Study On The Failure Modes And Image Recognitions Of The Typical Landslides Distributed Along The Sichuan-Tibet Railway

The Sichuan-Tibet Railway(STR)starts from Chengdu to Lasa,spanning 1543 km.The construction of STR will not only greatly boost the economy of Tibet,but also can guarantee national security.However,the region along the Sichuan-Tibet railway is characterized by complex and special disaster-bearing environments,such as high seismic intensity,high in-situ stress and high steepness,coupled with low temperature,leading to the extensive development of geological hazards such as high-level collapse rockfalls,high-altitude and long distance landslides,giant debris flows,and glacial lake outburst disaster chains.These result in many disaster risk problems for the engineering construction and safe operation of STR.Thus,to ensure the construction and operational safety of STR,the research on the geological disaster mode and the identification map along the STR is a great reference for the early warning and risk prevention of serious geological disasters.In this paper,the research on the deformation and failure modes and identification patterns of landslides along the STR were carried out by a series of field investigations and numerical simulationmethod.In this paper,we firstly analyzed the hazard environment along the railway through the field investigation and indoor collection of regional geological data,Moveover,based on the material composition,formation conditions,evolution and development characteristics,together with the field investigation results of landslide some typical landslides along STR were classified.Through the results both field investigation and numerical simulation of landslide slip process,this paper obtained the deformation and failure characteristics of various landslides along the STR at each stage,and finally the identification map of landslide evolution along STR was established.Main research results are listed as follows:(1)Based on the field survey results the landslides along the railway are divided into two types,that is,loose accumulation landslide and rock landslide.Then,they are further subdivided into ten subtypes according to their formation conditions,evolution process,and development features,including slide-tension cracking(rock),bendingshearing,creep-shearing,tension cracking-shearing,toppling-tension crackingshearing,step-path slide,wedge slide,compression-shearing,slide-tension cracking(loose)and creep-tension cracking.(2)Based on the numerical simulation analysis of different landslide types,the original models of landslides are summarized,and obtained the displacement and deformation changes during early stage,sliding process and final accumulation characteristics.(3)Combined with the landslide examples along the STR and the result of simulated slipping process,we summarized the features of different types of landslides in different stages,and drew the development features of landslides in four status:primitive topographic feature,early-identification,disaster before identification,ability for causing disaster identification.Finally,we established the landslides identification map along the STR and four recognition index:cause disaster condition index,early identification index,disaster before identification index,and ability for causing disaster identification index,which correspond to the four status.