A simulation method and apparatus for projectile-type landslide motion

Abstract

This invention discloses a method and apparatus for simulating the motion of a projectile landslide. The method includes: acquiring rock mass parameters of the projectile rock mass; calculating the initial state parameters of the projectile rock mass during the landslide; analyzing the flight process of the projectile rock mass in the air using an aerodynamic analysis model based on the rock mass parameters and the initial state parameters to determine the state parameters of the projectile rock mass before impact with the ground; and analyzing the motion process of the projectile rock mass after impact and after impact using a discrete element method (DEM) model based on the state parameters before impact with the ground to obtain the final shape of the projectile rock mass. This embodiment, by simultaneously utilizing both an aerodynamic analysis model and a DEM model, can more realistically simulate the motion process of a projectile landslide.

Description

Technical Field

[0001] This invention relates to the field of numerical simulation in civil engineering, and in particular to a method and apparatus for simulating projectile-type collapse and landslide motion. Background Technology

[0002] Studying projectile landslides is crucial for selecting residential sites. Generally, such landslides may occur when seismic forces or gravity loads are sufficiently large and the landslide source area is located at a high elevation. These projectile landslides are characterized by significant features, typically generating high-speed, long-range dynamic processes. The aerodynamic properties of the projectile rock mass can be analyzed using airfoil theory, allowing for the determination of the projectile's velocity and distance before impact. However, research on the disintegration and motion of the projectile after impact is lacking. Summary of the Invention

[0003] The main objective of this invention is to provide a method and apparatus for simulating the motion of projectile landslides, which can more realistically simulate the motion process of projectile landslides.

[0004] To achieve the above-mentioned objectives, this invention provides a method for simulating projectile landslide motion, comprising: acquiring rock mass parameters of the projectile rock mass; calculating the initial state parameters of the projectile rock mass during the landslide; analyzing the flight process of the projectile rock mass in the air using an aerodynamic analysis model based on the rock mass parameters and the initial state parameters to determine the state parameters of the projectile rock mass before impacting the ground; and analyzing the motion process of the projectile rock mass after impact and impact with the ground using a discrete element method (DEM) model based on the state parameters of the projectile rock mass before impacting the ground to obtain the final shape of the projectile rock mass.

[0005] The rock mass parameters include at least one of the following: internal friction angle, cohesion, and tensile strength.

[0006] The acquisition of rock mass parameters of the projectile rock mass includes obtaining the rock mass parameters of the projectile rock mass according to the Hoek-Brown criterion.

[0007] The initial state parameters include at least one of the following: the initial velocity of the projected rock mass during the landslide, and the angle between the axis of the projected rock mass and the horizontal plane.

[0008] The calculation of the initial velocity of the projected rock mass during the landslide includes:

[0009] The initial velocity v0 of the projected rock mass during the landslide is calculated using the following formula:

[0010]

[0011] Where h is the drop of the centroid of the projectile rock mass, f is the frictional force between the projectile rock mass and the bedrock, s is the path traveled by the projectile rock mass, m is the mass of the projectile rock mass, and β is the angle between the bedrock and the horizontal axis.

[0012] The state parameters of the projected rock mass before impacting the ground include at least one of the following: velocity, horizontal displacement, and vertical displacement upon impact.

[0013] The aerodynamic analysis model is established based on the following formula:

[0014]

[0015]

[0016]

[0017]

[0018]

[0019] Where x and y are the horizontal and vertical coordinates, respectively; F L For lift; F R For resistance; C L and C R These represent the lift and drag coefficients, respectively; t is time; S is the projected area of ​​the projectile; ρ is the air density; G e α is the dimensionless lift-topographic effect correction coefficient; m is the mass of the projectile; α is the angle of attack; β is the angle between the bedrock and the horizontal axis.

[0020] In the DEM model, crack propagation is calculated and monitored based on a viscous fracture model to simulate the impact and subsequent motion process after impact with the ground.

[0021] The step of analyzing the motion process of the projected rock mass after impact and impact with the ground using a discrete element method (DEM) model based on the state parameters of the projected rock mass before impact with the ground includes:

[0022] Input joint physical parameters: initial tensile strength Initial cohesion c0, initial normal stiffness Initial tangential stiffness Initial internal friction angle

[0023] Based on the aforementioned viscous fracture model, the propagation of cracks along artificial joints is calculated and monitored; and

[0024] An iterative algorithm was used to correct joint parameters to simulate the impact fracturing and subsequent movement of projectile rock along artificial joint surfaces.

[0025] This invention also provides a simulation device for projectile landslide motion, comprising: an acquisition module for acquiring rock mass parameters of the projectile rock mass; a calculation module for calculating the initial velocity of the projectile rock mass during the landslide; a first processing module for analyzing the flight process of the projectile rock mass in the air using an aerodynamic analysis model based on the rock mass parameters and the initial velocity, to determine the state parameters of the projectile rock mass before impacting the ground; and a second processing module for analyzing the motion process of the projectile rock mass after impact and after impact using a discrete element method (DEM) model based on the state parameters of the projectile rock mass before impacting the ground, to obtain the final shape of the projectile rock mass.

[0026] Beneficial effects of the embodiments of the present invention:

[0027] In this embodiment of the invention, both aerodynamic analysis models and DEM models are used for analysis, thus enabling a more realistic simulation of the motion process of projectile-type landslides. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the morphology of the landslide source area in a projectile-type collapse.

[0029] Figure 2 Schematic diagram of the aerodynamic effects of projectile rock mass;

[0030] Figure 3 This is a schematic flowchart of an embodiment of the simulation method for projectile-type landslide motion of the present invention;

[0031] Figure 4 yes Figure 3 A flowchart illustrating an embodiment of step S26;

[0032] Figure 5 yes Figure 3 A flowchart illustrating another embodiment of step S26 in the process;

[0033] Figure 6 This is a schematic diagram of an embodiment of the simulation device for projectile-type landslide motion of the present invention. Detailed Implementation

[0034] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0035] In the following description, the use of suffixes such as "module," "part," or "unit" to denote elements is solely for the purpose of illustrative purposes and has no specific meaning in itself. Therefore, "module," "part," or "unit" may be used interchangeably.

[0036] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0037] The present invention will be described below with reference to the accompanying drawings and embodiments.

[0038] Example

[0039] like Figure 3 The diagram shown is a flowchart illustrating an embodiment of the simulation method for projectile-type landslide motion according to the present invention. Wherein, Figure 3 The simulation method shown can simulate projectile-type landslides in rock masses, thus providing a reference for rock mass analysis and settlement site selection. Specifically, for example... Figure 3 As shown, the simulation method includes the following steps:

[0040] Step S20: Obtain the rock mass parameters of the ejected rock mass.

[0041] Among them, the rock mass parameters include at least one of the following: internal friction angle, cohesion and tensile strength.

[0042] In step S20, the rock mass parameters of the projectile rock mass can be obtained using the Hoek-Brown criterion.

[0043] Specifically, the Hoek-Brown criterion is an empirical formula used to predict rock fracture. In 1980, Evert Hoek and E.T. Brown derived this empirical formula while studying underground excavation engineering. In 1988, they collaborated on an article extending the theory to open-pit mining and slope stability research. In 2002, Hoek et al. updated the theory, combining it with the well-known Geological Strength Index (GSI) theory in rock mechanics. Due to the structural properties of rocks, the Hoek-Brown criterion adds assessment indicators to the rock, reflecting as many physical parameters of the original rock as possible.

[0044] Step S22: Calculate the initial state parameters of the ejected rock mass during the landslide.

[0045] The initial state parameters include at least one of the following: the initial velocity of the projected rock mass during the landslide, and the angle between the axis of the projected rock mass and the horizontal plane.

[0046] like Figure 1 and Figure 2 The diagram shown illustrates the morphology of the landslide source area and the aerodynamic effects of the projectile rock mass in a projectile-type landslide. (For reference) Figure 1 and Figure 2 Based on the conversion relationship between potential energy and kinetic energy, the initial velocity v0 of the projected rock mass during a landslide can be calculated using the following formula.

[0047] Depend on We can obtain:

[0048]

[0049] And, v x =v0cosβ and v y =v0sinβ

[0050] Where h is the drop in elevation of the centroid of the projectile rock mass, f is the frictional force between the projectile rock mass and the bedrock, s is the path traveled by the projectile rock mass, m is the mass of the projectile rock mass, and β is the angle between the bedrock and the horizontal axis (i.e., the ox axis). x v y These are the initial horizontal velocity and the numerical velocity, respectively.

[0051] Step S24: Based on the rock mass parameters obtained in step S20 and the initial state parameters calculated in step S22, the aerodynamic analysis model is used to analyze the flight process of the projected rock mass in the air in order to determine the state parameters of the projected rock mass before it impacts the ground.

[0052] Since the rock mass is ejected into the air at high speed after separating from the landslide source area, its flight motion is subject to aerodynamic forces similar to those experienced by an aircraft wing during takeoff and descent before impacting the ground. Therefore, an aerodynamic analysis model can be used to analyze the aerodynamic effects experienced by the ejected rock mass during high-speed flight.

[0053] When using an aerodynamic analysis model to analyze the flight process of a projected rock mass in the air, the analysis is considered complete when any point on the bottom boundary of the projected rock mass contacts the ground, representing the maximum falling displacement of the projected rock mass, thus obtaining the state parameters of the projected rock mass before impact with the ground. These state parameters include at least one of the following: the velocity at impact with the ground, the horizontal displacement, and the vertical displacement; where the horizontal and vertical displacements represent the positions of the rock mass upon impact with the ground.

[0054] The aerodynamic analysis model in this embodiment is based on the following formula:

[0055]

[0056]

[0057]

[0058]

[0059]

[0060] Where x and y are the horizontal and vertical coordinates, respectively; F L For lift; F R For resistance; C L and C R These represent the lift and drag coefficients, respectively; t is time; S is the projected area of ​​the projectile; ρ is the air density; G e α is the dimensionless lift-topographic effect correction coefficient; m is the mass of the projectile; α is the angle of attack; β is the angle between the bedrock and the horizontal axis.

[0061] Alternatively, numerical discretization can be used to calculate the above formulas. For example, to ensure the accuracy of the numerical solution, the fourth-order Runge-Kutta method can be used for analysis and discretization. The discretization process is as follows:

[0062]

[0063]

[0064]

[0065] Where Δt is the smallest time step; p, q, k ij (i, j = 1, 2, 3, 4) are temporary variables in the numerical calculation process.

[0066] In addition, the lift coefficient C can be obtained based on the results of wind tunnel tests. L drag coefficient C R The relationship between the angle of attack α and the following is as follows:

[0067] C L (α)=Aα-B

[0068] C R (α)=C L / Cα-D)

[0069] In the above formula, A, B, C and D are fitting parameters based on the curves obtained from wind tunnel tests.

[0070] It should be noted that, since the projected rock mass has a relatively short flight time, its rotational effect has minimal impact on its flight process; furthermore, the rotational momentum of the projected rock mass is very small during flight, resulting in a negligible aerodynamic force. Therefore, the aerodynamic analysis model used in this embodiment neglects the rotational effect of the projected rock mass.

[0071] Step S26: Based on the state parameters of the projected rock mass before impact with the ground determined in step S24, use the DEM model to analyze the motion process of the projected rock mass after impact with the ground and to obtain the final shape of the projected rock mass.

[0072] The Discrete Element Method (DEM) is a particle discrete material analysis method first proposed by Professor Cundall PA in 1971 based on the principles of molecular dynamics. This method was initially applied to the analysis of rock mechanics problems and has since been gradually applied to the fields of bulk materials and powder engineering. The basic principle of DEM is to treat jointed rock masses as composed of discrete rock blocks and joint surfaces between them, allowing for translation, rotation, and deformation of the rock blocks, while the joint surfaces can be compressed, separated, or slid. Therefore, the rock mass is considered a discontinuous discrete medium. Large displacements, rotations, and sliding, and even block separation, can exist within it, thus allowing for a relatively realistic simulation of the nonlinear large deformation characteristics in jointed rock masses. The general solution process of the Discrete Element Method (DEM) is as follows: the solution space is discretized into a discrete element matrix, and adjacent elements are connected using appropriate connecting elements according to the actual problem. The relative displacement between elements is the fundamental variable; the normal and tangential forces between two elements can be obtained from the relationship between force and relative displacement. The resultant force and resultant torque of the forces acting on the element in each direction with other elements, as well as the external forces caused by other physical fields acting on the element, are calculated. The acceleration of the element can be obtained according to Newton's second law of motion. Time integration is then performed to obtain the velocity and displacement of the element. Thus, the velocity, acceleration, angular velocity, linear displacement, and rotation angle of all elements at any given time are obtained. The DEM, by establishing a parameterized model of a solid particle system, simulates and analyzes particle behavior, providing a platform for solving numerous comprehensive problems involving particles, structures, fluids, and electromagnetics and their couplings. It has become a powerful tool for process analysis, design optimization, and product development.

[0073] In step S26, crack propagation is calculated and monitored based on the viscous fracture model in the DEM model to simulate the impact and subsequent motion process on the ground. In this embodiment, considering that most rock impact failure occurs under tensile-shear conditions, the viscous fracture model is applied to the DEM method. This model is suitable for simulating the elasto-plastic failure of rock crack propagation under tensile-shear conditions and can consider plastic / friction dissipation mechanisms, as well as the reduction in the normal stiffness of the blocks in the model and the changes in tensile strength and cohesion between joints. It has advantages in simulating rock impact failure problems.

[0074] Specifically, the DEM model is divided into n elements by artificial joints, and the viscous fracture model of the joints can simulate the elasto-plastic propagation and failure process of rock fractures along artificial joints during rock impact. The viscous fracture model assumes that the total relative displacement u of the joints between blocks is composed of elastic displacement ue Inelastic displacement u i Composition, inelastic displacement u i Due to plastic displacement u p and fracture displacement u f Composition, namely:

[0075] u = u e +u i

[0076] u 4 =u p +u f

[0077] The formula for calculating the inelastic displacement norm is:

[0078]

[0079] When the joints between rock blocks can no longer transfer the load, the formula for calculating the limit norm of inelastic displacement under tension is:

[0080]

[0081] Among them, G f For the fracture energy, σ t0 This represents the initial tensile strength.

[0082] Under tension, the tensile strength σ t It can be viewed as a linear function of the inelastic displacement norm:

[0083]

[0084] Calculate the normal stress. The functional relationship between normal stress and displacement is as follows:

[0085]

[0086] Where, k n0 Let be the initial normal stiffness, and α be the integrity parameter, characterizing the ratio of the relative motion length (area) that a joint can produce. The calculation formula is:

[0087]

[0088] Where D is the microscopic failure parameter, characterizing the decrease in contact stiffness during fracture, and is calculated using the following formula:

[0089]

[0090] Where, k n0 Let k be the initial normal stiffness. ns To reduce the normal stiffness.

[0091] Similarly, under shear conditions, cohesion can be viewed as a linear function of the inelastic displacement norm:

[0092]

[0093] When the joints between rock blocks can no longer transfer the load, the formula for calculating the limit norm of inelastic displacement under shear state is:

[0094]

[0095] The functional relationship between shear stress and displacement is as follows:

[0096]

[0097] The formulas for calculating α and D are the same as those for the tensile case.

[0098] Specifically, such as Figure 4 As shown, step S26 may include the following sub-steps:

[0099] Step S30: Input joint physical parameters into the DEM model. These joint physical parameters include: initial tensile strength. Initial cohesion c0, initial normal stiffness Initial tangential stiffness Initial internal friction angle

[0100] Step S32: Based on the viscous fracture model, calculate and monitor the propagation of cracks along artificial joints.

[0101] Step S34: Use an iterative algorithm to correct the joint parameters and simulate the impact fracture and subsequent movement process of the projected rock mass along the artificial joint surface.

[0102] The following is combined with Figure 5 The above process will be explained in more detail. Figure 5 In this example, we will mainly use the N+1 step as an example. The superscripts N and N+1 represent the numerical variables of the Nth and N+1th steps, respectively. The superscript 0 represents the initial variables in the numerical simulation, and the subscripts n and s represent the joint normal and tangential variables.

[0103] Specifically, in step 401, information such as velocity, joint physical parameters, and DEM calculation parameters are input. Then, in step 402, the variables of step N are calculated. Next, in step 403, during the (N+1)th numerical iteration, the relative normal displacement of the joint is calculated, expressed as... The relative tangential displacement is expressed as Then, in step 404, the relative normal displacement increment and the relative tangential displacement increment are calculated, and are expressed as follows:

[0104]

[0105]

[0106] Where, Δu n Δu represents the relative normal displacement increment. s This represents the relative tangential displacement increment.

[0107] And in step 404, based on the contact constitutive relation of the joint viscous fracture model, the normal stress in step N+1. Tangential stress τ N+1 It can be represented as:

[0108]

[0109]

[0110] in, For normal stiffness, This refers to the tangential stiffness.

[0111] In step 405, substituting the stress formula from step N+1 into the fracture surface function, we obtain:

[0112]

[0113] In step 406, the relationship between F and 0 is determined. If F ≤ 0, the joint surface state between the blocks is within the elastic range, and no change in the joint parameters is required. Then, step 412 is executed to determine whether N+1 is less than N. max If the maximum number of steps is less than 0, proceed to step 413; otherwise, if the maximum number of steps has been reached, proceed to step 410 to update the block position, and then skip step 411 to end the process. If F > 0, it indicates that the joint surface is in a plastic region, and proceed to steps 407-409: use the return mapping algorithm to correct the joint parameters. Specifically, in step 407, the normal stress is calculated. and tangential stress τ N+1 Specifically, the initial stiffness and elastic function relationships are used for recalculation:

[0114]

[0115]

[0116] in, and The elasticity prediction value is given above. Since the elasticity prediction value is actually in the plastic stage, a callback procedure is needed to correct it.

[0117]

[0118]

[0119] Therefore, the expression for the fracture surface function is updated to:

[0120]

[0121] Where λ is the inelastic multiplier and m represents the direction of the inelastic displacement, these two values ​​are calculated in step 408.

[0122] Additionally, in step 409, the inelastic displacement norm is updated as follows:

[0123]

[0124] Based on the update of the inelastic displacement norm, the tensile strength, cohesion, and internal friction angle in step N+1 are updated as follows:

[0125]

[0126]

[0127]

[0128] By combining the formulas for the fracture surface function and the calculation of λ and m, the normal stress and tangential stress in step N+1 are updated as follows:

[0129]

[0130]

[0131] Then, update the normal stiffness and tangential stiffness according to the following formula:

[0132]

[0133]

[0134] The degenerate stiffness can be expressed as:

[0135]

[0136]

[0137] Then, in step 410, after updating the block position, in step 411, it is determined whether N+1 is less than N. max (Maximum number of steps), if it is less than, proceed to step 413, otherwise proceed to step 414 to obtain the final accumulation shape after the colliding of the ejected rock mass.

[0138] In this embodiment, both aerodynamic analysis models and DEM models are used for analysis, thus enabling a more realistic simulation of the motion process of a projectile landslide.

[0139] like Figure 6 The diagram shown is a structural schematic of an embodiment of the projectile landslide simulation device 5 of the present invention. It includes: an acquisition module 51 for acquiring rock mass parameters of the projectile rock mass; a calculation module 52 for calculating the initial velocity of the projectile rock mass during the landslide; a first processing module 53 for analyzing the flight process of the projectile rock mass in the air using an aerodynamic analysis model based on the rock mass parameters and initial velocity to determine the state parameters of the projectile rock mass before impacting the ground; and a second processing module 54 for analyzing the motion process of the projectile rock mass after impact and after impact using a discrete element method (DEM) model based on the state parameters of the projectile rock mass before impacting the ground to obtain the final shape of the projectile rock mass. Since many implementation details in the device embodiment have been described in the foregoing method embodiments, they will not be repeated here.

[0140] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0141] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0142] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method.

[0143] Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, controller, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0144] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for simulating projectile-type landslide motion, characterized in that, include: Obtain the rock mass parameters of the ejected rock mass; Calculate the initial state parameters of the projected rock mass during the landslide; Based on the rock mass parameters and initial state parameters, an aerodynamic analysis model is used to analyze the flight process of the projected rock mass in the air, so as to determine the state parameters of the projected rock mass before impacting the ground. as well as Based on the state parameters of the projected rock mass before impacting the ground, the discrete element method (DEM) model is used to analyze the motion process of the projected rock mass after impact and after impacting the ground, and the final shape of the projected rock mass is obtained. In the DEM model, crack propagation is calculated and monitored based on the viscous fracture model to simulate the impact and subsequent motion process after impact with the ground. The step of analyzing the motion process of the projected rock mass before and after impact with the ground using a discrete element method (DEM) model based on the state parameters of the projected rock mass before impact includes: Input joint physical parameters: initial tensile strength Initial cohesion c0, initial normal stiffness Initial tangential stiffness Initial internal friction angle Based on the viscous fracture model, the propagation of cracks along artificial joints is calculated and monitored; and an iterative algorithm is used to correct joint parameters to simulate the impact fracture and subsequent motion process of projectile rock mass along artificial joint surfaces. The initial state parameters include at least one of the following: the initial velocity of the projected rock mass during the landslide, and the angle between the axis of the projected rock mass and the horizontal plane; The calculation of the initial velocity of the projected rock mass during the landslide includes: The initial velocity v0 of the projected rock mass during the landslide is calculated using the following formula: Where h is the drop of the centroid of the projectile rock mass, f is the frictional force between the projectile rock mass and the bedrock, s is the path traveled by the projectile rock mass, m is the mass of the projectile rock mass, and β is the angle between the bedrock and the horizontal axis.

2. The simulation method for projectile-type landslide motion as described in claim 1, characterized in that: The rock mass parameters include at least one of the following: internal friction angle, cohesion, and tensile strength.

3. The simulation method for projectile-type landslide motion as described in claim 2, characterized in that: The process of obtaining the rock mass parameters of the projectile rock mass includes: obtaining the rock mass parameters of the projectile rock mass according to the Hoek-Brown criterion.

4. The simulation method for projectile-type landslide motion as described in claim 1, characterized in that: The state parameters of the projected rock mass before impacting the ground include at least one of the following: velocity, horizontal displacement, and vertical displacement upon impact.

5. The simulation method for projectile-type landslide motion as described in claim 1, characterized in that: The aerodynamic analysis model is established based on the following formula: Where x and y are the horizontal and vertical coordinates, respectively; F L For lift; F R For resistance; C L and C R These represent the lift and drag coefficients, respectively; t is time; S is the projected area of ​​the projectile; ρ is the air density; G e α is the dimensionless lift-topographic effect correction coefficient; m is the mass of the projectile; α is the angle of attack; β is the angle between the bedrock and the horizontal axis.

6. The simulation apparatus for the simulation method of projectile landslide motion according to any one of claims 1 to 5, characterized in that, include: The acquisition module is used to acquire the rock mass parameters of the ejected rock mass; The calculation module is used to calculate the initial velocity of the projected rock mass during the landslide; The first processing module is used to analyze the flight process of the projected rock mass in the air using an aerodynamic analysis model based on the rock mass parameters and initial velocity, so as to determine the state parameters of the projected rock mass before impacting the ground. as well as The second processing module is used to analyze the motion process of the projected rock mass after impact and impact with the ground using a discrete element method (DEM) model based on the state parameters of the projected rock mass before impact with the ground, and to obtain the final shape of the projected rock mass.

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