A simulation method for projectile collapse and landslide based on rock mass fragmentation degree prediction

Abstract

The application provides a simulation method for projectile collapse and landslide based on rock mass fragmentation degree prediction, which has the characteristics of high fragmentation degree prediction accuracy, DEM discrete parameter self-adaptive optimization and significant simulation efficiency improvement. The quantitative relationship between the theoretical fragmentation degree and the impact velocity and the rock mass parameters is established, so that the scientific prediction of the rock mass fragmentation degree is realized. The fragmentation degree is dynamically associated with the DEM sub-block quantity and the bonding strength, so that the subjectivity and limitations of the original manual setting of the sub-block quantity are overcome. Through the introduction of the "prediction-simulation-verification-iteration" closed-loop optimization mechanism, the fragmentation degree prediction accuracy is more than 85%, the trial calculation number of the DEM model is greatly reduced, and the sub-block distribution range after the rock mass impact which is more in line with the actual situation can be output, thereby providing reliable technical support for the fine layout of the protection engineering such as the rock arresting net.

Description

Technical Field

[0001] This invention relates to the field of numerical simulation in civil engineering, and in particular to a method for simulating projectile collapses and landslides based on the prediction of rock mass fragmentation. Background Technology

[0002] Projectile landslides are a common geological hazard caused by the instability of steep slopes under seismic or gravity loads. Their typical characteristic is the high-speed separation of rock masses from the landslide source area, followed by impact with the ground after a certain distance through the air, further fracturing, disintegration, and movement. These disasters are characterized by their suddenness, wide impact range, and complex movement trajectories, posing a serious threat to mountain settlements, transportation routes, and critical infrastructure. Therefore, conducting accurate simulations of the entire movement process of projectile landslides is of significant theoretical and engineering importance for disaster risk assessment, protective engineering deployment, and the selection of residential sites.

[0003] Currently, some progress has been made in the simulation research of projectile landslides. Existing technologies include using aerodynamic models to analyze the trajectory of rock masses during their flight phase, such as establishing lift, drag, and motion equations based on airfoil theory, which can accurately predict the attitude, velocity, and impact point of the rock mass before impact. Other studies use the Discrete Element Method (DEM) to simulate the fragmentation and movement of rock masses after impact, simulating their fracture, separation, and accumulation behavior by discretizing the rock mass into several sub-blocks and setting their bond strength. However, existing methods have significant shortcomings when combining aerodynamic models with DEM models: the number of discrete sub-blocks in the DEM model often relies on pre-set human experience, lacking a theoretical correlation with the actual degree of rock mass fragmentation. Inappropriate sub-block settings can lead to distortion in the simulated trajectory after impact, and significant deviations in the fragmentation pattern from reality, thus affecting the reliability of protective engineering design. Furthermore, existing methods require multiple trial calculations to adjust discrete parameters during simulation, resulting in low efficiency and failing to meet the needs of rapid and accurate assessment in engineering practice.

[0004] Therefore, there is an urgent need in this field for a projectile collapse and landslide simulation method that can automatically and accurately determine the discrete parameters of DEM and realize the integration of rock mass fragmentation prediction and simulation verification, so as to overcome the problems of existing technologies such as reliance on human experience, insufficient simulation accuracy, and low trial calculation efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a method for simulating projectile collapses and landslides based on rock mass fragmentation prediction, so as to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides a method for simulating projectile-type landslides based on rock mass fragmentation prediction, comprising the following steps: S1. Obtain the rock mass parameters and initial state parameters of the ejected rock mass; S2. Based on the rock mass parameters and initial state parameters, use an aerodynamic analysis model to analyze the flight process of the projected rock mass in the air and determine its state parameters before impacting the ground; S3. Based on the state parameters and rock mass parameters before impact, the theoretical fragmentation degree of the rock mass is calculated using a fragmentation degree prediction model; S4. Based on the theoretical fragmentation degree, determine the number of discrete sub-blocks of the rock mass and the initial bond strength between the sub-blocks in the discrete element method DEM model; S5. Use the DEM model to simulate the impact of the projectile rock mass and its subsequent motion to obtain the simulated fragmentation degree; S6. Compare the theoretical fragmentation with the simulated fragmentation. If the error exceeds the set threshold, iteratively optimize the correction coefficient in the fragmentation prediction model until the error meets the requirements. S7. Output the final accumulation morphology and sub-block distribution range of the projected rock mass.

[0007] Preferably, in step S1, the rock mass parameters include at least one of internal friction angle, cohesion, density, and tensile strength; the initial state parameters include at least one of initial velocity and projection angle at the time of landslide.

[0008] Preferably, in step S3, the breakage prediction model is: ; in, For theoretical fragmentation, For correction factor, For the density of the rock mass, For the impact speed, It represents cohesive force.

[0009] Preferably, in step S4, the number of discrete sub-blocks is determined by the following formula: ; in, and These are the preset minimum and maximum number of sub-blocks, respectively. This represents the theoretical fragmentation degree.

[0010] Preferably, in step S4, the initial bonding strength between the sub-blocks is set by the following formula: ; in, As the reference bond strength, This is the decay index.

[0011] Preferably, in step S5, the simulated breakage degree is calculated using the following formula: ; in, This represents the initial total number of bonds in the DEM model. This represents the number of bonds that were damaged during the simulation.

[0012] Preferably, in step S5, the DEM model uses a viscous fracture model to simulate the crack propagation and block separation process. The viscous fracture model includes the nonlinear relationship between normal stress, tangential stress and displacement, and considers the coupling effect between plastic displacement and fracture displacement.

[0013] Preferably, in step S6, the method for iteratively optimizing the correction coefficients in the breakage prediction model is as follows: ; in, These are the correction factors before the update. This is the learning rate.

[0014] Preferably, it further includes: S8. Based on the final sub-block distribution range, generate a protective engineering layout suggestion map, whereby the protective engineering includes at least one of rockfall netting and crash barriers.

[0015] The present invention also provides a projectile-type landslide simulation device based on rock mass fragmentation prediction, comprising: The parameter acquisition module is used to acquire rock mass parameters and initial state parameters; The flight analysis module is used to perform aerodynamic analysis; The breakage prediction module is used to calculate the theoretical breakage and guide the DEM discretization; The DEM simulation module is used to perform impact and motion process simulations. The verification and optimization module is used to compare and iteratively optimize the fragmentation prediction results; The results output module is used to output the final shape of the rock mass and protection recommendations.

[0016] The present invention achieves the following beneficial technical effects compared to the prior art: This invention provides a method for simulating projectile landslides based on rock mass fragmentation prediction. This method features high accuracy in fragmentation prediction, adaptive optimization of DEM discrete parameters, and significantly improved simulation efficiency. Specifically, by establishing a quantitative relationship between theoretical fragmentation, impact velocity, and rock mass parameters, it achieves a scientific prediction of the degree of rock mass fragmentation. By dynamically linking fragmentation with the number of DEM sub-blocks and bonding strength, it overcomes the subjectivity and limitations of manually setting the number of sub-blocks. Furthermore, by introducing a closed-loop optimization mechanism of "prediction-simulation-verification-iteration," the accuracy of fragmentation prediction reaches over 85%, significantly reducing the number of DEM model calculations and outputting a more realistic distribution range of sub-blocks after rock mass impact. This provides reliable technical support for the refined deployment of protective engineering projects such as rockfall barriers. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 The flowchart of the projectile collapse and landslide simulation method based on rock mass fragmentation prediction provided by the present invention is shown in the figure. Detailed Implementation

[0019] 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.

[0020] The purpose of this invention is to provide a simulation method for projectile collapse and landslide based on rock mass fragmentation prediction. Its core lies in establishing a closed-loop optimization mechanism of "fracture degree prediction - discretization adaptation - iterative verification" to achieve quantitative prediction of rock mass fragmentation degree and automatic optimization of discrete element model parameters.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1: This invention provides a method for simulating projectile-type landslides based on rock mass fragmentation prediction, such as... Figure 1 As shown, this method first obtains basic rock mass parameters, including the internal friction angle, through on-site investigation or experimental testing. Cohesion ,density ,tensile strength The mechanical properties are used to calculate the initial state parameters of rock mass landslides based on topographic data.

[0023] Among them, the initial velocity Using the law of conservation of energy Calculated, in the formula This represents the elevation difference of the centroid of the projectile rock mass. This refers to the frictional force between the rock mass and the bedrock. For the path of motion, This refers to the rock mass quality.

[0024] After obtaining the initial parameters, an aerodynamic analysis model was used to simulate the airborne flight process of the rock mass. This model is based on airfoil theory and solves for lift-related parameters. ,resistance The set of motion equations is used to accurately calculate the trajectory and state parameters of the rock mass before it impacts the ground.

[0025] The formula for calculating lift is: ; The formula for calculating resistance is: ; And through a system of differential equations: ; ; Describes the movement patterns of rock masses in the air.

[0026] In the formula, This is a dimensionless correction factor for lift-terrain effects. and respectively with the angle of attack The relevant lift and drag coefficients, Let be the projected area of ​​the projectile. Let be the air density. The precise velocity of the rock mass before impact with the ground can be obtained by numerically solving this system of differential equations using the fourth-order Runge-Kutta method. Key parameters such as location coordinates.

[0027] Based on impact speed Based on rock mass parameters, the theoretical fracture degree is calculated using a fracture degree prediction model. The model expression is: ,in, The correction factor is set to an initial value of 1.0. For the density of the rock mass, This model considers the influence of the ratio of impact kinetic energy to rock shear strength on the degree of fragmentation, and its physical meaning is clear. Theoretical degree of fragmentation. The value range is [0,1], and the larger the value, the higher the degree of rock mass fragmentation.

[0028] In the discrete element modeling stage, based on the theoretical fragmentation degree Automatically determine the discrete parameters of the DEM model. Number of sub-blocks. Through formula Calculation, where and Set to 5 and 20 respectively to ensure the dispersion matches the degree of fragmentation. Initial bond strength between sub-blocks. Through formula The settings, in which, Based on the tensile strength of the rock mass Confirmed, decay index Set the value to 1.0. This parameter setting allows the bond strength to decrease naturally as the degree of fragmentation increases, which is consistent with the physical laws of rock mass fracture.

[0029] In the DEM simulation, a viscous fracture model was used to simulate the crack propagation and block separation behavior after rock mass impact. This model decomposes the total relative displacement of joints into elastic displacements. Inelastic displacement Inelastic displacement includes plastic displacement. and fracture displacement By establishing normal stress and shear stress The constitutive relation is determined, and an integrity parameter is introduced. and microscopic damage parameters This method describes the stiffness degradation process and accurately simulates the fracture behavior of rock masses under combined tensile and shear forces. After the simulation is completed, the failure-bond ratio is statistically analyzed. With total number of bonds The ratio is used to calculate the simulated fragmentation degree. .

[0030] To improve prediction accuracy, an iterative optimization mechanism is established. This involves comparing the theoretical fragmentation degree. With simulated fragmentation The difference, when the error exceeds the threshold of 0.05, is determined by the formula. Update correction coefficients The learning rate Set it to 0.1. Repeat the fragmentation prediction and DEM simulation steps until the error between the theoretical and simulated values ​​meets the requirements. At this point, the fragmentation prediction accuracy can reach over 85%.

[0031] The final output includes the final rock mass accumulation morphology, sub-block distribution range, and movement trajectory, and can generate optimized layout schemes for protective engineering projects such as rockfall barriers and crash barriers based on the spatial distribution characteristics of the sub-blocks. To verify the effectiveness of this method, a typical slope engineering case was used, with input rock mass parameters... , , , The initial velocity was calculated. Impact speed After three iterations of optimization, the correction coefficients were... Converging to 1.025, theoretical fragmentation degree. With simulated fragmentation The error was reduced to 0.03, and the number of sub-blocks was automatically adjusted to 17, effectively predicting the fragmentation distribution pattern after rock mass impact and providing accurate basis for the design of protective engineering.

[0032] Example 2: The present invention also provides a projectile-type landslide simulation device based on rock mass fragmentation prediction, comprising: The parameter acquisition module is used to acquire rock mass parameters and initial state parameters; The flight analysis module is used to perform aerodynamic analysis; The breakage prediction module is used to calculate the theoretical breakage and guide the DEM discretization; The DEM simulation module is used to perform impact and motion process simulations. The verification and optimization module is used to compare and iteratively optimize the fragmentation prediction results; The results output module is used to output the final shape of the rock mass and protection recommendations.

[0033] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0034] It should be noted that the components mentioned in the above embodiments are all general standard parts or components known to those skilled in the art. Their structures and principles can be learned by those skilled in the art through technical manuals or conventional experimental methods.

[0035] This invention has illustrated its principles and implementation methods using specific examples. The descriptions of these embodiments are merely illustrative of the method and its core ideas; furthermore, those skilled in the art will recognize that modifications may be made to the specific implementation methods and application scope based on the principles of this invention. Therefore, the content of this specification should not be construed as limiting the invention.

Claims

1. A simulation method for projectile collapse and landslide based on rock mass fragmentation prediction, characterized in that, Includes the following steps: S1. Obtain the rock mass parameters and initial state parameters of the ejected rock mass; S2. Based on the rock mass parameters and initial state parameters, use an aerodynamic analysis model to analyze the flight process of the projected rock mass in the air and determine its state parameters before impacting the ground; S3. Based on the state parameters and rock mass parameters before impact, the theoretical fragmentation degree of the rock mass is calculated using a fragmentation degree prediction model; S4. Based on the theoretical fragmentation degree, determine the number of discrete sub-blocks of the rock mass and the initial bond strength between the sub-blocks in the discrete element method DEM model; S5. Use the DEM model to simulate the impact of the projectile rock mass and its subsequent motion to obtain the simulated fragmentation degree; S6. Compare the theoretical fragmentation with the simulated fragmentation. If the error exceeds the set threshold, iteratively optimize the correction coefficient in the fragmentation prediction model until the error meets the requirements. S7. Output the final accumulation morphology and sub-block distribution range of the projected rock mass.

2. The method for simulating projectile landslides based on rock mass fragmentation prediction as described in claim 1, characterized in that, In step S1, the rock mass parameters include at least one of the following: internal friction angle, cohesion, density, and tensile strength; the initial state parameters include at least one of the following: initial velocity at the time of landslide and projection angle.

3. The method for simulating projectile landslides based on rock mass fragmentation prediction as described in claim 1, characterized in that, In step S3, the fragmentation prediction model is: ； in, For theoretical fragmentation, For correction factor, For the density of the rock mass, For the impact speed, It represents cohesive force.

4. The method for simulating projectile landslides based on rock mass fragmentation prediction as described in claim 1, characterized in that, In step S4, the number of discrete sub-blocks is determined by the following formula: ； in, and These are the preset minimum and maximum number of sub-blocks, respectively. This represents the theoretical fragmentation degree.

5. The method for simulating projectile landslides based on rock mass fragmentation prediction as described in claim 1, characterized in that, In step S4, the initial bond strength between the sub-blocks is set by the following formula: ； in, As the reference bond strength, This is the decay index.

6. The method for simulating projectile landslides based on rock mass fragmentation prediction as described in claim 1, characterized in that, In step S5, the simulated fragmentation degree is calculated using the following formula: ； in, This represents the initial total number of bonds in the DEM model. This represents the number of bonds that were damaged during the simulation.

7. The method for simulating projectile landslides based on rock mass fragmentation prediction as described in claim 1, characterized in that, In step S5, the DEM model uses a viscous fracture model to simulate the crack propagation and block separation process. The viscous fracture model includes the nonlinear relationship between normal stress, tangential stress and displacement, and considers the coupling effect between plastic displacement and fracture displacement.

8. The method for simulating projectile landslides based on rock mass fragmentation prediction as described in claim 1, characterized in that, In step S6, the method for iteratively optimizing the correction coefficients in the fragmentation prediction model is as follows: ； in, These are the correction factors before the update. This is the learning rate.

9. The method for simulating projectile landslides based on rock mass fragmentation prediction as described in claim 1, characterized in that, Also includes: S8. Based on the final sub-block distribution range, generate a protective engineering layout suggestion map, whereby the protective engineering includes at least one of rockfall netting and crash barriers.

10. A projectile-type landslide simulation device based on rock mass fragmentation prediction, characterized in that, include: The parameter acquisition module is used to acquire rock mass parameters and initial state parameters; The flight analysis module is used to perform aerodynamic analysis; The breakage prediction module is used to calculate the theoretical breakage and guide the DEM discretization; The DEM simulation module is used to perform impact and motion process simulations. The verification and optimization module is used to compare and iteratively optimize the fragmentation prediction results; The results output module is used to output the final shape of the rock mass and protection recommendations.

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