Study On The Motion Characteristic And The Accumulation State Of Collapse Flow

Collapse flow is a common geological disaster.Its movement process is fast,its movement distance is long,and its destructiveness is huge,which poses a great threat to the lives and property of the people.In this paper,following the principle of controlling single variable,using the new discrete element software Matdem to carry out numerical simulation,the effects of different particle size,different volume,different landslide height,different landslide angle and other factors on the motion characteristics and accumulation pattern of collapse flow are studied.The SPSS analysis software was used to analyze the data obtained by the simulation,the conclusions as below:(1)The particle size,volume,landslide height and landslide angle of the collapse flow have different effects on the equivalent friction coefficient and the center movement distance of the collapse flow.The particle size is larger,the volume is larger,the landslide height is higher and the landslide angle is smaller,the equivalent friction coefficient of the collapse flow is smaller,the center movement distance of the collapse flow is farther,the fluidity of the collapse flow is stronger;The law of variation between the center movement distance of different particle size with the equivalent friction angle is approximately linear.The law of variation between the center movement distance of different volume with the equivalent friction angle is approximately linear.The law of variation between the center movement distance of different landslide height with the equivalent friction angle is not approximately linear.The law of variation between the center movement distance of different landslide angle with the equivalent friction angle is approximately linear.(2)The particle size,volume,landslide height and landslide angle of the collapse flow have different effects on the accumulation pattern of the collapse flow.The accumulation pattern of different particle sizes of the collapse flow is similar;The accumulation pattern of different volume of the collapse flow is similar;The accumulation pattern of different landslide height of the collapse flow is similar,When the landslide height is less than 4.7m,the collapse flow cannot completely slide out of the slideway;The accumulation pattern of different landslide angle of the collapse flow is similar,when the landslide angle is greater than 60 degrees,the collapse flow cannot slide completely out of the slideway,when the landslide angle is less than 20 degrees,the collapse flow cannot slide completely from the starting position.(3)The particle size,volume,landslide height and landslide angle of the collapse flow have different effects on the accumulation length of the collapse flow.The particle size is larger,the volume is larger,the landslide height is higher and the landslide angle is smaller,the accumulation length of the collapse flow is longer.The law of variation between the accumulation length of different particle size with the equivalent friction angle is not approximately linear.The law of variation between the accumulation length of different volume with the equivalent friction angle is approximately linear.The law of variation between the accumulation length of different landslide height with the equivalent friction angle is not approximately linear.The law of variation between the accumulation length of different landslide angle with the equivalent friction angle is not approximately linear.(4)The particle size,volume,landslide height and landslide angle of the collapse flow have different effects on the accumulation width,the accumulation range and the accumulation area of the collapse flow.The particle size is larger,the volume is larger,the landslide height is higher and the landslide angle is smaller,the accumulation width and the accumulation range of the collapse flow is wider,the accumulation area of the collapse flow is bigger.(5)The particle size,volume,landslide height and landslide angle of the collapse flow have different effects on the accumulation height of the collapse flow.The particle size is larger,the volume is smaller,the landslide height is higher and the landslide angle is smaller,the accumulation height of the collapse flow is lower.(6)The particle size is larger,the fluidity of the collapse flow is stronger,the main reason is that under the same volume conditions,the particle size is larger,the number of particles is smaller,the collisions between particles is fewer,so the energy dissipated by collision is less.The volume is larger,the fluidity of the collapse flow is stronger,the main reason is that under the same particle size conditions,the volume is larger,the number of particles is bigger,although the number of collisions between particles increases and the energy dissipated by collisions increases,the total energy of the collapse flow increases with the increase of volume.The landslide height is higher,the fluidity of the collapse flow is stronger,the main reason is that the landslide height is higher,the gravitational potential energy of the collapse flow is higher.During the process of landslide,the gravitational potential energy is transformed into kinetic energy,and the particle velocity of the debris flow increases,so the movement distance is farther.The landslide angle is smaller,the fluidity of the collapse flow is stronger,the main reason is that the landslide angle of the collapse flow decreases and the length of landslide slide increases,on the premise that the collapse flow speed can meet the collapse flow slipping out of the slide,the collapse flow slides farther when the slope angle is smaller.(7)Through the correlation and regression analysis of the simulated data,the empirical formula for calculating the sliding distance of the collapse flow is derived.The error between the distance by calculated and the distance from actual collapse flow is within a reasonable range,so the formula can be used to calculate and predict the sliding distance of actual collapse flow.