Rainfall and earthquake coupled slope simulation method and system

Abstract

The invention provides a rainfall and earthquake coupled slope simulation method and system. The method comprises the following steps: constructing a coupling numerical model through multi-physics field data of a slope; the dynamic coupling effect of rainfall and earthquake is simulated by initializing a seepage field and loading earthquake power; the stability of the simulation result is comprehensively evaluated through iteration of a strength reduction method, and whole-process coupling from seepage to dynamic response of the slope is achieved. SeismoSignal is used for processing seismic waves, and the problem that the value of kinematics parameters is not zero when the seismic action is finished is avoided; the allowable maximum negative pore water pressure boundary is assigned to the slope surface of the side slope, the actual steady-state seepage field of the side slope is restored, and the seepage field in the side slope under different rainfall conditions is accurately calculated; by adopting an unsaturated soil dynamic seepage model for a seepage field, Rayleigh damping is introduced and an earthquake load is applied, so that cross-time scale coupling is realized. The method is simple and convenient to operate, high in calculation efficiency and accurate in calculation result, and has practical significance and value in research of the problem in the rock-soil field.

Description

Technical Field

[0001] The present invention belongs to the technical field of slope stability analysis, and in particular relates to a rainfall and earthquake coupled slope simulation method and system. Background Art

[0002] With the rapid development of highway construction in mountainous areas, the number and scale of slopes encountered during construction are increasing, and the impact of these hazards is also increasing, posing significant safety risks to the normal construction and operation of highway projects. Therefore, to ensure highway safety, it is necessary to manage and control slope safety threats through preliminary slope research and reinforcement. Slope instability and failure are the result of a combination of internal and external factors. Factors affecting slope stability include soil strength, slope shape, earthquakes, rainfall, and human activities. Currently, research both domestically and internationally focuses on the stability of slopes under rainfall and earthquake loads. Gao Junli proposed an unsaturated seepage differential equation based on an infiltration model for porous media under rainfall conditions, converting unstable seepage into stable seepage. Liu Zizhen et al. used the limit equilibrium strip method to study the effects of rainfall on slope stability. Their results showed that the effect of seepage forces and inter-strip forces decrease with increasing rainfall infiltration depth. Huang Runqiu et al. proposed that slope sliding under earthquakes occurs in the following stages: slope cracking, relaxation, high-speed collapse, vibration accumulation, secondary ejection, and debris flow accumulation. Qi Shengwen et al. explored the failure mechanism of slopes under earthquakes, arguing that slope failure during earthquakes is caused by a combination of seismic forces and a sharp increase in pore water pressure within the slope. These findings have shed some light on the stability of slopes under different conditions, such as rainfall and earthquakes. However, little research has been conducted on the stability of slopes under the coupled effects of rainfall and earthquakes. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a slope simulation method and system for coupling rainfall and earthquake, which is used for coupling the entire process of slope from seepage to dynamic response.

[0004] The technical solution adopted by the present invention to solve the above technical problems is: a slope simulation method for coupling rainfall and earthquake, comprising the following steps: S1: Acquire and preprocess multi-physics data of the slope including soil and water characteristics and ground motion data; S2: Construct a multi-physics coupled numerical model of the slope by initializing the seepage field and loading the gravity load; S3: Simulate the dynamic coupling of rainfall and earthquake; S4: Use the strength reduction method to iteratively evaluate the stability of the simulation results.

[0005] According to the above scheme, in step S1, the specific steps are: S11: Fit the soil-water characteristic curve of the slope by obtaining the saturated permeability coefficient and saturated volumetric water content of the slope's rock and soil mass; fit the unsaturated permeability coefficient curve using the Van Genuchten model and the Mualem model; establish a non-linear mapping relationship between pore water pressure, degree of saturation, and permeability to calibrate the unsaturated soil-water characteristics of the slope's rock and soil mass. S12: Preprocess the seismic motion data of the slope by screening seismic waves that meet the site conditions of the slope and performing baseline correction, filtering, and time-frequency characteristic analysis on the seismic waves.

[0006] According to the above solution, in step S2, the specific steps are as follows: S21: Extract the cross-sectional diagram based on the on-site data, and use the Mohr-Coulomb elastoplastic model to simulate the fill of the slope to establish a three-dimensional geological model. S22: Apply the gravity load to the initial stress field of the slope for in-situ stress balance, and output the reference data of the initial pore pressure field and displacement field.

[0007] Furthermore, in step S21, the specific steps are as follows: Establish a three-dimensional model of the slope through finite element software and divide the mesh, and apply boundary conditions to the boundaries in each direction respectively. Based on the porous media seepage theory, combine the law of conservation of mass and the unsaturated Darcy's law to derive the transient seepage equation of the fluid in the slope. Set the Mohr-Coulomb elastoplastic constitutive model parameters of the slope according to the Mohr-Coulomb yield criterion.

[0008] Furthermore, in step S21, the specific steps for deriving the transient seepage equation are as follows: For the fluid flowing in the porous media, describe the seepage velocity using the extended Darcy's law based on the relative permeability, saturated permeability, pore water pressure, gravitational acceleration, and elevation. Obtain the mass conservation equation of the source term or sink term based on the density of water, volumetric water content, and seepage velocity. Expand and simplify the mass conservation equation according to the time term and seepage term respectively. Introduce Biot's theory to calculate the change in porosity and correct the mass conservation equation. Obtain the relative permeability through the closure equations of the Van Genuchten model and the Mualem model.

[0009] According to the above solution, in step S3, the specific steps are as follows: S31: Set the drainage boundary conditions and apply the rainfall load to simulate the rainfall infiltration process. S32: Simulate the coupling of seismic dynamic response through dynamic analysis.

[0010] Further, in the step S32, the specific steps are as follows: S321: Import the preprocessed ground motion data; S322: Establish the dynamic theory control equation and introduce the Rayleigh damping model parameters to improve the calculation accuracy; S323: Synchronously record the dynamic responses of the acceleration field and the plastic strain field of the slope through the Mohr-Coulomb elastoplastic constitutive model; the specific steps are as follows: Analyze the force conditions of the nodes of the model and establish the dynamic equilibrium equation of the entire structure; According to the orthogonality condition of the vibration modes, establish the relationship between the mass matrix coefficient and the stiffness matrix coefficient as the Rayleigh damping model parameters and the damping ratio of the vibration modes and the natural frequency of the vibration modes.

[0011] According to the above solution, in the step S4, the strength reduction method is used to analyze the results of the simulation of the coupling effect, and the specific steps are as follows: Construct the mapping relationships between the reduction coefficient and the shear strength indexes cohesion and internal friction angle respectively: Use the bisection method to iteratively solve the instability critical point of the slope for the mapping relationships; Take the reduction coefficient of the slope at the instability critical point as the stability safety factor of the slope.

[0012] According to the above solution, it further includes the step S5: visually present the analysis results from multiple dimensions, including generating the spatio-temporal evolution cloud maps of the seepage field - stress field - displacement field, plotting the time history curves of the pore water pressure at the key nodes, and establishing the response surface of the safety factor and the rainfall intensity or seismic intensity.

[0013] A slope simulation system for rainfall and earthquake coupling, A parameter preparation sub-module, which is used to obtain and preprocess the multi-physical field data of the slope including the hydro-mechanical characteristics and ground motion data; A model construction sub-module, which is used to construct a multi-physical field coupling numerical model of the slope through seepage field initialization and loading of gravity loads; A simulation sub-module, which is used to simulate the dynamic coupling effect of rainfall and earthquake; An evaluation sub-module, which is used to comprehensively evaluate the stability of the simulation results by iterative use of the strength reduction method.

[0014] The beneficial effects of the present invention are as follows: 1. For the slope simulation method and system for rainfall and earthquake coupling of the present invention, a multi-physical field coupling numerical model of the slope is constructed through the multi-physical field data of the slope; the dynamic coupling effect of rainfall and earthquake is simulated through seepage field initialization and loading of seismic forces; the strength reduction method is used to iteratively conduct a comprehensive stability evaluation of the simulation results, realizing the full-process coupling of the slope from seepage to dynamic response.

[0015] 2. The present invention uses SeismoSignal to process seismic waves, avoiding the problem that the kinematic parameters do not take zero values at the end of the ground motion action; 3. The present invention removes the errors in the seismic wave records and uses the strength reduction method to obtain the accurate slope safety factor.

[0016] 3. By assigning the maximum allowable negative pore water pressure boundary to the slope surface, the present invention effectively restores the actual steady-state seepage field of the slope, accurately calculates the seepage field inside the slope under different rainfall conditions; by adopting the unsaturated soil dynamic permeability model for the seepage field, introducing Rayleigh damping and applying seismic loads, cross-time-scale coupling is achieved, which can be applied to complex models, restore the real slope landslide process, is easy to operate, has high calculation efficiency and accurate calculation results, and has practical significance and value in the research of this problem in the geotechnical field.

[0017] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following-described drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 is the flowchart of the embodiment of the present invention.

[0020] Figure 2 is the typical slope profile diagram of the embodiment of the present invention.

[0021] Figure 3 is the three-dimensional model mesh diagram of the embodiment of the present invention.

[0022] Figure 4 is the Mohr-Coulomb failure model diagram of the embodiment of the present invention.

[0023] Figure 5 is the yield model diagram of Mohr-Coulomb and Mises of the embodiment of the present invention.

[0024] Figure 6 is the relationship diagram between the volumetric water content and the negative pore pressure of the embodiment of the present invention.

[0025] Figure 7 is the relationship diagram between the permeability coefficient and the matrix suction of the embodiment of the present invention.

[0026] Figure 8It is the pore water pressure distribution diagram of the embodiment of the present invention.

[0027] Figure 9 It is the seismic time history curve diagram of the embodiment of the present invention.

[0028] Figure 10 It is the plastic zone diagram after the earthquake is applied in the embodiment of the present invention.

[0029] Figure 11 It is the lateral displacement diagram of each position of the slope in the embodiment of the present invention.

[0030] Figure 12 It is the longitudinal displacement diagram of each position of the slope in the embodiment of the present invention.

[0031] Figure 13 It is the slope reduction coefficient and the lateral displacement diagram of the slope apex in the embodiment of the present invention. Detailed implementation manners

[0032] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] Embodiment 1 Refer to Figure 1 , and the specific steps of a slope simulation method for rainfall and earthquake coupling are as follows: S1: Obtain and preprocess the multi-physical field data of the slope including soil-water force characteristics and ground motion data; S2: Construct a multi-physical field coupling numerical model of the slope through seepage field initialization and loading of gravity loads; S3: Simulate the dynamic coupling effect of rainfall and earthquake; S4: Use the strength reduction method to iteratively conduct a comprehensive stability evaluation of the simulation results.

[0034] Further, in step S1, the specific steps are: S11: Fit the soil-water characteristic curve of the slope by obtaining the saturated permeability coefficient and saturated volume water content of the rock and soil mass of the slope; fit the unsaturated permeability coefficient curve with the Van Genuchten model and the Mualem model; establish a non-linear mapping relationship between pore water pressure, water saturation and permeability to calibrate the unsaturated soil-water force characteristics of the rock and soil mass of the slope; S12: Preprocess the ground motion data of the slope by screening seismic waves that meet the site conditions of the slope and performing baseline correction, filtering and time-frequency characteristic analysis on the seismic waves.

[0035] According to the above solution, in step S2, the specific steps are: S21: Extract the cross-sectional diagram based on the on-site data, and establish a three-dimensional geological model by simulating the fill material of the slope using the Mohr-Coulomb elastoplastic model; S22: Apply the gravity load to the initial stress field of the slope for in-situ stress balance, and output the reference data of the initial pore pressure field and displacement field.

[0036] Further, in step S21, the specific steps are as follows: Establish a three-dimensional model of the slope through finite element software and divide the mesh, and apply boundary conditions to the boundaries in each direction respectively; Based on the porous medium seepage theory, combine the mass conservation law and the unsaturated Darcy's law to derive the transient seepage equation of the fluid in the slope; Set the Mohr-Coulomb elastoplastic constitutive model parameters of the slope according to the Mohr-Coulomb yield criterion.

[0037] Further, in step S21, the specific steps for deriving the transient seepage equation are as follows: For the fluid flowing in the porous medium, describe the seepage velocity according to the relative permeability, saturated permeability, pore water pressure, gravitational acceleration, and elevation using the extended Darcy's law; Obtain the mass conservation equation of the source term or sink term according to the density of water, volumetric water content, and seepage velocity; Expand and simplify the mass conservation equation according to the time term and seepage term respectively; Introduce Biot theory to calculate the porosity change and correct the mass conservation equation; Obtain the relative permeability through the Van Genuchten model and the Mualem model to close the equation.

[0038] In step S3, the specific steps are as follows: S31: Set the drainage boundary conditions and apply the rainfall load to simulate the rainfall infiltration process; S32: Simulate the seismic dynamic response coupling through dynamic analysis.

[0039] Further, in step S32, the specific steps are as follows: S321: Import the preprocessed ground motion data; S322: Establish the dynamic theory control equation, and introduce the Rayleigh damping model parameters to improve the calculation accuracy; S323: Synchronously record the dynamic responses of the acceleration field and plastic strain field of the slope through the Mohr-Coulomb elastoplastic constitutive model; the specific steps are as follows: Analyze the force conditions of the nodes of the model and establish the dynamic equilibrium equation of the entire structure; According to the orthogonality condition of vibration modes, establish the relationship between the mass matrix coefficient and stiffness matrix coefficient as the Rayleigh damping model parameters and the damping ratio of vibration modes and the natural frequency of vibration modes.

[0040] In step S4, the strength reduction method is used to analyze the results of the simulated coupling effect. The specific steps are as follows: The mapping relationships between the reduction coefficient and the shear strength index cohesion and internal friction angle are constructed respectively: The mapping relationship is iteratively solved by using a bisection method to determine the critical point of slope instability; The reduction factor of the slope at the critical point of instability is used as the stability safety factor of the slope.

[0041] The method also includes step S5: visually presenting the analysis results from multiple dimensions, including generating a spatiotemporal evolution cloud map of the seepage field, stress field, and displacement field, drawing a time history curve of the pore water pressure at key nodes, and establishing a response surface between the safety factor and rainfall intensity or earthquake intensity.

[0042] This embodiment constructs a multi-physics field coupled numerical model of the slope using the multi-physics field data of the slope; simulates the dynamic coupling of rainfall and earthquake by initializing the seepage field and loading seismic dynamics; and uses the strength reduction method to iteratively perform a comprehensive stability evaluation of the simulation results, thereby achieving full-process coupling of the slope from seepage to dynamic response.

[0043] Example 2 The steps of this embodiment are the same as those of embodiment 1, except that each step is applied to a specific example. Specifically, the following steps are included: S1: Preprocessing of multi-physics parameters of slope including soil and water characteristics and ground motion data; S11: Calibration of hydraulic properties of unsaturated soil; The saturated permeability coefficient and saturated volumetric water content of the slope rock and soil were obtained by using the on-site construction data and the sample data point function provided by GeoStudio:SEEP / W software. The soil-water characteristic curve (SWCC) of the rock and soil was further fitted, and the relationship between volumetric water content and negative pore pressure was shown in the figure below. Figure 6 As shown; the unsaturated permeability coefficient curve is fitted by the Van Genuchten model and the Mualem model, and the relationship between the permeability coefficient and the matrix suction is shown in Figure 7 As shown; a nonlinear mapping relationship between pore water pressure, saturation and permeability is established; S12: Preprocessing of ground motion data; Using the Seismoselect platform, we input the seismic intensity and post-earthquake conditions and selected seismic waveforms that matched the site conditions. Finite element simulations were performed using the Pacific Data Center to analyze the selected seismic waveforms and investigate the dynamic response patterns. This seismic waveform contains complete three-dimensional ground motion data, and X-axis ground motion data was used to investigate the three-dimensional dynamic response of the high embankment slope. This seismic waveform was input at the base of the high embankment slope as an acceleration time history. The original ground motion recording was maintained for 40 seconds to ensure that the peak acceleration occurred within this timeframe.

[0044] Use SeismoSignal to complete baseline correction, filtering, and time-frequency characteristic analysis of seismic waves; usually, the slope is in a static state at the end of the ground motion. To avoid non-zero values of kinematic parameters at the end of the ground motion and remove errors in the seismic wave records, etc., use the seismic wave processing software SeismoSignal to process the seismic waves, and the excitation intensity of the seismic waves is 0.1g. The seismic time history curve is as Figure 9 shown.

[0045] S2: Construct a multi-physical field coupling numerical model of the slope; S21: According to the on-site engineering data and a typical cross-sectional view of the high-fill embankment slope, as Figure 2 shown, use the Mohr-Coulomb elastoplastic model to simulate and establish a three-dimensional geological model.

[0046] The slope ratio of this embankment model ranges from 1:1.5 to 1:2.0, a slope platform is set, the platform width is 2m, the top width of the embankment is 12.75m, the central fill height is 38.75m, and three layers of geogrids are set on the top layer for reinforcement. Among them, the sericite schist rock and soil mixture filler are simulated using the Mohr-Coulomb elastoplastic model. The geogrids use the Shell element model, the thickness of the foundation soil layer is 3m for gravel soil, 10m for strongly weathered dolomite albite quartz schist, and 37m for moderately weathered dolomite albite quartz schist. The parameters of various materials refer to Table 1.

[0047] Table 1 Material parameter table

[0048] According to the soil material parameters and slope surface diagram of this project, use the ABAQUS finite element software to establish a three-dimensional model and divide the mesh according to the C3D8P eight-node hexahedron element, three-way linear displacement, and three-way linear pore pressure. The model thickness is 50m, with a total of 15057 nodes and 13116 mesh elements, as Figure 3 shown; this model uses fixed boundary conditions, no constraint is applied to the upper boundary, vertical constraints are applied to the lower boundary while horizontal constraints are applied, and only horizontal constraints are applied to the left, right, front, and back boundaries; assume the groundwater level is -3m, a drainage boundary is set at 3m underground, and no drainage is assumed at other positions by default.

[0049] In ABAQUS, based on the porous medium seepage theory, combine the mass conservation law and the unsaturated Darcy's law to derive the transient seepage equation: For the fluid flow in the porous medium, assume the density of water is , the volumetric water content is , the Darcy velocity (m / s) is , the source / sink term (such as rainfall infiltration or pumping, kg / (m·s)) is , the mass conservation equation is expressed as:

[0050] Let the relative permeability (dimensionless) be , the saturated permeability be , the dynamic viscosity of water be , the pore water pressure be , the acceleration due to gravity be , the elevation be , and the extended Darcy's law is adopted in ABAQUS to describe the seepage velocity:

[0051] Substitute Darcy's law into the mass conservation equation and expand each term: Expand it in terms of the time term as:

[0052] Assume simplification: the porosity is constant (ignoring soil deformation) or the change of porosity with time is considered in coupled consolidation; the water density is constant (ignoring compressibility).

[0053] Expand it in terms of the seepage term as:

[0054] Let the degree of saturation of the soil be , ignoring the density change and the time variation of porosity, simplify the equation to the final form:

[0055] When considering soil deformation, introduce Biot's theory; let the Biot coefficient be , usually 1; the volumetric strain be , the bulk modulus of soil particles be ; then the change of porosity is:

[0056] The modified mass conservation equation is:

[0057] [[ID=6l]]Substitute and obtain:

[0058] In ABAQUS, close the equation through the following model: Let the capillary pressure be , , n, and m are fitting parameters ( ), the residual saturation be , the saturated saturation be , obtained by using the Van Genuchten model:

[0059] Let the effective saturation be , and the relative permeability is obtained by using the Mualem model:

[0060] Set the parameters of the Mohr-Coulomb elastoplastic constitutive model; select Mohr-Coulomb in the plastic model of geotechnical engineering, and the obtained results are more in line with the actual situation.

[0061] When using ABAQUS simulation for analysis, the material of the embankment fill is regarded as isotropic; according to the Mohr-Coulomb yield criterion, when the shear stress at any point in the microelement is equal to the shear strength, the microelement will fail at this position. Let τ be the shear strength; c be the internal cohesion of the embankment fill; σ be the normal stress of the embankment fill; φ be the internal friction angle of the embankment fill, and the expression of the yield criterion is:

[0062] Let and , 、 and are the first principal stress, the second principal stress and the third principal stress respectively, and the mean stress is , then from Figure 4 the Mohr-Coulomb failure model diagram shown, we get: ; ; Substitute into the previous formula to get: ; To sum up, on the π plane, the yield models of Mohr-Coulomb and Mises are as Figure 5 shown.

[0063] S22: Generate the initial state field of the slope; Transfer and balance the initial stress field through the ODB import method; Apply the gravity load for in-situ stress balance (Geostatic analysis step); Output the reference data of the initial pore pressure field and displacement field; S3: Simulate the dynamic coupling effect of rainfall and earthquake; S31: Set the drainage boundary conditions and apply the rainfall load to simulate the rainfall infiltration process; Add a rainfall analysis step (Rainfall analysis step) and select transient seepage; Apply a uniform rainfall load to the slope surface with a rainfall intensity of 60 mm / d and a time setting of 5 d; After the rainfall is applied, the pore water pressure diagram is as shown in Figure 8 the following; S32: Simulate the seismic dynamic response coupling through dynamic analysis; S321: Import the preprocessed seismic wave time history data (Seismic analysis step); S322: Establish the dynamic theory control equation and introduce the Rayleigh damping model parameters to improve the calculation accuracy; The specific steps are as follows: Let p be the gravity and other static body forces; be the volume force of the solid skeleton, be the displacement vector, be the material density; be the damping coefficient; be the inertial force; be the damping force; Then the body force received by the unit node under dynamic action is:

[0064] Considering the action of the node force shown in the above formula, let [M] be the overall mass matrix of the structure; [C] be the overall damping matrix of the structure; [K] be the overall stiffness matrix of the structure; {F} be the nodal load array of the structure; {u''} be the nodal acceleration array of the structure; {u'} be the nodal velocity array of the structure; {u} be the nodal displacement array of the structure; Establish the dynamic equilibrium equation of the entire structure as:

[0065] Let and be the mass matrix coefficient and the stiffness matrix coefficient respectively, then in the above formula:

[0066] According to the orthogonality condition of the vibration mode, establish and the relationship between the damping ratio of the vibration mode and the natural frequency of the vibration mode:

[0067] Combine the above two formulas to find the mass matrix coefficient and the stiffness matrix coefficient as the Rayleigh damping model parameters respectively as: .

[0068] S323: Simultaneously record the dynamic response of the acceleration field and plastic strain field through the Mohr-Coulomb dynamic constitutive model; The model uses a fixed bottom boundary and side constraints for lateral displacement in static mode. In seismic analysis, the bottom of the embankment is set as a fixed boundary, and the surrounding areas of the model are changed to free field boundaries, forming an infinite half-space region with the static boundary of the ground, making the constructed model more consistent with actual engineering.

[0069] Extract the first two natural frequencies of the structure by adding a Frequency analysis step, solve the Rayleigh damping according to the formula in step S322, check the Rayleigh damping in the dynamic analysis step and add and coefficient.

[0070] The seismic wave acceleration time history curve is applied to the bottom through the load module of ABAQUS.

[0071] A monitoring point is set at the center of the embankment and the longitudinal slope foot, slope top and step of the embankment slope, and the longitudinal displacement and lateral displacement curves of each monitoring point are analyzed and drawn. Figure 10 , the lateral displacement of each position is as follows Figure 11 , the longitudinal displacement of each position is as follows Figure 12 shown.

[0072] S4: Conduct a comprehensive stability evaluation of the simulation results; the specific steps are: The strength reduction method is to divide the shear strength index of soil, cohesion c, and internal friction angle φ, by the reduction coefficient FV1 in the finite element software to obtain and , and then substitute these two parameters into the formula as new calculation parameters and continue the calculation. As the reduction coefficient FV1 gradually increases, the shear strength of the rock slope gradually weakens. When the slope weakens due to the weakening of shear strength until it reaches instability, the corresponding reduction coefficient FV1 is the stability safety factor FS of the slope. and They are: , ; Add a reduce analysis step, set the field variation FV1, and set the material properties according to the strength reduction formula as the field variation FV1 changes.

[0073] Combine the lateral displacement of the slope vertex and FV1 to obtain Figure 13 , FV1 corresponding to the first sudden change in lateral displacement is the slope stability safety factor of 1.28.

[0074] It should be understood that the sequence numbers of the steps in the above embodiments do not imply the order of execution. The order of execution of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0075] Embodiment 3 This embodiment is used to implement the principle of the above method embodiment to construct a system, including a parameter preparation sub-module, a model construction, a simulation sub-module, and an evaluation sub-module.

[0076] The parameter preparation sub-module is used to obtain and preprocess the multi-physical field data of the slope, including the characteristics of water and soil forces and seismic motion data; The model construction sub-module is used to construct a multi-physical field coupling numerical model of the slope by initializing the seepage field and loading the gravity load; The simulation sub-module is used to simulate the dynamic coupling effect of rainfall and earthquake; The evaluation sub-module is used to comprehensively evaluate the stability of the simulation results by iterative strength reduction method.

[0077] Each sub-module is mainly used to implement each step of the method embodiment, which will not be elaborated here.

[0078] It should be noted that according to the needs of implementation, each step / component described in the present application can be split into more steps / components, or two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0079] This embodiment also includes a processor, a communication interface, a memory, and a communication bus; wherein the processor, the communication interface, and the memory complete communication with each other through the communication bus; a computer program is stored in the memory, and when the program is executed by the processor, the processor executes the steps of a slope simulation method for rainfall and earthquake coupling.

[0080] This embodiment also provides a computer-readable storage medium, on which an executable instruction is stored, and when the instruction is executed by the processor, the processor implements a slope simulation method for rainfall and earthquake coupling.

[0081] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects.

[0082] Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0083] This application is described with reference to the flowcharts of the method and computer program product according to Embodiment 1 of this application and the block diagrams of the device (system) according to Embodiment 3. It should be understood that each process or block in the flowchart or block diagram, as well as the combination of processes or blocks in the flowchart or block diagram, can be implemented by computer program instructions.

[0084] These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a rainfall and earthquake coupled slope simulation system for implementing the functions specified in one process Figure 1 one process or multiple processes or blocks Figure 1 or multiple blocks.

[0085] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device implements the functions specified in one process Figure 1 one process or multiple processes or blocks Figure 1 or multiple blocks.

[0086] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide the steps of a rainfall and earthquake coupled slope simulation method for implementing the functions specified in one process Figure 1 one process or multiple processes or blocks Figure 1 or multiple blocks.

[0087] The above embodiments are only used to illustrate the design concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes or modifications made according to the principles and design concepts disclosed in the present invention are within the protection scope of the present invention.

Claims

1. A slope simulation method coupling rainfall and earthquake, characterized in that: It includes the following steps: S1: Obtain and preprocess the multi-physical field data of the slope, including hydro-mechanical characteristics and ground motion data; S2: Construct a multi-physical field coupling numerical model of the slope by initializing the seepage field and loading the gravity load; S3: Simulate the dynamic coupling effect of rainfall and earthquake; S4: Use the strength reduction method to iteratively conduct a comprehensive stability evaluation of the simulation results.

2. The slope simulation method coupling rainfall and earthquake according to claim 1, wherein: In the step S1, the specific steps are as follows: S11: Fit the soil-water characteristic curve of the slope by obtaining the saturated permeability coefficient and saturated volumetric water content of the rock and soil mass of the slope; fit the unsaturated permeability coefficient curve with the Van Genuchten model and the Mualem model; establish a non-linear mapping relationship between pore water pressure, saturation, and permeability to calibrate the unsaturated hydro-mechanical characteristics of the rock and soil mass of the slope; S12: Preprocess the ground motion data of the slope by screening seismic waves that meet the site conditions of the slope and performing baseline correction, filtering, and time-frequency characteristic analysis on the seismic waves.

3. A slope simulation method coupling rainfall and earthquake according to claim 1, characterized in that: In the step S2, the specific steps are as follows: S21: Extract the cross-sectional diagram according to the field data, and use the Mohr-Coulomb elastoplastic model to simulate the fill of the slope to establish a three-dimensional geological model; S22: Apply the gravity load to the initial stress field of the slope for in-situ stress balance, and output the reference data of the initial pore pressure field and displacement field.

4. A slope simulation method coupling rainfall and earthquake according to claim 3, characterized in that: In the step S21, the specific steps are as follows: Establish a three-dimensional model of the slope by finite element software and divide the grid, and apply boundary conditions to the boundaries in each direction respectively; Based on the porous media seepage theory, combine the mass conservation law and the unsaturated Darcy's law to derive the transient seepage equation of the fluid in the slope; Set the Mohr-Coulomb elastoplastic constitutive model parameters of the slope according to the Mohr-Coulomb yield criterion.

5. A slope simulation method coupling rainfall and earthquake according to claim 4, characterized in that: In the step S21, the specific steps of deriving the transient seepage equation are as follows: For the fluid flowing in the porous media, describe the seepage velocity according to the relative permeability, saturated permeability, pore water pressure, gravitational acceleration, and elevation by using the extended Darcy's law; Obtain the mass conservation equation of the source term or sink term according to the density of water, volumetric water content, and seepage velocity; Expand and simplify the mass conservation equation according to the time term and seepage term respectively; Introduce the Biot theory to calculate the change in porosity and correct the mass conservation equation; Obtain the relative permeability by closing the equation with the Van Genuchten model and the Mualem model.

6. A slope simulation method coupling rainfall and earthquake according to claim 1, characterized in that: In the step S3, the specific steps are as follows: S31: Set the drainage boundary conditions and apply the rainfall load to simulate the rainfall infiltration process; S32: Simulate the seismic dynamic response coupling through dynamic analysis.

7. A slope simulation method coupling rainfall and earthquake according to claim 6, characterized in that: In the step S32, the specific steps are as follows: S321: Import the preprocessed ground motion data; S322: Establish the dynamic theory control equation and introduce the Rayleigh damping model parameters to improve the operation accuracy; S323: Synchronously record the dynamic responses of the acceleration field and plastic strain field of the slope through the Mohr-Coulomb elastoplastic constitutive model; the specific steps are as follows: Analyze the force condition of the nodes of the model and establish the dynamic equilibrium equation of the whole structure; According to the orthogonality condition of vibration modes, establish the relationships between the mass matrix coefficients and stiffness matrix coefficients, which are the parameters of the Rayleigh damping model, and the damping ratios of vibration modes and the natural frequencies of vibration modes.

8. A slope simulation method coupling rainfall and earthquake according to claim 1, characterized in that: In the step S4 described above, the strength reduction method is used to analyze the results of the simulated coupling effect. The specific steps are as follows: Construct the mapping relationships between the reduction coefficient and the shear strength indexes cohesion and internal friction angle respectively: Use the bisection method to iteratively solve the instability critical point of the slope for the mapping relationships; Take the reduction coefficient of the slope at the instability critical point as the stability safety factor of the slope.

9. A slope simulation method coupling rainfall and earthquake according to claim 1, characterized in that: It also includes step S5: visually present the analysis results from multiple dimensions, including generating the spatio-temporal evolution cloud maps of the seepage field - stress field - displacement field, plotting the time history curves of the pore water pressure at key nodes, and establishing the response surface of the safety factor and the rainfall intensity or seismic intensity.

10. A slope simulation system for rainfall and earthquake coupling, characterized in that: A parameter preparation sub-module, which is used to obtain and preprocess the multi-physical field data of the slope, including the hydro-mechanical characteristics and ground motion data; A model construction sub-module, which is used to construct a multi-physical field coupling numerical model of the slope by initializing the seepage field and loading the gravity load; A simulation sub-module, which is used to simulate the dynamic coupling effect of rainfall and earthquake; An evaluation sub-module, which is used to comprehensively evaluate the stability of the simulation results by iteratively using the strength reduction method.

Images