Landslide construction simulation method based on finite element

Abstract

The invention discloses a landslide construction simulation method based on finite elements, particularly relates to the field of construction simulation, and realizes whole-process dynamic simulation through GTS-NX software. Firstly, a three-dimensional finite element model is established based on geological exploration data, a Mohr-Coulomb elastic-plastic constitutive model is adopted, and the bulk modulus and the shear modulus are calculated through the elastic modulus and the Poisson's ratio. The initial ground stress is simulated by adopting a self-weight stress field method, and the initial displacement influence is eliminated by adopting a displacement difference method. In construction process simulation, the unit passivation / activation technology is adopted to accurately reproduce the excavation and support time sequence, and cyclic calculation of excavation-stress release-support-balance is achieved. In nonlinear analysis, superposition of an elastic stress field and a plastic stress field is considered, and an unloading influence factor is introduced to correct anisotropy of a deformation modulus. A safety coefficient is calculated through a strength reduction method, a multi-working-condition evaluation system is established, a monitoring data fusion and parameter inversion mechanism is developed, and a three-level early warning system is formed.

Description

Technical Field

[0001] The present invention relates to the technical field of construction simulation, and more particularly to a landslide construction simulation method. Background Art

[0002] Landslides are a major geological hazard that impacts the safety of engineering construction and infrastructure. Their occurrence is closely related to multiple factors, including geological conditions, soil moisture, and construction activities. Frequent landslides not only threaten life and property, but also lead to project delays and significant economic losses.

[0003] In the analysis of landslides, in terms of exploration, due to the complexity of the geological conditions, landslides are affected by many external conditions, making it difficult to accurately determine the location of the sliding surface and the characteristics of the rock and soil. At the same time, due to the heterogeneity of the rock and soil and the complexity of other structures within the rock and soil, it is very difficult to generalize the landslide model. The quantitative analysis results are mostly based on many assumptions, and the reliability of the results has certain limitations. At the same time, in terms of stability analysis, due to the complex coupling scenarios of multiple factors such as geology, hydrology, and meteorology, stability needs to comprehensively consider complex conditions such as the nonlinearity of the soil, the seepage-stress coupling effect, and the dynamic disturbance of construction. The analysis conditions are complex, difficult, and not very accurate. In terms of control construction, traditional single construction only needs to consider the stress of a single structure, thereby conducting a stress-strain analysis. Complex support structures need to consider the synergistic force effect between support structures and the coupling with the stratum. At the same time, construction excavation processes need to be superimposed. This results in safety hazards in each construction process in the control project after the landslide occurs, which is prone to secondary disasters.

[0004] The complexity of landslide investigation and analysis, coupled with the multi-factor impact, creates significant uncertainty in the actual construction process, leading to deficiencies in construction safety and reliability. Landslide prevention and control generally employs a support-first, excavation-later approach to eliminate or mitigate landslide hazards. Therefore, a landslide construction simulation method is needed to simulate and analyze each construction step. This approach allows for detailed simulation of the stresses and strains in the rock, soil, and support structures during landslide construction, providing effective technical support for slope stability assessment and risk control at all stages of landslide construction. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a landslide construction simulation method based on finite elements, which can simulate and analyze the landslide construction process to solve at least one problem raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: A1: Establish a finite element model of the landslide and determine the geometric shape, rock and soil stratification, and physical and mechanical parameters of the landslide based on landslide investigation, survey, and indoor and outdoor geotechnical test data; A2: Use the self-weight stress field method to simulate the initial ground stress; A3: Construction process simulation defines the construction phase groups, including excavation, support, and working condition changes; and uses the unit passivation function to simulate the excavation process; A4: Nonlinear mechanical analysis, calculating the elastic unloading stress field and nonlinear unloading stress field caused by excavation unloading, and simulating excavation unloading; A5: Simulate different construction conditions and use the strength reduction method to calculate the slope safety factor and determine stability.

[0007] Preferably, in step A1, based on landslide investigation, exploration, and indoor and outdoor geotechnical experimental data, including drilling data, geological profiles, rock and soil sampling test results, and field investigation data; a three-dimensional modeling technology is used to construct the geometric shape of the landslide body, clarify the landslide boundary, sliding surface location, and rock and soil layer characteristics; physical and mechanical parameters of each rock and soil layer are obtained through indoor and field tests, including physical parameters such as natural density, saturated density, porosity, and permeability coefficient, as well as shear strength index, deformation parameters, and tensile strength mechanical parameters, and a rock and soil parameter database is established; Shear strength indicators include cohesion and internal friction angle; deformation parameters include elastic modulus and Poisson's ratio; Based on the analysis results of rock and soil properties, the Mohr-Coulomb elastoplastic model is selected to simulate the nonlinear mechanical behavior of rock and soil. The bulk modulus K and shear modulus G of the rock and soil are input according to the experimental data, where K and G are calculated through the elastic modulus E and Poisson's ratio.

[0008] Preferably, in step A2, the self-weight stress field method is used to calculate the rock mass self-weight stress field and save the initial displacement field, and the initial displacement needs to be deducted in the subsequent stage; The specific calculation method of rock mass self-weight stress field is: ,in, It is expressed as the rock mass self-weight stress field, It is expressed as the specific gravity of the rock mass above the survey point, and H is expressed as the distance between the survey point and the ground surface; When the self-weight stress field method is used to simulate the initial geostress, a finite element model of the slope is established, including rock and soil stratification, material parameter assignment, and boundary condition setting. In the GTS-NX software, by defining the gravitational acceleration and rock and soil density distribution, a static equilibrium calculation is performed to obtain the initial stress field generated by the self-weight of the rock mass. This stress field includes the vertical stress component σz and the horizontal stress components σx and σy. The horizontal stress component is determined according to the lateral pressure coefficient.

[0009] Preferably, in step A3, a complete construction phase group is established in GTS-NX, and the entire construction process is divided into several calculation phases according to the actual construction plan of "support first and then excavation" or "excavation and support at the same time". Each phase clearly defines the construction content it contains, such as excavation of the nth layer of soil, anchor support construction, drainage system installation, etc., while taking into account changes in different working conditions, such as the application of external loads such as rainfall and earthquakes. Through the construction phase manager, the sequence and duration of each phase can be flexibly adjusted to ensure that the simulation process strictly corresponds to the actual construction plan.

[0010] During the excavation simulation, element passivation technology is used to gradually remove the rock and soil. This is achieved by multiplying the stiffness matrix of the elements in the area to be excavated by a minimal coefficient, reducing their contribution to the overall stiffness matrix to zero. This process requires precise control of the range of passivated elements to ensure consistency with the actual excavation profile. Simultaneously, GTS-NX automatically calculates the stress release and redistribution caused by element passivation, accurately reflecting the unloading effects of excavation. For layered excavation projects, elements in the corresponding areas are gradually passivated according to the design elevation, and the displacement and stress changes for each excavation step are recorded.

[0011] Preferably, in step A4, the elastic unloading stress field is calculated by Hooke's law to reflect the stress release of the rock and soil in the elastic stage; while the nonlinear unloading stress field needs to take into account the plastic deformation of the rock and soil and the nonlinear behavior of joint and crack expansion, and the Mohr-Coulomb yield criterion is used for iterative calculation; in specific implementation, GTS-NX automatically calculates the stress release caused by each step of excavation through the incremental iteration method, wherein the elastic part is directly obtained through the constitutive relationship, and the plastic part needs to be integrated according to the flow law and hardening model for plastic strain; for deep excavation projects, the influence of unloading rate on nonlinear deformation needs to be considered, and the viscoplastic model is used to simulate the time effect.

[0012] The simulation of excavation unloading usually assumes that the stress distribution of the rock slope after excavation is equal to the original ground stress field plus the adjusted stress field caused by nonlinear unloading. The adjusted stress field caused by nonlinear unloading consists of two parts: one is the elastic unloading stress field caused by pure unloading, which causes elastic deformation of the rock mass; the other is the nonlinear unloading stress field caused by cracking and sliding of the internal structural surface of the rock mass due to unloading. In actual calculations, GTS-NX uses field variable mapping technology to accurately superimpose various stress components and automatically checks whether the superimposed stress field meets the equilibrium conditions. In particular, stress verification is required near potential sliding surfaces to ensure that the shear stress does not exceed the shear strength. For large and complex slopes, it is recommended to use the block superposition method, first calculating the local stress adjustment of each excavation area, and then performing overall synthesis.

[0013] Preferably, in step A5, based on the characteristics of the landslide project and the site environmental conditions, a multi-level working condition simulation system including conventional construction, extreme weather and earthquake effects is constructed; a benchmark working condition model is established to simulate the mechanical response of the entire process of graded excavation and progressive support; for rainfall conditions, the unsaturated seepage theory is used to couple the stress field analysis, and the rainfall intensity is set to 50mm / d, 100mm / d, and 150mm / d, and the duration is 24h, 72h, and 120h. The seepage field is solved by the Richard equation, and the spatiotemporal evolution law of the pore water pressure and its influence on the slope stability are analyzed; for earthquake conditions, based on the results of the site earthquake hazard analysis, representative seismic waves are selected, and the explicit dynamic analysis method is used to simulate the dynamic response of the slope under the action of seismic motion.

[0014] The technical effects and advantages of the present invention are as follows: The present invention establishes a finite element model of the landslide and determines the geometric shape, rock and soil layers, and physical and mechanical parameters of the landslide body based on geological exploration data. The landslide boundary and sliding surface are clarified through three-dimensional modeling technology. The parameters of the Mohr-Coulomb elastic-plastic model are input according to the test data, and the three-dimensional finite element mesh is generated using GTS-NX software to realize the self-weight stress field simulation. The construction process is divided into excavation and support, and the unit passivation and activation technology is used for accurate simulation. The calculation is dynamically adjusted at each stage. The nonlinear mechanical analysis combines elastic and nonlinear unloading stress fields, considers the influence of excavation on the properties of the rock mass, and uses the strength reduction method to evaluate the slope safety factor. The extreme weather and earthquake effects are comprehensively considered. , establish multi-level working condition simulation, develop safety factor sensitivity analysis, build a multi-source monitoring data fusion platform, realize real-time monitoring and parameter optimization, and establish a three-level early warning mechanism; the present invention establishes a three-dimensional geological model, which can more comprehensively consider the nonlinear characteristics of the rock and soil, the initial stress state and the stress redistribution during the construction process, and provide a more accurate numerical basis for landslide stability assessment; in addition, combined with advanced monitoring technology and model inversion methods, it can track the dynamic response of the rock and soil during the construction process in real time, which helps to timely discover potential landslide risks, realize the refined simulation of the landslide construction process, and provide an effective technical means for slope stability assessment and risk prevention and control. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the method of the present invention. DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] See also Figure 1 As shown, the present invention provides a landslide construction simulation method based on finite element, comprising: A1: Establish a finite element model of the landslide and determine the geometric shape, rock and soil stratification, and physical and mechanical parameters of the landslide based on landslide investigation, survey, and indoor and outdoor geotechnical test data; In step A1, based on the landslide investigation, exploration, and indoor and outdoor geotechnical test data, including drilling data, geological profiles, rock and soil sampling test results, and field investigation data, three-dimensional modeling technology is used to construct the geometric shape of the landslide body, clarify the landslide boundary, sliding surface location, and rock and soil layer characteristics. Through indoor and field tests, the physical and mechanical parameters of each rock and soil layer are obtained, including physical parameters such as natural density, saturated density, porosity, and permeability, as well as shear strength index, deformation parameters, and tensile strength mechanical parameters, and a rock and soil parameter database is established. Shear strength indicators include cohesion and internal friction angle; deformation parameters include elastic modulus and Poisson's ratio; Based on the results of rock and soil property analysis, the Mohr-Coulomb elastoplastic model is selected to simulate the nonlinear mechanical behavior of rock and soil. The bulk modulus K and shear modulus G of the rock and soil are input according to the test data, where K and G are calculated using the elastic modulus E and Poisson's ratio. The calculation method of bulk modulus is as follows: , where K represents the bulk modulus and E represents the elastic modulus. Expressed as Poisson's ratio; The calculation method of shear modulus is as follows: , where G represents the shear modulus and E represents the elastic modulus. Expressed as Poisson's ratio; Key parameters such as density, cohesion, internal friction angle, and tensile strength of each rock and soil layer are input simultaneously. For special rock and soil layers, such as weak interlayers or fractured zones, their mechanical parameters need to be set individually, taking into account the spatial variability of the parameters. Utilizing the processing capabilities of GTS-NX software, a three-dimensional finite element mesh is generated based on the established landslide geometric model. During meshing, adaptive meshing technology is used to locally densify the potential sliding surface area, the periphery of the support structure, and the stress concentration area to ensure that the mesh density in these key areas meets the calculation accuracy requirements. At the same time, a gradient mesh transition technology is used at the model boundary to avoid stress distortion. After meshing is completed, a mesh quality check is required to ensure that the unit shape is regular and the aspect ratio is reasonable, providing a high-quality discrete model foundation for subsequent numerical calculations.

[0018] A2: Use the self-weight stress field method to simulate the initial ground stress; In step A2, the self-weight stress field method is used to calculate the rock mass self-weight stress field and save the initial displacement field. The initial displacement needs to be deducted in the subsequent stage. The specific calculation method of rock mass self-weight stress field is: ,in, It is expressed as the rock mass self-weight stress field, It is expressed as the specific gravity of the rock mass above the survey point, and H is expressed as the distance between the survey point and the ground surface; When using the self-weight stress field method to simulate initial geostress, a finite element model of the slope is established, including rock and soil stratification, material parameter assignment, and boundary condition settings. In GTS-NX software, by defining the gravitational acceleration and rock and soil density distribution, a static equilibrium calculation is performed to obtain the initial stress field generated by the rock mass's self-weight. This stress field includes the vertical stress component σz and horizontal stress components σx and σy. The horizontal stress component is determined based on the lateral pressure coefficient. The calculation method of pressure coefficient is as follows: ,in, Expressed as the lateral pressure coefficient, Expressed as Poisson's ratio; While calculating the initial stress field, the corresponding initial displacement field is automatically generated. Since the slope is in a state of mechanical equilibrium in its natural state in actual engineering, the initial displacement should theoretically be zero. Therefore, the calculated initial displacement field is saved as the reference value. When simulating the subsequent construction stage, the displacement result u obtained in each calculation step needs to be subtracted from the initial displacement field u0, that is, , thus obtaining the real construction-induced displacement.

[0019] A3: Construction process simulation defines the construction phase groups, including excavation, support, and working condition changes; and uses the unit passivation function to simulate the excavation process; In step A3, a complete construction phase group is established in GTS-NX. The entire construction process is divided into several calculation phases according to the actual construction plan of "support first, then excavation" or "excavation and support at the same time". Each phase clearly defines the construction content it includes, such as excavation of the nth layer of soil, anchor support construction, drainage system installation, etc., while considering changes in different working conditions, such as the application of external loads such as rainfall and earthquakes. The construction phase manager can flexibly adjust the sequence and duration of each phase to ensure that the simulation process strictly corresponds to the actual construction plan.

[0020] During the excavation simulation, element passivation technology is used to gradually remove the rock and soil. This is achieved by multiplying the stiffness matrix of the elements in the area to be excavated by a minimal coefficient, reducing their contribution to the overall stiffness matrix to zero. This process requires precise control of the range of passivated elements to ensure consistency with the actual excavation profile. Simultaneously, GTS-NX automatically calculates the stress release and redistribution caused by element passivation, accurately reflecting the unloading effects of excavation. For layered excavation projects, elements in the corresponding areas are gradually passivated according to the design elevation, and the displacement and stress changes for each excavation step are recorded.

[0021] The simulation of the support structure adopts the unit activation technology; the units of the support structure are included in the overall model at the beginning of modeling, but are initially set to a passivated state; when the simulation reaches the corresponding construction stage, the support effect is applied by activating these units and assigning them material properties; for special supports such as prestressed anchor rods, initial prestress is applied during activation; the activated support units will immediately participate in the overall stress of the structure, and their interaction with the rock and soil is achieved through contact units or common nodes.

[0022] The complete construction simulation follows the dynamic construction principle, that is, the calculation is carried out in stages according to the cyclic process of "excavation → stress release → support → new balance"; the calculation results of each construction stage will be used as the initial conditions for the next stage to realize the continuous simulation of the construction process.

[0023] A4: Nonlinear mechanical analysis, calculating the elastic unloading stress field and nonlinear unloading stress field caused by excavation unloading, and simulating excavation unloading; In step A4, the elastic unloading stress field is calculated using Hooke's law, reflecting the stress release of the rock and soil in the elastic stage. The nonlinear unloading stress field needs to consider the plastic deformation of the rock and soil and the nonlinear behavior of joint and crack expansion, and is iteratively calculated using the Mohr-Coulomb yield criterion. In specific implementation, GTS-NX automatically calculates the stress release caused by each excavation step through an incremental iteration method. The elastic part is directly obtained through the constitutive relationship, while the plastic part requires plastic strain integration based on the flow law and hardening model. For deep excavation projects, the influence of the unloading rate on the nonlinear deformation must also be considered, and the viscoplastic model is used to simulate the time effect.

[0024] The simulation of excavation unloading usually assumes that the stress distribution of the rock slope after excavation is equal to the original ground stress field plus the adjusted stress field caused by nonlinear unloading. The adjusted stress field caused by nonlinear unloading consists of two parts: one is the elastic unloading stress field caused by pure unloading, which causes elastic deformation of the rock mass; the other is the nonlinear unloading stress field caused by cracking and sliding of the internal structural surface of the rock mass due to unloading. The specific calculation method of the excavation unloading stress field is as follows: ,in, It is expressed as the redistributed stress field after excavation unloading, It is expressed as the initial ground stress field of the slope, It is expressed as the redistributed stress field caused by elastic unloading, It is expressed as the redistributed stress field caused by nonlinear unloading; After the slope excavation is unloaded, the physical and mechanical properties of the rock mass undergo significant changes, such as the deformation modulus in the unloading direction. The deformation modulus of the rock mass in the vertical direction is much smaller than that in the vertical direction. The range of the unloading zone also varies depending on the magnitude and direction of the ground stress and the structural characteristics of the rock mass. Therefore, the deformation value of the slope after unloading is: ,in, It is expressed as the deformation value of the slope after unloading. It is expressed as the initial ground stress field of the slope, It is expressed as the redistributed stress field caused by nonlinear unloading, Expressed as the deformation modulus in the unloading direction; In actual calculations, GTS-NX uses field variable mapping technology to accurately superimpose various stress components and automatically checks whether the superimposed stress field meets the equilibrium conditions. In particular, stress verification is required near potential sliding surfaces to ensure that the shear stress does not exceed the shear strength. For large and complex slopes, it is recommended to use the block superposition method, first calculating the local stress adjustment of each excavation area, and then performing overall synthesis.

[0025] The anisotropic correction of the rock deformation modulus targets the excavated unloading zone. The original deformation modulus is corrected by introducing an unloading influence factor, where the unloading influence factor is negatively correlated with the degree of unloading. In specific implementation, the unloading influence range is inverted based on monitoring data. A curve is established that shows the relationship between the degree of unloading and modulus attenuation. In the finite element model, the spatially varying distribution of the unloading influence factor is defined through field variables. For layered rock masses, a transversely isotropic or orthotropic constitutive model is adopted, taking into account the anisotropy caused by the occurrence of the structural surface. GTS-NX provides a custom material subroutine interface to implement complex modulus attenuation models. The exponential attenuation model is specifically as follows: , where k represents the material parameter, is expressed as plastic strain, Expressed as the initial elastic modulus of the material, Expressed as the initial elastic modulus of the material after undergoing plastic strain.

[0026] A5: Simulate different construction conditions and use the strength reduction method to calculate the slope safety factor and determine stability; In step A5, based on the characteristics of the landslide project and the site environmental conditions, a multi-level working condition simulation system is constructed, including conventional construction, extreme weather and earthquake effects. A baseline working condition model is established to simulate the mechanical response of the entire process of graded excavation and progressive support. For rainfall conditions, the unsaturated seepage theory is used to couple the stress field analysis, with rainfall intensities set to 50 mm / d, 100 mm / d, and 150 mm / d, and durations of 24 h, 72 h, and 120 h. The seepage field is solved using the Richard equation, and the temporal and spatial evolution of pore water pressure and its impact on slope stability are analyzed. For earthquake conditions, based on the results of the site seismic hazard analysis, representative seismic waves are selected, and the explicit dynamic analysis method is used to simulate the dynamic response of the slope under the action of seismic motion. An improved strength reduction method is used to quantitatively evaluate slope stability: a multi-criteria instability identification system is established, which comprehensively calculates convergence, characteristic point displacement mutation, and plastic zone coherence indicators; Develop parameter sensitivity analysis methods and use orthogonal experimental design to determine the influence weights of rock mass parameters on safety factors; Construct a three-dimensional safety factor cloud map to intuitively display the stability differences of different areas of the slope; The calculation method of safety factor is as follows: ,in, Expressed as safety factor, It is expressed as shear strength, and T is expressed as actual shear stress; Comparative analysis of safety factors under different working conditions: Normal working conditions: Fs≥1.30 (first level slope) Heavy rain conditions: Fs ≥ 1.15 (considering the increase in pore water pressure) Earthquake conditions: Fs ≥ 1.10 (including dynamic amplification effect) Introduce reliability theory, calculate slope failure probability, and improve the risk assessment system.

[0027] A multi-source monitoring data fusion platform was constructed, integrating data from multiple sources, including surface displacement monitoring (GNSS, total station), deep deformation monitoring (inclinometer), and groundwater level monitoring. An automatic comparison algorithm was developed to calculate the correlation coefficient (R²) and relative error (δ) between simulated and monitored values ​​in real time. A parameter inversion procedure was triggered when R² < 0.8 or δ > 15%. An intelligent optimization algorithm was used for parameter inversion, focusing on optimizing the strength parameters and permeability coefficient of the sliding zone soil. Establish a three-level early warning mechanism: Blue warning (displacement rate 1-2 mm / d): Strengthen monitoring; Yellow warning (displacement rate 2-5 mm / d): Take reinforcement measures; Red alert (displacement rate > 5mm / d): Emergency evacuation.

[0028] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. The landslide construction simulation method based on finite element is characterized by: include: A1: Establish a finite element model of the landslide and determine the geometric shape, rock and soil stratification, and physical and mechanical parameters of the landslide based on landslide investigation, survey, and indoor and outdoor geotechnical test data; A2: Use the self-weight stress field method to simulate the initial ground stress; A3: Construction process simulation defines the construction phase groups, including excavation, support, and working condition changes; and uses the unit passivation function to simulate the excavation process; A4: Nonlinear mechanical analysis, calculating the elastic unloading stress field and nonlinear unloading stress field caused by excavation unloading, and simulating excavation unloading; A5: Simulate different construction conditions and use the strength reduction method to calculate the slope safety factor and determine stability.

2. The landslide construction simulation method based on finite element method according to claim 1, characterized in that: In step A1, based on landslide investigation, exploration, and indoor and outdoor geotechnical experimental data, including drilling data, geological profiles, rock and soil sampling test results, and field investigation data, three-dimensional modeling technology is used to construct the geometric shape of the landslide body, clarify the landslide boundary, sliding surface location, and rock and soil stratification characteristics. Through indoor and field tests, the physical and mechanical parameters of each rock and soil layer are obtained, including natural density, saturated density, porosity, permeability, as well as shear strength index, deformation parameters, and tensile strength mechanical parameters, and a rock and soil parameter database is established.

3. The landslide construction simulation method based on finite element method according to claim 1, characterized in that: In step A2, the self-weight stress field method is used to calculate the rock mass self-weight stress field and save the initial displacement field. The initial displacement needs to be deducted in the subsequent stage. When using the self-weight stress field method to simulate the initial geostress, a finite element model of the slope is established, including rock and soil stratification, material parameter assignment, and boundary condition setting. In the GTS-NX software, by defining the gravitational acceleration and rock and soil density distribution, a static equilibrium calculation is performed to obtain the initial stress field generated by the rock mass's self-weight.

4. The landslide construction simulation method based on finite element method according to claim 1, characterized in that: In step A3, a complete construction phase group is created in GTS-NX. The entire construction process is divided into several calculation phases according to the "support before excavation" or "excavation and support" construction schemes. Each phase clearly defines its construction content, taking into account variations in different working conditions. The sequence and duration of each phase can be adjusted using the Construction Phase Manager. During the excavation simulation, element passivation is used to gradually remove the rock mass. This is accomplished by multiplying the stiffness matrix of the elements in the area to be excavated by a minimal coefficient, reducing their contribution to the overall stiffness matrix to zero. This process controls the extent of the passivated elements to align with the actual excavation profile. Simultaneously, GTS-NX calculates the stress release weight distribution caused by element passivation, reflecting the unloading effect of excavation. For layered excavation projects, the elements in the corresponding areas are gradually passivated according to the design elevation, and the displacement and stress changes of each excavation step are recorded.

5. The landslide construction simulation method based on finite element method according to claim 1, characterized in that: In step A4, the elastic unloading stress field is calculated using Hooke's law, reflecting the stress release of the rock and soil in the elastic stage. The nonlinear unloading stress field needs to consider the plastic deformation, joint and crack expansion, and nonlinear behavior of the rock and soil, and is iteratively calculated using the Mohr-Coulomb yield criterion. In specific implementation, GTS-NX automatically calculates the stress release caused by each excavation step through an incremental iteration method. The elastic part is directly obtained through the constitutive relationship, and the plastic part is integrated according to the flow law and hardening model for plastic strain. For deep excavation projects, the influence of unloading rate on nonlinear deformation is also considered, and the viscoplastic model is used to simulate the time effect.

6. The landslide construction simulation method based on finite element method according to claim 5, characterized in that: The simulation of excavation unloading assumes that the stress distribution of the rock slope after excavation is equal to the original ground stress field plus the adjusted stress field caused by nonlinear unloading. The adjusted stress field caused by nonlinear unloading includes two parts: one is the elastic unloading stress field caused by pure unloading, which causes elastic deformation of the rock mass; the other is the nonlinear unloading stress field caused by cracking and sliding of the internal structural surface of the rock mass due to unloading. The calculation method of the excavation unloading stress field is as follows: ,in, It is expressed as the redistributed stress field after excavation unloading, It is expressed as the initial ground stress field of the slope, It is expressed as the redistributed stress field caused by elastic unloading, It is represented as the redistributed stress field caused by nonlinear unloading.

7. The landslide construction simulation method based on finite element method according to claim 5, characterized in that: After the slope is excavated and unloaded, the physical and mechanical properties of the rock mass change, and the deformation modulus in the unloading direction The deformation modulus of the rock mass is much smaller than that in the vertical direction. The range of the unloading zone also varies depending on the magnitude and direction of the ground stress and the structural characteristics of the rock mass. The deformation value of the slope after unloading is: ,in, It is expressed as the deformation value of the slope after unloading. It is expressed as the initial ground stress field of the slope, It is expressed as the redistributed stress field caused by nonlinear unloading, Expressed as the deformation modulus in the unloading direction.

8. The landslide construction simulation method based on finite element method according to claim 1, characterized in that: In step A5, based on the characteristics of the landslide project and the site environmental conditions, a multi-level working condition simulation system was constructed, encompassing conventional construction, extreme weather conditions, and earthquake effects. A baseline working condition model was established to simulate the full mechanical response of graded excavation and progressive support. For rainfall conditions, unsaturated seepage theory coupled stress field analysis was used to analyze the spatiotemporal evolution of pore water pressure and its impact on slope stability. For earthquake conditions, based on the results of site seismic hazard analysis, seismic waves are selected and the explicit dynamic analysis method is used to simulate the dynamic response of the slope under the action of seismic motion.

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