A landslide-jam-river disaster chain scenario analysis method and device

Abstract

The application provides a landslide blocking river disaster chain scenario analysis method, relates to the technical field of geotechnical engineering and geological disasters, and comprises the following steps: constructing a numerical model of a landslide blocking river scenario and performing grid division according to geological survey data and remote sensing measurement data, and generating blocks and material points; searching for contact between the blocks and the material points, calculating coupling contact force between the blocks and the material points based on a penalty function method and a momentum exchange method; calculating block intercontact force; mapping mass and momentum information of the material points to background grid nodes where the material points are located; solving a motion equation of the blocks and a control equation of MPM background grid nodes based on external force and block intercontact force, so as to update positions, velocities and stress states of all the blocks and all the material points, output final results, and complete whole-process analysis of a landslide blocking river disaster chain. The technical scheme is beneficial to deepening understanding of a landslide blocking river disaster chain and development of disaster prevention and reduction work.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geotechnical engineering and geological disasters, and particularly relates to a landslide blocking river disaster chain scenario analysis method and equipment. BACKGROUND

[0002] At present, the research on the whole process of landslide blocking river disaster chain mainly includes theoretical analysis, laboratory test and numerical simulation. Due to the complexity of geological conditions and the diversity of disaster-causing factors, a simplified model cannot be applied to actual engineering, and a large-scale experiment process is cumbersome and expensive, so numerical simulation is the main means to study the landslide blocking river disaster chain.

[0003] At present, a single numerical simulation method cannot reflect the complex interaction between multi-phase and multi-scale media, so a coupling simulation method is usually used, that is, the solid and fluid are simulated by different numerical methods, and the interaction force between the two is reflected by additional contact force, such as the coupling of discrete element and smooth particle flow, material point method and finite volume method. The discrete element method considers that the solid is composed of a series of spheres, and the mechanical behavior of the solid is reflected by the interaction of the spheres.

[0004] However, in the region with active tectonic movement, there are a large number of joints. The randomly distributed joints cut the rock mass into blocks of different sizes and shapes. Under this geological condition, the rock mass cannot be regarded as granular material, and the discrete element method cannot capture the complex motion process such as collision, rotation and decomposition of polyhedral blocks. The discontinuous deformation analysis method (DDA) takes an arbitrary polyhedron as a basic unit, and uses a direct search algorithm to obtain the interaction between arbitrary polyhedrons, which can effectively simulate the whole process of landslide instability and failure.

[0005] For fluid, the smooth particle flow needs special processing when dealing with complex boundary problems, and its calculation efficiency and convergence speed are both low. The finite volume method needs to divide the calculation grid, and in complex geological conditions, finer grid needs to be used to avoid grid distortion. The material point method combines the advantages of Euler grid and Lagrangian particle, in which the physical information is recorded by the particle, and the calculation is carried out on the background grid node, and is widely used in the simulation of surface flow. SUMMARY

[0006] The purpose of the present application is to solve the problems of the existing landslide blocking river disaster chain scenario analysis method, such as the inability to study the interaction between rock bodies of arbitrary shape and water bodies, low calculation efficiency and inaccurate simulation results, and to provide a landslide blocking river disaster chain scenario analysis method.

[0007] The above-mentioned purpose of the present application is realized by the following technical solutions:

[0008] S1: constructing a numerical model of landslide blocking river scenario and carrying out grid division according to geological survey data and remote sensing measurement data, generating DDA blocks and MPM material points;

[0009] S2: searching for contact between DDA blocks and MPM material points, calculating normal and tangential coupling contact forces between the two based on penalty function method and momentum exchange method, and applying the coupling contact forces as external forces to the calculation of DDA blocks and MPM material points respectively;

[0010] S3: searching for contact between DDA blocks, calculating block contact forces; mapping mass and momentum information of MPM material points to background grid nodes where the material points are located;

[0011] S4: solving motion equations of DDA blocks and control equations of MPM background grid nodes respectively based on external forces and block contact forces;

[0012] S5: updating positions, velocities and stress states of all DDA blocks and all MPM material points according to the motion equations and the control equations, outputting final results, and completing whole-process analysis of landslide blocking river disaster chain.

[0013] Optionally, step S1 comprises:

[0014] Based on geological survey data and remote sensing measurement data, the geometric shape of the slope, the spatial distribution characteristics of the faults and joint structures in the rock mass, and the river channel shape of the river are generalized;

[0015] A numerical model containing the landslide area and the river water area is established by using a three-dimensional modeling software in combination with the spatial distribution characteristics and the river channel shape;

[0016] The landslide body of the numerical model is discretized into a plurality of polyhedral elements and simulated by using a discontinuous deformation analysis method, i.e., the landslide body is cut into DDA blocks composed of a plurality of tetrahedrons or hexahedrons;

[0017] The river water body of the numerical model is discretized into a plurality of material points and simulated by using a material point method, i.e., the river water body is discretized into a series of MPM material points carrying mass, momentum and stress information;

[0018] The block contact information and the background grid information in the simulation process are initialized respectively.

[0019] Optionally, the step of initializing the block contact information and the background grid information in the simulation process respectively comprises:

[0020] The contact information of the DDA blocks is all cleared; and the background grid information of the MPM material points is all cleared.

[0021] Optionally, step S2 comprises:

[0022] MPM particles are converted into spheres with a radius equal to the initial distance of the MPM particle; the contact search between the DDA block and the MPM particle is set as the contact search between the sphere and the polyhedron, and a three-level contact search strategy is adopted to search for the contact between the DDA block and the MPM particle, and the contact search process is divided into three stages as follows:

[0023] S21: Rough search: based on the bounding box method, it is quickly judged whether there is a potential contact possibility between the DDA block and the MPM particle;

[0024] S22: Fine search: for the DDA block and the MPM particle with potential contact, the distance from the center of the MPM particle to each surface of the DDA block is calculated, and if the minimum distance is less than the equivalent radius of the MPM particle, it is determined that contact occurs;

[0025] S23: True contact surface determination: when the MPM particle is close to the edge or corner point of the DDA block, the relative position relationship between the projection point of the MPM particle on the surface of the DDA block and the surface boundary is calculated to determine the unique true contact surface.

[0026] Optionally, step S2 further comprises:

[0027] The coupling contact force includes a normal coupling contact force and a tangential coupling contact force;

[0028] The normal coupling contact force The calculation formula is as follows:

[0029]

[0030]

[0031] Wherein represents the initial distance of the MPM particle; represents the distance from the i-th MPM particle to each surface of the polyhedron; represents the normal contact stiffness coefficient; represents the normal embedding amount, which refers to the depth of the particle penetrating into the surface of the DDA block; represents the normal contact damping coefficient, which is used to simulate the energy dissipation in the collision process; represents the normal relative velocity of the particle and the block at the contact point; represents the unit normal vector of the contact surface, which is directed from the inside to the outside of the block; The tangential coupling contact force

[0032] The calculation formula is as follows:

[0033] ​

[0034] where is the tangential relative velocity of the block and particle, is the tangential component of velocity on the contact surface; denotes the mass of the particle, the mass of the MPM particle; denotes the time step of the calculation.

[0035] Optionally, step S3 comprises:

[0036] The calculation of the inter-block contact force between DDA blocks is as follows:

[0037] The bounding box method is used to roughly search whether contact occurs between blocks. For two blocks that may have potential contact, the distance between the vertex of block i and all the faces of block j and the distance between all the edges of the two blocks are calculated respectively. If the distance is less than 0, the two blocks have contact.

[0038] For the two blocks that have contact, the contact force can be written as:

[0039]

[0040] where and are the normal and tangential contact forces between blocks, and are the normal and tangential contact stiffnesses, and are the normal and tangential embedding distances, and are the normal and tangential contact dampings, and are the normal and tangential relative velocities, is the contact surface normal vector, is the projection of velocity on the contact surface;

[0041] The mass and momentum information of the MPM particle is mapped to the background grid node where it is located. The specific steps of include:

[0042] The information of the particle is mapped to the background grid node, and the mass , momentum , internal force , external force of the particle at time t can be written as:

[0043]

[0044] where , , , and Let be the mass, momentum, density, Cauchy stress, and body force of the MPM material point at time t; This indicates the number of material points corresponding to the background grid node; This indicates calculating the gradient; It represents the coupling force acting on a material point, consisting of normal coupling force and tangential coupling force; The weighting function between the background mesh and the material points can be written as:

[0045]

[0046] in It is a characteristic function. It is a shape function; Represents the computational domain; Indicates volume.

[0047] Optionally, step S4 includes:

[0048] The specific steps for calculating the equations of motion of the DDA are as follows:

[0049] Select the centroid of each DDA block The degrees of freedom are the quantities to be solved:

[0050]

[0051] in and For the translation and rotation of the centroid; and For the normal strain and shear strain of the block;

[0052] Based on the central difference scheme, the equation of motion for the DDA is:

[0053]

[0054] Where M, C, and K are the mass matrix, damping matrix, and stiffness matrix of the block, respectively. The resultant force of the block consists of internal forces, external forces, and coupling forces; Indicates a time step; Indicates the displacement in the previous step;

[0055] The specific steps for calculating the governing equations of the MPM background mesh nodes are as follows:

[0056] The speed of MPM background grid nodes can be written as:

[0057]

[0058] in and They are nodes exist and velocity at time t, and respectively the internal and external forces of node i; denotes denotes time t mass of node i.

[0059] Optionally, step S5 comprises:

[0060] updating the position, velocity and stress state of DDA blocks, the results of which can be directly obtained according to the results of the motion equation;

[0061] updating the position, velocity and stress state of MPM particles, which requires converting the information of the calculated background grid nodes to MPM particles, the velocity and displacement expressions of which are:

[0062]

[0063] wherein and denote the displacement of p particle at t and time t; and denote the velocity of p particle at t and time t; denotes the number of background grid nodes corresponding to the particle; denotes the weight function between the background grid and the particle; and denote the velocity of i background grid at t and time t; denotes the time step;

[0064] the strain and vorticity expressions are:

[0065]

[0066] wherein denotes the strain increment of the next step; denotes the vorticity increment of the next step;

[0067] the stress expression is:

[0068]

[0069] wherein is the fluid viscosity, is the unit vector, is the water pressure; denotes the stress increment of the next step; denotes the stress increment of the next step; denotes Strain rate tensor at the time instant;

[0070] It is judged whether the calculation reaches a preset termination condition, if not, it returns to step S2 to calculate the next time step; if so, the calculation is terminated and the final result is outputted;

[0071] The final result includes: the velocity and displacement curves of each monitoring point of the landslide with time, the water level elevation curve of the opposite bank with time, and the energy change law results of the landslide body and water body during the landslide process.

[0072] An electronic device includes a processor, a memory, a user interface and a network interface, the memory is used to store instructions, the user interface and the network interface are used to communicate with other devices, and the processor is used to execute the instructions stored in the memory to make the electronic device execute a landslide blocking river disaster chain scenario analysis method.

[0073] A computer readable storage medium stores instructions, when the instructions are executed, a landslide blocking river disaster chain scenario analysis method is executed.

[0074] The technical scheme provided by the present application has the beneficial effects that:

[0075] For slope engineering, the direct contact algorithm is used to search the interaction between polyhedral blocks, which can reflect the complex motion process such as collision, rotation and decomposition of polyhedral blocks of any shape. The material point method is used to simulate the motion process of fluid, which has higher calculation efficiency and convergence accuracy. The contact search and contact force calculation algorithm of polyhedral blocks and particles is proposed, which realizes the solution of complex interaction between multiphase and multiscale media. This method can realize the scenario deduction of the whole process of landslide starting, slope movement, water blocking and accumulation blocking, avoid complex and time-consuming experimental research, and is convenient to operate and has strong repeatability, which is conducive to deepening the understanding of landslide blocking river disaster chain and the development of disaster prevention and mitigation work. BRIEF DESCRIPTION OF DRAWINGS

[0076] The present application will be further described below in combination with the drawings and examples, and the drawings are as follows:

[0077] Figure 1 It is the method flowchart of the present application embodiment in the present application embodiment;

[0078] Figure 2 It is the calculation flowchart of the material point method in the present application embodiment;

[0079] Figure 3 It is the contact search diagram of the material point particle and the DDA block in the present application embodiment;

[0080] Figure 4is a schematic diagram of normal contact force calculation between material point particles and DDA blocks in the embodiment of the present application;

[0081] Figure 5 is a schematic diagram of contact force calculation between DDA blocks in the embodiment of the present application;

[0082] Figure 6 is a numerical model diagram of a typical landslide river-blocking disaster chain in the embodiment of the present application;

[0083] Figure 7 is a whole-process deduction result of a landslide river-blocking disaster chain in the embodiment of the present application;

[0084] Figure 8 is a velocity and displacement change curve of a typical rock mass in a landslide river-blocking disaster chain in the embodiment of the present application;

[0085] Figure 9 is a water level height change curve diagram of the opposite bank in a landslide river-blocking disaster chain in the embodiment of the present application;

[0086] Figure 10 is a change curve diagram of each part of energy in a landslide river-blocking disaster chain in the embodiment of the present application;

[0087] Figure 11 is a schematic diagram of an electronic device structure in the embodiment of the present application. DETAILED DESCRIPTION

[0088] In order to have a clearer understanding of the technical features, objects and effects of the present application, the specific embodiments of the present application will be described in detail with reference to the drawings.

[0089] The embodiment of the present application provides a landslide river-blocking disaster chain scenario analysis method.

[0090] Please refer to Figure 1 , Figure 1 is a flowchart of a landslide river-blocking disaster chain scenario analysis method in the embodiment of the present application, comprising:

[0091] S1: according to the geological survey data and the remote sensing measurement data, a numerical model of the landslide river-blocking scene is constructed and meshed, and DDA blocks and MPM material points are generated;

[0092] S2: the contact between the DDA blocks and the MPM material points is searched, the normal and tangential coupling contact forces between the two are calculated based on the penalty function method and the momentum exchange method, and the coupling contact forces are applied as external forces to the calculation of the DDA blocks and the MPM material points, respectively;

[0093] S3: the contact between the DDA blocks is searched, the contact force between the blocks is calculated; the mass and momentum information of the MPM material points are mapped to the background grid nodes where they are located;

[0094] S4: solving the motion equation of the DDA block and the control equation of the MPM background grid node based on the external force and the contact force between the blocks;

[0095] S5: updating the position, velocity and stress state of all DDA blocks and all MPM particles according to the motion equation and the control equation, outputting the final result, and completing the whole process analysis of the landslide blocking river disaster chain.

[0096] Step S1 comprises:

[0097] Based on the geological survey data and remote sensing measurement data, the geometric shape of the slope, the spatial distribution characteristics of the faults and joint structures in the rock mass, and the river channel shape of the river are generalized;

[0098] A numerical model including the landslide area and the river water area is established by using a three-dimensional modeling software combined with the spatial distribution characteristics and the river channel shape;

[0099] The landslide body of the numerical model is discretized into a plurality of polyhedral elements and simulated by using the discontinuous deformation analysis method, i.e. the sliding body is cut into DDA blocks composed of a plurality of tetrahedrons or hexahedrons;

[0100] The river water body of the numerical model is discretized into a plurality of particles and simulated by using the material point method, i.e. the river water body is discretized into a series of MPM particles carrying mass, momentum and stress information;

[0101] The block contact information and the background grid information in the simulation process are initialized respectively.

[0102] The step of initializing the block contact information and the background grid information in the simulation process respectively comprises:

[0103] The contact information of the DDA block is all cleared; the background grid information of the MPM particle is all cleared.

[0104] Step S2 comprises:

[0105] The MPM particle is converted into a sphere with a radius of the initial distance of the MPM particle; the contact search between the DDA block and the MPM particle is set as the contact search between the sphere and the polyhedron, a three-level contact search strategy is adopted to search the contact between the DDA block and the MPM particle, and the contact search process is divided into three stages as follows

[0106] S21: rough search: based on the bounding box method, it is quickly judged whether there is a potential contact possibility between the DDA block and the MPM particle;

[0107] The application provides an embodiment of roughly judging whether the DDA block and the MPM particle are in contact by using the bounding box method. The bounding box of the polyhedron can be written as:

[0108]

[0109]

[0110] wherein and are the minimum and maximum coordinates of the polyhedron bounding box, is the coordinate of each vertex, and n is the number of vertices.

[0111] For the particle, the bounding box can be written as:

[0112]

[0113]

[0114] wherein and are the minimum and maximum coordinates of the particle bounding box, is the coordinate of the particle; represents the initial distance of the MPM particle;

[0115] The polyhedron will be in potential contact with the particle only when all the components in the following formula are not true:

[0116]

[0117]

[0118] wherein is the contact search distance, which is equal to the particle radius in the application.

[0119] S22: Fine search: for the DDA block and the MPM particle in potential contact, the distance from the center of the MPM particle to each surface of the DDA block is calculated, and if the minimum distance is smaller than the equivalent radius of the MPM particle, it is determined that the contact occurs.

[0120] The application provides an embodiment of determining the contact position by fine search once the potential contact occurs between the block and the particle. There can be three types of point-point contact, point-edge contact and point-surface contact between the block and the particle, and since the point-point contact and the point-edge contact can be converted into the point-surface contact, only the point-surface contact needs to be considered. The distance from the particle to each surface of the polyhedron is:

[0121]

[0122] wherein is any point on the surface, is the particle coordinate, is the surface normal vector. When contact is considered to occur, and the contact point coordinates are: .

[0123] S23: Real contact surface determination: when the MPM particle is close to the edge or corner point of the DDA block, the relative position relationship between the projection point of the MPM particle on the surface of the DDA block and the surface boundary is calculated to determine the unique real contact surface.

[0124] The application provides an embodiment as follows: when the particle is close to the edge or vertex of the polyhedron, it may simultaneously contact two or three surfaces, and therefore it is necessary to determine the real contact surface in the third stage. The application considers that the plane where the particle projection point is located is the real contact surface. The edge of the surface is composed of vertices and connecting the block vertex and the projection point, and the dot product and mixed product of and are calculated as follows:

[0125]

[0126] If and , it is considered that the projection point is on the boundary of the surface, otherwise, the included angle between the two vectors is calculated:

[0127]

[0128]

[0129]

[0130] Finally, the sum of all included angles is calculated:

[0131]

[0132] where m is the number of edges, if , it is considered that the projection point is in the surface, otherwise, it is out of the surface. Finally, the surface where the projection point is located is regarded as the real contact surface, and the contact force calculation is performed on the surface.

[0133] Step S2 further includes:

[0134] The coupling contact force includes: normal coupling contact force and tangential coupling contact force;

[0135] The calculation formula of the normal coupling contact force is as follows:

[0136]

[0137]

[0138] wherein denotes the initial distance of the MPM material point; denotes the distance of the MPM material point to the faces of the polyhedron; denotes the normal contact stiffness coefficient; denotes the normal penetration distance, which refers to the depth of the material point penetrating into the surface of the DDA block; denotes the normal contact damping coefficient, which is used to simulate the energy dissipation in the collision process; denotes the normal relative velocity of the material point and the block at the contact point; denotes the unit normal vector of the contact surface, which is directed from the inside to the outside of the block;

[0139] tangential coupling contact force is calculated as follows:

[0140]

[0141] wherein is the tangential relative velocity of the block and the particle, is the tangential component of the velocity on the contact surface; denotes the mass of the particle, the mass of the MPM material point; denotes the time step of the calculation.

[0142] Step S3 comprises:

[0143] The calculation of the inter-block contact force between the DDA blocks is as follows:

[0144] The bounding box method is used to roughly search whether contact occurs between the blocks. For two blocks that may have potential contact, the distance from the vertex of the block i to all the faces of the block j and the distance between all the edges of the two blocks are calculated respectively. If the distance is less than 0, the two blocks have contact.

[0145] For the two blocks that have contact, the contact force can be written as:

[0146]

[0147] wherein and are the normal and tangential contact forces between the blocks, and are the normal and tangential contact stiffnesses, and are the normal and tangential penetration distances, and are normal and tangential contact damping, and are normal and tangential relative velocities, is the contact surface normal vector, is the projection of velocity on the contact surface;

[0148] The specific steps of mapping the mass and momentum information of the MPM particle to the background grid node where it is located include:

[0149] Mapping the information of the particle to the background grid node, its mass , momentum , internal force , external force at time t can be written as:

[0150]

[0151] where , , , and are the mass, momentum, density, Cauchy stress and body force of the MPM particle at time t; represents the number of particles corresponding to the background grid node; represents the gradient; represents the coupling force suffered by the particle, which consists of normal coupling force and tangential coupling force; is the weight function between the background grid and the particle, which can be written as:

[0152]

[0153] where is the characteristic function, is the shape function; represents the calculation domain; represents the volume.

[0154] Step S4 includes:

[0155] The steps of calculating the motion equation of DDA are as follows:

[0156] The free degree of each DDA block center is selected as the solution quantity:

[0157]

[0158] where and are the translation and rotation of the center; and the normal strain and shear strain of the block;

[0159] Based on the central difference scheme, the motion equation of DDA is:

[0160]

[0161] where M, C and K are the mass matrix, damping matrix and stiffness matrix of the block, is the resultant force of the block, which is composed of the internal force, external force and coupling force; denotes the time step; denotes the displacement of the last step;

[0162] The steps of calculating the control equation of the MPM background grid node are as follows:

[0163] The velocity of the MPM background grid node can be written as:

[0164]

[0165] where and are the velocities of the node at the time and , respectively; and are the internal force and external force of the node i, respectively; denotes the mass of the node at the time .

[0166] Step S5 includes:

[0167] The position, velocity and stress state of the DDA block are updated, and the results can be directly obtained according to the results of the motion equation;

[0168] The position, velocity and stress state of the MPM particle are updated, and the information of the calculated background grid node needs to be converted to the MPM particle, and the velocity and displacement expressions of the MPM particle are:

[0169]

[0170] where and denote the displacement of the p particle at the time t and ; and denote the velocity of the p particle at the time t and ; denotes the number of background grid nodes corresponding to the particle; denotes the weight function between the background grid and the particle; and ​denotes the velocity of the i-th background mesh at time t and denotes the time step;

[0171] The strain and vorticity expressions are:

[0172]

[0173] where denotes the strain increment of the next step; denotes the vorticity increment of the next step;

[0174] The stress expression is:

[0175]

[0176] where is the fluid viscosity, is the unit vector, is the water pressure; denotes the stress increment of the next step; denotes the stress increment of the next step; denotes the rate of strain tensor at time t;

[0177] It is judged whether the calculation reaches the preset termination condition, if not, it returns to step S2 to calculate the next time step; if yes, the calculation is terminated and the final result is output, and the whole process analysis of the landslide blocking river disaster chain is completed.

[0178] As an embodiment, a typical landslide blocking river disaster chain project is selected for research. A numerical simulation model of the typical landslide blocking river disaster chain is established, such as Figure 6 ​The base rock is U-shaped, with a size of 40.0 m x 50.0 m x 12.5 m, and the wedge-shaped landslide is located in the middle of the left bank. The wedge-shaped landslide is controlled by two groups of joints, with occurrences of 45°∠35° and 135°∠30°, respectively. The dip and dip angle of the slope surface are 90°∠45°, and the stereographic projection result shows that the wedge-shaped landslide is in an unstable state. The wedge-shaped landslide is discretized into 67 tetrahedrons and simulated by DDA. Seven monitoring points (A to G) are set to record the motion characteristics of the blocks. The depth of the river is 2.5 meters, and the surface and bottom widths are 10 meters and 5 meters, respectively, which are simulated by MPM. Eleven monitoring points (P1 to P11) are set on the right bank to record the water level, with a spacing of 5 m, and the calculation time step is 0.00005 s, with a total of 200000 steps. The contact information of the DDA part and the background grid information of the MPM part are initialized. The contact between the DDA blocks and the MPM particles is retrieved, and the coupling contact force is calculated. The coupling contact force is added to the DDA and MPM calculations as an external force. The contact between the DDA blocks is retrieved, and the block contact force is calculated, while the particle information is mapped to the background grid. The motion equation of DDA and the control equation of MPM are calculated respectively. The information of DDA blocks and the information of MPM particles are updated respectively. It is judged whether it is the last step of calculation, if not, return to step S2 to continue calculation, until the calculation is to the last step and the calculation is ended. Finally, the whole process of the landslide blocking river disaster chain of the model is obtained, as shown in Figure 7 The velocity and displacement curves of each monitoring point of the landslide with time are shown in Figure 8 The water level elevation curve of the opposite bank with time is shown in Figure 9 The energy change law of the landslide and water body during the landslide is shown in Figure 10 The above results can comprehensively analyze the whole process of the landslide blocking river disaster chain, and provide a reference for disaster prevention and mitigation.

[0179] The application also discloses an electronic device. Referring to Figure 11 , Figure 11 is a structural schematic diagram of an electronic device disclosed by the embodiment of the application. The electronic device 500 can include at least one processor 501, at least one network interface 504, a user interface 503, a memory 505, and at least one communication bus 502.

[0180] The communication bus 502 is used to realize the connection and communication between the components.

[0181] The user interface 503 can include a display screen, and the optional user interface 503 can further include a standard wired interface and a wireless interface.

[0182] The network interface 504 can optionally include a standard wired interface and a wireless interface (such as a WI-FI interface).

[0183] The application also discloses a computer readable storage medium, which stores a plurality of instructions adapted to be loaded by a processor to execute the landslide-jam-river disaster chain scenario analysis method.

[0184] The above merely describes exemplary embodiments of the present disclosure, and cannot limit the scope of the present disclosure. Any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure.

[0185] The present application is intended to cover any variations, uses, or adaptive changes of the present disclosure that follow the general principles of the present disclosure and include common knowledge or conventional technical means in the technical field of the present disclosure not recorded in the present disclosure. The scope and spirit of the present disclosure are defined by the claims.

Claims

1. A landslide-blocked-river disaster chain scenario analysis method, characterized in that, The method comprises the following steps: S1: constructing a numerical model of a landslide blocking river scenario and performing grid division according to geological survey data and remote sensing measurement data, and generating DDA blocks and MPM material points; S2: searching for contact between the DDA blocks and the MPM material points, calculating normal and tangential coupling contact forces between the DDA blocks and the MPM material points based on a penalty function method and a momentum exchange method, and applying the coupling contact forces as external forces to calculation of the DDA blocks and the MPM material points respectively; Step S2 further comprises: The coupling contact forces comprise normal coupling contact forces and tangential coupling contact forces; Normal coupling contact force The formula for calculating the normal coupling contact force is as follows: wherein represents the initial distance of the MPM particle; represents the distance of the MPM particle to the face of the polyhedron; represents the distance of the MPM particle to the face of the polyhedron; represents the normal contact stiffness coefficient; represents the normal penetration, which is the depth of the particle penetrating into the DDA block surface; represents the normal contact damping coefficient, which is used to simulate the energy dissipation during the collision process; represents the normal relative velocity of the particle and the block at the contact point; represents the unit normal vector of the contact surface, which is directed from the inside to the outside of the block; Tangential coupling contact force The formula for calculating the contact force is as follows: wherein is the tangential relative velocity of the block and the particle, is the tangential component of the velocity on the contact surface; denotes the mass of the particle, i.e. the mass of the MPM particle; denotes the time step of the calculation; S3: searching for contact between the DDA blocks, calculating block contact forces, and mapping mass and momentum information of the MPM material points to background grid nodes where the MPM material points are located; S4: solving a motion equation of the DDA blocks and a control equation of the MPM background grid nodes respectively based on the external forces and the block contact forces; Step S4 comprises: The step of calculating the motion equation of the DDA is specifically as follows: Selecting the center of mass of each DDA block The degrees of freedom are the solution quantities: wherein and are the translational and rotational movement of the centroid; and are the normal and shear strain of the block. The motion equation of the DDA based on a central difference format is as follows: where M, C and K are the mass matrix, the damping matrix and the stiffness matrix of the block, is the resultant force of the block, consisting of the internal force, the external force and the coupling force; denotes the time step; denotes the displacement of the previous step; The step of calculating the control equation of the MPM background grid nodes is specifically as follows: The velocity of the MPM background grid nodes can be written as: wherein and are the velocities of the nodes at and time, and are the internal and external forces of the node i, respectively; denotes the acceleration of the node at time S5: updating positions, velocities and stress states of all the DDA blocks and all the MPM material points according to the motion equation and the control equation, outputting final results, and completing whole-process analysis of a landslide blocking river disaster chain.

2. The landslide-flood disaster chain scenario analysis method according to claim 1, characterized in that, Step S1 comprises: Based on the geological survey data and the remote sensing measurement data, geometric shapes of the slope, spatial distribution characteristics of faults and joint structural surfaces in the rock mass, and a river channel shape of the river are generalized; A numerical model containing a landslide region and a river water region is established by using a three-dimensional modeling software in combination with the spatial distribution characteristics and the river channel shape; The landslide body of the numerical model is discretized into a plurality of polyhedral elements and simulated by using a discontinuous deformation analysis method, namely, the landslide body is cut into DDA blocks composed of a plurality of tetrahedrons or hexahedrons; The river water body of the numerical model is discretized into a plurality of material points and simulated by using a material point method, namely, the river water body is discretized into a series of MPM material points carrying mass, momentum and stress information; Block contact information and background grid information in a simulation process are initialized respectively.

3. The landslide-flood disaster chain scenario analysis method according to claim 2, characterized in that, The step of initializing the block contact information and the background grid information in the simulation process respectively comprises: Contact information of the DDA blocks is all cleared, and background grid information of the MPM material points is all cleared.

4. The landslide-flood disaster chain scenario analysis method of claim 1, wherein, Step S2 comprises: The MPM material points are converted into spheres, and a radius of the spheres is an initial distance of the MPM material points; contact between the DDA blocks and the MPM material points is searched for as contact between the spheres and the polyhedrons, a three-level contact searching strategy is adopted, and contact between the DDA blocks and the MPM material points is searched for, and a contact searching process is divided into three stages as follows: S21: rough searching: whether there is potential contact possibility between the DDA blocks and the MPM material points is quickly judged based on a bounding box method; S22: fine search: for the DDA block and MPM material point with potential contact, the distance from the center of MPM material point to each surface of DDA block is calculated, if the minimum distance is less than the equivalent radius of MPM material point, it is determined that contact occurs; S23: true contact surface determination: when the MPM material point is close to the edge or corner point of the DDA block, the relative position relationship between the projection point of the MPM material point on each surface of the DDA block and the surface boundary is calculated to determine the unique true contact surface.

5. The method of claim 1, wherein, Step S3 comprises: The calculation of the inter-block contact force between DDA blocks is as follows: The bounding box method is used to roughly search whether contact occurs between blocks, for two blocks that may have potential contact, the distance from the vertex of block i to all surfaces of block j and the distance between all edges of the two blocks are calculated respectively, if the distance is less than 0, the two blocks have contact; For the two blocks that have contact, the contact force can be written as: where and are the normal and tangential contact forces between the blocks, and are the normal and tangential contact stiffnesses, and are the normal and tangential embedment distances, and are the normal and tangential contact dampings, and are the normal and tangential relative velocities, is the contact surface normal vector, is the projection of the velocity on the contact surface; The specific steps of mapping the mass and momentum information of the MPM material point to the background grid node where it is located include: mapping the information of the material points to the background mesh nodes, which are the mass , momentum , internal force , external force can be written as: where , , , and are the mass, momentum, density, Cauchy stress and body force of the MPM material point at time t; denotes the number of material points corresponding to the background mesh node; denotes the gradient; denotes the coupling force experienced by the material point, which consists of the normal coupling force and the tangential coupling force; is the weight function between the background mesh and the material point, which can be written as: wherein is a characteristic function, is a shape function; denotes the computation domain; denotes the volume.

6. The method of analyzing a landslide-flood disaster chain scenario according to claim 1, wherein, Step S5 comprises: The position, velocity and stress state of the DDA block are updated, and the results can be directly obtained according to the results of the motion equation; The position, velocity and stress state of the MPM particle are updated, and the information of the calculated background grid node needs to be converted to the MPM material point, the displacement and velocity expression of which is: where and denote the displacement of the p-th material point at time t and ; and denote the velocity of the p-th material point at time t and ; denotes the number of background mesh nodes corresponding to the material point; denotes the weight function between the background mesh and the material point; and denote the velocity of the i-th background mesh at time t and ; denotes the time step; The strain and vorticity expression is: wherein represents the strain increment of the next step; represents the vorticity increment of the next step; The stress expression is: wherein is the fluid viscosity, is the unit vector, is the water pressure; denotes the stress increment of the next step; denotes the strain rate tensor at the time instant It is judged whether the calculation reaches the preset termination condition, if not, it returns to step S2 for the calculation of the next time step; if yes, the calculation is terminated and the final result is outputted; The final result includes: the velocity and displacement curves of each monitoring point of the landslide with time, the water level elevation curve of the opposite bank with time, and the energy change law results of the landslide and water body during the landslide process.

7. An electronic device, comprising: The electronic device comprises a processor, a memory, a user interface and a network interface, the memory is used to store instructions, the user interface and the network interface are used to communicate with other devices, and the processor is used to execute the instructions stored in the memory, so that the electronic device executes the landslide blocking river disaster chain scenario analysis method of any one of claims 1-6.

8. A computer-readable storage medium, characterized in that, The computer readable storage medium stores instructions, when the instructions are executed by a computer, a landslide blocking river disaster chain scenario analysis method of any one of claims 1-6 is executed.

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