FDEM simulation method and system for rock slope fracture instability

Abstract

The invention discloses an FDEM simulation method and system for rock slope fracture instability, and relates to the technical field of geotechnical engineering. The method comprises the following steps: acquiring rock mass mechanical parameters and three-dimensional morphological parameters of a target rock slope; based on the rock mass mechanical parameters and the three-dimensional morphological parameters, constructing a numerical model of the target rock slope by using an FDEM; configuring initial conditions for the numerical model, applying initial gravitational acceleration, and configuring updating conditions when the total kinetic energy of the numerical model is reduced to a preset value; after updating condition configuration is completed, increasing the gravitational acceleration step by step until the variable quantity of the total kinetic energy meets a preset condition, and recording the final gravitational acceleration; and determining the safety coefficient of the target rock slope according to the final gravitational acceleration. According to the invention, the whole catastrophe process of the rock slope from crack initiation and extension, sliding to block macroscopic movement can be accurately simulated, and the safety coefficient with clear physical significance is obtained based on the dynamic instability critical state.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering technology, and in particular to an FDEM simulation method and system for rock slope fracturing and instability. Background Technology

[0002] Rock slope engineering is widespread in my country's hydropower, transportation, and mining sectors. Especially as infrastructure construction expands into the geologically complex central and western regions, these projects often feature steep slopes and are significantly affected by construction disturbances. Once landslides and instability occur, they can cause serious damage. Slope stability is directly related to the safety of engineering construction and operation; therefore, accurately predicting the location of instability and the failure process is crucial and a prerequisite for scientifically developing protective measures.

[0003] Current research mainly relies on theoretical analysis, physical experiments, field monitoring, and numerical simulation. While numerical simulation has advantages such as low cost, high efficiency, adjustable parameters, and strong visualization, existing methods have significant limitations: traditional continuous numerical methods (such as finite element method (FEM), finite difference method (DEM), and boundary element method (BEM) can only simulate the continuous deformation behavior of rock masses, making it difficult to characterize the entire process of crack initiation, propagation, and movement of fractured blocks, thus failing to reflect the macroscopic movement laws of rock blocks after instability; while discontinuous methods (such as discrete element method (DEM), particle element method (PFC), and discontinuous deformation analysis method (DDA)) can simulate block movement, but they are insufficient in simulating the evolution process of complex fracture networks within rock masses, and often suffer from distortion due to excessively large element sizes in engineering-scale applications.

[0004] The continuous-discontinuous coupling method (FDEM method) has demonstrated applicability in rock mechanics, but its application is currently concentrated on laboratory-scale specimens or underground tunnel engineering. For the simulation of the entire process of rock slope instability and failure, especially the coupling mechanism of crack propagation and block movement at the engineering scale, existing research has not yet formed a systematic and reliable numerical simulation system, making it difficult to accurately capture the dynamic evolution of slopes from gradual failure to overall instability. This technological gap restricts the effective assessment and prevention of slope safety risks. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides an FDEM simulation method and system for rock slope fracturing and instability, which can accurately simulate the entire catastrophic process of rock slope from crack initiation and propagation, to slippage and macroscopic block movement, and obtain a safety factor with clear physical meaning based on the dynamic instability critical state.

[0006] To achieve the above objectives, the present invention provides an FDEM simulation method for rock slope fracturing and instability, comprising:

[0007] Obtain the rock mass mechanical parameters and three-dimensional morphological parameters of the target rock slope;

[0008] Based on the rock mass mechanical parameters and three-dimensional morphological parameters, a numerical model of the target rock slope was constructed using FDEM.

[0009] Initial conditions are configured for the numerical model and an initial gravitational acceleration is applied. When the total kinetic energy of the numerical model drops to a preset value, update conditions are configured.

[0010] After the update conditions are configured, the gravitational acceleration is increased step by step over time until the change in total kinetic energy meets the preset conditions, and the final gravitational acceleration is recorded.

[0011] The safety factor of the target rock slope is determined based on the final gravitational acceleration.

[0012] The initial conditions include fixing the bottom boundary, removing the horizontal boundary self-constraint, enabling hysteresis damping and viscous damping, and setting the rock cohesion and tensile strength to N times their respective actual values; N>1; the update conditions include fixing the horizontal boundary, disabling the hysteresis damping, and setting the rock cohesion and tensile strength to their respective actual values.

[0013] Optionally, the numerical model is characterized in that the contact discrimination code attribute value of the grid nodes corresponding to the slope toe and slope surface is set to 1, and the contact discrimination code attribute value of the remaining grid nodes is set to 0.

[0014] Optionally, the formula for calculating the hysteresis damping is:

[0015]

[0016] In the formula, η represents hysteresis damping, m i Let denot i be the mass of grid node i, β be the hysteresis damping coefficient, E be the elastic modulus, and ρ be the material density.

[0017] Optionally, the formula for calculating the viscous damping is:

[0018]

[0019] In the formula, μ represents viscous damping, and h j Let be the side length of triangular element j, E be the elastic modulus, and ρ be the material density.

[0020] Optionally, during the initial application of gravitational acceleration, the hysteresis damping coefficient is set as the critical hysteresis damping coefficient.

[0021] Optionally, when increasing the gravitational acceleration step by step, the following formula is used:

[0022] g = g0 - 0.1 × (T - T0) / ΔT and T > T0

[0023] In the formula, g is the current gravitational acceleration, g0 is the initial gravitational acceleration, T is the current calculation time step, T0 is the calculation time step when the total kinetic energy drops to the preset value, and ΔT is the gravitational loading rate.

[0024] Optionally, the preset condition is that the total kinetic energy of the current time step is greater than the total kinetic energy of the previous 10,000 time steps, and the difference is greater than a preset threshold.

[0025] Optionally, the formula for calculating the safety factor is:

[0026]

[0027] In the formula, SF represents the safety factor, and g f g is the final gravitational acceleration, and g0 is the initial gravitational acceleration.

[0028] The present invention also provides an FDEM simulation system for rock slope fracturing and instability, comprising:

[0029] The data acquisition unit is used to acquire the rock mass mechanical parameters and three-dimensional morphological parameters of the target rock slope;

[0030] The model building unit is used to construct a numerical model of the target rock slope using FDEM based on the rock mass mechanical parameters and three-dimensional morphological parameters.

[0031] Simulation unit, used for:

[0032] Initial conditions are configured for the numerical model and an initial gravitational acceleration is applied. When the total kinetic energy of the numerical model drops to a preset value, update conditions are configured.

[0033] After the update conditions are configured, the gravitational acceleration is increased step by step over time until the change in total kinetic energy meets the preset conditions, and the final gravitational acceleration is recorded.

[0034] The safety factor of the target rock slope is determined based on the final gravitational acceleration.

[0035] The initial conditions include fixing the bottom boundary, removing the horizontal boundary self-constraint, enabling hysteresis damping and viscous damping, and setting the rock cohesion and tensile strength to N times their respective actual values; N>1; the update conditions include fixing the horizontal boundary, disabling the hysteresis damping, and setting the rock cohesion and tensile strength to their respective actual values.

[0036] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0037] The FDEM simulation method for rock slope fracturing and instability provided by this invention establishes a numerical model of the target rock slope. During the initial gravity loading stage, a dual damping mechanism (hysteresis damping and viscous damping) is employed to synergistically dissipate energy, and the rock cohesion and tensile strength are temporarily increased to N times their actual values, ensuring the model efficiently reaches static equilibrium under artificially reinforced conditions. Subsequently, in the condition update stage, the true strength parameters are restored and boundary constraints are adjusted, creating a realistic physical environment for progressive failure. This phased strategy successfully overcomes the technical obstacle of traditional discontinuous methods in simulating the initiation and propagation of internal rock fractures, achieving accurate simulation from micro-fracture evolution to macroscopic slippage. By gradually increasing the gravitational acceleration until a sudden change in the model's kinetic energy occurs, the critical state of slope instability is directly correlated, and a safety factor is determined based on the final gravitational acceleration. This invention abandons traditional simplification assumptions, giving the calculated safety factor clear physical meaning and dynamic evolution basis. It not only accurately quantifies slope stability but also intuitively presents the catastrophic mechanism of instability failure, providing a reliable basis for engineering protection design. Attached Figure Description

[0038] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same parts.

[0039] Figure 1 This is a schematic diagram of the FDEM simulation method for rock slope fracturing and instability, as shown in an embodiment of the present invention.

[0040] Figure 2 This is a flowchart illustrating the FDEM simulation method for rock slope fracturing and instability according to an embodiment of the present invention.

[0041] Figure 3 This is a schematic diagram of the FDEM slope numerical model shown in an embodiment of the present invention;

[0042] Figure 4 This is a schematic diagram illustrating the contact point between the slope toe and the slope surface in an embodiment of the present invention;

[0043] Figure 5 This is a schematic diagram of the boundary conditions during the initial gravity application stage, as shown in an embodiment of the present invention.

[0044] Figure 6 This is a schematic diagram of the boundary conditions during the gravitational acceleration loading stage as shown in an embodiment of the present invention;

[0045] Figure 7 This is a kinetic energy curve during the initial application of gravity, as shown in an embodiment of the present invention.

[0046] Figure 8 This is a schematic diagram illustrating the method for determining the safety factor in an embodiment of the present invention;

[0047] Figure 9 This is a schematic diagram illustrating the gravitational acceleration loading process in an embodiment of the present invention;

[0048] Figure 10 This is a schematic diagram illustrating the simulation results of the final failure mode of the slope in an embodiment of the present invention;

[0049] Figure 11 This is a schematic diagram of the module structure of an FDEM simulation system for rock slope fracturing and instability, as shown in an embodiment of the present invention. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] Please see Figure 1 and Figure 2 , Figure 1 A schematic diagram of the FDEM simulation method for rock slope fracturing and instability; Figure 2 This is a flowchart of the FDEM simulation method for rock slope fracturing and instability.

[0052] FDEM simulation methods for rock slope fracturing and instability include:

[0053] S101: Obtain the rock mass mechanical parameters and three-dimensional morphological parameters of the target rock slope.

[0054] Among them, rock mass mechanical parameters can be determined through comprehensive analysis of field geological surveys, indoor rock mechanics tests, and relevant engineering geological data. Rock mass mechanical parameters include: elastic modulus, Poisson's ratio, material density, cohesion, internal friction angle, tensile strength, Type I fracture energy, Type II fracture energy, joint penalty value, normal contact stiffness, tangential contact stiffness, sliding friction angle, and uniaxial compressive strength, etc. These parameters accurately describe the physical and mechanical properties and potential failure behavior of rock materials, and together define the mechanical response of rocks in the process of continuous deformation, crack initiation and propagation, block contact friction, and final failure. They are the basis for constructing numerical models that conform to the actual rock mass characteristics.

[0055] Three-dimensional morphological parameters are a digital representation of the actual geometric shape of the target rock slope, which directly determines the geometric accuracy and boundary conditions of the constructed numerical model. In applications, based on detailed engineering geological mapping, topographic survey data (such as contour maps, digital elevation models DEM), or three-dimensional laser scanning point cloud data, key geometric information such as the overall contour, slope height, slope angle, slope surface morphology, step distribution (such as open-pit mine slopes), and spatial distribution characteristics of potential structural surfaces (such as joints and faults) of the slope can be accurately obtained.

[0056] S102: Based on rock mechanics parameters and three-dimensional morphological parameters, a numerical model of the target rock slope is constructed using FDEM.

[0057] In applications, a continuous-discontinuous coupling method (FDEM) can be used for modeling, ensuring that the model's geometry maintains a 1:1 scale with the actual engineering project to guarantee the realism of stress distribution, deformation characteristics, and instability process simulations. During construction, a geometric outline framework of the target rock slope is established based on precise three-dimensional morphological parameters, and then discretized into a mesh system composed of triangular elements. These triangular elements serve as the basic computational units, and their dimensions must be rationally divided according to the simulation accuracy requirements and potential fracture areas to ensure that the element size is sufficient to capture the expected fracture propagation path.

[0058] To prevent non-physical embedding of fractured rock blocks after slope instability, the contact discrimination code (i1nobf[inopo]) of the mesh nodes corresponding to the slope toe and slope surface boundaries is set to 1, while the value of this attribute for nodes inside the model is set to 0. This defines these boundary nodes as contact detection points, forcing them to participate in contact force calculations in subsequent calculations. This effectively prevents illegal penetration of fractured blocks under gravity, providing a physical basis for simulating macroscopic movements such as block slippage and collisions.

[0059] See Figure 3 and Figure 4 , Figure 3 This is a schematic diagram of the numerical model of the slope. Figure 4 A schematic diagram is provided for the contact point between the slope toe and the slope surface; the slope inclination angle is set to 80°. For example... Figure 4As shown, the contact point setting method between the slope toe and the slope surface is as follows: the contact discrimination code (i1nobf[inopo]) attribute value of the slope toe and slope surface nodes is set to 1, while the i1nobf[inopo] attribute value of other nodes is set to 0. In FDEM simulation, setting the i1nobf[inopo] attribute value of a node to 1 indicates that a contact search needs to be performed on that node in every calculation step, i.e., to determine whether other triangular elements have intruded into its neighboring area. Once an intrusion is detected, the contact force calculation module is triggered to perform the corresponding contact force calculation. Conversely, if the attribute is set to 0, the contact search process for that node is skipped, assuming that no contact will occur, thereby saving computational resources.

[0060] in, Figure 3 The input parameters used in the numerical model of the middle slope are shown in Table 1 below.

[0061] Table 1 Input Parameters

[0062]

[0063] S103: Configure initial conditions for the numerical model and apply initial gravitational acceleration, and configure update conditions when the total kinetic energy of the numerical model drops to a preset value.

[0064] The initial conditions include fixing the bottom boundary, removing the self-constraint of the horizontal boundary, enabling hysteresis damping and viscous damping, and setting the rock cohesion and tensile strength to N times their respective actual values; N>1. The update conditions include fixing the horizontal boundary, disabling hysteresis damping, and setting the rock cohesion and tensile strength to their respective actual values.

[0065] In applications, after the numerical model is built, specific initial conditions need to be configured and an initial gravity field applied. The goal is to make the model reach initial static equilibrium in an artificially enhanced stable state. First, the vertical movement of the bottom boundary of the model is fixed to simulate the constraints of the actual foundation. At the same time, the constraints of the horizontal boundaries on the left and right sides of the model are removed, allowing them to move freely in the horizontal direction to simulate a more realistic far-field ground response and avoid the boundary conditions from unduly restricting the initial stress distribution.

[0066] To efficiently dissipate the kinetic energy oscillations generated when the model is suddenly subjected to gravity, and to promote its rapid and smooth approach to a static equilibrium state, it is necessary to simultaneously activate two damping mechanisms: hysteresis damping and viscous damping. These two damping mechanisms work together to effectively absorb the system's kinetic energy.

[0067] Specifically, the formula for calculating hysteresis damping is:

[0068]

[0069] In the formula, η represents hysteresis damping, m i Let denot i be the mass of grid node i, β be the hysteresis damping coefficient, E be the elastic modulus, and ρ be the material density.

[0070] The formula for calculating viscous damping is:

[0071]

[0072] In the formula, μ represents viscous damping, and h j Let be the side length of triangular element j, E be the elastic modulus, and ρ be the material density.

[0073] The following damping force is applied to the nodes to rapidly dissipate the model's kinetic energy:

[0074] f i =-ηv i

[0075] In the formula, f i Let v be the damping force at node i. i Let be the velocity of node i, and the negative sign indicates that the direction of the damping force is opposite to the direction of the velocity.

[0076] Furthermore, during the initial gravitational acceleration loading stage, the hysteresis damping coefficient can be set to a specific optimal value, namely the critical hysteresis damping coefficient, which can suppress system vibration to the greatest extent. The critical hysteresis damping coefficient can be obtained according to the method described in the invention patent "Numerical Simulation Method for Instability and Disaster Process of Tunnel Surrounding Rock Fracturing and Swelling." Figure 3 In the numerical model of the slope, the critical damping coefficient β is set to 0.019.

[0077] During the initial gravitational acceleration loading phase, the key is to temporarily and significantly enhance the rock material's resistance to failure. Specifically, the rock's cohesion (resistance to shear failure) and tensile strength (resistance to tensile failure) are both set to N (e.g., 1000) times their actual engineering values. This ensures that no cracking or damage occurs within the rock during the entire process of establishing the initial stress field in the model, thus obtaining a complete and undamaged initial stress state, laying a reliable foundation for subsequent realistic simulation of the failure process.

[0078] The initial gravitational acceleration (standard value -9.8 m / s²) 2 The boundary conditions (vertically downwards) are applied to all nodes of the model in one computational time step. Subsequently, the model undergoes computational evolution under the combined effects of the set boundary conditions, the activated dual damping mechanism, and the strengthened material strength.

[0079] During the initial gravitational acceleration loading phase, the bottom boundary of the model is fixed in the vertical direction, while it is free in the horizontal direction, as shown below. Figure 5 As shown; once the model reaches equilibrium, the left and right boundaries are fixed in the horizontal direction, while remaining free in the vertical direction, as... Figure 6 As shown.

[0080] The core criterion for determining whether a numerical model has reached its initial static equilibrium state is the model's total kinetic energy. When the model's total kinetic energy decreases and stabilizes below a pre-set, very small threshold, it is considered that the motion within the system has essentially ceased, and the stress has reached equilibrium. This pre-set kinetic energy threshold can be adjusted according to the actual size and complexity of the model.

[0081] like Figure 7 As shown, the total kinetic energy of the model is less than the preset value:

[0082]

[0083] In the formula: E k Where N is the total kinetic energy of the model, and N is the total number of nodes. The specific preset value is adjusted according to the size of the model. For example, using... Figure 3 Taking the slope numerical model as an example, the preset value of kinetic energy 1 can be set to 0.4kJ.

[0084] When the total kinetic energy of the numerical model drops to the preset value, it can be confirmed that it has reached initial equilibrium. The model configuration then needs to be updated immediately to suit the simulation of subsequent gradual failure and instability. The update operations mainly include: changing the boundary constraints, changing the previously free left and right boundaries in the horizontal direction to fixed boundaries in the horizontal direction (limiting the overall lateral displacement of the model), while allowing freedom in the vertical direction; disabling the hysteresis damping mechanism, no longer using this damping; and restoring the cohesion and tensile strength of the rock from the previously artificially inflated high values ​​(1000 times the true value) to their actual engineering values.

[0085] At this point, the numerical model has completed the transformation from an artificially reinforced stable state to a real physical and mechanical state, and is now capable of realistically simulating the entire process of rock initiation, expansion, and eventual macroscopic slippage and instability in subsequent steps.

[0086] S104: After the update condition configuration is completed, increase the gravitational acceleration step by step until the change in total kinetic energy meets the preset condition and then stop, and record the final gravitational acceleration.

[0087] The preset condition is that the total kinetic energy of the current time step is greater than the total kinetic energy of the previous 10,000 time steps, and the difference is greater than a preset threshold.

[0088] After the configuration conditions are updated, the model enters the gravity acceleration loading phase. The core of this phase is to simulate the gradual depletion of the slope's safety reserve by progressively increasing the gravity field. Specifically, a discretized time-step control method is adopted, automatically making a slight increase to the current gravity acceleration at the end of each calculation time step. This discrete, step-by-step loading method ensures both precise controllability of the loading process and avoids the numerical instability that may result from continuous loading.

[0089] Specifically, when increasing gravitational acceleration step by step, the following formula is used:

[0090] g = g0 - 0.1 × (T - T0) / ΔT and T > T0

[0091] In the formula, g is the current gravitational acceleration, g0 is the initial gravitational acceleration, T is the current calculation time step, T0 is the calculation time step when the total kinetic energy drops to the preset value, and ΔT is the gravitational loading rate.

[0092] As the gravitational acceleration continues to accumulate and increase, the stress state within the model is constantly adjusted. Under the true strength parameters (which have been restored to actual values), the rock material begins to undergo a progressive damage process. Microcracks first initiate in stress concentration areas (such as near the toe of the slope or structural surfaces), and then steadily expand along weak paths, gradually forming a through-type potential slip surface. During this stage, the dynamic response of the model is relatively stable, and the total kinetic energy remains at a low level of fluctuation.

[0093] The determination of slope instability relies on the monitoring of abrupt changes in the model's total kinetic energy. The total kinetic energy value at the current time step is calculated and tracked in real time, and dynamically compared with the average total kinetic energy value at earlier historical moments (such as the previous 10,000 time steps). When the current total kinetic energy value is detected to be significantly higher than the historical average, and the magnitude of the exceedance reaches a preset critical threshold, the instability criterion is triggered.

[0094] Specifically, the criterion for a sudden change in the model's kinetic energy is as follows:

[0095] E k,t -E k,t-10000 > Preset value 2, and T > T0

[0096] In the formula, E k,t E represents the model kinetic energy at the current time step. k,t-1000 This represents the model's kinetic energy over the first 10,000 time steps. Regarding the above... Figure 3 In the numerical model of the slope, the preset value 2 can be set to 0.2 kJ.

[0097] This sudden increase in kinetic energy is a direct indicator of catastrophic damage to the slope: the potential slip surface is completely connected, the rock mass structure loses its overall stability, and the fractured blocks begin to slide and collide violently along the slip surface, resulting in a step increase in the total kinetic energy of the model.

[0098] When the aforementioned kinetic energy mutation condition (preset condition) is detected and met, the further increase of gravitational acceleration is automatically terminated. The gravitational acceleration value experienced by the model at this moment is recorded; this value is the final gravitational acceleration that leads to slope instability and failure. This value not only indicates the ultimate bearing capacity of the slope but is also the core basis for calculating the safety factor. By capturing the precise moment of the kinetic energy mutation to determine instability, this method can objectively reflect the dynamic critical point of the slope from stability to instability, avoiding errors caused by subjective human judgment.

[0099] S105: Determine the safety factor of the target rock slope based on the final gravitational acceleration.

[0100] Based on the recorded final gravitational acceleration value, the stability quantification index of the target rock slope—the safety factor—can be directly calculated. The physical meaning of the safety factor characterizes the proportional relationship between the actual anti-sliding capacity of the slope under real geological and mechanical conditions and the sliding driving force under its current stress state; it is a core parameter for engineering safety assessment. Specifically, it is the absolute value of the critical gravitational acceleration (i.e., the final gravitational acceleration value) that will lead to slope instability and failure, divided by the absolute value of standard Earth's gravitational acceleration. Standard gravitational acceleration is taken as the initially applied constant value, directed vertically downwards.

[0101] The method for determining the slope safety factor SF is as follows: when the model's kinetic energy undergoes a significant abrupt change, such as... Figure 8 As shown, the safety factor is: [To be continued, the acceleration due to gravity is stopped].

[0102]

[0103] In the formula, SF represents the safety factor, and g f g is the final gravitational acceleration, and g0 is the initial gravitational acceleration.

[0104] Gravity loading process as follows Figure 9 As shown, the simulation results of slope instability and failure are as follows: Figure 10 As shown; continue with Figure 3 Taking the slope numerical model in the example, the final calculation can be obtained. Figure 3 The safety factor SF of the numerical model for the middle slope is 1.66.

[0105] In practice, the calculated safety factor has significant engineering value. It not only provides a quantitative evaluation index for slope stability, helping engineers determine the level of engineering risk, but also guides the targeted design of subsequent reinforcement measures. For example, areas with a safety factor close to the critical value of 1 will indicate areas requiring focused reinforcement.

[0106] Corresponding to the aforementioned application function implementation method embodiments, the present invention also provides an FDEM simulation system for rock slope fracturing and instability and corresponding embodiments.

[0107] Please see Figure 11 , Figure 11 This is a schematic diagram of the module structure of an FDEM simulation system for rock slope fracturing and instability.

[0108] An FDEM simulation system for rock slope fracturing and instability includes:

[0109] Data acquisition unit 11 is used to acquire the rock mass mechanical parameters and three-dimensional morphological parameters of the target rock slope;

[0110] Model building unit 12 is used to construct a numerical model of the target rock slope using FDEM based on rock mechanics parameters and three-dimensional morphological parameters.

[0111] Simulation unit 13 is used for:

[0112] Configure initial conditions for the numerical model and apply an initial gravitational acceleration; and configure update conditions when the total kinetic energy of the numerical model drops to a preset value.

[0113] After the condition configuration is updated, the gravitational acceleration is increased step by step over time until the change in total kinetic energy meets the preset condition and then it stops. The final gravitational acceleration is then recorded.

[0114] The safety factor of the target rock slope is determined based on the final gravitational acceleration.

[0115] The initial conditions include fixing the bottom boundary, removing the self-constraint of the horizontal boundary, enabling hysteresis damping and viscous damping, and setting the rock cohesion and tensile strength to N times their respective actual values; N>1. The update conditions include fixing the horizontal boundary, disabling hysteresis damping, and setting the rock cohesion and tensile strength to their respective actual values.

[0116] Regarding the system in the above embodiments, the specific manner in which each unit module performs operations has been described in detail in the embodiments related to the method, and will not be elaborated further here.

[0117] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for FDEM simulation of rock slope fracturing and instability, characterized in that, include: Obtain the rock mass mechanical parameters and three-dimensional morphological parameters of the target rock slope; Based on the rock mass mechanical parameters and three-dimensional morphological parameters, a numerical model of the target rock slope was constructed using FDEM. Initial conditions are configured for the numerical model and an initial gravitational acceleration is applied. When the total kinetic energy of the numerical model drops to a preset value, update conditions are configured. After the update conditions are configured, the gravitational acceleration is increased step by step over time until the change in total kinetic energy meets the preset conditions, and the final gravitational acceleration is recorded. The safety factor of the target rock slope is determined based on the final gravitational acceleration. The initial conditions include fixing the bottom boundary, removing the horizontal boundary self-constraint, enabling hysteresis damping and viscous damping, and setting the rock cohesion and tensile strength to N times their respective actual values; N>1; the update conditions include fixing the horizontal boundary, disabling the hysteresis damping, and setting the rock cohesion and tensile strength to their respective actual values.

2. The FDEM simulation method for rock slope fracturing and instability according to claim 1, characterized in that, In the numerical model, the contact discrimination code attribute value of the grid nodes corresponding to the slope toe and slope surface is set to 1, and the contact discrimination code attribute value of the remaining grid nodes is set to 0.

3. The FDEM simulation method for rock slope fracturing and instability according to claim 1, characterized in that, The formula for calculating the hysteresis damping is as follows: In the formula, η represents hysteresis damping, m i Let denot i be the mass of grid node i, β be the hysteresis damping coefficient, E be the elastic modulus, and ρ be the material density.

4. The FDEM simulation method for rock slope fracturing and instability according to claim 1, characterized in that, The formula for calculating the viscous damping is: In the formula, μ represents viscous damping, and h j Let be the side length of triangular element j, E be the elastic modulus, and ρ be the material density.

5. The FDEM simulation method for rock slope fracturing and instability according to claim 3, characterized in that, During the application of the initial gravitational acceleration, the hysteresis damping coefficient is set as the critical hysteresis damping coefficient.

6. The FDEM simulation method for rock slope fracturing and instability according to claim 1, characterized in that, When increasing the gravitational acceleration step by step over time, the following formula is used: g = g0 - 0.1 × (T - T0) / ΔT and T > T0 In the formula, g is the current gravitational acceleration, g0 is the initial gravitational acceleration, T is the current calculation time step, T0 is the calculation time step when the total kinetic energy drops to the preset value, and ΔT is the gravitational loading rate.

7. The FDEM simulation method for rock slope fracturing and instability according to claim 1, characterized in that, The preset condition is that the total kinetic energy of the current time step is greater than the total kinetic energy of the previous 10,000 time steps, and the difference is greater than a preset threshold.

8. The FDEM simulation method for rock slope fracturing and instability according to claim 1, characterized in that, The formula for calculating the safety factor is: In the formula, SF represents the safety factor, and g f g is the final gravitational acceleration, and g0 is the initial gravitational acceleration.

9. An FDEM simulation system for rock slope fracturing and instability, characterized in that, include: The data acquisition unit is used to acquire the rock mass mechanical parameters and three-dimensional morphological parameters of the target rock slope; The model building unit is used to construct a numerical model of the target rock slope using FDEM based on the rock mass mechanical parameters and three-dimensional morphological parameters. Simulation unit, used for: Initial conditions are configured for the numerical model and an initial gravitational acceleration is applied. When the total kinetic energy of the numerical model drops to a preset value, update conditions are configured. After the update conditions are configured, the gravitational acceleration is increased step by step over time until the change in total kinetic energy meets the preset conditions, and the final gravitational acceleration is recorded. The safety factor of the target rock slope is determined based on the final gravitational acceleration. The initial conditions include fixing the bottom boundary, removing the horizontal boundary self-constraint, enabling hysteresis damping and viscous damping, and setting the rock cohesion and tensile strength to N times their respective actual values; N>1; the update conditions include fixing the horizontal boundary, disabling the hysteresis damping, and setting the rock cohesion and tensile strength to their respective actual values.

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