Dynamic Stability Analysis of Embankment Along the Qinghai-Tibet Railroad in Permafrost Regions

This paper firstly gives a introduction of real-time strong-motion observation tests which are carried out in a permafrost region of the Beilu River segment along the Qinghai-Tibet Railway, the real-time acceleration data at different part of embankment are collected when trains passing. The experiment shows that there is an obvious attenuation effect during the waveform transfer process from the shoulder to the slope toe. Based on the site test results, two different kinds of embankment are set up, which is a crushed-rock embankment and another is a plain-fill embankment. Then the field test data and dynamic finite element analysis method of two dimensions linearly equivalent were used to analyze the characteristics of dynamic transmission and displacement response of both types of embankments bearing the load of a train. The numerical results showed that vibration acceleration was decreased through the crushed-rock layer, which could improve the stability of the embankment construction. Also, the vibration settlement caused by train loading was decreased obviously in the crushed-rock layer, in which the maximum settlement displacement was only 0.81 mm, while that of the plain-fill embankment reached 1.87 mm. Moreover, the influences from underlying active layer on the dynamic stability of the plain-fill embankment at different seasons were analyzed. The amount of deformation at the same location in summertime is far more than that in wintertime.