Research On Disaster Causing Factors And Stability Evaluation Of Loess Landslides Occoured During Xi'an-Yanan High-speed Railway

In this paper,a comparative study is carried out on the loess landslide along Xi'an to Yan'an high-speed railway from the perspective of spatial distribution,topography and landslip types of the landslide.In view of the main style of soil rock contact surface landslides along the line,The different level's factors of landslide are analyzed.Moreover,the influence degree of these factors on the possibility of landslide is studied by AHP theory.By means of FLAC numerical simulation,the stability and stress and strain characteristics of slope and soil moisture content in different values are studied.Further understanding of the relationship between the key factors and the overall stability of the slope is further deepened.The following research results have been obtained:(1)The area of Ziwuling is the largest segment of the landslide density distribution along the Xi'an to Yan'an high-speed railway with a larger scale.The density of landslides in Wang Yi and Yintai is relatively small,which is mainly related to the drainage conditions of good surface water in the mountain area.The landslides along the line have the characteristics of cluster distribution.(2)By using the GIS software to analyze the topography and geomorphology of 5886 landslide hazard points drawn by the whole coil,it is concluded that the slope height,slope rate and slope are important topographic factors affecting the development of landslides.The landslides along the line are mainly developed in the East and the West.This is closely related to the north-south direction of the basin in the study area.(3)There are four development types of loess landslides in the study area,namely landslide in the loess layer,landslide on the contact surface of soil and rock,shear slide out of bedrock surface,and mixed landslide of soil and rock.an the sliding surface of the soil and rock mixed type landslides is often folded line.(4)Through the fuzzy comprehensive analysis and evaluation theory,the importance rating of ten factors affecting the possibility of landslide is obtained,and the two most important factors are soil water content and slope.(5)The internal relationship between soil moisture content along the soil layer and the value of soil strength parameters C and phi was studied by linear fitting.It was found that in the process of soil moisture content increasing from 10% to 25%,cohesive C increased at a constant speed and then leveled,and the internal friction angle was increased first and then decreased.(6)The finite element numerical simulation results show that the loess slope safety factor has a clear linear negative correlation with slope and soil moisture content.With the increase of slope and water content,the stress concentration at the toe of the slope and the plastic zone in the slope gradually pass through the upper part of the slope.