The Geometrical Morphology And Formation Mechanism Of Fine Debris In Touzhai Rock Avalanche

Rock avalanche is a kind of geological disaster with strong destructive power.It has the characteristics of sudden suddenness,fast speed,long migration distance,high energy and strong destructive power.And it often brings great danger to people's lives and property.Such disasters sometimes occur in Yunnan Province.The Late Permian Emeishan basalt is the material basis of rock avalanche and is widely distributed in this area.Therefore,it is of great theoretical significance and reality for the study of the Emeishan basalt in the Late Permian.The Late Permian Emeishan basalt is the material basis of large-scale high-speed long-distance landslide.The study of the geometrical characteristics of fine debris is one of the most important influencing factors affecting the high-speed remote displacement of the rock avalanche in Touzhai.However,the research on large-scale high-speed remote landslides is still focused on its inducing factors and kinematics mechanism.The study of the characteristics of the deposits also stays on the gradation characteristics?mineral composition and so on.Few scholars have studied the influence of the geometrical features of fine debris on its high-speed remote displacement,and there is no complete evaluation standard for the fine-grained geometrical features in the world.This research work provides a reference value for the study of the geometrical features of the rock debris and the high-speed remote displacement mechanism.At the same time,the two-dimensional geometric morphology parameters obtained based on digital image processing technology also provide reliable data support for future numerical simulation.In addition,it also shows that the Touthai rock avalanche experienced a long-term gestation process before it occurred,which is helpful for the identification of potential rock avalanche disasters.Through the above research,the following conclusions are drawn:(1)Digital image processing technology has high precision and flexibility,and has obvious advantages and wide application compared with traditional methods.It can be applied to the study of the geometry and formation mechanism of the rock avalanche in Touzhai.(2)The basalt fine debris is quantitatively evaluated by parameters such as long and short axis,axial coefficient,area,perimeter,roundness,angularity,rectangularity,solidity,fractal dimension,etc,and the basalt is fined by polarized light microscopy and scanning electron microscopy.Debris was qualitatively evaluated.On this basis,it is proved that the reason why the fine clasts of Touzhai basalt present rounded geometry is weathering rather than rounding.(3)The Touzhai rock avalanche is caused by the geological tectonic action(primary and secondary structures),unloading,chemical weathering and chemical and physical weathering coupling with physical weathering.Creep,when the deformation of the slope develops to a certain extent and causes the lock segment to be finally cut,the Touzhai rock avalanche occurs.It shows that the Touzhai avalanche experienced a long-term gestation process before it occurred,which helps to identify the future rock avalanche disaster.