The Mechanism Study And Movement Characteristics Prediction Of Shuanghuyu Landslide

In Northern Shaanxi,the terrain is complex,rainfall is concentrated,rainfall induced landslides pose a serious threat to the safety of local people's lives and property,it is of great theoretical and practical significance to carry out landslide mechanism and movement characteristics prediction research for landslide risk assessment and disaster prevention and mitigation.In this paper,taking shuanghuyu loess landslide in Zizhou County as the research object,based on the test and analysis of the influence of water on the macroscopic mechanical characteristics and microstructure characteristics of landslide rock and soil mass,the instability mechanism and movement characteristics of landslide are studied and predicted by using finite element and discrete element numerical analysis methods,The main conclusions are as follows:(1)The shear strength of landslide soil decreases with the increase of soil moisture content.With the increase of water content,the internal friction angle decreases,while the cohesion increases first and then decreases.The failure modes of shear specimens are bulging and simple shear under different moisture content.(2)Under the same confining pressure,the landslide soil is more likely to be compacted with the increase of water content,the overhead pores decrease,the embedded pores increase,and the shear strength of the soil decreases.With the increase of water content,the area proportion and average shape coefficient of soil particles increase,while the probability entropy decreases,which indicates that the degree of clustering and roundness of particles increases,and the directivity increases.Under the action of shear force,the debris particles of natural water content soil increase,and the bite between particles increases.However,the saturated water content soil particles appear obvious granulation,and the contact area between the single particles decreases.The two kinds of soil particles show inconsistent changes in the average diameter,probability distribution index of area and fractal dimension of distribution.(3)When the soil moisture content is more than 20%,the landslide is unstable,and with the increase of rainfall time and rainfall intensity,the soil moisture content and pore water pressure increase,the soil matrix suction decreases,and the effective stress on the surface of the slope decreases significantly.The failure characteristics of landslide are typical push failure.The landslide consumes 6.31×1010J of gravitational potential energy in 107s from starting to stopping,the average peak velocity is 6m/s,the average displacement is 87m,and the peak impact force of landslide increases first and then decreases with the distance between the slope toe.