The Application Of Three-Dimensional Laser Scanning System In Geometry Morphology Of Coarse Debris Of Touzhai Landslide

LHLLDP?Large high-speed Long-runout Landslide-Debris Flow?is a geological disaster with strong destructive power.It is characterized by long-distance migration,high speed,strong impulsive and destructive force and high energy.However,mountains and canyons are stretched in an uninterrupted way in Yunnan region due to the rather complex tectonic setting in this area.Moreover,the specific tectonic setting is susceptible to LHLLDF.Emeishan basalt,distributedbroadly in Yunnan province,is a kind of volcanic rock series.More importantly,it can easily incur LHLLDF.Therefore,the research of Emeishan basalt-LHLLDF possesses significances in both theoretical and practical level.The geometric features of Emeishan basaltserving as the substantial basis of LHLLDF are the prominent influential factors of LHLLDF.At present,those relevant researches mainly focuson the kinematics of rock avalanche-debris flow and the triggers of events.However,a systematic research on the morphological characteristics of basalt debris does not yet exist.Thus,based on a three-dimensional laser scanning system,this paper builds a three-dimensional digital model of coarse debris of Touzhai landslide and Chenggong quarry.By discussing the characteristics and potential laws of coarse debris of the Touzhai landslide through quantitative analysis and comparison between two-dimensional and three-dimensional morphological characteristics,a set of measuring and statistical methods by using 3D laser scanner is established.In addition,the present paper constructsa precisely structure model of rock debris andrestores geometrical parameters of detrital particles.And then,the causes of the Touzhai landslide were discussed thoroughly.Thus it is fair to say that this studycan serve as a basis for the future research of P₂?rock collapse for further numerical simulation,and can provide reliable fundamental data for the evaluation of rockavalanche.This papermainly focused on the following aspects:?1?Applying three-dimensional laser scanning system to scan coarse debris of Touzhai landslide and Chenggong quarry,and establishing a 3D digital model of each sample by Reverse Modeling;?2?Intercepting 3D orthographic views by 3D digital model,andevaluating two-dimensional morphological characteristics of sample through Image J,which include Axial Coefficient,Circularity,Roundness,Solidity,etc.,and then exploring the internal relations between those statistical parameters;?3?Evaluating three-dimensional morphological characteristics of each sample on the basis of3D digital model,which include shape characterization parameters such as parameters of topography,angular features,fractal dimension and so on and then analyzing and exploring the internal relations between them;?4?Conducting detailed fieldwork andcorresponding indoor morphological parameter study for the purpose of discussing the causes of the Touzhai landslide.By thestudy above,conclusionscan be drawn as following:?1?Three-dimensional laser scanning system can be usedto construct an accurate 3D digital model of the object.Besides,the measurement result are in agreement with standard value,which proves to be permeable within error limits.?2?The mean of Axial parameter of coarse debris of Touzhai landslide is 1.395.It will decrease if the particle diameter increases.The statistical results of Flatness and Elongation show that coarse debris of Touzhai landslide mostly exist in a spherical and uniformshape,but the samples of Chenggong quarry are sharper and their geometry is more variable.the shape rankwill decrease,if the particle size increases.?3?The average Circularity of coarse debris of Touzhai landslide is 0.725.the average Circularity will increase as the migration distance increases.There is a clear positive correlation between Circularity and Solidity.So is the case with Roundness and Solidity.In addition,the details of the particle will be more obvious if the volume increases,and the particle will be more circular and lessangular if the migration distance increases.Furthermore,the Specific Surface Area of particle will decrease if the particle diameter increases.The mean of Specific Surface Area of coarse debris of Touzhai landslide is 0.225 m²/kg,and the mean of samples from Chenggong quarry is0.257 m²/kg,which shows the coarse debris of Touzhai landslide possesses a compact structure and fine psephicity.?4?The above result shows that the Psephicity increases with the particle diameter.The Sphericity can better characterize the regularity extent of rock particles;the Sphericity increases with the migration distance.The mean of Psephicity of coarse debris of Touzhai landslide is 0.853,and the mean of Sphericity is 0.793.Three-Dimensional Fractal Dimension can well reflect Three-Dimensional morphological characteristics of coarse debris of Touzhai landslide.?5?Weathering and its products has asignificant impact on the emergence of the Touzhai landslide.