The Rearch Of The Deformation Rules Of Qinghai-Tibet Railway Frozen Soil Embankment

Qinghai-Tibet railway is the highest altitude railway in the world and is built in the typical plateau frozen soil environment. The railway line pass through permafrost area about 546.63km, which include melted area about 101.68km.The frozen soil along the Qinghai-Tibet railway line was infected by the special geography and climate character of Tibet plateau, it was mainly in high temperature high ice permafrost with high thermo sensitive and low thermal stability, the season alternative raised the soil moisture phase transition process is easily to make the embankment transformed and destroyed. Since the Qinghai-Tibet railway was built in 2006, the railway embankment appears the situation of foundation cracking and settlement deformation. As the global warming the permafrost in Tibet plateau turn up to degradation ablation and incrassation mobile layer continuously, which will make the frozen soil embankment deformation and destruction worse. The railway embankment deformation will not only infect the running speed of train and the comfort level of passenger, but also infect the train travel safety greatly.At first, this text combine the frozen soil rudimentary knowledge make an introduction to the general situation of Qinghai-Tibet railway frozen soil embankment, based on relevant departments statistical data, we analysis the factor and deformation features to Qinghai-Tibet railway frozen soil embankment deformation. The frozen soil embankment deformation and destruction process was very complex and with numerous influencing factors. The freeze thawing destruction which changes along the season was related by the influencing of temperature field, moisture field and stress field. Changes in temperature field will bring the redistribution of the soil water phase change and migration; the moisture phase change will make soil stress and strain changes, and which will bring the embankment freezing expansion and melt subsidence deformation. Based on research the mathematical models of the Coupled of the moisture-heat-stress fields of the frozen soil, we take ANSYS to make freezing thawing numerical simulation, Comparing numerical simulation result with the observational data to analysis the deformation rules and character of Qinghai-Tibet railway permafrost embankment.