Experimental Study On The Deposition Characteristics Of Viscous Debris Flows Using Point Cloud Data Processing

As a frequent geological disaster in mountainous areas,debris flow poses a great threat to the safety of people's lives and property,and the safe operation of structures and transportation facilities in the activity area.Impact and burying are the most significant ways of debris flow disasters.At present,the research on the impact of debris flow has made great progress,and there are only sporadic studies on silting damage.The two-phase material composition directly affects the sediment flow characteristics,stagnation process and the morphological characteristics of the debris flow.This paper analyzes the influence of the two-phase material composition on the debris flow accumulation characteristics based on the two-phase flow theory.The paper selects three factors of viscosity coefficient,volume concentration,and particle size as the two-phase material indicators of debris flow,and selects washout distance,accumulation area,accumulation thickness,and accumulation width as the characteristics of debris flow accumulation,which are carried out through the indoor model test of debris flow accumulation characteristics.There are 64 sets of experiments under the combination of 4 kinds of viscosity coefficient,4 kinds of volume concentration,and 4 kinds of particle size.A three-dimensional laser scanner and consumer drone aerial photography are used to obtain point cloud data and image data in the accumulation area.For point cloud data,use Cyclone software and Visual Studio 2017 integrated development environment based on C++language programming to extract feature parameters such as punching distance,accumulation area,accumulation thickness,accumulation width,etc.,and analyze the impact of two-phase material indicators on the feature parameters of debris flow accumulation geomorphology.The law of influence.the result shows:(1)T he two-phase material composition affects the morphological characteristics of debris flow deposits.The plane morphology of the debris flow accumulation area is rod-shaped,tongue-shaped,elliptical,irregular shape and other geometric forms.When the viscosity coefficient and volume concentration increase,the geometric form of the accumulation body changes from"slender"to"short and wide".Change trend:The accumulation body presents a solid-liquid mixing trend with the increase of the viscosity coefficient of the slurry,and presents a solid-liquid separation trend with the increase of the particle size.(2)The rushing distance of the debris flow(0?6.45m)is affected by the viscosity coefficient and volume concentration,and decreases rapidly as the viscosity coefficient and volume concentration increase.When the viscosity coefficient?=0.3Pa·s,the volume concentration Cv=0.3,and the particle size d=20mm combined conditions(T₁₁₄ working condition),the maximum punching distance is 6.45 m;the debris flow accumulation area(0-11.529 m²)varies with the viscosity The coefficient increases,the volume concentration increases,and the particle size decreases gradually.When the viscosity coefficient?=0.3Pa·s,the volume concentration Cv=0.3,and the particle size d=20mm combined conditions(T₁₁₄ working condition),the maximum accumulation area is 11.529 m²;the debris flow accumulation thickness(0?0.159 m)is affected by the volume concentration,It increases rapidly with the increase of volume concentration.When the viscosity coefficient?=0.7Pa·s,the volume concentration Cv=0.6,and the particle size d=10mm,the combined condition(T₃₄₃ working condition)reaches the maximum value of 0.159m.The particle size has a more complicated influence on the thickness of the accumulation,and it interacts with the volume concentration on the debris flow accumulation to control the change of the accumulation thickness.The average accumulation width of debris flow(0?2.9m)decreases with the increase of volume concentration,and increases with the increase of particle size;the maximum accumulation width of debris flow(0?3.382m)gradually increases with the decrease of viscosity coefficient and increase of particle size.Big.When the viscosity coefficient?=0.3Pa·s,the volume concentration Cv=0.6,and the particle size d=20mm(T₁₄₄ working condition),the maximum accumulation width reaches the extreme value of 3.382m.(3)Establish a three-factor fixed-effect linear model considering the interaction.Through the analysis of variance,it can be obtained that the volume concentration of debris flow has the strongest influence on the accumulation characteristic parameters,while the viscosity coefficient and particle size have different degrees of significance for different accumulation characteristic parameters.(4)By drawing the effect diagrams of each accumulation feature factor and according to Taguchi factor classification criteria,the different influencing factors of the terrain feature parameters were classified into important,robust,adjusted,and secondary factor categories.(5)Through non-linear regression analysis,formulas for predicting debris flow rushing distance,maximum accumulation width,and debris flow accumulation area considering viscosity coefficient,volume concentration,and particle size were established.Each fitting formula R² is 0.95272,0.73024,0.92379 in turn.The characteristic parameters of debris flow deposits,such as the distance,accumulation area,accumulation thickness,and accumulation width,directly affect the disaster range of the debris flow,and are of great significance to the risk assessment of debris flow disasters,disaster prediction and prediction,prevention and control engineering design and construction,land planning and utilization,etc.The research results can provide theoretical support for the study of debris flow accumulation geomorphology and prediction of the disaster range of debris flow.