Earth-rock aggregate landslide disaster chain whole process simulation method and system

Abstract

The invention provides a whole-process simulation method and system for an earth-rock mixture landslide disaster chain. The method comprises the following steps: step 1, constructing a solid model and dispersing the solid model into an equidistant particle model; respectively endowing each particle with a basic parameter value and setting a particle type; step 2, constructing a general constitutive model for simultaneously representing the soil body and the rock of the earth-rock mixture landslide; 3, performing particle contact judgment by taking the earth-rock aggregate landslide soil particles, the downstream building particles and the terrain static boundary particles as center particles, and simulating the deformation behavior of the center particles based on the constructed general constitutive model for simultaneously representing the earth-rock aggregate landslide soil body and the rock; step 4, setting a starting discrimination standard of erosion of the soil body and the building along the way; and step 5, carrying out visual output on the calculated characteristic information of each central particle. According to the method, the soil-rock aggregate landslide impact disaster-causing effect can be evaluated more reasonably.

Description

Technical Field

[0001] The invention relates to the technical field of landslide simulation, and in particular to a method and system for simulating the entire process of a soil-rock mixture landslide disaster chain. Background Art

[0002] Once a soil-rock mixture landslide occurs, it is often accompanied by great destructive power, which may cause the destruction of buildings, roads, bridges and other construction facilities, seriously threatening the lives and safety of surrounding residents and pedestrians. Secondly, landslides may also cause problems such as soil and water loss and soil erosion, affecting the sustainable use of land and ecological balance. In addition, due to the existence of its own block rock, the impact damage to buildings along the way and downstream during the movement of soil-rock mixture landslides is often more serious than that of pure soil landslides. Therefore, soil-rock mixture landslides are seriously harmful and pose a potential threat to human life, ecological environment and social economy. How to predict the triggering mode of soil-rock mixture landslides, calculate the impact process of soil-rock mixture landslides, and effectively prevent and control soil-rock mixture landslides are all key issues of concern to the academic and engineering communities.

[0003] There are currently a variety of existing technologies and methods for predicting the sliding surface and analyzing the stability of soil-rock mixture landslides. The following are some commonly used technologies: ① Geological survey and monitoring: Through geological survey and on-site monitoring, obtain geological, hydrogeological and other information of soil-rock mixtures, and monitor the deformation of landslide bodies in real time to evaluate the stability of landslides. However, such methods are usually costly and mainly target known landslide bodies. It is difficult to predict potential landslide bodies, and there is a lag in data transmission. ② Statistical analysis: Through statistical analysis of historical landslide case data, a statistical model is established to predict the location and stability of the sliding surface of the landslide. This method requires a large amount of landslide data, and the prediction of the sliding surface position relies on experience, which is subjective, and it is difficult to consider the impact of gravel on the sliding surface position in soil-rock mixture landslides. ③ Remote sensing technology: Use aerial remote sensing, satellite remote sensing and other technologies to obtain information such as terrain, vegetation, and hydrology in the landslide area, analyze and monitor the geological environment of the landslide, and then evaluate the stability of the landslide. This method is mainly aimed at large-scale areas, and the resolution is limited. Data transmission is affected by weather and has a certain lag. ④ Numerical simulation method: Use numerical simulation programs or software (such as FLAC, UDEC, PLAXIS, etc.) to establish a soil-rock mixture mechanical model, consider the physical and mechanical properties of soil-rock materials, and perform landslide sliding surface prediction and stability analysis. Commonly used numerical methods include finite element method, boundary element method, discrete element method, etc. Numerical simulation methods are currently the trend of development because of their speed and low cost.

[0004] However, in the numerical simulation, especially for landslide triggering criteria, landslide propagation impact large deformation process and hazard assessment, there are few studies that can quantitatively consider the influence of crushed stones. Some methods of randomly generating blocks of stone are based on generalized models, and the obtained block shapes have some limitations, which are still different from the actual block size and shape. In addition, for the simulation of landslide hazard chains, since landslides go from static solid state to propagation state and then to the final accumulation state, traditional single numerical simulation methods are often difficult to simulate the whole process of soil-rock mixture landslide hazard chain. At present, various numerical simulation methods are still under development.

[0005] In the study of the constitutive model of soil-rock mixture landslide materials, the material constitutive behavior of soil-rock mixture is usually nonlinear and inelastic, and has large nonlinear deformation and strain softening characteristics. At present, there are still some limitations in the study of the constitutive model of soil-rock mixture materials: (1) There is still a lack of a universal and accurate constitutive model that describes the mechanical properties of soil-rock mixtures. Soil-rock mixtures are composed of various particles such as soil particles and rock fragments, and have a porous medium structure. They contain multiphase media such as gas, water and solid particles. The establishment and study of multiphase medium models are relatively complex; (2) The constitutive dynamic effects of soil-rock mixture landslide materials are not considered enough. Under external loads such as earthquakes, explosions or engineering vibrations, soil-rock mixtures will experience dynamic effects, such as wave propagation and dynamic instability. However, the existing constitutive models of soil-rock mixtures do not consider the dynamic effects enough and cannot accurately describe the mechanical behavior of soil-rock mixtures under dynamic loads. (3) The study of micro-macro coupling effects is insufficient: the macroscopic mechanical properties of soil-rock mixtures are affected by the interaction between microscopic particles and structural characteristics, and there is a micro-macro coupling effect. Irregular shape is an important property of particles. Limited by technical methods and calculation conditions, the numerical simulation of granular materials in the early stage often used simple particle shapes such as spheres and ellipsoids. With the development of numerical simulation technology, the numerical simulation of granular materials has gradually become more refined. In recent years, three-dimensional laser scanning technology has developed rapidly. The use of three-dimensional laser scanning equipment can quickly obtain scanning point cloud data of the particle surface, and the geometric data information can be processed to establish a fine block aggregate library. However, there is currently insufficient research on the relationship between the microstructure and macroscopic mechanical properties of soil-rock mixtures, and a complete theoretical framework and effective constitutive model have not yet been formed. (4) The evolution mechanism of the whole process of landslide initiation-impact of soil-rock mixtures under extreme conditions such as rainfall. Existing studies have focused on the process of landslide initiation, such as using the finite element method to calculate the landslide stability coefficient. However, this method is difficult to reasonably deal with large deformation problems, and there is still a lack of characterization of the movement and impact process after the landslide initiation. Summary of the invention

[0006] The present invention is made to solve the above-mentioned problems, and its purpose is to provide a method and system for simulating the whole process of landslide disaster chain of soil-rock mixture, to establish a multiphase medium model, to consider the dynamic effect, to study the micro-macro coupling effect and the whole process of landslide initiation impact under complex loads, so as to more accurately describe the mechanical behavior of soil-rock mixture and provide a reliable theoretical basis for engineering practice.

[0007] To achieve the above object, the technical solution of the method of the present invention is:

[0008] A method for simulating the whole process of a soil-rock mixture landslide disaster chain comprises the following steps:

[0009] Step 1. Construct a three-dimensional solid model of the landslide, a three-dimensional solid model of the terrain, and a three-dimensional model of the rock mass respectively; and discretize them into equidistant particle models; assign basic parameter values ​​to each particle and set the particle type;

[0010] Step 2. Construct a general constitutive model that simultaneously characterizes the soil and rock of the soil-rock mixture landslide;

[0011] Step 3. Take the soil particles of the landslide of the soil-rock mixture, the particles of the downstream building, and the static boundary particles of the terrain as the central particles, respectively, to make particle contact judgment, simulate the deformation behavior of the central particles based on the universal constitutive model that simultaneously characterizes the soil and rock of the landslide of the soil-rock mixture, and couple and calculate the characteristic information of different central particles respectively;

[0012] Step 4. Set the criteria for determining the initiation of soil and building erosion along the way, and calculate the initiation process of building erosion under the impact of landslide based on the characteristic information of different central particles;

[0013] Step 5. Visualize the characteristic information of each central particle obtained by calculation and control it by particle type to achieve material output classification.

[0014] Furthermore, in step 1, a three-dimensional model of the blocks is constructed by three-dimensionally scanning a plurality of real blocks, and a three-dimensional solid model of the landslide body with random positions, random shapes and specified block content is generated in the landslide body;

[0015] Acquire the contour lines or elevation point information of the established three-dimensional terrain and fit them into a closed three-dimensional solid model of the terrain;

[0016] The three-dimensional entity model of the landslide body, the three-dimensional entity model of the terrain, and the three-dimensional model of the block rock are discretized into equidistant particle models.

[0017] Furthermore, the method for constructing a three-dimensional stone model comprises:

[0018] Scan multiple real stones in three dimensions and label them, calculate the volume and mass of the stones, and establish a stone database;

[0019] The maximum particle size of each stone in the stone database and the maximum particle size in the direction perpendicular to the maximum particle size are calculated to generate a sphere with the maximum particle size D of the stone as the diameter, a rectangle with the maximum particle size D as the long side and the maximum particle size B in the direction perpendicular to the maximum particle size as the short side, or an ellipsoid with the maximum particle size D as the long side and the maximum particle size B in the direction perpendicular to the maximum particle size as the short side as the stone three-dimensional model.

[0020] Furthermore, the method for constructing a three-dimensional solid model of a landslide body includes:

[0021] Generate a random block rock 3D model, and randomly generate random points K inside the irregular landslide body according to the principle that the block rock 3D models do not invade each other, are inside the landslide body and do not invade the boundary. i , with K i Generate a corresponding block stone three-dimensional model for the center; record the position information K of the center point of the block stone three-dimensional model i (X0, Y0, Z0);

[0022] K i The coordinate system is established with (X0, Y0, Z0) as the center, and the gravel inside the block stone 3D model is randomly rotated around the X' axis, Y' axis, and Z' axis by θ x ,θ y ,θ z angle;

[0023] Continue to generate random block stone 3D models until the specified block stone content is reached.

[0024] Furthermore, the step 1 includes landslide soil particles, landslide boulders and downstream building dynamic boundary particles, and terrain static boundary particles;

[0025] The basic parameters of landslide particles include density, peak internal friction angle, peak cohesion, residual internal friction angle, residual cohesion, elastic modulus, Poisson's ratio, and friction coefficient;

[0026] The basic parameters set for terrain static boundary particles include: density, stiffness, and friction coefficient;

[0027] The basic parameters set for dynamic boundary particles include: density, peak internal friction angle, peak cohesion, residual internal friction angle, residual cohesion, elastic modulus, Poisson's ratio, and friction coefficient.

[0028] Furthermore, the general constitutive model for characterizing the soil and rock of the soil-rock mixture landslide in step 2 is:

[0029]

[0030] In the formula, is the total stress; is the stress caused by particle friction; is the stress generated by particle collision; Stress reduced due to soil softening caused by rainfall; stresses contributing to the solid constitutive model; The stress contributing to the particle flow constitutive model; p solid is the spherical stress tensor of the solid constitutive model; is the deviatoric stress tensor of the solid constitutive structure, also called the shear stress tensor; is the shear stress tensor of the fluid constitutive model; S represents the soil saturation, ranging from 0 to 1; p c represents matrix suction; α and β represent the vector direction of stress; δ αβ is a piecewise function, when α=β, δ αβ The value is 1, otherwise it is 0; is the solid constitutive equation, η is the equivalent viscosity, is the absolute value of the shear strain rate of the fluid constitutive part, is the shear strain rate of the fluid constitutive law, p fluid is the constitutive pressure of the fluid.

[0031] Furthermore, the step 3 simulates the deformation behavior of the central particle based on the constructed general constitutive model for characterizing the soil-rock mixture landslide soil and rock, including:

[0032] Taking the soil-rock mixture landslide soil particle as the central particle i, the control equation is as follows:

[0033]

[0034]

[0035] In the formula, ρ i is the density of the central particle i; t is the calculation time; m j is the mass of particle j; is the velocity difference between the central particle i and the surrounding particle j in the influence domain, i.e. The direction is β direction; W is the smooth kernel function, W ij,β represents the weight value of all particles j in the influence area centered on particle i in the β direction; x is the position coordinate of the base point, is the distance of particle i in the β direction; is the velocity gradient of the central particle i, that is, the acceleration of particle i; is the stress tensor of particle i, is the stress tensor of particle j, is the pressure of particle j, is the shear stress of particle j, g α is the acceleration of gravity; α and β represent the vector direction of stress. Stress is a third-order tensor. Both α and β can correspond to the three directions of x, y, and z. SR is the landslide soil particle area, SB is the terrain boundary particle area, and DB is the downstream building particle area.

[0036] Taking the downstream building particle as the central particle k, the control equation is as follows:

[0037]

[0038]

[0039]

[0040] In the formula, ρ k is the density of the central particle k; is the velocity difference between the central particle k and the surrounding particles j in the influence domain, i.e. W kj, β is the weight value of all particles j in the influence area centered on particle k in the β direction; is the distance of particle k in the β direction; m k is the mass of the central particle k; building A1 has mass M A1 , speed V A1 , inertia tensor I A1 , angular velocity Ω A1 and the center of gravity R A1 ; r k is the center of gravity of particle k; p k αβ is the pressure of particle k, τ k αβ is the shear stress of particle k, σ j αβ is the stress of particle j; F A2→k It is the collision force of the remaining stones or buildings on the k particles on stone A.

[0041] The terrain static boundary particles are taken as the central particles. The terrain boundary particles participate in the stress calculation, but the displacement is not updated, that is, the position of the terrain boundary particles is considered to be fixed.

[0042] Furthermore, the criterion for starting erosion of buildings along the way in step 4 is:

[0043]

[0044] Among them, F 冲击力 is the impact force on the building, F 抗倾覆 is the maximum anti-overturning force of the buildings along the way, and N is the total number of particles that make up the buildings along the way.

[0045] Furthermore, step 5 includes: in each time step, the field variable information of each particle is calculated by the smooth particle fluid dynamics method, and the obtained information is digital text information, which is converted into a binary VTK file output for visualization, wherein the particle output of different partitions is controlled by the particle type to realize material output classification.

[0046] On the other hand, the present invention provides a whole process simulation system of soil-rock mixture landslide disaster chain, comprising:

[0047] Particle model construction module: It is used to construct the three-dimensional solid model of the landslide body, the three-dimensional solid model of the terrain, and the three-dimensional model of the block stone respectively; and discretize them into equidistant particle models; assign basic parameter values ​​to each particle and set the particle type;

[0048] Constitutive model building module: It is used to build a general constitutive model that simultaneously characterizes the soil and rock of a soil-rock mixture landslide;

[0049] Coupling calculation module: It is used to determine particle contact by taking soil-rock mixture landslide soil particles, downstream building particles, and terrain static boundary particles as central particles, and simulate the deformation behavior of central particles based on the universal constitutive model that simultaneously characterizes soil-rock mixture landslide soil and rock, and couples and calculates characteristic information of different central particles respectively;

[0050] Erosion initiation judgment module: It is used to set the erosion initiation judgment criteria for soil and building along the way, and calculate the building erosion initiation process under the impact of landslide based on the characteristic information of different central particles;

[0051] Visualization output module: It is used to visualize the characteristic information of each central particle obtained by calculation, and control it through particle type to realize material output classification.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] (1) The present invention proposes a method for simulating the entire process of rainfall-induced soil-rock mixture landslide initiation and impact disaster, and establishes an unsaturated general constitutive model that takes into account rainfall infiltration and soil rate-related effects. The constitutive model can be used to simulate the behavior of soil and rock mass, such as yielding, fracture and crushing, and realize the process of the landslide body from static solid state to triggered quasi-static state, then to flowing state and finally to accumulated solid state. Each process can achieve automatic and smooth transition without any discrimination conditions, which makes up for the deficiency of single constitutive models such as Drucker-Prager in traditional landslide simulation that cannot consider the rate-related effects after soil yielding.

[0054] (2) The present invention breaks through the limitations of the generalized model used in the traditional process of modeling the rock mass of soil-rock mixture landslides, which is highly subjective, uncertain, and out of touch with engineering practice. A rock mass database based on a three-dimensional scanning method is established by taking into account the real rock mass shape. By randomly arranging rocks in the landslide body, a three-dimensional model of the landslide is constructed that takes into account the real rock mass shape and different rock mass contents. Finally, a high-fidelity modeling method for soil-rock mixture landslides is formed, with a modeling accuracy of millimeter level and a rock mass modeling content of more than 60%.

[0055] (3) The present invention takes into account the influence of rock fragmentation, rock content, position, shape, size, etc. inside the landslide body on the position of the potential sliding surface, and realizes real-time and accurate prediction of the potential sliding surface of the landslide, which makes up for the shortcomings of the existing model method that requires the preset sliding surface position, the assumption of the sliding surface shape or the inaccurate prediction of the landslide surface, resulting in distortion in the prediction of the subsequent landslide volume and disaster-causing impact process.

[0056] (4) The present invention can be used in the field of landslide warning and risk assessment. For soil-rock mixture landslides in high mountain canyon areas, this method takes into account the rainfall infiltration effect, simulates the entire process of landslide erosion initiation, scraping and entrainment, and can more reasonably evaluate the impact disaster effect of soil-rock mixture landslides. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0058] Figure 1 Schematic diagram of the geometric outline of the block stone in the embodiment of the present invention.

[0059] Figure 2 This is a schematic diagram of stone placement according to an embodiment of the present invention.

[0060] Figure 3 This is a schematic diagram of random rotation of stones inside a sphere according to an embodiment of the present invention.

[0061] Figure 4 A block diagram of a specified block content and gradation is generated for an embodiment of the present invention.

[0062] Figure 5 This is a schematic diagram of placing real stone blocks in modeling software according to an embodiment of the present invention.

[0063] Figure 6 This is a schematic diagram of an equidistant particle model of stone block No. 1 obtained by sampling with different particle spacings in an embodiment of the present invention.

[0064] Figure 7Schematic diagram of stress solution of the solid constitutive part of an embodiment of the present invention.

[0065] Figure 8 Schematic diagram of the success rate of single-grade block stone generation according to an embodiment of the present invention.

[0066] Fig. 9 Schematic diagram of the success rate of multi-graded block stone generation according to an embodiment of the present invention.

[0067] Fig.10 It is a schematic diagram of the process of constructing a three-dimensional solid model of a landslide body according to an embodiment of the present invention.

[0068] Fig.11 It is a schematic diagram of the sliding process of a soil-rock mixture landslide at the initial moment of an embodiment of the present invention.

[0069] Fig.12 It is a schematic diagram of the accumulation process of soil-rock mixture landslide at the final moment of an embodiment of the present invention.

[0070] Fig.13 It is a schematic diagram of the evolution of the sand column collapse velocity field and the slope line comparison at different times according to an embodiment of the present invention.

[0071] Fig.14 It is a schematic diagram of the evolution of the sand column collapse velocity field and the slope line comparison at different times according to an embodiment of the present invention.

[0072] Fig.15 It is a schematic diagram of the layout of the indoor impact test device according to an embodiment of the present invention.

[0073] Fig.16 Schematic diagram of the velocity field evolution process of sand column particles impacting the baffle according to an embodiment of the present invention.

[0074] Fig.17 This is a schematic diagram of the comparison results of the impact force of the sand column impacting the baffle in an embodiment of the present invention.

[0075] Fig.18 It is a schematic diagram of the landslide velocity field at different times with 0% rock content in an embodiment of the present invention.

[0076] Fig.19 It is a schematic diagram of the landslide velocity field at different times with a rock content of 25% in an embodiment of the present invention.

[0077] Fig. 20 This is a schematic diagram of the building erosion initiation process according to an embodiment of the present invention.

[0078] Fig.21 It is a schematic diagram of the impact force change during the building erosion startup process according to an embodiment of the present invention. DETAILED DESCRIPTION

[0079] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0080] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0081] A method for simulating the whole process of a soil-rock mixture landslide disaster chain comprises the following steps:

[0082] Step 1. Construct a 3D solid model of the landslide, a 3D solid model of the terrain, and a 3D model of the block stone respectively; and discretize them into equidistant particle models; assign basic parameter values ​​to each particle and set the particle type; in step 1, perform 3D scanning on multiple real blocks of stone to construct a 3D block stone model. Figure 1 The geometric outlines of different rocks are shown. (a), (b), (c), (d), and (e) are rock 1, rock 2, rock 3, rock 4, and rock 5, respectively. A three-dimensional solid model of a landslide with random positions, random shapes, and specified rock content is generated in the landslide.

[0083] After the real rock mass shape is obtained, soil-rock mixed landslides with different positions, shapes and rock mass contents are generated in the irregular landslide body. Figure 2 The method shown first calculates the maximum particle size of each stone in the stone pool, as well as the maximum particle size in the direction perpendicular to the maximum particle size, which are used to determine the subsequent diameter of the sphere and the long and short sides of the rectangle and ellipsoid. Then generate a sphere with the maximum particle size D of the stone as the diameter; a rectangle with the maximum particle size D as the long side and the maximum particle size B in the direction perpendicular to the maximum particle size as the short side; and an ellipsoid with the maximum particle size D as the long side and the maximum particle size B in the direction perpendicular to the maximum particle size as the short side. Ensure that the real three-dimensional stone model is contained in the sphere, rectangle or ellipsoid, and mark the volume, density, maximum particle size D and maximum particle size B in the direction perpendicular to the maximum particle size of each stone. Then, it is necessary to randomly place spheres, rectangles or ellipsoids with specified contents and random positions in the irregular landslide body, as shown in the following example. Figure 2 As shown in Figure 2, for the realization of random rock positions in the landslide body, taking a sphere as an example,

[0084] (a) Generate random spheres. According to the principle that spheres do not invade each other and spheres are inside the landslide body and do not invade the boundary, random points K are randomly generated inside the irregular landslide body. i , with K i Generate a corresponding sphere for the center of the circle;

[0085] (b) Determine whether the sphere meets the requirements. If there is intrusion between spheres or between the sphere and the landslide boundary, it is considered that the sphere generation has failed and the random point K needs to be regenerated. i , and then regenerate the sphere for judgment; when both the conditions of no intrusion between spheres and no intrusion between the sphere and the landslide body boundary are met, the sphere is considered to be generated successfully, and the position information K of the sphere center is recorded at this time i (X0,Y0,Z0).

[0086] (c) When the sphere K inside the irregular landslide i After generation, K i With (X0, Y0, Z0) as the center, a coordinate system is established, and the gravel inside the sphere is randomly rotated by θ around the X' axis, Y' axis, and Z' axis respectively. x ,θ y ,θ z Angle, such as Figure 3 As shown, denoted as: θ i =random(0,2π), i=x,y,z, random(0,2π) is a random number between 0 and 2π.

[0087] For the realization of the specified rock content in the landslide body, taking a sphere as an example, when a randomly located sphere is generated in an irregular landslide body and rocks are generated at random locations inside the sphere, the ratio of the generated rock mass to the total mass of the landslide body is calculated through the previously statistically obtained rock mass and other parameters, which is the current rock content of the landslide body. When the rock content inside the landslide body does not reach the specified rock content, random rocks will continue to be generated until the specified rock content is reached.

[0088] For the size of the stone, taking a sphere as an example, the volume transformation ratio coefficient ζ is set. When the user needs to generate stones of different sizes, it can be achieved by adjusting the size of the volume transformation ratio coefficient ζ (ζ>1 means enlarging the volume of the stone, ζ<1 means reducing the volume of the stone, and the default ζ=1 means keeping the original scanned stone volume).

[0089] For irregular landslides with specified grading and stone content, the existence of large and small rock models in the model makes it easier to consider the macro-micro coupling effect of crushed stone in subsequent calculations, such as Figure 4Generate a specified block rock gradation distribution ratio. First, determine the block rock ratio distribution to be generated, that is, formula (1), and then adjust the volume conversion ratio coefficient ζ each time the block rock is generated. For example, if the ratio between r0 and r1 is P0, if the imported block rock particle size is D, then let the random value range of ζ be between (r0 / D, r1 / D) until the generated block rock content reaches the P0 ratio. Then, for the ratio between r2 and r2 is P1, the same processing method is used until a soil-rock mixture landslide with the specified target gradation is generated.

[0090]

[0091] g(d) is the probability density distribution function, P0, P1~P n-1 is the ratio of different particle size ranges, d0, d1~d n-1 ,d n is the particle size of different rocks, d0 <d1<....<d n ,.

[0092] Acquire the contour lines or elevation point information of the established three-dimensional terrain and fit them into a closed three-dimensional solid model of the terrain;

[0093] The three-dimensional entity model of the landslide body, the three-dimensional entity model of the terrain, and the three-dimensional model of the block rock are discretized into equidistant particle models.

[0094] Landslides, three-dimensional terrain entities, and random rock models can be imported into the modeling software for visualization. Figure 5 This is a schematic diagram of the placement of real blocks. During the placement process, it is necessary to ensure that there is no overlap between the blocks. Subsequently, the solid model is discretized into an equidistant particle model using the following sampling algorithm: a point is set inside the solid model as the seed generation point, and a calculation domain M is set that includes the solid model. Particles are generated in this calculation domain. The particle generation judgment criteria are as follows: when a particle is within the boundary N of the solid model, this particle is generated; when a particle is not within the boundary N of the solid model, this particle is discarded, where the M area contains the N area. By setting the particle spacing, the accuracy of landslide modeling can reach the centimeter level, realizing high-fidelity modeling of three-dimensional landslide models. Figure 6 (1)-(4) adopt 0.02m, 0.01m, 0.005m and 0.0025m particle spacing sampling to obtain the equidistant particle model of the block stone, and the total number of particles is 2830, 19162, 140309 and 1074645 respectively. The smaller the particle spacing, the finer the block stone model is.

[0095] Step 1 includes landslide soil particles, landslide boulders and downstream building dynamic boundary particles, and terrain static boundary particles;

[0096] First, define the parameters of each model particle, and use the variable Type(i) to define the particle type for subsequent contact judgment:

[0097] For 1) landslide soil particle i, basic parameters such as density, peak internal friction angle, peak cohesion, residual internal friction angle, residual cohesion, elastic modulus, Poisson's ratio, friction coefficient, and particle type Type(i)=1 are defined.

[0098] For 2) terrain particle i (static boundary), basic parameters such as density, stiffness, friction coefficient, and particle type Type(i)=2 are defined.

[0099] For 3) landslide blocks and downstream building particles i, basic parameters such as density, peak internal friction angle, peak cohesion, residual internal friction angle, residual cohesion, elastic modulus, Poisson's ratio, friction coefficient, and particle type Type(i)=3 are defined.

[0100] And set the parameter interface. If there are new parameters, you can continue to add them in this module.

[0101] According to the defined particle type parameters, all particle contact types are judged. If the particle radius is set to r, the particle influence domain range is 2r (it can also be 3r or 4r. The larger the coefficient, the lower the calculation efficiency). That is, the contact calculation will be performed only when the distance between two particles does not exceed 2r. Taking landslide soil particles and rock particles as an example, for any two particles i and j, if (Type(i)=1).and.(Type(j)=3) or (Type(i)=3).and.(Type(j)=1) are satisfied at the same time, the contact between the landslide soil particles and the rock particles is calculated, that is, step 2.3. For the calculation of other different particle types, the steps are the same.

[0102] Step 2. Construct a general constitutive model that simultaneously characterizes the soil and rock of the soil-rock mixture landslide;

[0103] Landslides, as seemingly simple granular materials, exhibit more complex motion characteristics than solids and fluids: before a landslide occurs, soil particles remain in their original positions with only minor deformations; once instability and failure occur, soil particles exhibit large deformation and flow motion; due to friction between particles, they return to a static state after a period of time. In existing studies, the constitutive model of landslide soil is mainly based on elastic-plastic models, such as the Mohr-Coulomb and Drucker-Prager criteria applicable to geotechnical materials as yield functions. Soil is a granular material, and particle collisions are inevitable during large deformation failure, resulting in fluid-like motion. Many scholars have proposed flow constitutive models such as Bingham, Cross, and HBP models, which are applicable to Newtonian and non-Newtonian fluids. Before a landslide is triggered, scholars use a constitutive model based on solid mechanics to simulate the deformation characteristics of a landslide. After a landslide is triggered, large deformation occurs, and scholars often use a constitutive model based on fluids to simulate it. Two different constitutive models are used before and after the landslide is triggered. First, the parameters are not uniform. Second, the critical point of the transition between the solid constitutive model before the trigger and the fluid constitutive model after the trigger is difficult to determine. In addition, the rocks in the soil-rock mixture landslide are cracked during the movement. The existing numerical simulation methods, such as using DEM to simulate the rocks, cannot characterize the critical and dynamic behavior of the rocks. Therefore, there is a lack of a universal constitutive model that can simulate soil and rock at the same time.

[0104] According to the movement mechanism of solid and fluid, the stress in the solid stage is mainly generated by friction between particles, and the stress in the fluid stage is mainly generated by particle collision. After reaching the yield state, the existing solid constitutive models such as the Drucker-Prager model enter the plastic flow state. The strain rate change in the model is always 0, but at this time the landslide presents the characteristics of fluidization movement, and its stress changes with the strain, that is, the strain rate is not 0, so the solid constitutive model cannot reflect this characteristic. The fluid constitutive model is a rate-dependent constitutive model, which can reflect the evolution of strain rate with stress, but the fluid constitutive model is mainly suitable for high-speed particle flow, and cannot model the process of landslide triggering and entering yield, that is, it cannot predict the critical sliding and sliding surface position of the landslide.

[0105] Therefore, this patent proposes a universal constitutive model that has the advantages of both solid and fluid constitutive models. It does not need to set the solid-fluid phase change criteria, and can automatically achieve smooth conversion between solid and fluid behaviors through strain rate, and can simultaneously simulate complex behaviors such as soil yield and rock fracture. This patent proposes a universal constitutive model that can simulate the entire process of quasi-static, dynamic and accumulated solid state triggered by soil-rock mixture landslides. The total stress format of the model using stress decomposition is as follows:

[0106]

[0107] In the formula, is the total stress; is the stress caused by particle friction; is the stress generated by particle collision; Stress reduction due to soil softening caused by rainfall; stresses contributing to the solid constitutive model; The stress contributing to the particle flow constitutive model; p solid is the spherical stress tensor of the solid constitutive model; is the deviatoric stress tensor of the solid constitutive structure, also called the shear stress tensor; is the shear stress tensor of the fluid constitutive equation, which can be expressed as Solution; S represents soil saturation, ranging from 0 to 1; p c represents matrix suction; α and β represent the vector direction of stress; δ αβ is a piecewise function, when α=β, δ αβ The value is 1, otherwise it is 0; is the solid constitutive equation, η is the equivalent viscosity, is the absolute value of the shear strain rate of the fluid constitutive part, is the shear strain rate of the fluid constitutive law, p fluid is the constitutive pressure of the fluid, which can be obtained from the equation of state Find, where c s is the speed of sound, ρ0 is the initial density, γ is the shear strain, ρ i is the temporary density calculated at each moment.

[0108] For the reduction of soil strength due to rainfall, σ rain The solution involves p c The following formulas are mainly used to solve the matrix suction and S saturation:

[0109]

[0110] In the formula, n is the porosity, S is the saturation, K is w is the bulk modulus of the water phase, p c is the matrix suction, ρ w is the density of water phase, q w is the seepage rate, v s is the velocity of the soil phase, subscript s represents the soil phase, subscript w represents the water phase, S min is the residual saturation, S min is the maximum saturation, λ, p ref is the fitting parameter.

[0111] The constitutive model is implemented in the smooth particle fluid dynamics method, and the incremental method is used to iteratively calculate the stress value of the landslide soil particles. When the stress point σ in the nth calculation step is n In the elastic region shown in the figure, the generalized Hooke's law is used to calculate the test stress value σ of the n+1th calculation step*(n+1) :

[0112] σ *(n+1) =σ n +(ω·σ n -σ n @ω+2Gs solid +Kp solid δ αβ I)Δt (5)

[0113] Where: ω·σ n -σ n ω represents Jaumann stress (where ω is the rotation tensor), G and K are shear modulus and bulk modulus respectively. The conversion formulas of shear modulus and bulk modulus with elastic modulus E and Poisson's ratio υ are G=E / [2(1+υ)] and K=E / [3(1-2υ)], I is the second-order unit tensor, and Δt is the time step increment. The stress value σ calculated according to formula (5) is *(n+1) It may exceed the yield surface of the constitutive model or even appear in the tensile failure area, and needs to be corrected to obtain the stress value σ of the n+1th calculation step n+1 , and then pulled back to the yield surface.

[0114] The amendments mainly target That is, the stress contributed by the solid constitutive structure is as follows: Figure 7 As shown, the algorithm sets a △t time step, and calculates the stress increment at each time step and continuously updates it. When the stress exceeds the yield surface, the stress is pulled back to the yield surface. Figure 7 Three regions are displayed: elastic region, shear failure region, and tensile failure region. The following steps are performed at each time step and the stress value is updated.

[0115] Case 1: If and The particles undergo shear yielding, and the stress will be pulled back to the AB yield surface;

[0116] Case 2: If and The particles are in the elastic stage, no damage occurs, and the stress does not need to be corrected;

[0117] Case 3: If and The particles undergo shear yielding, and the stress will be pulled back to the AB yield surface;

[0118] Case 4: If and When the particle undergoes tensile yield, the stress will be pulled back to the AD yield surface;

[0119] When the soil yields, its stress value is pulled back to the yield surface. At this time, the soil or rock mass is equivalent to being destroyed, and the stress intensity decreases. Its strength value needs to be reduced. The formula is as follows:

[0120]

[0121] Where: φ(κ) is the real-time internal friction angle of soil or rock; φ r is the residual internal friction angle of soil or rock; φ p is the peak internal friction angle of soil or rock; c(κ) is the real-time cohesion of soil or rock; c r is the residual internal cohesion of soil or rock; c p is the peak cohesion of soil or rock; φ(κ) is the real-time internal friction angle calculated for each time step; c(κ) is the real-time cohesion calculated for each time step; the coefficient κ is related to the strain and η φ is the softening coefficient, which controls the speed of strength reduction. It is generally believed that the strength of rock mass after fracture is 0, so its residual internal friction angle and residual cohesion can be set to 0.

[0122] Step 3. Take the soil particles of the landslide of the soil-rock mixture, the particles of the downstream building, and the static boundary particles of the terrain as the central particles, respectively, to make particle contact judgment, simulate the deformation behavior of the central particles based on the universal constitutive model that simultaneously characterizes the soil and rock of the landslide of the soil-rock mixture, and couple and calculate the characteristic information of different central particles respectively;

[0123] The objects involved in the whole process of the evolution of the soil-rock mixture landslide hazard chain include landslide soil, rocks in the landslide, terrain static boundary, and downstream buildings. In this patent algorithm, the crushing and cracking of rocks are taken into account, and the landslide soil and rocks are simulated using the proposed general constitutive model. Since the soil and rocks use the same constitutive model, the soil particles and rock particles are uniformly recorded as the region SR (Soil and Rock) during contact search and judgment; the downstream buildings are simulated using the SPH dynamic boundary, recorded as DB (Dynamic boundary); the terrain static boundary is simulated using the SPH static boundary, recorded as SB (Static boundary).

[0124] 1) With soil particle i of the soil-rock mixture landslide as the center, the main contact relationships of soil particles are: contact with similar soil particles and rocks in the landslide, contact with dynamic boundary particles of downstream buildings, and contact with static boundary particles of terrain. First, contact judgment is performed, and then the following control equations are used to solve particle velocity, displacement, position and other information:

[0125]

[0126] In the formula, ρi is the density of the central particle i; t is the calculation time; m j is the mass of particle j; is the velocity difference between the central particle i and the surrounding particle j in the influence domain, i.e. The direction is β direction; W is the smooth kernel function, W ij,β represents the weight value of all particles j in the influence area centered on particle i in the β direction; x is the position coordinate of the base point, is the distance of particle i in the β direction; is the velocity gradient of the central particle i, that is, the acceleration of particle i; is the stress tensor of particle i, is the stress tensor of particle j, is the pressure of particle j, is the shear stress of particle j, g α is the acceleration of gravity; α and β represent the vector direction of stress. Stress is a third-order tensor. Both α and β can correspond to the three directions of x, y, and z. SR is the landslide soil particle area, SB is the terrain boundary particle area, and DB is the downstream building particle area.

[0127] 2) With the downstream building particle i as the center, there are three types of contact relationships, including: collision between the building and the soil and rocks, collision between multiple buildings, and contact between the building and the terrain boundary particles. Assume that the rock or building A is composed of a series of corresponding particles k, and calculate the particle velocity, displacement, position and other information based on the following formula:

[0128]

[0129]

[0130] In the formula, ρ k is the density of the central particle k; is the velocity difference between the central particle k and the surrounding particles j in the influence domain, i.e. W kj,β The weight value of all particles j in the influence area centered on particle k in the β direction; is the distance of particle k in the β direction; m k is the mass of the central particle k; building A1 has mass M A1 , speed V A1 , inertia tensor I A1 , angular velocity Ω A1 and the center of gravity R A1 ; r k is the center of gravity of particle k; p k αβ is the pressure of particle k, τ k αβis the shear stress of particle k, σ j αβ is the stress of particle j; F A2→k is the collision force of the remaining stones or buildings on the k particles on stone A, which is calculated by the following formula:

[0131] F A2→k =F n,ij +F t,ij (13)

[0132]

[0133] In the formula, F n,ij is the normal contact force; F t,ij is the tangential contact force; The normal stiffness coefficient is related to the elastic modulus, Poisson's ratio and particle radius, is the normal damping constant, e ij is the coefficient of restitution, k t,ij =2 / 7k n,ij is the tangential stiffness coefficient, γ n,ij =2 / 7γ n,ij is the tangential damping coefficient, δ ij =max(0,(d i +d j ) / 2-|r ij |) is the intrusion distance between particles, which is used to characterize the degree of collision between particles. ij is a unit vector, is the normal deformation rate. Tangential contact force F t,ij Given by:

[0134]

[0135] 3) With the terrain static boundary particles as the center, the main contact relationships are: contact with landslide soil particles and boulders, and contact with building particles. During the calculation process, the terrain boundary particles participate in the stress calculation, but the displacement is not updated, that is, the position of the terrain boundary particles is considered to be fixed.

[0136] Step 4. Set the criteria for determining the initiation of soil and building erosion along the way, and calculate the initiation process of building erosion under the impact of landslide based on the characteristic information of different central particles;

[0137] After the landslide starts, it will evolve and impact downstream, entraining soil along the way, causing the volume to increase. At the same time, when the landslide impacts a building, it may cause the building to be swept away together. This patent proposes an erosion initiation algorithm for soil and building along the way under the impact of a soil-rock mixture landslide. Erosion initiation occurs when the soil along the way yields under the impact of the landslide. For buildings along the way, the impact resistance of the rocks or buildings along the way is used as the judgment standard. When the impact force on the building is greater than the building's own anti-overturning force, the building will be washed away or even swept away by the landslide. The judgment criteria are as follows:

[0138]

[0139] According to formula (17), the impact force F on the building is calculated in each calculation step. 冲击力 It can realize real-time prediction of the impact response and deformation characteristics of buildings along the way under the impact of soil-rock mixture landslide, and at the same time give the starting criteria for impact erosion of soil-rock landslide, and compare the impact force with the maximum anti-overturning force of buildings along the way. When the impact force is greater than the anti-overturning force, the buildings along the way will be entrained or collapse, and will be subsequently eroded away by the landslide, causing the volume of the landslide to increase, forming a disaster amplification effect.

[0140] Step 5. Visualize the characteristic information of each central particle obtained by calculation and control it by particle type to achieve material output classification.

[0141] In each time step, the field variable information of each particle, such as stress, strain, displacement, velocity, acceleration, etc., is calculated by the smooth particle fluid dynamics method. The obtained information is digital text information, which is converted into binary VTK file output for visualization until the calculation is terminated when the preset calculation step is reached, and finally a series of output result files at different times are obtained. The particle output of different partitions is controlled by particle type, which can realize material output classification. Therefore, binary files containing particle information such as landslide soil, block stone and building can be output respectively. Such files can be displayed in some general open source software such as Paraview.

[0142] Example 1

[0143] This embodiment implements the modeling of random block stone content and gradation distribution, adopts the 1m×1m model to verify the sampling algorithm, and performs sampling modeling for single gradation (same block stone shape) and multi-gradation (different block stone shapes), taking into account different crushed stone shapes and different crushed stone contents.

[0144] Depend on Figure 8It can be seen that the content below 30% is generated very smoothly, but when the stone content increases, it is impossible to generate a stone content distribution that meets the requirements, and the larger the stone content, the larger the error between the calculated stone area and the target value. When the initial block area is small, this error will be relatively reduced. In view of the deficiency that single grading cannot generate a higher crushed stone content, the Fuller gradation sampling algorithm is used to improve it, and block distribution with different gradations, different shapes and different stone contents is selected. The success rate of block generation can reach 60%. The calculation results are shown in Fig. 9 shown.

[0145] For the 3D landslide modeling process, a 3D solid model of soil-rock mixed landslide was established based on 3D laser scanning technology, such as Fig.10 shown.

[0146] Example 2

[0147] This embodiment simulates the whole process of soil-rock mixture landslide initiation-movement-deposition. According to the established soil and rock particle model of soil-rock mixture landslide, the method of this patent is used for calculation. Fig.11 and Fig.12 The figure shows the results of the initiation and accumulation of soil-rock mixture landslides with different rock content. It can be seen that the position and shape of the rock will affect the distribution of the plastic zone of the landslide and the final accumulation process, and the plastic zone will have a rock-circling phenomenon near the rock. This case shows that the general constitutive model and numerical simulation method used in this patent can better calculate the entire process of the initiation-movement-accumulation of soil-rock mixture landslides.

[0148] Example 3

[0149] In this embodiment, the collapse test of a square particle column is numerically simulated, and a two-dimensional sand column collapse test is carried out to verify the rationality of the general constitutive model. The sand column is 0.2m long and 0.1m high. It collapses naturally under the action of gravity. The particle spacing of the sand column is set to 1mm. The material parameters of the sand column are as follows: density is 2040kg / m 3 , elastic modulus E=5.84Mpa, Poisson's ratio is 0.3, internal friction angle is 21.9°, and cohesion is 0.

[0150] Fig.13 The evolution of the collapse velocity field of the sand column at different times and the comparison of the particle flow contours are given. It can be seen that the numerical simulation results of this study are in good agreement with the experimental results, indicating that the SPH model established by this algorithm can predict the large deformation behavior of granular materials. When the sand column reaches equilibrium, the final accumulation shape is as follows Fig.14 As shown, according to the cumulative plastic strain distribution, an obvious shear band interface can be observed. It can be seen that the undisturbed area obtained in this study is basically consistent with the experimental results, which further proves the rationality of the current constitutive model.

[0151] Example 4

[0152] This embodiment compares the particle flow impact test to verify the reliability of the model in calculating the impact response of the landslide evolution process, and compares the indoor impact test results for the process of the landslide directly impacting the building. Fig.15 The indoor impact test device used is as follows. At the initial moment, after the wooden box door is opened, the fine sand moves along the chute under the action of gravity. The density of the fine sand is 1379kg / m 3 , the internal friction angle is 35°, and the cohesion is 0. A landslide impact baffle model is established, and the particle spacing is set to 0.01m. (a) is a real picture of the test device, and (b) is a schematic diagram of the geometric parameters of the test device.

[0153] Fig.16 The velocity field evolution process of the sand column impacting the baffle at different times is given. Fig.16 It can be seen that the simulation results are similar to the experimental phenomena. Fig.17 This is a comparison chart of the impact force time history curves obtained from indoor tests and numerical simulations. Fig.17 It shows that the time point of landslide impact on the baffle calculated in this study is basically consistent with the test. For the peak impact force, the peak impact force on the baffle in the test is 188.6N, and the peak impact force obtained in this study is 188.2N, which is slightly lower than the test value. The relative error of the peak impact force is 0.2%. Overall, it can be seen that the impact force obtained in this study is in good agreement with the test results.

[0154] Example 5

[0155] This embodiment simulates the dynamic process of landslides with different rock content triggering impact on buildings. In this embodiment, there is a concrete building with a height of 1.0m and a width of 0.5m at 3m from the foot of the slope, which simulates the dynamic process of contact and collision between the landslide body and the building. Fig.18 is the landslide velocity field of the slope without boulders at different times, Fig.19 The landslide velocity field of the slope with 25% rock content at different times. It can be seen that the front edge of the landslide moves faster while the rear edge moves slower. After contacting and colliding with the building, the speed decreases continuously and eventually tends to be stable. During the large deformation and destruction process, the rock will move, flip and collide. The existence of rock makes the velocity field of the soil fragmented and discontinuous.

[0156] Example 6

[0157] This embodiment sets the criterion for the initiation of landslide impact erosion. For a certain actual engineering case, a "landslide-terrain-building" coupling calculation model is established to obtain the initiation process of building erosion under the action of landslide impact ( Fig. 20 ), and the impact force variation process of the two buildings is given ( Fig.21), combined with the erosion initiation process and the impact force time history, it can be seen that the tower house closer to the landslide was first subjected to a severe impact, and its impact force was greater than the anti-overturning force, causing the tower house to collapse and then be carried away by erosion. As the red house building is far away from the landslide, when the landslide spreads to the house building, its kinetic energy dissipates more, and the red house has a larger gravity and strong anti-overturning ability, so the impact force it receives is less than the anti-overturning force, and the red house building does not collapse, that is, no erosion initiation occurs.

[0158] Example 7

[0159] This embodiment provides a soil-rock mixture landslide disaster chain whole process simulation system, including:

[0160] Particle model construction module: It is used to construct the three-dimensional solid model of the landslide body, the three-dimensional solid model of the terrain, and the three-dimensional model of the block stone respectively; and discretize them into equidistant particle models; assign basic parameter values ​​to each particle and set the particle type;

[0161] Constitutive model building module: It is used to build a general constitutive model that simultaneously characterizes the soil and rock of a soil-rock mixture landslide;

[0162] Coupling calculation module: It is used to determine particle contact by taking soil-rock mixture landslide soil particles, downstream building particles, and terrain static boundary particles as central particles, and simulate the deformation behavior of central particles based on the universal constitutive model that simultaneously characterizes soil-rock mixture landslide soil and rock, and couples and calculates characteristic information of different central particles respectively;

[0163] Erosion initiation judgment module: It is used to set the erosion initiation judgment criteria for soil and building along the way, and calculate the building erosion initiation process under the impact of landslide based on the characteristic information of different central particles;

[0164] Visualization output module: It is used to visualize the characteristic information of each central particle obtained by calculation, and control it through particle type to realize material output classification.

[0165] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0166] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if these modifications and variations of the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0167] Other parts not described in detail are all prior art.

Claims

1. A method for simulating the whole process of soil-rock mixture landslide disaster chain, characterized in that: The steps include: Step 1. Construct a three-dimensional solid model of the landslide, a three-dimensional solid model of the terrain, and a three-dimensional model of the rock mass respectively; and discretize them into equidistant particle models; assign basic parameter values ​​to each particle and set the particle type; Step 2. Construct a general constitutive model that simultaneously characterizes the soil and rock of the soil-rock mixture landslide; Step 3. Take the soil particles of the landslide of the soil-rock mixture, the particles of the downstream building, and the static boundary particles of the terrain as the central particles, respectively, to make particle contact judgment, simulate the deformation behavior of the central particles based on the universal constitutive model that simultaneously characterizes the soil and rock of the landslide of the soil-rock mixture, and couple and calculate the characteristic information of different central particles respectively; Step 4. Set the criteria for determining the initiation of soil and building erosion along the way, and calculate the initiation process of building erosion under the impact of landslide based on the characteristic information of different central particles; Step 5. Visualize the characteristic information of each central particle obtained by calculation and control it by particle type to achieve material output classification.

2. The method for simulating the whole process of a soil-rock mixture landslide disaster chain according to claim 1, characterized in that: In the step 1, a three-dimensional model of a rock block is constructed by three-dimensionally scanning a plurality of real rock blocks, and a three-dimensional solid model of a landslide body with a random position, a random shape and a specified rock block content is generated in the landslide body; Acquire the contour lines or elevation point information of the established three-dimensional terrain and fit them into a closed three-dimensional solid model of the terrain; The three-dimensional entity model of the landslide body, the three-dimensional entity model of the terrain, and the three-dimensional model of the block rock are discretized into equidistant particle models.

3. The method for simulating the whole process of a soil-rock mixture landslide disaster chain as claimed in claim 2, characterized in that: The block stone three-dimensional model construction method comprises: Scan multiple real stones in three dimensions and label them, calculate the volume and mass of the stones, and establish a stone database; The maximum particle size of each stone in the stone database and the maximum particle size in the direction perpendicular to the maximum particle size are calculated to generate a sphere with the maximum particle size D of the stone as the diameter, a rectangle with the maximum particle size D as the long side and the maximum particle size B in the direction perpendicular to the maximum particle size as the short side, or an ellipsoid with the maximum particle size D as the long side and the maximum particle size B in the direction perpendicular to the maximum particle size as the short side as the stone three-dimensional model.

4. The method for simulating the whole process of a soil-rock mixture landslide disaster chain as claimed in claim 3, characterized in that: The method for constructing a three-dimensional solid model of a landslide body includes: Generate a random block rock 3D model, and randomly generate random points K inside the irregular landslide body according to the principle that the block rock 3D models do not invade each other, are inside the landslide body and do not invade the boundary. i , with K i Generate a corresponding block stone three-dimensional model for the center; record the position information K of the center point of the block stone three-dimensional model i (X0, Y0, Z0); K i The coordinate system is established with (X0, Y0, Z0) as the center, and the gravel inside the block stone 3D model is randomly rotated around the X' axis, Y' axis, and Z' axis by θ x ,θ y ,θ z angle; Continue to generate random block stone 3D models until the specified block stone content is reached.

5. The method for simulating the whole process of a soil-rock mixture landslide disaster chain according to claim 1, characterized in that: The step 1 includes landslide soil particles, dynamic boundary particles, and topographic static boundary particles, wherein the dynamic boundary particles include landslide block particles and downstream building particles; The basic parameters of landslide soil particles include density, peak internal friction angle, peak cohesion, residual internal friction angle, residual cohesion, elastic modulus, Poisson's ratio, and friction coefficient; The basic parameters set for terrain static boundary particles include: density, elastic modulus, Poisson's ratio, and friction coefficient; The basic parameters set for dynamic boundary particles include: density, peak internal friction angle, peak cohesion, residual internal friction angle, residual cohesion, elastic modulus, Poisson's ratio, and friction coefficient.

6. The method for simulating the whole process of soil-rock mixture landslide disaster chain according to claim 1, characterized in that: The general constitutive model for characterizing the soil and rock of the soil-rock mixture landslide in step 2 is: In the formula, is the total stress; is the stress caused by particle friction; is the stress caused by particle collision; Stress reduced due to soil softening caused by rainfall; stresses contributing to the solid constitutive model; The stress contributing to the particle flow constitutive model; p solid is the spherical stress tensor of the solid constitutive model; is the deviatoric stress tensor of the solid constitutive structure, also called the shear stress tensor; is the shear stress tensor of the fluid constitutive S represents soil saturation, ranging from 0 to 1; p c represents matrix suction; α and β represent the vector direction of stress; δ αβ is a piecewise function, when α=β, δ αβ The value is 1, otherwise it is 0; is the solid constitutive equation, η is the equivalent viscosity, is the absolute value of the shear strain rate of the fluid constitutive part, is the shear strain rate of the fluid constitutive law, p fluid is the constitutive pressure of the fluid.

7. The method for simulating the whole process of soil-rock mixture landslide disaster chain according to claim 1, characterized in that: The step 3 simulates the deformation behavior of the central particle based on the constructed general constitutive model for characterizing the soil and rock landslide of the soil-rock mixture, including: Taking the landslide soil particle as the central particle i, the control equation is as follows: In the formula, ρ i is the density of the central particle i; t is the calculation time; m j is the mass of particle j; is the velocity difference between the central particle i and the surrounding particle j in the influence domain, i.e. The direction is β direction; W is the smooth kernel function, W ij,β represents the weight value of all particles j in the influence area centered on particle i in the β direction; x is the position coordinate of the base point, is the distance of particle i in the β direction; is the velocity gradient of the central particle i, that is, the acceleration of particle i; is the stress tensor of particle i, is the stress tensor of particle j, is the pressure of particle j, is the shear stress of particle j, g α is the acceleration of gravity; α and β represent the vector direction of stress, which is a third-order tensor. Both α and β can correspond to the three directions of x, y, and z; SR is the landslide soil particle area, SB is the terrain boundary particle area, and DB is the downstream building particle area; Taking the downstream building particle as the central particle k, the control equation is as follows: In the formula, ρ k is the density of the central particle k; is the velocity difference between the central particle k and the surrounding particles j in the influence domain, i.e. W kj,β The weight value of all particles j in the influence area centered on particle k in the β direction; is the distance of particle k in the β direction; m k is the mass of the central particle k; building A1 has mass M A1 , speed V A1 , inertia tensor I A1 , angular velocity Ω A1 and the center of gravity R A1 ; r k is the center of gravity of particle k; p k αβ is the pressure of particle k, τ k αβ is the shear stress of particle k, σ j αβ is the stress of particle j; F A2→k is the collision force of the remaining stones or buildings on the k-particles on stone A; The terrain static boundary particles are taken as the central particles. The terrain boundary particles participate in the stress calculation, but the displacement is not updated, that is, the position of the terrain boundary particles is considered to be fixed.

8. The method for simulating the whole process of soil-rock mixture landslide disaster chain according to claim 7, characterized in that: The criterion for determining the start of erosion of buildings along the way in step 4 is: Among them, F 冲击力 is the impact force on the building, F 抗倾覆 is the maximum anti-overturning force of the buildings along the way, and N is the total number of particles that make up the buildings along the way.

9. The method for simulating the whole process of soil-rock mixture landslide disaster chain according to claim 7, characterized in that: The step 5 includes: in each time step, the field variable information of each particle is calculated by the smooth particle fluid dynamics method, and the obtained information is digital text information, which is converted into a binary VTK file output for visualization, wherein the particle output of different partitions is controlled by the particle type to realize material output classification.

10. A soil-rock mixture landslide disaster chain whole process simulation system, characterized in that: include: Particle model construction module: It is used to construct the three-dimensional solid model of the landslide body, the three-dimensional solid model of the terrain, and the three-dimensional model of the block stone respectively; and discretize them into equidistant particle models; assign basic parameter values ​​to each particle and set the particle type; Constitutive model building module: It is used to build a general constitutive model that simultaneously characterizes the soil and rock of soil-rock mixed landslide; Coupling calculation module: It is used to determine particle contact by taking soil-rock mixture landslide soil particles, downstream building particles, and terrain static boundary particles as central particles, and simulate the deformation behavior of central particles based on the universal constitutive model that simultaneously characterizes soil-rock mixture landslide soil and rock, and couples and calculates characteristic information of different central particles respectively; Erosion initiation judgment module: It is used to set the erosion initiation judgment criteria for soil and building along the way, and calculate the building erosion initiation process under the impact of landslide based on the characteristic information of different central particles; Visualization output module: It is used to visualize the characteristic information of each central particle obtained by calculation, and control it by particle type to realize material output classification; The soil-rock mixture landslide disaster chain full-process simulation system is used to execute the steps in the soil-rock mixture landslide disaster chain full-process simulation method described in any one of claims 1-9.

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