Research On The Dynamic Process Of Landslide Debris Flow And The Characteristics Of River Blocking Accumulatio

High-speed remote landslide debris flow has the characteristics of large scale,complex movement mechanism and strong destructiveness.Once a large-scale landslide occurs,it is easy to cause serious loss of life and property.The barrier dam formed by the landslide debris flow blocking the river channel also usually poses a great threat to the safety of people ’s lives and property and the stability of the ecological environment.In order to study the dynamic river blocking process and accumulation characteristics of landslide debris flow,this paper carried out physical model tests on two kinds of layered landslide debris flow with different particle gradation,particle sequence and sliding bed slope and used numerical simulation to reproduce the physical model test process.(1)The order of importance of the factors affecting the particle velocity of the debris flow of the cutting landslide is particle gradation,sliding bed slope and particle gradation,while for the bedding landslide debris flow is particle sequence,particle gradation,and sliding bed slope.(2)The front velocity of debris flow of the cutting landslide increases with the increase of particle size and sliding bed slope,and the decrease of distance from fine particles to debris flow.The debris flow energy and damping energy dissipation of the landslide will increase with the increase of the proportion of medium and coarse particles,the increase of the slope of the sliding bed and the decrease of the distance between the medium and coarse particles and the surface layer of the debris flow.The velocity of the front edge of the bedding landslide debris flow increases with the increase of the particle size and the slope of the sliding bed,and the decrease of the distance between the fine particles and the surface layer of the debris flow.The debris flow energy of bedding landslide is characterized by debris flow with large proportion of medium and coarse particles.The closer the particle sequence is to the bottom of debris flow,the larger the kinetic energy is,while the debris flow particles with small proportion of medium and coarse content show the opposite trend.(3)The length L and high H of the debris flow accumulation body of the landslide debris flow are positively correlated with the proportion of coarse particle content and the slope of the sliding bed.The width W of the accumulation body increases first and then decreases with the increase of the proportion of medium and coarse particle content.The relationship between the geometry of the accumulation body and the particle sequence is : the length L of the accumulation body under low slope and the width W of the accumulation body under high slope decrease first and then increase with the fine particle sequence approaching the bottom of the debris flow,while the height H of the accumulation body under high slope is opposite to the width W.The length L and width W of the bedding landslide deposit increase with the increase of the proportion of coarse particles under low slope,and the height H of the deposit is positively correlated with the proportion of medium and coarse particles and the slope of the sliding bed.At the same time,the length L of the accumulation body decreases first and then increases with the fine particle sequence approaching the bottom of the debris flow at low slope,and the width W and high H increase with the fine particle initially approaching the bottom of the debris flow at high slope.(4)The particle gradation of landslide debris flow and the particle sequence of sliding body are the main important factors affecting the impact force of debris flow.The specific performance is as follows : the impact force of the debris flow of the slice landslide increases with the proportion of the coarse particle content,and the distance between the coarse particle sequence and the surface of the debris flow decreases.The impact force of the debris flow increases with the increase of the proportion of coarse particles and the decrease of the distance between the fine particle sequence and the surface of the debris flow.