more suitable for three-dimensional modeling. Common projection methods include Gaussian projection and Mercator projection. This processing step is crucial for accurately setting the geographical location and size of the model.

[0056] S1c. Determine the size and boundary of the research area

[0057] Based on the projected data, determine the length, width, and depth values of the research area. The depth of the research area must extend deep enough into the upper mantle layer to cover the key geological structures in the lithosphere. This ensures that the model can comprehensively simulate the interactions between the crust and the upper mantle.

[0058] S1d. Geological survey and data integration

[0059] Combine geological survey data and surface deformation inversion information to obtain the key geological structures in the lithosphere of the research area, such as the geometric information of faults. This includes parameters such as the strike, dip, and dip direction of the faults. This information is the basis for subsequent modeling and simulation and is related to the simulation accuracy and reliability.

[0060] S1e. Preliminary three-dimensional modeling

[0061] Use professional finite element mesh modeling software such as Coreform-Cubit or Gmsh to complete the preliminary three-dimensional modeling of the research area based on the above-collected geological data. In this step, ensure that the fault geometry in the model is correctly expressed, and the faults are connected or intersect with each other, avoiding gaps (as Figure 2 shown).

[0062] S1f. Interaction processing of faults and boundaries

[0063] For the faults in contact with the model boundary, ensure that these faults also intersect with the boundary surface in the three-dimensional model. This is to ensure that the boundary conditions in the simulation process can be correctly implemented and to ensure the accuracy of subsequent dynamic analysis (as Figure 3 shown).

[0064] Through the above steps, the three-dimensional mathematical model created in step S1 is not only accurately constructed based on actual geophysical data but also has all the necessary structures and characteristics for complex geological and seismic dynamics simulations.

[0065] S2. Divide different geological blocks and layers in the model

[0066] Utilize the geological information in the initial model, such as rock types, fault locations, and historical geological events, to divide different geological blocks and layers. This process involves a detailed division of the upper crust, middle crust, lower crust, and mantle, and each layer is assigned different properties based on its physical and chemical characteristics. This step is crucial for the accuracy of the simulation because different geological blocks and layers correspond to different mechanical properties and behaviors.

[0067] In step S2 of a preferred embodiment of the present invention, to divide different geological blocks and layers in the model, the detailed steps are as follows:

[0068] S2a. Obtain thickness information using a global crust model

[0069] Utilize the global crust model Crust1.0 to obtain detailed thickness information of different plates and layers in the study area. The Crust1.0 model provides data at a 1° resolution, including the elastic properties and specific structural depths of various layers such as water layer, ice layer, sedimentary layers at all levels (upper, middle, lower), upper crust, middle crust, lower crust, and mantle layer. These data are the basis for determining the physical and mechanical properties of each layer.

[0070] S2b. Three-dimensional modeling of layers and faults

[0071] Use professional finite element mesh modeling software (such as Coreform-Cubit or Gmsh) to load the preliminary three-dimensional model obtained from step S1. On this basis, refine and adjust the layer division in the model according to the information provided in the Crust1.0 model. In addition, ensure that all fault structures in the model are correctly represented and intersect accurately with adjacent faults or the model boundary to ensure the continuity and accuracy of the simulation (as Figure 4 shown).

[0072] S2c. Layer stratification and block cutting

[0073] Cut different lithospheric blocks in the model based on the fault and layer structures established in step S2b. Each block is assigned to the corresponding layer according to its geographical location and geological characteristics. This includes, but is not limited to, a detailed division of the upper crust, middle crust, and lower crust, and extending the lower mantle structure from the bottom of the lower crust to the bottom of the model (as Figure 5 shown).

[0074] S2d. Property assignment and confirmation

[0075] Specific physical and mechanical properties are assigned to each block and layer, and these properties are set according to the data provided by Crust1.0. These properties include, but are not limited to, elastic modulus, density, shear and P-wave velocities, etc. For viscoelastic layers, viscosity and strain characteristics are also included. This step is crucial for subsequent dynamic analysis as it determines the responses and interactions of each layer during the simulation.

[0076] Through these steps, step S2 ensures that the geological blocks and layers in the model are not only accurately divided but also have appropriate physical and mechanical properties. This provides the necessary basis for accurate dynamic simulation and analysis, ensuring that the simulation results can truly reflect the actual geological behavior.

[0077] S3. Perform finite element mesh generation on the model;

[0078] Apply finite element mesh generation to the three-dimensional model, discretizing the continuous geological body into tens of thousands of small elements, each of which can be analyzed individually. These elements usually adopt a tetrahedral shape to adapt to complex geological structures. After mesh generation, the physical properties of each element are determined according to the geological block and layer to which it belongs.

[0079] In step S3 of a preferred embodiment of the present invention, finite element mesh generation is performed on the model, and the detailed steps are as follows:

[0080] S3a. Load the modeled data

[0081] Use Coreform-Cubit or Gmsh software to load the completed models of fault modeling, plate division, and layer division. These model data already include structural details obtained from geological surveys, such as fault positions, plate boundaries, and detailed information of each layer.

[0082] S3b. Set the mesh parameters

[0083] Before starting mesh generation, first set an appropriate mesh size. The choice of mesh size is based on the overall size of the study area, the thickness of each layer, and the expected simulation accuracy requirements. Selecting an appropriate mesh size is a key factor in ensuring simulation efficiency and accuracy.

[0084] S3c. Perform mesh generation

[0085] Use the mesh generation function of the software to discretize the three-dimensional solid model with tetrahedral meshes. Tetrahedral meshes are suitable for geological models with complex terrains and large structural variations and can effectively capture the details of geological structures, such as Figure 6 shown.

[0086] S3d. Mesh quality assessment

[0087] After the mesh generation is completed, the quality of the generated mesh is evaluated. In particular, it is necessary to detect the condition number (Condition No.) of the Jacobian matrix of the mesh, which is a key indicator for measuring the mesh quality. The smaller the condition number of the Jacobian matrix, the smaller the mesh deformation and the higher the model accuracy.

[0088] S3e. Adjust and optimize the mesh

[0089] If the value of the condition number exceeds the recommended threshold (2 or below), then mesh refinement is carried out or other optimization measures are taken, such as adjusting the local size of the mesh or reconfiguring the mesh distribution, to ensure the optimization of the mesh and the accuracy of the overall model. This step is an important link to ensure the reliability of the simulation results, as Figure 7 shown.

[0090] Through the above steps, it is ensured that the model has a high-quality mesh structure before performing complex geological and seismic dynamics simulations. These mesh structures not only need to accurately represent the spatial relationships of geological entities, but also need to meet the requirements for accuracy and computational efficiency in computational analysis.

[0091] S4. Load the rheological properties of the lithosphere into the model;

[0092] In this step, the PyLith software is used to load the necessary elastic and viscoelastic material properties for different geological blocks of the three-dimensional model. First, the model file created and meshed using Coreform-Cubit or Gmsh software is loaded. For the upper crust, basic elastic properties such as density, P-wave velocity, and S-wave velocity are loaded; for the upper mantle with more complex behavior, additional viscoelastic properties including viscosity and strain characteristics in all directions are loaded. Then, the surface deformation field obtained based on GPS / InSAR technology is added as a boundary condition to the outer boundary of the model, ensuring that these conditions are consistent throughout the depth of the model. Finally, the motion characteristics are added to the faults in the model, and a time function with a constant slip rate is used to simulate fault activities, including the setting of the slip rate and the start time, to accurately reflect the dynamic behavior of the faults on the geological time scale. This series of operations ensures that the model can accurately simulate the deformation and response of the lithosphere in dynamic analysis.

[0093] In step S4 of a preferred embodiment of the present invention, the rheological properties of the lithosphere are loaded into the model, and the detailed steps are as follows:

[0094] S4a. Load the model file

[0095] Using the PyLith software, first load the model file created and meshed by Coreform-Cubit or Gmsh. This step is to ensure that the three-dimensional structure and mesh of the model are correctly loaded into the analysis software, preparing for subsequent material property assignment and dynamic simulation.

[0096] S4b. Create material groups

[0097] In PyLith, create corresponding material labels and groups for different blocks in the model. These material groups are classified according to the geological characteristics of each block. For example, the upper crust is assigned to the elastic material group, and the upper mantle is assigned to the viscoelastic material group. Specify the necessary database files for each material group to load the correct physical and mechanical properties.

[0098] S4c. Define material properties

[0099] Define elastic properties for the upper crust material group, including density, P-wave velocity, and S-wave velocity. These basic properties are necessary for simulating elastic response.

[0100] For the viscoelastic upper mantle material group, in addition to elastic properties, properties representing viscoelasticity such as viscosity, as well as anisotropic strain characteristics (normal strains in the X, Y, and Z directions, and shear viscous strains on the XY, YZ, and XZ planes) need to be loaded. In actual simulation, most strain data can be set to zero except for viscosity, which simplifies the computational complexity of the model while retaining key physical characteristics.

[0101] S4d. Add external boundary conditions

[0102] Use the PyLith software to add boundary conditions to the outer boundary of the model. These conditions can be obtained from the surface deformation field data interpolated by GPS / InSAR technology, as Figure 8 shown. Since the interpolated boundary conditions only have two-dimensional surface displacements, the applied boundary conditions do not change with depth, and the slip rate from depth 0 to the bottom of the model is the same as that on the surface. The application of the boundary conditions reflects the actually observed displacements on the surface, remaining consistent along the depth direction from the top to the bottom of the model, ensuring that the external driving force of the entire model is consistent with actual geological activities.

[0103] S4e. Configure fault movement characteristics

[0104] Configure the movement characteristics for the faults in the model. Define a slip time function with a constant slip rate in PyLith to simulate the activities of faults on the geological time scale. This function is set according to the following formula:

[0105]

[0106] where D(t) represents the slip at time t, V represents the slip rate, and t r represents the start time of the slip (the time when the rupture reaches this position). The slip rate is specified separately for each slip component, and the slip rate and start time of the slip may vary over the fault surface, as Figure 9 shown.

[0107] Through these steps, step S4 not only ensures that the lithosphere model has accurate rheological properties, but also provides the necessary physical basis for complex geodynamic simulations. These settings will directly affect the results of the simulation, helping scientists better understand and predict geological phenomena such as the behavior of earthquakes and crustal movements.

[0108] S5. Apply dynamic analysis

[0109] The last step is to apply dynamic analysis, using software such as PyLith to simulate the dynamic response of the entire lithosphere. The dynamic analysis is based on the principle of virtual displacement, taking into account the stiffness, mass of the structure, and the applied external loads. This analysis can not only predict the stress distribution in the lithosphere under static conditions, but also simulate the immediate effects caused by dynamic events such as earthquakes.

[0110] In step S5 of a preferred embodiment of the present invention, dynamic analysis is applied, and the detailed steps are as follows:

[0111] S5a. Apply the principle of virtual displacement

[0112] When performing dynamic simulation using PyLith software, first, according to the principle of virtual displacement (also known as the principle of virtual work), which is based on the equivalence of internal and external virtual work under the equilibrium state. Under this framework, the dynamic behavior of the system is described by the following equation:

[0113] δW = δU (2)

[0114] where δW represents the virtual work done by the external force, and δU represents the virtual strain energy generated inside the system when there is a virtual displacement caused by the external force. Equation (2) represents the general expression of the principle of virtual displacement.

[0115] S5b. Define external virtual work and internal strain energy

[0116] The expressions for virtual work and strain energy are as follows in detail:

[0117]

[0118]

[0119] These expressions calculate the work done by the concentrated force, body force, and surface force acting on the model and the volume integral of the virtual strain energy of each element inside the model, respectively. Among them, Equation (3) represents the basic term of the virtual work done by the external force. The right side of the equation is, in sequence, the work done by the concentrated force acting on the object or model, the work done by the body force on the model, and the work done by the external surface force on the model. Equation (4) represents the virtual strain energy generated by the object or model itself. The right side of the equation is the volume integral of the virtual strain energy of each model inside the model.

[0120] S5c. Construct the finite element control equation

[0121] According to the principle of virtual displacement, the finite element control equation is obtained to describe the static equilibrium state of the model:

[0122] KU = R (5)

[0123] Among them, K represents the stiffness matrix of the element assembly, U represents the displacement of the nodal points of the element position, and R represents the sum of the virtual work done by the external force and the initial stress of the model entity.

[0124] Equation (5) represents the representation method of the model element assembly in the static equilibrium state. If the acting force changes with time, then the displacement will also change accordingly. At this time, Equation (5) is only the equilibrium equation at a certain fixed moment. For actual dynamic problems, the load is applied rapidly, so the problem of inertial force must be considered during the solution. Using D'Alembert's principle, the inertial force of the element assembly can be considered as part of the body force.

[0125] S5d. Consider dynamic factors

[0126] In dynamic simulation, it is necessary to consider the changes of the acting force and displacement with time, especially for rapidly applied loads. At this time, D'Alembert's principle is used to incorporate the inertial force into consideration, and the dynamic equilibrium equation is updated as:

[0127]

[0128] The equation adds the term representing the work done by the inertial force on the basis of the static equilibrium equation (5). Among them, M is the mass matrix of the model structure, and is the acceleration of the node.

[0129] S5e. Conduct dynamic simulation

[0130] Use the above dynamic equilibrium equation to conduct actual dynamic simulation, ensuring that all necessary constraints and loads are considered. The simulation results will provide a detailed view of the lithosphere deformation and the surface deformation field, which is of great significance for understanding geological processes and predicting geological disasters.

[0131] Through these steps, step S5 ensures the accurate execution of the dynamic simulation, which can reflect the response of the lithosphere under different geological forces. The results of these simulations are of great value for both scientific research and practical applications.

[0132] A three-dimensional finite element simulation method for constructing the rheological characteristics of the lithosphere provided by the present invention significantly improves the accuracy of geological phenomenon prediction and the depth of understanding through a high-precision geological model and complex physical property simulations. This method not only deepens the scientific understanding of geological processes, especially in earthquake and plate dynamics, but also optimizes the risk assessment of geological disasters and the development strategy of underground resources. In addition, its contribution to education and practical applications also makes it a valuable tool in geological science and engineering practice, helping to improve the disaster response ability and resource utilization efficiency.

[0133] The three-dimensional finite element simulation device for constructing the rheological characteristics of the lithosphere described below can be correspondingly referred to the three-dimensional finite element simulation method for constructing the rheological characteristics of the lithosphere described above.

[0134] Please refer to the appendix Figure 10 , the present invention also provides a three-dimensional finite element simulation device for constructing the rheological characteristics of the lithosphere, including:

[0135] An input module 10, configured to receive three-dimensional mathematical model data based on geophysical data, where the model data includes topographic and geological structure information using the WGS84 coordinate system as the reference coordinate system;

[0136] A processing module 20, configured to:

[0137] Based on the received three-dimensional mathematical model data, perform the division of geological blocks and layers, and use a global crust model such as Crust1.0 to determine the properties of each geological layer;

[0138] Perform finite element mesh division on the model, including meshing using tetrahedral mesh elements and evaluating the mesh quality;

[0139] Load the rheological properties of the lithosphere for the model, including loading elastic and viscoelastic material properties for different blocks of the model, adding boundary conditions to the outer boundary of the model, and adding motion characteristics to faults;

[0140] A dynamic analysis module 30, configured to perform dynamic analysis using software, and this analysis module simulates the deformation of the lithosphere and the surface deformation field according to the principle of virtual displacement, including considering transient and periodic loads caused by geological events, and including the dynamic response caused by seismic events in the simulation;

[0141] An output module 40, configured to output simulation results, including a three-dimensional visualization representation of the deformation of the lithosphere and the surface deformation field.

[0142] The device of this embodiment can be used to execute the above method embodiment, and its principle and technical effects are similar, so they will not be elaborated here.

[0143] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A three-dimensional finite element simulation method for constructing lithosphere rheological characteristics, characterized in that: The following steps are involved: Creating a three-dimensional mathematical model, wherein the three-dimensional mathematical model is based on geophysical data and uses the WGS84 coordinate system as a reference coordinate system; Divide blocks and strata according to the geological data of the study area; Perform finite element meshing on the model; Load the model with rheological properties of the lithosphere; Apply dynamic analysis to simulate lithospheric deformation and surface deformation fields; The step of applying dynamic analysis to simulate the lithospheric deformation and surface deformation field is performed in PyLith software, by constructing a time-based dynamic analysis, taking into account the transient and periodic loads caused by geological events, and including the dynamic response caused by seismic events in the simulation; The step of applying dynamic analysis to simulate lithospheric deformation and surface deformation field further includes configuring a time-dependent slip rate function for a specific fault in PyLith, which quantitatively describes the slip rate and slip start time of the fault based on geological and seismic data; The dynamic analysis of the step of applying dynamic analysis to simulate the lithospheric deformation and the surface deformation field further includes considering the global and local stability of the model, and the response of the model to complex loading conditions.

2. A three-dimensional finite element simulation method for constructing lithosphere rheological characteristics according to claim 1, characterized in that: The step of creating a three-dimensional mathematical model includes building a three-dimensional model using terrain and geological structure data, and converting the longitude and latitude coordinates of the three-dimensional model into a plane coordinate system through Gaussian projection.

3. A three-dimensional finite element simulation method for constructing lithosphere rheological characteristics according to claim 1, characterized in that: The step of dividing blocks and layers according to the geological data of the study area includes using the Crust1.0 global crustal model to obtain the elastic properties and structural lower layer depth information of geological blocks and layers, and dividing the upper sedimentary layer, lower sedimentary layer, upper crust and lower crust into different layers based on these data.

4. A three-dimensional finite element simulation method for constructing lithosphere rheological characteristics according to claim 1, characterized in that: The step of performing finite element meshing on the model includes using Gmsh software to mesh each geological block and layer of the three-dimensional model through tetrahedral mesh elements, and performing quality assessment on the generated mesh to ensure the uniformity and applicability of the mesh.

5. A three-dimensional finite element simulation method for constructing lithosphere rheological characteristics according to claim 1, characterized in that: The step of loading the model with the rheological properties of the lithosphere includes loading elastic and viscoelastic material properties for different blocks of the model, adding boundary conditions to the outer boundary of the model, and adding motion characteristics to the faults.

6. A three-dimensional finite element simulation method for constructing lithosphere rheological characteristics according to claim 1, characterized in that: The method also includes: using the surface deformation data to determine the displacement and stress conditions of the outer boundary of the model, and applying these data around the boundary of the model to simulate the dynamic behavior of the earth's crust.

7. A three-dimensional finite element simulation device for constructing lithosphere rheological characteristics, used to implement the method according to any one of claims 1 to 6, characterized in that: include: An input module configured to receive three-dimensional mathematical model data based on geophysical data, wherein the model data includes terrain and geological structure information using a WGS84 coordinate system as a reference coordinate system; Processing module, configured as: Based on the received 3D mathematical model data, the division of geological blocks and strata is performed, and the properties of each geological layer are determined using a global crust model such as Crust1.0; Perform finite element meshing on the model, which includes meshing with tetrahedral mesh elements and evaluating the mesh quality; Load the model with rheological properties of the lithosphere, including loading elastic and viscoelastic material properties for different blocks in the model, adding boundary conditions to the outer boundaries of the model, and adding kinematic properties to faults; A dynamic analysis module configured to perform dynamic analysis using the software, the analysis module simulating the lithospheric deformation and the surface deformation field based on the virtual displacement principle, including considering the transient and periodic loads caused by geological events, and including the dynamic response caused by seismic events in the simulation; An output module is configured to output simulation results, including three-dimensional visualization representations of lithospheric deformation and surface deformation fields.

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