Rock-soil body dynamic damage simulation method based on energy dissipation hot spots

Abstract

The invention provides a rock-soil body dynamic failure simulation method based on energy dissipation hot spots. The rock-soil body dynamic failure simulation method comprises the steps that a near-field dynamics and discrete element coupling model used for describing the mechanical state of particles under the earthquake action is constructed; calculating particle stress information; calculating the particle speed and displacement according to the particle stress information, and analyzing the damage process according to the energy dissipation hot spots to obtain a calculation result; and outputting a calculation result and drawing a cloud picture. According to the method, a near-field dynamics and discrete element coupling model is constructed for the slope instability phenomenon under the earthquake action and is applied to discrete element software, and a method for describing deformation and damage characteristics of a slope under earthquake disturbance is formed; according to the rock-soil body dynamic failure simulation method based on the energy dissipation hot spots, the shape and characteristics of the sliding surface are analyzed, the slope instability process under the earthquake load is reflected, the prediction precision and the sliding surface recognition accuracy are improved, and the rock-soil body dynamic failure simulation method has remarkable advantages in prediction of rock-soil body progressive failure and sudden landslide.

Description

Technical Field

[0001] The present invention relates to the field of geotechnical engineering technology, and in particular to a method for simulating dynamic failure of geotechnical bodies based on energy dissipation heat points by coupling discrete elements with peridynamics. Background Art

[0002] The discrete element method has good adaptability to discontinuous medium problems and is relatively mature in studying large displacement deformation and nonlinear relationships. It is widely used in various fields such as geotechnical engineering, structural geology, geophysics, mining engineering, and has achieved many important results.

[0003] Previous studies have often used the discrete element method (DEM) to simulate the failure of rock and soil. While DEM can effectively reflect large deformations and fractures in simulations of conditions such as earthquakes, traditional DEM contact models are primarily suitable for static testing and lack accuracy in dynamic failure simulations.

[0004] On this basis, the destruction process of rock and soil under dynamic conditions can be simulated by introducing peridynamics. Peridynamics naturally supports wave propagation and non-local interactions, and can more realistically simulate the propagation of seismic waves in rock and soil and the long-range force effects it induces; the discrete element method accurately describes the dynamic response of the particle scale, including inertial effects and frictional heating, and the two can work together to reveal the spatial distribution of seismic load energy accumulation and release. The introduction of peridynamic theory can more completely reveal the physical mechanism of destruction under seismic loads. In recent years, studies have attempted to couple peridynamics with discrete element methods for the simulation of particle systems, such as the PD-DEM-IB-CLBM framework that emphasizes material failure and particle impact, and the neural network constitutive model based on volume constraints, state-type peridynamic theory, and discrete element data.

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

[0006] In response to the shortcomings of the existing technology, the present invention provides a method for simulating dynamic failure of rock and soil based on energy dissipation heat points to solve the technical problem that the existing seismic disturbance simulation method relies on empirical judgment of static calculations and cannot meet the scenario requirements of dynamic disturbance and energy evolution analysis.

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

[0008] S1) Construct a peridynamics and discrete element coupled model to describe the mechanical state of particles under earthquake action;

[0009] S2) Based on the discrete element method, input simulation parameters and conditions into the coupling model to determine whether the time step has been reached; if the 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 cloud map;

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

[0011] Preferably, in step S1), constructing a peridynamics and discrete element coupling model specifically includes the following steps:

[0012] S11), detecting whether the particle is in the neighborhood within the generated particle model, and if so, generating a peridynamic bond;

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

[0014] S13), applying a peridynamic calculation coupling model to the generated bonds.

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

[0016] S21), initializing the parameters of the peridynamics and discrete element coupling model, inputting simulation parameters, and determining the size of the coupling model;

[0017] S22), determining the coordinates of discrete particles;

[0018] S23), numbering the discrete particles and inputting corresponding data information;

[0019] S24), applying initial boundary conditions and determining the time step;

[0020] S25), inputting seismic waves, calculating particle force information according to the calculation rules of peridynamics, and analyzing the dynamic failure process of rock and soil based on energy dissipation heat points;

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

[0022] The beneficial effects of the present invention are:

[0023] 1. This paper constructs a peridynamics and discrete element coupling model to address the phenomenon of slope instability under earthquakes, and applies it to discrete element software to form a method for describing the deformation and failure characteristics of slopes under earthquake disturbances;

[0024] 2. The present invention analyzes the shape and characteristics of the sliding surface through a rock and soil dynamic destruction simulation method based on energy dissipation heat points, reflects the process of slope instability under seismic loads, improves the prediction accuracy and sliding surface identification accuracy, and has significant advantages in the prediction of progressive rock and soil destruction and sudden landslides. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the process of the present invention;

[0026] Figure 2 Schematic diagram of peridynamics principle in an embodiment of the present invention;

[0027] Figure 3 Schematic diagram of perifield dynamics bond state in an embodiment of the present invention;

[0028] Figure 4 Schematic diagram of the slope instability calculation model of the Nigawa slope under the KOBE earthquake load in an embodiment of the present invention;

[0029] Figure 5 This is the earthquake acceleration time history curve in the embodiment of the present invention;

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

[0031] Figure 7 This is a cloud diagram of the energy field of the landslide process in an embodiment of the present invention. DETAILED DESCRIPTION

[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, this embodiment provides a method for simulating dynamic failure of rock and soil based on energy dissipation heat points, including the following steps:

[0034] S1) Constructing a peridynamics and discrete element coupled model for describing the mechanical state of particles under earthquake action; specifically comprising the following steps:

[0035] S11), detecting whether the particle is in the neighborhood within the generated particle model, and if so, generating a peridynamic bond;

[0036] S12), setting relevant parameters of the coupling model; including neighborhood radius, calculation boundary radius, cohesion, normal-to-tangential stiffness ratio, and damping coefficient;

[0037] S13) Apply the peridynamic calculation coupling model to the generated bond, and the calculation method is as follows:

[0038] In this embodiment, the function between the bond force and the bond is Calculate, where T is the vector state of the bond force, t is the scalar state of the force, is the vector state of force along the bond deformation direction, through the bond deformation Y <ξ> is expressed as

[0039] For the scalar state of the force t , which can be expressed as: Among them, c is the coefficient, s is the elongation of the bond, and e is the parameter that controls whether the bond breaks.

[0040] S2) Based on the discrete element method, input simulation parameters and conditions into the coupling model to simulate the dynamic failure of the rock and soil; 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 cloud map;

[0041] In this embodiment, it is determined whether the simulation time step is reached; if the simulation time step is not reached, the particle force information is calculated. Specifically, the following steps are included:

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

[0043] S22), determining the coordinates of discrete particles;

[0044] This embodiment determines the discrete particle coordinates based on the initial generation coordinates of the particles and the displacement information in each time step.

[0045] S23), numbering the discrete particles and inputting corresponding data information;

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

[0047] S24), applying initial boundary conditions and determining the time step;

[0048] In this embodiment, the bottom and left and right sides of the model are viscoelastic boundaries, and the rest are free boundaries. A time step that is too short will result in excessive instantaneous displacement of the particles, while a time step that is too long will result in low computational efficiency. Therefore, an appropriate time step value needs to be selected.

[0049] S25), inputting seismic waves, calculating particle force information according to the calculation rules of peridynamics; analyzing the dynamic failure process of the rock and soil based on the energy dissipation heat point; and analyzing the concentrated area of ​​rock and soil failure according to the calculated energy size;

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

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

[0052] In this embodiment, the particle force information is calculated according to the peridynamics calculation rules as follows:

[0053] Peridynamic models such as Figure 2 As shown in the peridynamic model, the continuum is discretized into a finite number of material points with mass, volume, and density. For each individual particle, the area near it is regarded as its neighborhood. Other particles in the neighborhood will interact with the particle, that is, form bonds. The bond state diagram is shown in Figure 3 As shown, the function between bond force and bond is expressed as:

[0054]

[0055] Where, T is the vector state of the bond force, t is the scalar state of the force, is the vector state of force along the bond deformation direction, through the bond deformation Y <ξ> is expressed as

[0056] For the scalar state of the force t , whose expression is:

[0057]

[0058] Where c is the coefficient; s is the elongation of the bond; e is the parameter that controls whether the bond breaks;

[0059] in:

[0060]

[0061] Where, 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 peridynamic equilibrium equation is expressed as:

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

[0064] Where ρ is density; u is displacement; b is body density; force state T It is a function of both the bond length ξ and the position x and time t; x and x′ represent the coordinates of two different points in space; ü represents acceleration; dV x′ Represents the volume element at point x′.

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

[0066] The total energy E during the simulation D,total Including kinetic energy E k,total , total friction energy E f,total , PD bond deformation energy consumption E PD,elastic and PD bond breaking energy E 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 the velocity and displacement of the particle. The kinetic energy E k,total for:

[0069]

[0070] Where N is the number of particles; m i is the mass of particle i; v i is the average velocity of particle i; I i is the moment of inertia of particle i; ω i is the angular velocity of particle i.

[0071] The average velocity v of the particle i i Affected by the combined effects of static bonding and dynamic bonding, namely:

[0072]

[0073] Where, is the velocity effect of static bonding on particle i; is the velocity effect of dynamic bonding on particle i.

[0074] Effect of dynamic bonding on the velocity of particle i Expressed as:

[0075]

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

[0077] For the bonded particles, the friction energy The work derived from the sliding friction between particles is:

[0078]

[0079] Where μ is the coefficient of sliding friction between particles; is the normal force between particles; is the increment of the tangential relative displacement between particles;

[0080] set up is the tangential displacement increment in a certain time step, then the friction energy in each time step Δt is for:

[0081]

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

[0083]

[0084] Where contacts(i) represents the set of all contact bonds.

[0085] In this embodiment, the inter-particle normal force Contains different components of static adhesion and PD bond force, namely:

[0086]

[0087] Where, is the normal force generated by static bonding; is the bond force generated by dynamic adhesion; n1 is the projection of PD bond force in the contact normal direction; is the peridynamic bond force.

[0088] The PD bond deformation energy consumption E PD,elastic Expressed as:

[0089]

[0090] Where, is the deformation energy density of each PD bond; S ij is the bond association area, which is the average of the areas of the two particles; C is the bond stiffness; ξ ij is the bond vector between particles i and j; η ij is the displacement difference vector between particles i and j.

[0091] The PD bond breaking energy E PD,fracture Expressed as:

[0092]

[0093] Where N F is the number of broken bonds.

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

[0095]

[0096] in, t is the scalar state of the bond force, d m 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] Drawing the energy dissipation heat spots into cloud maps can facilitate the observation of the formation of sliding surfaces and the movement of landslide bodies in slope models. The analysis of energy dissipation can also naturally capture the process from continuum fracture to discrete particle flow, and also play a certain role in the complex failure mode of landslides with rock fragmentation and debris mixing. It can more realistically simulate the propagation of seismic waves in rock and soil and the long-range force effects it induces, reveal the spatial distribution law of energy accumulation and release under seismic loads, and optimize the prediction of progressive destruction of rock and soil and sudden landslides.

[0099] The Great Hanshin Earthquake that occurred on January 17, 1995 was used as the simulation object. Figure 4 Shown is a simplified slope model of the Nigawa slope. The top surface of the model is a free boundary, and the other boundaries are viscoelastic. A gravity field is added, and KOBE seismic waves are input from the bottom of the model to observe the slope failure characteristics.

[0100] The maximum vertical acceleration of the KOBE earthquake wave can reach 0.426g, accounting for 89% of the comprehensive horizontal acceleration (0.476g), which is much higher than the proportion used in conventional design. Figure 5The KOBE seismic wave shown contains acceleration waveforms in the north-south, east-west, and vertical directions. This measured record clearly demonstrates a significant increase in vertical ground motion near the epicenter, demonstrating the importance of considering the role of vertical acceleration in landslide failure analysis. In particular, its coupling with the horizontal component can significantly deepen the failure surface, thereby reducing the slope safety factor. The Nigawa slope runs northeast-southwest. 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.

[0101] like Figure 6 As shown in the figure, the distribution of particles in the slope changed significantly before and after the earthquake. The light blue color represents the slope outline before the landslide, while the dark blue color shows the particle position after the landslide. This comparison reveals that particles in the upper and middle portions of the slope experienced a significant decline due to the earthquake, with the slippage primarily concentrated in the shallow structure. The rest of the slope remained relatively stable, revealing the extent of the landslide and the deformation trend.

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

[0103] The above embodiments and descriptions are only for explaining the principles and best embodiments of the present invention. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and improvements, which shall fall within the scope of the invention to be protected.

Claims

1. A method for simulating dynamic failure of rock and soil based on energy dissipation heat points, characterized in that: The steps include: S1) Construct a peridynamics and discrete element coupled model to describe the mechanical state of particles under earthquake action; S2) Based on the discrete element method, input simulation parameters and conditions into the coupling model to determine whether the time step has been reached; if the 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 cloud map; S3) traverse all particles, calculate particle velocity and displacement according to particle force information, and analyze the destruction process according to energy dissipation heat points to obtain calculation results; output the calculation results and draw a cloud map.

2. The method for simulating dynamic failure of rock and soil based on energy dissipation heat points according to claim 1, characterized in that: In step S1), a peridynamics and discrete element coupling model is constructed, which specifically includes the following steps: S11), detecting whether the particle is in the neighborhood within the generated particle model, and if so, generating a peridynamic bond; S12), setting relevant parameters of the coupling model; S13), applying a peridynamic calculation coupling model to the generated bonds.

3. The method for simulating dynamic failure of rock and soil based on energy dissipation heat points according to claim 1, characterized in that: In step S2), it is determined whether the time step has been reached; if the time step has not been reached, the particle force information is calculated; specifically, the following steps are included: S21), initializing the parameters of the peridynamics and discrete element coupling model, inputting simulation parameters, and determining the size of the coupling model; S22), determining the coordinates of discrete particles; S23), numbering the discrete particles and inputting corresponding data information; S24), applying initial boundary conditions and determining the time step; S25), inputting seismic waves, calculating particle force information according to the calculation rules of peridynamics, and analyzing the dynamic failure process of rock and soil based on energy dissipation heat points; S26) Output the energy field cloud map and analyze the failure mode of the sliding surface.

4. The method for simulating dynamic failure of rock and soil based on energy dissipation heat points according to claim 2, characterized in that: The function between bond force and bond is expressed as: Where, T is the vector state of the bond force, t is the scalar state of the force, is the vector state of force along the bond deformation direction, through the bond deformation Y <ξ> is expressed as For the scalar state of the force t , whose expression is: Where c is the coefficient; s is the elongation of the bond; e is the parameter that controls whether the bond breaks; in: Where, X <ξ> represents the unit vector state; t represents the current moment; t′ represents any past moment between the initial moment and the current moment; ξ represents the bond length; s0 represents the bond length threshold.

5. The method for simulating dynamic failure of rock and soil based on energy dissipation heat points according to claim 3 is characterized by: The total energy E during the simulation D,total Including kinetic energy E k,total , total friction energy E f,total , PD bond deformation energy consumption E PD,elastic and PD bond breaking energy E PD,fracture ,Right now: AND D,total =And k,total +E f,total +E PD,elastic +E PD,fracture 。 6. The method for simulating dynamic failure of rock and soil based on energy dissipation heat points according to claim 5, characterized in that: The kinetic energy E k,total for: Where N is the number of particles; m i is the mass of particle i; v i is the average velocity of particle i; I i is the moment of inertia of particle i; ω i is the angular velocity of particle i.

7. The method for simulating dynamic failure of rock and soil based on energy dissipation heat points according to claim 6, characterized in that: The average velocity v of the particle i i Affected by the combined effects of static bonding and dynamic bonding, namely: Where, is the velocity effect of static bonding on particle i; is the velocity effect of dynamic bonding on particle i; Effect of dynamic bonding on the velocity of particle i Expressed as: Where H i is the set of all particles in the neighborhood of particle i; c is the bond stiffness; ξ ij is the bond vector between particles i and j; η ij is the displacement difference vector between particles i and j.

8. The method for simulating dynamic failure of rock and soil based on energy dissipation heat points according to claim 5 is characterized by: For the bonded particles, the friction energy The work derived from the sliding friction between particles is: Where μ is the coefficient of sliding friction between particles; is the normal force between particles; is the increment of the tangential relative displacement between particles; The interparticle normal force Contains different components of static adhesion and PD bond force, namely: Where, is the normal force generated by static bonding; is the bond force generated by dynamic adhesion; n1 is the projection of PD bond force in the contact normal direction; is the peridynamic bond force; set up is the tangential displacement increment in a certain time step, then the friction energy in each time step Δt is for: Therefore, the total friction energy E f,total The calculation expression is: Where contacts(i) represents the set of all contact bonds.

9. The method for simulating dynamic failure of rock and soil based on energy dissipation heat points according to claim 5, characterized in that: The PD bond deformation energy consumption E PD,elastic Expressed as: Where, is the deformation energy density of each PD bond; S ij is the bond association area, which is the average of the areas of the two particles; C is the bond stiffness; ξ ij is the bond vector between particles i and j; η ij is the displacement difference vector between particles i and j; The PD bond breaking energy E PD,fracture Expressed as: Where N F is the number of broken bonds.

10. The method for simulating dynamic failure of rock and soil based on energy dissipation heat points according to claim 1, characterized in that: In step S3), the particle velocity V is calculated according to the particle force result: Among them, t is the scalar state of the bond force, d m 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: Δs=VΔt.

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