Study Of Deposit Position And Motion Process Of Landslide-debris Avalanches

Debris flow is a common and major geological disaster in China,which is destructive and could be sudden,and leads to huge casualties and economic losses.Consequently,the development of society and economy are restricted.However,the motion mechanism and hazard scope have been being the studying focus of scholars all over the world.Using indoor model test,this paper simulated the sliding and accumulation process of landslide debris avalanches under certain special condition.Then,this paper acquired and further analyzed the deposit position of each granule of landslide-debris avalanches.In addition,this paper analyzed the motion mechanism of landslide-debris avalanches.Results show: The deposit position of the slide-debris is of regularity.Specifically,these particles that are symmetrical on the central axis of slope board are still symmetrical after the slide;the deposit position of these granules in consecutive region previously is not continuous after the slide;the deposit position of the particles is affected by its initial position conspicuously;the inside holistic rolling of slide-debris is founded in the process of slide.PFC3D was used to simulate the debris flow under different working conditions.And the effects of different factors on the movement of the landslide-debris flow were studied.Then,the locomotory mechanism of the debris flow particles was further analyzed.The results show that: There is an overall forward tilting of the particles in the front of the initial deposit,and bounce is the major motion form of the upper particles in the front;In the acceleration phase,bounce is the main movement of the initial particles that in the upper part;The particles located at the upper rear of the initial deposit will diffuse outward in the horizontal direction perpendicular to the slope;Slope height has a great effect on the size of particle distribution,distance between its stacking position and slope toe,and the diffusion angle of particle accumulation distribution.However,the influence of slope height on the landslide-debris flow could be obvious,until the slope height is large enough.The friction coefficient of slope has a significant influence on the degree of dispersion and stop position of particles in the debris flow.The inclination of slope has an obvious influence on the spacing between location of particle accumulation and slope toe,and the randomness of particles' stacking position.Based on model test and numerical simulation,this paper studies the accumulation and distribution of landslide-debris flow and analyzes its motion mechanism.The results provide reliable reference for the research of motion mechanism of landslide-debris and for back-tracking the initial state of slopes.