Energy dissipation hot spot-based simulation method for dynamic failure of rock and soil mass

Abstract

The application provides a rock-soil body dynamic damage simulation method based on an energy dissipation hot spot, comprising the following steps: constructing a near-field dynamics and discrete element coupling model for describing the mechanical state of particles under the action of an earthquake; calculating the force information of the particles; calculating the particle velocity and displacement according to the force information of the particles, and analyzing the damage process according to the energy dissipation hot spot to obtain a calculation result; and outputting the calculation result and drawing a cloud chart. The application constructs a near-field dynamics and discrete element coupling model for the slope instability phenomenon under the action of an earthquake, and applies the model to a discrete element software to form a method for describing the deformation and damage characteristics of a slope under the disturbance of an earthquake; the application analyzes the shape and characteristics of a sliding surface through the rock-soil body dynamic damage simulation method based on the energy dissipation hot spot, reflects the process of slope instability under the action of an earthquake, improves the prediction accuracy and the recognition accuracy of the sliding surface, and has a significant advantage in the prediction of the progressive damage of rock-soil bodies and sudden landslides.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering technology, and in particular to a method for simulating the dynamic failure of geotechnical bodies based on energy dissipation heat dissipation points using discrete element method coupled with near-field dynamics. Background Technology

[0002] The discrete element method is well-suited for problems in discontinuous media and is relatively mature in studying large displacement deformation and nonlinear relationships. It has been widely applied in various fields such as geotechnical engineering, structural geology, geophysics, and mining engineering, and has achieved many important results.

[0003] In previous studies, the discrete element method (DEM) has been commonly used to simulate the failure of soil and rock masses. The DEM can effectively reflect large deformation and fracture phenomena in simulations of working conditions such as earthquakes. However, traditional DEM contact models are mostly applicable to static tests and lack accuracy in dynamic failure scenarios.

[0004] Building upon this foundation, perifield dynamics can be introduced to simulate the failure process of soil and rock masses under dynamic conditions. Perifield dynamics naturally supports wave propagation and nonlocal interactions, enabling a more realistic simulation of seismic wave propagation in soil and rock masses and the resulting long-range force effects. The discrete element method (DEM) accurately characterizes the particle-scale dynamic response, including inertial effects and frictional heat generation. Together, these two methods can reveal the spatial distribution patterns of seismic load energy accumulation and release. Introducing perifield dynamics theory can more comprehensively reveal the physical mechanisms of failure under seismic loads. In recent years, research has attempted to couple perifield dynamics with the DEM for granular system simulation, such as the PD-DEM-IB-CLBM framework emphasizing material failure and particle impact, and neural network constitutive models based on volume-constrained and state-based perifield dynamics theory and discrete element data.

[0005] However, existing methods mostly focus on near-field modeling of particle erosion, compression, or elastic response, while lacking system-coupled simulation of slip failure mechanisms in highly dynamic processes such as earthquake-induced landslides. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for simulating the dynamic failure of rock and soil masses based on energy dissipation and heat dissipation points. This method solves the technical problem that existing earthquake disturbance simulation methods rely on empirical judgments based on static calculations, which cannot meet the needs of scenarios involving dynamic disturbances and energy evolution analysis.

[0007] The technical solution of this invention is: a method for simulating the dynamic failure of rock and soil based on energy dissipation and heat dissipation points, comprising the following steps:

[0008] S1) Construct a near-field dynamics and discrete element coupled model to describe the mechanical state of particles under seismic action;

[0009] S2) Based on the discrete element method, input simulation parameters and conditions into the coupled model and determine whether the time step has been reached; if the time step has not been reached, calculate the force information of the particles; if the time step has been reached, directly output the calculation results and draw a contour map.

[0010] S3) Traverse all particles, calculate particle velocity and displacement based on particle force information, and analyze the failure process based on energy dissipation and heat dissipation points to obtain calculation results; output the calculation results and draw a cloud map.

[0011] Preferably, in step S1), the near-field dynamics and discrete element coupled model is constructed, which specifically includes the following steps:

[0012] S11) Detect whether the particles are in the neighborhood within the generated particle model. If they are in the neighborhood, generate a near-field dynamic bond.

[0013] S12) Set the relevant parameters of the coupling model;

[0014] S13) Apply a near-field dynamics calculation coupling model to the generated bonds.

[0015] Preferably, in step S2), it is determined whether the time step has been reached; if the time step has not been reached, the force information of the particles is calculated; specifically, the following steps are included:

[0016] S21) Initialize the parameters of the near-field dynamics and discrete element coupling model, input simulation parameters, and determine the size of the coupling model;

[0017] S22) Determine the coordinates of discrete particles;

[0018] S23) Number the discrete particles and input the corresponding data information;

[0019] S24) Apply initial boundary conditions and determine the time step;

[0020] S25) Input seismic waves, calculate particle force information according to the calculation rules of near-field dynamics, and analyze the dynamic failure process of rock and soil based on energy dissipation and heat dissipation points;

[0021] S26) Output energy field cloud map and analyze the failure mode of the sliding surface.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. This invention constructs a near-field dynamics and discrete element coupled model for slope instability under seismic loading, and applies it to discrete element software to form a method for describing the deformation and failure characteristics of slopes under seismic disturbance.

[0024] 2. This invention uses a dynamic failure simulation method for soil and rock masses based on energy dissipation and heat dissipation points to analyze the shape and characteristics of the sliding surface, reflect the process of slope instability under seismic loads, improve the prediction accuracy and sliding surface identification accuracy, and has significant advantages in the prediction of progressive failure of soil and rock masses and sudden landslides. Attached Figure Description

[0025] Figure 1 This is a schematic flowchart of the method of the present invention;

[0026] Figure 2 This is a schematic diagram of the near-field dynamics principle in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of near-field dynamics bond states in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the slope instability calculation model of Nigawa slope under KOBE seismic load in an embodiment of the present invention;

[0029] Figure 5 The above is a time history curve of seismic acceleration in an embodiment of the present invention;

[0030] Figure 6 This is a before-and-after comparison image of a landslide in an embodiment of the present invention;

[0031] Figure 7 This is an energy field cloud map of the landslide process in an embodiment of the present invention. Detailed Implementation

[0032] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0033] like Figure 1 As shown in the figure, this embodiment provides a method for simulating the dynamic failure of rock and soil based on energy dissipation and heat dissipation points, including the following steps:

[0034] S1) Construct a near-field dynamics and discrete element coupled model to describe the mechanical state of particles under seismic loading; specifically including the following steps:

[0035] S11) Detect whether the particles are in the neighborhood within the generated particle model. If they are in the neighborhood, generate a near-field dynamic bond.

[0036] S12) Set the relevant parameters of the coupled model, including neighborhood radius, computational boundary radius, cohesion, normal-tangential stiffness ratio, and damping coefficient;

[0037] S13) Apply a near-field dynamics calculation coupling model to the generated bonds, and the calculation method is as follows:

[0038] In this embodiment, the function between bond force and bond is obtained through... Calculation, where T The vector state of bond forces. t It is a scalar state representing the magnitude of the force. As a vector state of force along the bond deformation direction, through bond deformation morphology Y <ξ> represents

[0039] For the scalar state of the magnitude of the force t , can be represented as: Where c is a coefficient, s is the bond elongation, and e is a parameter that controls whether the bond breaks.

[0040] S2) Based on the discrete element method, input simulation parameters and conditions into the coupled model to simulate the dynamic failure of the soil and rock mass; determine whether the simulation time step has been reached; if the simulation time step has not been reached, calculate the particle force information; if the time step has been reached, directly output the calculation results and draw a contour map.

[0041] In this embodiment, it is determined whether the simulation time step has been reached; if the simulation time step has not been reached, the force information of the particles is calculated; specifically, the following steps are included:

[0042] S21) Initialize the parameters of the near-field dynamics and discrete element coupled model, input simulation parameters, and determine the model size; in this embodiment, the input simulation parameters include neighborhood radius, calculated boundary radius, cohesion, normal-tangential stiffness ratio, damping coefficient, critical elongation, boundary conditions, etc.

[0043] S22) Determine the coordinates of discrete particles;

[0044] In this embodiment, the coordinates of discrete particles are determined based on the initial generation coordinates of the particles and the displacement information within each time step.

[0045] S23) Number the discrete particles and input the corresponding data information;

[0046] In this embodiment, the input data information includes the particle's coordinates, radius, velocity, force, torque, bonding state, and number of particles in the neighborhood;

[0047] S24) Apply initial boundary conditions and determine the time step;

[0048] In this embodiment, the bottom and left and right sides of the model are viscoelastic boundaries, while the rest are free boundaries. Too short a time step will result in excessive instantaneous displacement of the particles, while too long a time step will result in low computational efficiency. Therefore, it is necessary to select a suitable time step value.

[0049] S25) Input seismic waves and calculate particle force information according to the calculation rules of near-field dynamics; analyze the dynamic failure process of rock and soil based on energy dissipation heat dissipation points; analyze the failure concentration area of ​​rock and soil based on the calculated energy magnitude;

[0050] S26) Output energy field cloud map and analyze the failure mode of the sliding surface.

[0051] S3) Traverse all particles, calculate particle velocity and displacement based on particle force information, and analyze the failure process based on energy dissipation and heat dissipation points to obtain calculation results; output the calculation results and draw a cloud map.

[0052] In this embodiment, the calculation method for calculating the force information of particles based on the calculation rules of near-field dynamics is as follows:

[0053] Near-field dynamics model such as Figure 2 As shown, in the near-field dynamics model, the continuum is discretized into a finite number of material points with mass, volume, and density. For each individual particle, its surrounding region is considered its neighborhood. Other particles within this neighborhood will interact with the particle, i.e., form bonds. A schematic diagram of the bond states is shown below. Figure 3 As shown, the function relating bond force and bond is expressed as:

[0054]

[0055] In the formula, T The vector state of bond forces. t It is a scalar state representing the magnitude of the force. As a vector state of force along the bond deformation direction, through bond deformation morphology Y <ξ> represents

[0056] For the scalar state of the magnitude of the force t Its expression is:

[0057]

[0058] In the formula, c is a coefficient; s is the elongation of the bond; and e is a parameter that controls whether the bond breaks.

[0059] in:

[0060]

[0061] In the formula, X <ξ> represents the unit vector state; t represents the current time; t′ represents any past time between the initial time and the current time; ξ represents the bond length; s0 represents the bond length threshold.

[0062] In this embodiment, the equilibrium equation of motion for near-field dynamics is expressed as:

[0063] ρü(t,t)=∫{ T [x,t]<x′-x> - T [x′,t]<x-x′>}dV x′ +b(x,t);

[0064] In the formula, ρ is density; u is displacement; b is body density; and the force state is... T It is a function of both bond length ξ and position x and time t; x and x′ represent the coordinates of two different points in space; ü represents acceleration; dV x′ Let x' represent the volume element at point x′.

[0065] In this embodiment, the dynamic failure process of rock and soil is analyzed based on energy dissipation and heat dissipation points; the details are as follows:

[0066] Total energy E during the simulation process D,total Including kinetic energy E k,total Total frictional energy E f,total Energy consumption E for PD bond deformation PD,elastic Energy consumption E for PD bond breaking PD,fracture ,Right now:

[0067] E D,total =E k,total +E f,total +E PD,elastic +E PD,fracture .

[0068] In this embodiment, the kinetic energy of the particle is calculated based on its velocity and displacement, and the kinetic energy E is... k,total for:

[0069]

[0070] In the formula, N is the number of particles; m i v is the mass of particle i; i I is the average velocity of particle i; i Let ω be the moment of inertia of particle i; i Let be the angular velocity of particle i.

[0071] The average velocity v of particle i i It is subject to the combined effects of static and dynamic bonding, namely:

[0072]

[0073] In the formula, The effect of static adhesion on the velocity of particle i; This represents the velocity effect of kinetic adhesion on particle i.

[0074] The effect of kinetic adhesion on the velocity of particle i Represented as:

[0075]

[0076] In the formula, H i Let be the set of all particles in the neighborhood of particle i; c is the bond stiffness; ξ ij Let η be the bond vector between particle i and particle j; ij Let be the displacement difference vector between particle i and particle j.

[0077] For the corresponding particles in the bond, frictional energy The work originating from the sliding friction between particles, namely:

[0078]

[0079] In the formula, μ is the coefficient of sliding friction between particles; This refers to the normal force between particles; This represents the tangential relative displacement increment between particles;

[0080] set up Let be the tangential displacement increment within a certain time step, then the frictional energy within each time step Δt is... for:

[0081]

[0082] Therefore, the total frictional energy E f,total The calculation expression is:

[0083]

[0084] In the formula, contacts(i) represents the set of all contact bonds.

[0085] In this embodiment, the interparticle normal force It includes different components of static adhesion and PD bond forces, namely:

[0086]

[0087] In the formula, The normal force generated by static bonding; n1 represents the bond force generated by dynamic adhesion; n2 represents the projection of the PD bond force onto the contact normal. These are near-field dynamic bond forces.

[0088] The energy dissipation E of PD bond deformation PD,elastic Represented as:

[0089]

[0090] In the formula, The deformation energy density for each PD bond; S ij ξ represents the bond area, which is the average of the areas of the two particles; C represents the bond stiffness; ij Let η be the bond vector between particle i and particle j; ij Let be the displacement difference vector between particle i and particle j.

[0091] The energy consumption E for PD bond breaking is described. PD,fracture Represented as:

[0092]

[0093] In the formula, N F This represents the number of broken bonds.

[0094] In this embodiment, the particle velocity V is calculated based on the force results of the particle:

[0095]

[0096] in, t d is a scalar state representing the magnitude of the bond force. m Here, Δt is the damping coefficient, Δt is the unit time step, and m is the unit mass of the particle; the relative particle displacement Δs at each time step is obtained by multiplying the particle velocity by the unit time step.

[0097] Δs = VΔt.

[0098] By plotting energy dissipation points as cloud maps, it is easy to observe the generation of sliding surfaces and the movement of landslide bodies in slope models. The analysis of energy dissipation can also naturally capture the process from continuous fracture to discrete particle flow. It also plays a role in the complex failure mode of landslides involving rock mass fracturing and debris mixing. It can more realistically simulate the propagation of seismic waves in rock and soil and the long-range force effects they cause, reveal the spatial distribution law of energy accumulation and release under seismic load, and optimize the prediction of progressive failure of rock and soil and sudden landslides.

[0099] Using the Great Hanshin Earthquake that occurred on January 17, 1995 as the simulation object, such as Figure 4 The image shows a simplified model of the Nigawa slope. The upper surface of the model is a free boundary, while the other boundaries are viscoelastic. A gravity field is applied, and KOBE seismic waves are input from the bottom of the model to observe the slope's failure characteristics.

[0100] The maximum vertical acceleration of the KOBE seismic wave can reach 0.426g, accounting for 89% of the total horizontal acceleration (0.476g), far exceeding the proportion used in conventional design. Figure 5The KOBE seismic wave shown contains acceleration waveforms in three directions: north-south, east-west, and vertical. This measured record clearly demonstrates a significant increase in vertical ground motion near the epicenter, indicating that the effect of vertical acceleration must be considered in landslide failure analysis. In particular, its coupling effect with the horizontal component may significantly deepen the failure surface, thereby reducing the slope safety factor. The Nigawa slope is distributed along a northeast-southwest direction. In the numerical simulation, vertical seismic waves were input vertically from the bottom of the model, while east-west seismic waves were input horizontally from the right side of the bottom of the model.

[0101] like Figure 6 As shown, the changes in particle distribution on the slope before and after the earthquake are significant. Light blue represents the slope outline before the landslide, and dark blue represents the particle location after the landslide. The comparison reveals that particles in the upper and middle parts of the slope underwent significant sliding under the earthquake, with the slippage mainly concentrated in the shallow structure. The remaining parts of the slope remained relatively stable, revealing the extent and deformation trend of the landslide.

[0102] like Figure 7 As shown in the energy field cloud map, the sliding surface is a concentrated area of ​​frictional energy, bond fracture energy, and bond deformation energy. Furthermore, the kinetic energy of the landslide body is often slightly greater than in other areas. Therefore, the location and shape of the sliding surface can be determined based on the energy field cloud map. The sliding surface, marked with a red line, represents a typical shallow arc-shaped shear failure path. The sliding surface originates in the middle of the slope, penetrates the shallow soil layer, and emerges at the toe, indicating that the sliding is mainly concentrated in the surface loose particle area and has not penetrated into the stable bedrock layer. The failure surface exhibits a downward curving trend, consistent with the "shear-slip" characteristics of slope instability under seismic loading, and the sliding mass undergoes overall displacement along this curved surface. The morphology of the sliding surface in the figure reflects the consistency between the simulation results and the mechanical judgment surface, verifying that this landslide belongs to the shallow sliding failure type induced by seismic disturbance.

[0103] The embodiments and descriptions above are merely illustrative of the principles and preferred embodiments of the present invention. Various changes and modifications may be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method for simulating dynamic failure of rock and soil masses based on energy dissipation and heat dissipation points, characterized in that, Includes the following steps: S1) Construct a near-field dynamics and discrete element coupled model to describe the mechanical state of particles under seismic loading; specifically including the following steps: S11) Detect whether the particles are in the neighborhood within the generated particle model. If they are in the neighborhood, generate a near-field dynamic bond. The functional expression between bond force and bond is: ； In the formula, The vector state of bond forces. It is a scalar state representing the magnitude of the force. As a vector state of force along the bond deformation direction, through bond deformation morphology Represented as ; For the scalar state of the magnitude of the force Its expression is: ； In the formula, For coefficients; Elongation of the bond; This is a parameter that controls whether the key breaks; in: ； ； In the formula, Represents a unit vector state; Indicates the current moment; This represents any past moment between the initial moment and the current moment; Indicates bond length; Indicates the bond length threshold; S12) Set the relevant parameters of the coupling model; S13) Apply a near-field dynamics calculation coupling model to the generated bonds; S2) Based on the discrete element method, input simulation parameters and conditions into the coupled model and determine whether the time step has been reached; if the time step has not been reached, calculate the force information of the particles; if the time step has been reached, directly output the calculation results and draw a contour map. Determine if the time step has been reached; if not, calculate the force information of the particles; specifically, this includes the following steps: S21) Initialize the parameters of the near-field dynamics and discrete element coupling model, input simulation parameters, and determine the size of the coupling model; S22) Determine the coordinates of discrete particles; S23) Number the discrete particles and input the corresponding data information; S24) Apply initial boundary conditions and determine the time step; S25) Input seismic waves, calculate particle force information according to the calculation rules of near-field dynamics, and analyze the dynamic failure process of rock and soil based on energy dissipation and heat dissipation points; S26) Output energy field cloud map and analyze the failure mode of the sliding surface; S3) Traverse all particles, calculate particle velocity and displacement based on particle force information, and analyze the failure process based on energy dissipation and heat dissipation points to obtain calculation results; output the calculation results and draw a cloud map.

2. The method for simulating dynamic failure of soil and rock mass based on energy dissipation and heat dissipation points according to claim 1, characterized in that: Total energy during the simulation process Including kinetic energy Total frictional energy Energy consumption due to PD bond deformation Energy consumption from PD bond breakage ,Right now: 。 3. The method for simulating dynamic failure of soil and rock mass based on energy dissipation and heat dissipation points according to claim 2, characterized in that: The kinetic energy for: ； In the formula, This refers to the number of particles; Particles The quality; Particles The average speed; Particles Moment of inertia; Particles angular velocity.

4. The method for simulating dynamic failure of soil and rock mass based on energy dissipation heat dissipation point according to claim 3, characterized in that: The particles average speed It is subject to the combined effects of static and dynamic bonding, namely: ； In the formula, For static bonding of particles The resulting speed effect; For kinetic adhesion of particles The resulting speed effect; Kinetic adhesion to particles The speed effect Represented as: ； ； In the formula, Particles The set of all particles in the neighborhood of ; For key stiffness; Particles and granules The key vector; Particles and granules The displacement difference vector.

5. The method for simulating dynamic failure of soil and rock mass based on energy dissipation and heat dissipation points according to claim 4, characterized in that: For the corresponding particles in the bond, frictional energy The work originating from the sliding friction between particles, namely: ； In the formula, The coefficient of sliding friction between particles; This refers to the normal force between particles; This represents the tangential relative displacement increment between particles; The interparticle normal force It includes different components of static adhesion and PD bond forces, namely: ； ； In the formula, The normal force generated by static bonding; Bond forces generated by dynamic adhesion; 1 represents the projection of the PD bond force onto the contact normal; For near-field dynamic bond forces; set up Let be the internal tangential displacement increment at a certain time step, then each time step Internal frictional energy for: ； Therefore, the total frictional energy The calculation expression is: ； In the formula, This represents the set of all contact bonds.

6. The method for simulating dynamic failure of soil and rock mass based on energy dissipation and heat dissipation points according to claim 5, characterized in that: The energy consumption of PD bond deformation Represented as: ； ； In the formula, The deformation energy density for each PD bond; The area of ​​the bond is the average of the areas of the two particles. For key stiffness; Particles and granules The key vector; Particles and granules The displacement difference vector; Particles The set of all particles in the neighborhood of ; This refers to the number of particles; The energy consumption of PD bond breaking Represented as: ； In the formula, This represents the number of broken bonds.

7. The method for simulating dynamic failure of rock and soil based on energy dissipation and heat dissipation points according to claim 1, characterized in that: In step S3), the particle velocity is calculated based on the force results of the particles. : in, It is a scalar state representing the magnitude of the bond force. The damping coefficient is... For a unit time step, Per unit mass of particle; relative particle displacement at each time step The result is obtained by multiplying the particle velocity by the unit time step: 。

Images