DYNAMIC RESPONSE OF HIGH-TEMPERATURE FROZEN SOIL ROADBED UNDER TRAIN DYNAMIC LOADING

The Qinghai-Tibet Railway across frozen soil regions and high-temperature frozen soil roadbed is influenced by a lot of factors. The dynamic response of frozen soil roadbed under dynamic train loading is important for the construction and maintenance of the Qinghai-Tibet Railway. The influence of train dynamic loading to high-temperature frozen soil roadbed is investigated in this paper. Based on the frozen soil dynamic parameters in situ a high-temperature frozen soil roadbed model is presented with soil dynamics theory and FEM. The two different roadbed models of thawed soil and frozen soil layer under train dynamic loading are calculated with this model, and the vertical displacement, hydrostatic pressure and maximum shear stress are obtained. Comparing with these results, the conclusions are as follows: (1) Within 15m beside roadbed, maximum shear stress decreases obviously below 5m from roadbed surface, which is effected badly by train dynamic loading. (2) If high temperature frozen soil under natural surface 2m thaws, the dynamic response of train dynamic loading to the lower soil layer is obvious.