Dynamic response analysis of railway embankments under train loads in permafrost regions of the Qinghai-Tibet Plateau

Using real-time strong-motion observation tests of a crushed-rock embankment and a plain-fill embankment in a permafrost region of the Beiluhe River section along Qinghai-Tibet Railway (QTR), we collected the real-time acceleration data when trains were passing. We used field test data and dynamic finite element analysis software (two-dimensional, nonlinear) to analyze the characteristics of dynamic transmission, displacement response, and the stress-strain relationship of both types of embankments bearing the load of a train. By comparing the dynamic response characteristics of the plain-fill embankment, we analyzed the dynamic transmission mechanism of the crushed-rock embankment of QTR. The results showed that vibration acceleration transmission was decreased through the crushed-rock layer, which could improve the stability of the embankment. 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. Thus, the crushed-rock layer changed the state of stress-strain within the embankment, which helped increase the maximum principal stress of the embankment and decrease the amplitude and range of the maximum shear strain.