A method and system for mapping the runout of near-fault monolithic coseismic landslides

Abstract

The present application relates to the technical field of coseismic landslide risk assessment, and particularly relates to a near-fault monomer coseismic landslide movement range mapping method and system. The method comprises the following steps: obtaining fault structure data of a study area; positioning a main seismogenic fault based on the fault structure data, and performing rupture mechanism analysis to obtain source parameter data; constructing a fault geometry structure and crust medium structure model containing three-dimensional terrain based on the fault structure data and the source parameter data to obtain three-dimensional structure model data; setting fault source parameters and stratum velocity medium parameters based on the source parameter data and the three-dimensional structure model data to obtain seismic simulation input parameters. The present application accurately reproduces the whole process from the triggering of a near-fault coseismic landslide to accumulation through an integrated physical driving simulation framework, and high-precision evaluates the three-dimensional movement range and risk zoning, thereby providing a reliable basis for risk assessment and disaster prevention decision-making.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of co-seismic landslide risk assessment, and particularly relates to a method and system for mapping movement range of near-fault monomer co-seismic landslide. BACKGROUND

[0002] Accurate prediction and mapping of the movement range of co-seismic landslide induced by near-fault region earthquake is a key technical problem in the quantitative risk assessment of major monomer landslide in earthquake active area. The velocity pulse effect of fault rupture, wave propagation and topographic amplification effect are crucial to the start, movement and threat range prediction of large co-seismic landslide, which mainly occurs near the earthquake rupture source. However, the conventional co-seismic landslide movement range simulation and mapping method has the following limitations:

[0003] Lack of consideration of the physical mechanism of the causative fault: the traditional co-seismic landslide movement range simulation ignores the investigation and research on the causative fault, such as the nature of the causative fault, the maximum potential magnitude, the source rupture mechanism, and thus the velocity pulse effect of near-fault ground motion and the physical properties of the set earthquake event.

[0004] Empirical ground motion time history cannot accurately describe the ground motion characteristics of the landslide area: the ground motion obtained by traditional probabilistic seismic hazard analysis reflects the long-term macroscopic law of an area, which cannot represent the characteristics of a single earthquake event, and ignores the particularity of the causative structure and topography of the landslide area and the influence of the generation, propagation process of the seismic wave and the local site condition ground motion.

[0005] The whole process simulation framework of source-propagation medium-co-seismic landslide instability is still not built: the current monomer co-seismic landslide movement range simulation and mapping method mechanically divides the whole process of source-propagation medium-co-seismic landslide instability into three independent processes of earthquake generation, landslide dynamic response and landslide movement range simulation for analysis, which leads to insufficient coupling of each stage and poor accuracy of landslide movement range mapping. SUMMARY

[0006] Therefore, it is necessary to provide a method and system for mapping movement range of near-fault monomer co-seismic landslide to solve at least one of the above technical problems.

[0007] To achieve the above-mentioned purpose, a method for mapping movement range of near-fault monomer co-seismic landslide comprises the following steps:

[0008] Step S1: obtaining the fault structure data of the study area; based on the fault structure data, locating the main causative fault and performing rupture mechanism analysis to obtain source parameter data;

[0009] Step S2: constructing a fault geometry structure and crust medium structure model containing three-dimensional terrain based on the fault structure data and the source parameter data, obtaining three-dimensional structure model data; setting fault source parameters and stratum velocity medium parameters based on the source parameter data and the three-dimensional structure model data, obtaining seismic simulation input parameters; simulating a wideband ground motion field based on the three-dimensional structure model data and the seismic simulation input parameters, obtaining ground motion simulation result data;

[0010] Step S3: constructing a finite element-discrete element coupling analysis geological model of the landslide area based on the ground motion simulation result data and the preset on-site drilling and wave velocity test results, obtaining landslide dynamic analysis model data; performing deformation-unstable-motion-accumulation whole process simulation analysis on the landslide under the seismic condition based on the landslide dynamic analysis model data, obtaining landslide motion simulation result data;

[0011] Step S4: estimating a three-dimensional motion range based on the landslide motion simulation result data, and generating landslide instability motion range mapping data.

[0012] Preferably, the present application also provides a near-fault single landslide co-seismic motion range mapping system for executing the near-fault single landslide co-seismic motion range mapping method described above, and the near-fault single landslide co-seismic motion range mapping system comprises:

[0013] A source feature recognition and parameterization module is configured to obtain fault structure data of a study area; locate main seismogenic faults based on the fault structure data, and perform a rupture mechanism analysis to obtain source parameter data;

[0014] A three-dimensional ground motion field modeling and simulation module is configured to construct a fault geometry structure and crust medium structure model containing three-dimensional terrain based on the fault structure data and the source parameter data, obtain three-dimensional structure model data; set fault source parameters and stratum velocity medium parameters based on the source parameter data and the three-dimensional structure model data, obtain seismic simulation input parameters; simulate a wideband ground motion field based on the three-dimensional structure model data and the seismic simulation input parameters, obtain ground motion simulation result data;

[0015] A landslide dynamics coupling analysis module is configured to construct a finite element-discrete element coupling analysis geological model of the landslide area based on the ground motion simulation result data and the preset on-site drilling and wave velocity test results, obtain landslide dynamic analysis model data; perform deformation-unstable-motion-accumulation whole process simulation analysis on the landslide under the seismic condition based on the landslide dynamic analysis model data, obtain landslide motion simulation result data;

[0016] A motion range mapping and risk evaluation module is configured to estimate a three-dimensional motion range based on the landslide motion simulation result data, and generate landslide instability motion range mapping data.

[0017] The application breaks through the problem of insufficient coupling caused by the separated modeling of the source, medium and landslide dynamic response in the traditional method, can truly reflect the velocity pulse characteristics of near-fault ground motion and its influence on the landslide triggering process; introduces the accurate description of the seismogenic fault properties, maximum potential magnitude and rupture mechanism in the source characteristic acquisition, ensures the physical consistency of the input ground motion conditions and actual earthquake events; fully considers the joint action of regional tectonic conditions, three-dimensional complex topography and stratum heterogeneity on seismic wave propagation and site ground motion amplification in the ground motion simulation stage, realizes the wideband, high spatial resolution near-fault strong ground motion field reproduction; in the landslide dynamics analysis, the finite element and discrete element coupling combined with the multi-stage mixed constitutive relation can continuously describe the whole process of the slope from initial deformation, failure to high-speed movement and final accumulation, capture the spatio-temporal evolution of the kinematic and dynamic characteristics of the landslide; in the motion range determination and visualization link, based on the simulation results and the combination of geometric calculation, the accuracy of three-dimensional motion range and risk zoning is significantly improved, which can provide high-reliability scientific basis for the risk quantitative evaluation, emergency disposal and disaster prevention and mitigation decision of major single landslide in the earthquake active area. BRIEF DESCRIPTION OF DRAWINGS

[0018] Other features, objects and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments made with reference to the accompanying drawings:

[0019] Figure 1 A step flowchart of a near-fault single coseismic landslide motion range mapping method of the application;

[0020] Figure 2 A method flowchart of the application;

[0021] Figure 3 A three-dimensional half-space homogeneous model and grid design diagram;

[0022] Figure 4 A seismic peak acceleration (PGA) simulation result diagram considering three-dimensional terrain;

[0023] Figure 5 A diagram of obtaining time history curve of ground motion with velocity pulse characteristics at the bottom of the landslide;

[0024] Figure 6 A landslide engineering geological profile;

[0025] Figure 7 A landslide finite element-discrete element coupling analysis geological model schematic diagram;

[0026] Figure 8The figure is used for simulating and analyzing the whole process of landslide deformation-destabilization-motion-accumulation under earthquake condition;

[0027] Figure 9 The figure is used for landslide destabilization motion range and danger zoning. DETAILED DESCRIPTION

[0028] The technical method of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0029] In addition, the drawings are only schematic illustrations of the present application and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus repeated description thereof will be omitted. Some block diagrams shown in the drawings are functional entities, which do not necessarily have to correspond to physically or logically independent entities. The functional entities can be implemented in the form of software, or in one or more hardware modules or integrated circuits, or in different network and / or processor methods and / or microcontroller methods.

[0030] It should be understood that although the terms "first", "second" and the like can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of the exemplary embodiments, a first element can be called a second element, and similarly a second element can be called a first element. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] To achieve the above-mentioned purpose, please refer to Figures 1 to 9 The present application provides a method for mapping the motion range of near-fault monomer co-seismic landslide, which comprises the following steps:

[0032] Step S1: Obtain the fault structure data of the study area; locate the main seismogenic fault based on the fault structure data, and perform rupture mechanism analysis to obtain the source parameter data;

[0033] Step S2: Construct a fault geometry structure and crust medium structure model containing three-dimensional terrain based on the fault structure data and the source parameter data to obtain three-dimensional structure model data; set the fault source parameters and stratum velocity medium parameters based on the source parameter data and the three-dimensional structure model data to obtain the seismic simulation input parameters; simulate the wideband ground motion field based on the three-dimensional structure model data and the seismic simulation input parameters to obtain the ground motion simulation result data;

[0034] Step S3: based on the seismic motion simulation result data and the preset field drilling and wave velocity test results, a finite element-discrete element coupling analysis geological model of the landslide area is constructed to obtain landslide dynamic analysis model data; based on the landslide dynamic analysis model data, a whole process simulation analysis of deformation-destabilization-motion-accumulation of the landslide under the seismic condition is performed to obtain landslide motion simulation result data;

[0035] Step S4: based on the landslide motion simulation result data, a three-dimensional motion range is estimated to generate landslide destabilization motion range mapping data.

[0036] Preferably, step S1 comprises the following steps:

[0037] Step S11: near-field active fault investigation and detection are performed on the study area to obtain fault structure data containing spatial distribution characteristics, activity history, activity intensity, activity rate and paleoseismic activity sequence of the fault;

[0038] Step S12: based on the fault structure data, precise positioning of the main seismogenic fault is performed to obtain fault geometric parameter data containing strike, tendency and brittle-ductile transition zone depth;

[0039] Step S13: based on the fault geometric parameter data, rupture mechanism analysis of the main seismogenic fault is performed to obtain source parameter data containing fault type, slip mode, focal depth and maximum potential magnitude.

[0040] In the embodiment of the present application, when investigating and detecting near-field active fault in the research area, first, based on high-resolution remote sensing images (resolution better than 0.5 m), 1:50,000 geological maps, active fault trench exploration results and regional earthquake catalog data, investigation profiles are arranged along the potential seismogenic structure belt, the position and elevation of the surface trace of the fault are measured by using the total station and differential GPS combined measurement, the accuracy is not less than ±0.05 m, at the same time, fault gouge, fault breccia and stratum samples in the upper and lower plates in the trench exploration profile are collected, the fault activity age is determined by optical dating and carbon-14 dating; combined with the thickness difference and age of the faulted stratum in the profile, the average activity rate of the fault (unit: mm / a) is calculated, and the fault activity history sequence and paleoseismic activity sequence are prepared by using the results of seismic geological survey. Based on the above fault structure data, the most control seismogenic fault around the landslide area is locked, the fault trend (angle measurement accuracy 0.1°), the tendency (angle measurement accuracy 0.1°) and the depth of the brittle-ductile transition zone (based on the results of seismic tomography inversion, the resolution is not less than 500 m) are accurately extracted by superimposing the fault spatial distribution and topographic relief data on the ArcGIS platform, and the continuity and accuracy are verified by using the structure measurement method. After obtaining the fault geometric parameters, combined with the regional stress field inversion results and the focal mechanism solution, the fault type (strike-slip, thrust, normal or composite type) is determined, the slip mode (determined by fault rub marks analysis and focal mechanism solution) is determined, the focal depth is calculated by using the seismic waveform inversion data and the fault geometric parameters (the average value of waveform inversion and focal mechanism solution is taken, the accuracy is controlled in ±0.1 km), and the maximum potential magnitude is calculated according to the Chinese seismic parameter zoning map and the historical maximum earthquake magnitude empirical relationship wherein is the fault breakable length (unit: km), , is a constant determined according to regional statistical results (4.0 and 1.0 respectively), the maximum potential magnitude is calculated, and finally the focal parameter data including fault type, slip mode, focal depth and maximum potential magnitude is formed.

[0041] Preferably, the step S2 of constructing the fault geometric structure and crustal medium structure model containing three-dimensional terrain based on the fault structure data and the focal parameter data comprises:

[0042] obtaining the regional geological plan, the drilling comprehensive columnar diagram and the field investigation results of the research area;

[0043] determining the main stratum structure and thickness of the research area based on the regional geological plan, the drilling comprehensive columnar diagram and the field investigation results, to obtain stratum structure data;

[0044] dividing the engineering geology rock group of the research area based on the stratum structure data, to obtain engineering geology rock group data;

[0045] Based on the engineering geology rock group data, a fault geometric structure and a crust medium structure model containing three-dimensional terrain are constructed to obtain three-dimensional structure model data.

[0046] In the embodiment of the present application, firstly, a regional geological plan of a research area with a scale not less than 1:50,000, a drilling comprehensive columnar chart of a drilling depth not less than 200 m and high-precision field geological survey results are acquired, the stratum distribution and fault position in the geological plan are spatially matched with the lithology, thickness and contact relationship in the drilling columnar chart, the spatial extension range and thickness distribution of the main strata in the research area are determined by using the cross-section checking method, the thickness precision is controlled within ±2 m, and stratum structure data are obtained; on the basis of the stratum structure data, according to the Engineering Geology Rock Group Classification Standard, the strata are divided into soft rock group, relatively soft rock group, hard bedrock group and Quaternary loose sediment rock group according to the criteria of lithological composition, mechanical properties and weathering degree, and each rock group is endowed with density (unit: ), P-wave velocity Vp (unit: m / s), S-wave velocity Vs (unit: m / s) and Poisson's ratio , the parameter value range is referred to the regional indoor rock-soil mechanics test results and the land lithosphere velocity structure model, the density precision is controlled within ±50 , the wave velocity precision is controlled within ±50 m / s, and engineering geology rock group data are obtained; subsequently, the engineering geology rock group data are superimposed with high-resolution DEM (resolution better than 5 m), the fault geometric information (including strike angle, dip angle and brittle-ductile transition zone depth) is accurately superimposed in the three-dimensional modeling environment and the continuity of the fault plane and the stratum interface is maintained, the three-dimensional entity of the fault geometric structure and the crust medium structure is generated by using the layered stretching method, and the spatial grid is divided according to the hexahedral element division principle, the element length is controlled within 300 m, the grid is encrypted by 3 times within 1 km range at the edge of the landslide area to improve the local calculation precision, and finally, the three-dimensional structure model data consistent with the fault structure data and the source parameter data and containing the real terrain fluctuation are formed.

[0047] Preferably, the setting of the fault source parameters and the stratum velocity medium parameters based on the source parameter data and the three-dimensional structure model data in step S2 comprises:

[0048] The stratum grouping and the hexahedral grid are divided based on the three-dimensional structure model data to obtain grid division data;

[0049] The virtual ground motion monitoring station at the bottom of the landslide area is set based on the grid division data to obtain monitoring station layout data;

[0050] The fault plane is discretized based on the source parameter data to obtain sub-fault distribution data;

[0051] Determine the position, slip direction and slip amount of each sub-fault by using the sub-fault distribution data, and obtain fault slip amount distribution data;

[0052] Calculate the seismic moment of each sub-source by using the fault slip amount distribution data, and obtain seismic moment distribution data;

[0053] Set the rupture initiation point, initial rupture velocity and source time function based on the seismic moment distribution data, and obtain complete source parameter data;

[0054] Set the P-wave velocity, S-wave velocity and density of each stratum based on the complete source parameter data, and obtain stratum velocity medium parameter data;

[0055] Integrate the complete source parameter data and the stratum velocity medium parameter data, and obtain the input parameters of the seismic simulation.

[0056] In the embodiment of the application, first, grouping is performed in the three-dimensional structure model that has been constructed according to the stratum distribution characteristics, strata with the same lithology and mechanical properties are grouped into a group, and spatial grid subdivision is completed by using the hexahedral element division principle on the GID platform, the grid element length is controlled to be 300 m, 3 times of grid encryption is implemented within 1 km from the edge of the landslide area to improve the local calculation precision, and grid division data is obtained; in the grid division result, three virtual seismic motion monitoring stations are arranged along the center position of the bottom of the landslide area and the downstream extension direction in turn, the station spacing is controlled to be 200 m, the elevation is consistent with the terrain elevation, and monitoring station layout data is obtained; then, the fault plane is discretized according to the length 0.5 km and the width 0.5 km rectangular grid along the strike and dip directions according to the fault geometric parameters in the source parameter data, and sub-fault distribution data is obtained; in each sub-fault element, the slip direction (expressed by the strike angle and the dip angle) is determined according to the nodal plane parameters in the source mechanism solution, and the slip amount is set in combination with the fault rupture mode, the slip amount range is limited to 0.5 m to 3.0 m according to the experience value of the same type of fault event of regional historical earthquakes, and fault slip amount distribution data is formed; the seismic moment calculation formula wherein is the seismic moment (unit: ), is the shear modulus (unit: Pa), which is determined according to the engineering geological rock group parameters (range ) of the stratum where the sub-fault is located, is the sub-fault area (unit: ), To calculate the slip (unit: m), the seismic moment of each sub-source was obtained, yielding seismic moment distribution data. Based on this, the rupture initiation point was set as the sub-fault location with the most favorable stress concentration during fault rupture. The initial rupture velocity was controlled between 2.5 km / s and 3.5 km / s, and the duration of the source time function was set to 2.0 s to 5.0 s according to empirical formulas, forming complete source parameter data. Combining the stratigraphic grouping information from the three-dimensional structural model, the P-wave velocity, S-wave velocity, and density were set for each stratigraphic layer. The P-wave velocity range was 2500 m / s to 6000 m / s, the S-wave velocity range was 1400 m / s to 3500 m / s, and the density range was 2100 m / s to 3500 m / s. ~2800 Finally, the complete source parameter data and the formation velocity medium parameter data are integrated to obtain the earthquake simulation input parameters that include source rupture information and medium velocity information.

[0057] Preferably, step S2, which involves simulating the broadband ground motion field based on the three-dimensional structural model data and the seismic simulation input parameters, includes:

[0058] Based on the three-dimensional structural model data and the earthquake simulation input parameters, the propagation of three-dimensional non-uniform seismic waves in the study area was simulated to obtain broadband ground motion field data.

[0059] Based on broadband ground motion field data, ground motion time histories with velocity pulse characteristics are picked up by virtual ground motion monitoring stations to obtain ground motion simulation results data.

[0060] In this embodiment of the invention, the constructed three-dimensional structural model is first discretized in a three-dimensional spectral element method computational environment. Two types of computational grids are then divided according to region: a global low-frequency region grid with a unit side length not exceeding 300 m, and local grid refinement is implemented within a 1 km radius of the landslide area and fault, ensuring that the local unit side length meets the following wavelength sampling requirements to guarantee the highest frequency resolution, satisfying the formula... ,in The local unit side length (m) has an upper limit of 30 m; The local minimum P-wave velocity is taken as 1400 m / s. The target highest frequency (taken as 10 Hz); The number of sampling points required for each shortest wavelength is set to 5; this yields the following results in the landslide-sensitive area. Finally, the local mesh was rounded to no more than 30 m to meet the numerical analytical accuracy; a fourth-order interpolation spectral element was used for spatial solution, and the time step was limited by the Courant number according to the stability condition to satisfy... Therefore, the time step The value does not exceed In this embodiment, take Then when time , with as the calculation step to ensure numerical stability and accuracy; the boundary conditions are set as the free surface of the ground surface, and the remaining boundaries are applied with the absorbing boundary conditions, the thickness of the absorbing layer is set to 10 spectral element units, and the convolution type perfectly matched absorbing layer is used to realize energy dissipation to simulate the infinite half-space of the earth; the body force source term is applied according to the sub-fault distribution and seismic moment distribution data obtained by discretizing the fault in the time domain seismic source, and the rupture starting point, initial rupture velocity and source time function are distributed according to the fault slip distribution in space and time, the calculation time length is taken as 8 s, and the velocity time history and acceleration time history are saved in the whole process; the spatial output is obtained by arranging virtual seismic monitoring stations in the grid section position in the three-dimensional structure model, at least 3 stations are arranged in the main sliding direction at the bottom of the landslide area, the station spacing is 200 m, the station sampling rate is set to 200 Hz to meet the sampling requirement of the upper limit frequency of 10 Hz, and the station output includes three-component velocity time history, three-component acceleration time history, peak ground acceleration (PGA), peak ground velocity (PGV), Arias intensity and base frequency domain response spectrum (period 0.1 s-2.0 s) and other parameters; after the numerical solution is completed, the velocity time history with the velocity pulse characteristics is extracted for each virtual station, and it is formatted as the seismic motion simulation result data in time synchronization.

[0061] Preferably, the step S3 of constructing the finite element-discrete element coupling analysis geological model of the landslide area based on the seismic motion simulation result data and the preset field drilling and wave velocity test result data comprises:

[0062] Performing engineering geological drilling and in-hole wave velocity testing on the main profile of the landslide area to obtain field drilling and wave velocity test result data;

[0063] Obtaining landslide fine structure data based on the field drilling and wave velocity test result data combined with the field investigation results;

[0064] Constructing a landslide finite element-discrete element coupling analysis geological model based on the landslide fine structure data to obtain a coupling analysis geological model;

[0065] Inputting the bottom seismic time history of the coupling analysis geological model based on the seismic motion simulation result data to obtain seismic boundary condition data;

[0066] Applying the free field boundary conditions on the left and right sides of the coupling analysis geological model based on the seismic boundary condition data to obtain complete boundary condition data;

[0067] Determining the rock and soil medium parameters based on the field investigation results;

[0068] Integrating the coupling analysis geological model, the complete boundary condition data and the rock and soil medium parameters into landslide dynamic analysis model data.

[0069] In the embodiment of the present application, first, a geological drilling profile line is laid along the main sliding direction of the landslide area, passing through the landslide source area, the middle of the landslide and the landslide accumulation area. Three drillings with a drilling depth of not less than 50 m are arranged on the profile line, the drilling interval is controlled to be 80 m to 120 m, and in each drilling, the wave velocity test in the hole is carried out, the wave velocity sampling interval is not more than 1 m, and the field drilling and wave velocity test result data including the stratum lithology, layer thickness, interlayer contact relationship and longitudinal and transverse wave velocity distribution are formed. On this basis, combined with the information of the landslide rear edge tension crack position, shear outlet shape, surface subsidence area distribution and slope body structural surface occurrence obtained by field investigation, the landslide engineering geological profile is drawn, and the landslide fine structure data including the boundary shape of each rock layer and the distribution of the fracture zone are formed. According to the fine structure data, a finite element-discrete element coupled analysis geological model including the slope structure, sliding surface position, sliding body thickness and fracture zone range is established in a three-dimensional modeling environment. The finite element unit is used to simulate the overall deformation area of the landslide, and the discrete element unit is used to simulate the fracture zone and the accumulation body area. The unit grid edge length is controlled to be 1 m to 3 m, and the unit division at the sliding surface is ensured to be consistent with the strike of the structural surface. The three-component velocity history recorded by the virtual seismic motion monitoring station at the bottom of the landslide area in the seismic motion simulation result data is taken as the bottom input, and the velocity history is applied to the model bottom node by time step , and the complete boundary condition data is formed. The medium parameters of the rock-soil body are determined according to the results of the in-situ shear test, the indoor triaxial compression test and the direct shear test, including the density (value range 2100 to 2700 ), internal friction angle (value range 25° to 38°), cohesion (value range 15 to 120 kPa), elastic modulus (value range Pa), and Poisson's ratio (value range 0.25 to 0.35), and the finite element and discrete element units of the corresponding regions are respectively given. Finally, the coupled analysis geological model, the complete boundary condition data and the medium parameters of the rock-soil body are integrated in the same calculation environment to form the landslide dynamic analysis model data with real terrain, geological structure, dynamic input and physical parameters.

[0070] Preferably, the step S3 of simulating and analyzing the whole process of deformation-destabilization-motion-accumulation of the landslide under the earthquake condition based on the landslide dynamic analysis model data includes:

[0071] setting a self-combined and optimized mixed constitutive model based on the landslide dynamic analysis model data to obtain the mixed constitutive model parameters;

[0072] ​Based on the parameters of the hybrid constitutive model, the Mohr-Coulomb constitutive model of the solid element is selected and set during the landslide initiation process, and the constitutive model data of the solid element is obtained.

[0073] Based on the parameters of the hybrid constitutive model, the interface fracture model of the virtual contact surface based on plastic strain is selected and set to obtain the constitutive model data of the virtual contact surface.

[0074] The friction model dependent on the velocity of the solid element contact surface after landslide initiation is adopted and set based on the parameters of the hybrid constitutive model to obtain the constitutive model data of the contact surface after initiation.

[0075] Based on the constitutive model data of solid elements, constitutive model data of virtual contact surfaces, and constitutive model data of contact surfaces after startup, the finite element-discrete element coupled simulation process is analyzed to obtain coupled simulation analysis data.

[0076] The entire landslide process was simulated based on coupled simulation analysis data, and the landslide motion simulation results were obtained.

[0077] In this embodiment of the invention, a self-optimized hybrid constitutive model is first set up in a finite element-discrete element coupled computational environment. The mechanical responses at different stages are coupled through staged constitutive relations to form a hybrid constitutive model parameter set. In the landslide initiation stage, the solid element adopts a Mohr-Coulomb constitutive model, and the parameter values ​​are based on the results of indoor triaxial compression tests and direct shear tests, wherein the cohesion... The value ranges from 15 to 120 kPa, and the internal friction angle is... The value ranges from 25° to 38°, and the elastic modulus is... Range of values ~ Pa, Poisson's ratio The value ranges from 0.25 to 0.35, generating constitutive model data for solid elements. For virtual contact surfaces such as sliding surfaces and structural surfaces, an interface fracture model based on plastic strain is adopted in the landslide initiation stage. The fracture criterion is that the equivalent plastic strain reaches a preset fracture strain threshold. In this embodiment The range is 0.002 to 0.005. When the threshold is reached, the stiffness of the contact surface degrades and the strength is reduced, generating virtual contact surface constitutive model data. After the landslide enters the acceleration phase, the contact surface between the sliding body and the sliding bed adopts a velocity-dependent friction model, and its friction coefficient is calculated according to the formula. Calculation, where The static friction coefficient is taken as 0.55 to 0.65. The coefficient of kinetic friction is taken as 0.35 to 0.45. The tangential sliding velocity of the contact surface (unit: m / s). For the critical speed (0.5 m / s), the contact surface constitutive model data after starting is generated; in the coupling calculation process, the finite element part is used for solving the overall continuous deformation response of the landslide, the discrete element part is used for capturing the crushing of the sliding body, the interaction between blocks and the dynamic evolution of the accumulation body, and the two are iterated synchronously through the node-particle interaction force transmission on the public contact surface; while the seismic boundary condition and the free field boundary condition are applied, the velocity field, displacement field and contact force field of the whole field are updated and stored by time step The coupling simulation analysis data including landslide starting time, main sliding segment deformation process, sliding body velocity change and accumulation area morphology are obtained; finally, the numerical reproduction of the whole process of the landslide is completed based on the coupling simulation analysis data, and the landslide motion simulation result data including sliding distance distribution, sliding time history, accumulation range geometry and three-dimensional motion trajectory are output.

[0078] Preferably, step S4 comprises the following steps:

[0079] Step S41: extracting the motion distance on the main sliding profile of the landslide based on the landslide motion simulation result data to obtain the motion distance data of the main sliding profile of the landslide;

[0080] Step S42: extracting the width of the rear edge / shear exit area of the landslide in the direction perpendicular to the main sliding direction based on the landslide motion simulation result data to obtain the width data of the landslide source area;

[0081] Step S43: determining the diffusion angle data based on the existing landslide cases in the field investigation results;

[0082] Step S44: calculating the width of the accumulation body based on the width data of the landslide source area, the motion distance data of the main sliding profile of the landslide and the diffusion angle data to obtain the width data of the accumulation body;

[0083] Step S45: determining the three-dimensional motion range of the landslide based on the width data of the landslide source area, the motion distance data of the main sliding profile of the landslide and the width data of the accumulation body to obtain the three-dimensional motion range data of the landslide;

[0084] Step S46: performing three-dimensional visualization on the three-dimensional motion range data of the landslide to obtain the mapping data of the unstable motion range of the landslide.

[0085] In the embodiment of the present application, firstly, a profile line coinciding with the landslide axis is laid along the main sliding direction in the three-dimensional displacement field of the landslide movement simulation result, the position change of the sliding body front edge at different time steps is tracked by using the displacement contour line, the maximum front edge displacement value from the start to the final stop of the sliding body is determined, and the displacement value is taken as the movement distance of the landslide main sliding profile to form the landslide main sliding profile movement distance data; then, the planar shape boundary of the landslide rear edge and the shear exit area is extracted in the same movement simulation result, the maximum width is measured along the direction perpendicular to the main sliding direction, and the measurement accuracy is not less than 0.5 m to obtain the landslide source area width data; then, according to the existing same type landslide cases in the field investigation results, the diffusion angle is statistically analyzed in combination with the terrain conditions, the source characteristics and the historical accumulation range, and the value range is 5°-15° in the embodiment of the present application to form the diffusion angle data; according to the above three types of data, the trigonometric function is taken in radian system in the formula calculation process to obtain the accumulation body width data; on this basis, the landslide source area width data, the landslide main sliding profile movement distance data and the accumulation body width data are combined in the three-dimensional coordinate system, the three-dimensional polygon boundary is constructed by using the landslide main sliding profile length, the accumulation body width and the landslide elevation difference, the three-dimensional movement range of the landslide is determined, and the landslide three-dimensional movement range data is generated; finally, the landslide three-dimensional movement range data is imported into the ARCGIS platform, the three-dimensional visualization rendering is performed under the condition of the projection coordinate system I and the DEM data superposition, the classification color scale is allocated according to the risk classification (high, medium and low) during the rendering, the scale, the compass, the legend and the coordinate grid are added in the map, and the landslide instability movement range mapping data is output.

[0086] Preferably, the calculation formula of the accumulation body width in step S44 is specifically:

[0087] ;

[0088] wherein, is the accumulation body width, represents the landslide source area width, is the sliding distance on the landslide main sliding profile obtained by simulation, is the diffusion angle, and the value range is 5°-15°.

[0089] In the embodiment of the present application, firstly, the sliding body front edge displacement time sequence is extracted along the main sliding direction from the landslide movement simulation result data obtained in step S3, and the maximum displacement is determined as the sliding distance on the landslide main sliding profile (unit: m, and the measurement accuracy is not more than ±1.0 m); the landslide source area width (unit: m, and the measurement accuracy is not more than ±0.5 m) is measured by the maximum projection width of the landslide rear edge / shear exit area perpendicular to the main sliding direction, and the measurement is directly reading the value by using the distance measuring tool in the ARCGIS platform after the DEM (resolution ≤5 m) and the elevation profile are superimposed; the diffusion angle From the field investigation results in step S11 and the statistical results of the same type of landslide, the value range is limited to , and sampling is performed with a minimum step of 0.5°; the width of the accumulation body is calculated according to the following formula, and the angle is first converted into radian and then the tangent is calculated: , wherein each quantity is in meters, and the trigonometric function operation is calculated according to a high-precision numerical value (at least three decimal places are retained); in order to quantify the calculation uncertainty, error propagation evaluation is introduced, and let , , be the uncertainties of the three items, respectively, then the uncertainty of the width of the accumulation body is approximately given by the following formula: ; in the engineering application example, if , , then when , the calculation process is , , and is obtained; when , the calculation process is , and is obtained; the calculation result is recorded in the form of a table and is superimposed with DEM for verification, if it does not conform to the terrain constraint, then the value range of and is modified according to the field statistics of the same type of landslide, and the modified calculation is repeated until the value is consistent with the terrain boundary, and finally , , and are output as the width data of the accumulation body after error evaluation.

[0090] Preferably, the present application also provides a near-fault single-body co-seismic landslide movement range mapping system for executing the near-fault single-body co-seismic landslide movement range mapping method described above, and the near-fault single-body co-seismic landslide movement range mapping system comprises:

[0091] A seismic source feature recognition and parameterization module is configured to obtain fault structure data of a study area; based on the fault structure data, a main seismogenic fault is located, and a rupture mechanism analysis is performed to obtain seismic source parameter data;

[0092] A three-dimensional ground motion field modeling and simulation module is configured to construct a fault geometry structure and crust medium structure model containing three-dimensional terrain based on the fault structure data and the seismic source parameter data, to obtain three-dimensional structure model data; based on the seismic source parameter data and the three-dimensional structure model data, fault source parameters and stratum velocity medium parameters are set to obtain seismic simulation input parameters; based on the three-dimensional structure model data and the seismic simulation input parameters, a wideband ground motion field is simulated to obtain ground motion simulation result data;

[0093] ​The landslide dynamics coupling analysis module is configured to construct a finite element-discrete element coupling analysis geological model of the landslide area based on the seismic motion simulation result data and preset site drilling and wave velocity test results, and obtain landslide dynamic analysis model data; and to perform simulation analysis on the whole process of deformation-destabilization-motion-accumulation of the landslide under the seismic condition based on the landslide dynamic analysis model data, and obtain landslide motion simulation result data.

[0094] The motion range mapping and risk evaluation module is configured to estimate a three-dimensional motion range based on the landslide motion simulation result data, and generate landslide destabilization motion range mapping data.

[0095] Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is not limited by the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the application file are intended to be included in the present application.

[0096] The above description is merely a specific implementation of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for mapping the movement range of a near-fault single-unit coseismic landslide, characterized in that, The method comprises the following steps: Step S1: obtaining fault structure data of the study area; Based on the fault structure data, the main seismogenic fault is located, and the rupture mechanism analysis is carried out to obtain the source parameter data; Step S2: based on the fault structure data and the source parameter data, a fault geometry structure and crustal medium structure model containing three-dimensional terrain is constructed to obtain three-dimensional structure model data; based on the source parameter data and the three-dimensional structure model data, the fault source parameters and the stratum velocity medium parameters are set to obtain the seismic simulation input parameters; based on the three-dimensional structure model data and the seismic simulation input parameters, the wideband ground motion field is simulated to obtain the ground motion simulation result data; Step S3: based on the ground motion simulation result data and the preset site drilling and wave velocity test results, a finite element-discrete element coupled analysis geological model of the landslide area is constructed to obtain landslide dynamic analysis model data; based on the landslide dynamic analysis model data, the deformation-destabilization-motion-accumulation whole process simulation analysis of the landslide under the seismic condition is carried out to obtain the landslide motion simulation result data; Step S4: based on the landslide motion simulation result data, the three-dimensional motion range is estimated, and the landslide instability motion range mapping data is generated.

2. The method of claim 1, wherein, Step S1 comprises the following steps: Step S11: carrying out near-field active fault investigation and detection in the study area to obtain fault structure data containing fault spatial distribution characteristics, activity history, activity intensity, activity rate and paleoseismic activity sequence; Step S12: based on the fault structure data, the main seismogenic fault is accurately located to obtain fault geometry parameter data containing strike, dip and brittle-ductile transition zone depth; Step S13: based on the fault geometry parameter data, the main seismogenic fault is analyzed to obtain source parameter data containing fault type, slip mode, source depth and maximum potential magnitude.

3. The method of claim 1, wherein: In step S2, based on the fault structure data and the source parameter data, the fault geometry structure and the crustal medium structure model containing three-dimensional terrain are constructed, which comprises: Obtaining regional geological plan, drilling comprehensive columnar chart and field investigation results of the study area; Based on the regional geological plan, drilling comprehensive columnar chart and field investigation results, the main stratum structure and thickness of the study area are determined to obtain stratum structure data; Based on the stratum structure data, the engineering geology rock group division of the study area is carried out to obtain engineering geology rock group data; Based on the engineering geology rock group data, the fault geometry structure and the crustal medium structure model containing three-dimensional terrain are constructed to obtain three-dimensional structure model data.

4. The method of claim 1, wherein: In step S2, based on the source parameter data and the three-dimensional structure model data, the fault source parameters and the stratum velocity medium parameters are set, which comprises: Based on the three-dimensional structure model data, the stratum grouping and hexahedral grid are divided to obtain grid division data; Based on the grid division data, the virtual ground motion monitoring station at the bottom of the landslide area is set to obtain monitoring station layout data; Based on the source parameter data, the fault surface is discretely processed to obtain sub-fault distribution data; Using the sub-fault distribution data, the position, slip direction and slip amount of each sub-fault are determined to obtain fault slip amount distribution data; Using the fault slip amount distribution data, the seismic moment of each sub-source is calculated to obtain seismic moment distribution data; Setting a rupture starting point, an initial rupture velocity and a source time function based on the seismic moment distribution data to obtain complete source parameter data; Setting a P-wave velocity, a S-wave velocity and a density of each stratum based on the complete source parameter data to obtain stratum velocity medium parameter data; Integrating the complete source parameter data and the stratum velocity medium parameter data to obtain seismic simulation input parameters.

5. The method of claim 1, wherein: The step S2 includes: Simulating a three-dimensional non-uniform seismic wave propagation in the research area based on the three-dimensional structure model data and the seismic simulation input parameters to obtain wide-band ground motion field data; Picking up a ground motion time history with a velocity pulse feature through a virtual ground motion monitoring station based on the wide-band ground motion field data to obtain ground motion simulation result data.

6. The method of mapping near-fault single monolithic coseismic landslide runout according to claim 1, wherein, The step S3 includes: Performing engineering geological drilling and in-hole wave velocity testing on a main profile of the landslide area to obtain field drilling and wave velocity testing result data; Obtaining landslide fine structure data based on the field drilling and wave velocity testing result data in combination with field investigation results; Constructing a landslide finite element-discrete element coupling analysis geological model based on the landslide fine structure data to obtain a coupling analysis geological model; Inputting a ground motion time history at the bottom of the coupling analysis geological model based on the ground motion simulation result data to obtain ground motion boundary condition data; Applying free field boundary conditions to the left and right sides of the coupling analysis geological model based on the ground motion boundary condition data to obtain complete boundary condition data; Determining rock-soil medium parameters based on field investigation results; Integrating the coupling analysis geological model, the complete boundary condition data and the rock-soil medium parameters into landslide dynamic analysis model data.

7. The method of claim 1, wherein: The step S3 includes: Setting a self-combined and optimized mixed constitutive model based on the landslide dynamic analysis model data to obtain mixed constitutive model parameters; Selecting and setting a Mohr-Coulomb constitutive model of a solid element in a landslide starting process based on the mixed constitutive model parameters to obtain solid element constitutive model data; Selecting and setting a plastic strain-based interface fracture model of a virtual contact surface based on the mixed constitutive model parameters to obtain virtual contact surface constitutive model data; Selecting and setting a velocity-dependent friction model of a contact surface after a landslide starts based on the mixed constitutive model parameters to obtain post-starting contact surface constitutive model data; Analyzing a finite element-discrete element coupling simulation process based on the solid element constitutive model data, the virtual contact surface constitutive model data and the post-starting contact surface constitutive model data to obtain coupling simulation analysis data; Simulating a whole landslide process based on the coupling simulation analysis data to obtain landslide motion simulation result data.

8. The method of claim 1, wherein: The step S4 includes the following steps: Step S41: Extracting a motion distance on a main sliding profile of a landslide based on landslide motion simulation result data to obtain main sliding profile motion distance data of the landslide; Step S42: Extracting a motion distance on a main sliding profile of a landslide based on landslide motion simulation result data to obtain main sliding profile motion distance data of the landslide; Step S42: Extract the width of the landslide rear edge / cutout area in the direction perpendicular to the main sliding direction based on the landslide motion simulation result data, to obtain landslide source area width data; Step S43: Determine the diffusion angle data based on the existing landslide cases in the field investigation results; Step S44: Calculate the accumulation body width based on the landslide source area width data, the landslide main sliding profile motion distance data, and the diffusion angle data, to obtain accumulation body width data; Step S45: Determine the three-dimensional motion range of the landslide based on the landslide source area width data, the landslide main sliding profile motion distance data, and the accumulation body width data, to obtain landslide three-dimensional motion range data; Step S46: Perform three-dimensional visualization on the landslide three-dimensional motion range data, to obtain landslide instability motion range mapping data.

9. The method of claim 8, wherein: The calculation formula of the accumulation body width in step S44 is specifically: ； wherein, is the width of the accumulation body, represents the width of the landslide source area, is the simulated sliding distance on the main sliding profile of the landslide, is the diffusion angle, which is in the range of 5°-15°.

10. A system for mapping near-fault single monolithic coseismic landslide runout, comprising: The near-fault single landslide motion range mapping system comprises: A seismic source feature recognition and parameterization module, configured to obtain fault structure data of a research area; locate a main seismogenic fault based on the fault structure data, and perform a rupture mechanism analysis to obtain seismic source parameter data; A three-dimensional ground motion field modeling and simulation module, configured to construct a fault geometry structure and crust medium structure model containing three-dimensional terrain based on the fault structure data and the seismic source parameter data, to obtain three-dimensional structure model data; set fault source parameters and stratum velocity medium parameters based on the seismic source parameter data and the three-dimensional structure model data, to obtain seismic simulation input parameters; simulate a wideband ground motion field based on the three-dimensional structure model data and the seismic simulation input parameters, to obtain ground motion simulation result data; A landslide dynamics coupling analysis module, configured to construct a finite element-discrete element coupling analysis geological model of a landslide area based on the ground motion simulation result data and preset field drilling and wave velocity test results, to obtain landslide dynamic analysis model data; perform a deformation-instability-motion-accumulation whole process simulation analysis on the landslide under seismic conditions based on the landslide dynamic analysis model data, to obtain landslide motion simulation result data; A motion range mapping and risk evaluation module, configured to estimate a three-dimensional motion range based on the landslide motion simulation result data, to generate landslide instability motion range mapping data.

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