Study On The Stability Of The Slope Of Malan Loess In The Xieliupo Slope Of Rainfall

Loess is a special soil mainly distributed in northwest,north and northeast China,pores and vertical joints development,soil drying structure is stable,stability after water,stability drops sharply,accompanied by obvious collapsibility.Under the action of water bodies such as rainfall,the loess area is prone to landslides,landslides and other geological disasters,which seriously endangering people's life and property safety,while the degree of immersion and pressure is the key factors.Based on the analysis of the basic physical properties of Malan loess,this paper systematically studies the effect of water content on the strength of loess soil,and a typical example of slope is given,Analysis of rainfall induced loess slope sliding characteristics,and discusses the mechanism of disaster-inducing mechanism of loess slope.The main research contents are as follows:(1)The water content,density,particle distribution curve,liquid plastic limit and the collapsibility coefficient of the original loess in the landslide of spillway slope were determined by conventional geotechnical tests.(2)Through the conventional three-axis test,the strength law and failure form of soil mass of undisturbed and remolded loess under different moisture content were studied.With the increase of water content,the stress strain curve changes from strain softening to strain hardening,and with the increase of circumference,the strain hardening characteristics of the soil body are more obvious.The body strain increases with the increase of water content,from shearing to shearing,when shearing,the soil-like pattern of waist drum-type destruction,and when shearing is a split-type destruction mode.The viscous force of the undisturbed loess has an exponential function relationship with the moisture content,while the reshaping loess viscosity force is linear lying with the moisture content.With the increase of water content,the softening effect of shearing strength of undisturbed loess is more obvious than that of remolded loess,but the effect of water content on the friction Angle of undisturbed loess and remolded loess is less.(3)By integrating the strength reduction finite element method and ABAQUS software,this paper analyzes the influence of the failure criterion,the grid division and the dilatancy Angle of soil mass calculated by finite element method on the safety factor of loess landslide through typical examples.On this basis,the safety factors of the original luteal body soil under different moisture content and different slope angles are analyzed.The research shows that displacement mutation as the criterion of slope failure has better applicability,the sparsity of grid division has little influence on the landslide safety factor,and the horizontal displacement at the slope foot increases with the decrease of the safety factor.With the increase of rainfall,the moisture content of loess soil increases,and the safety factor of slope decreases gradually,which triggers the movement of loess landslide until disaster occurs.