Settlement analysis of embankment-bridge transition section in the permafrost regions of Qinghai-Tibet Railway
WANG Jinchang;WU Qingbai;Qinghai-Tibet Railway Company;State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences;
Since the beginning of the Qinghai-Tibet Railway operation,the train has safely run for nearly ten years owing to better stability of permafrost engineering. However,it is also inevitable to appear some damages to the railway. Survey results in-situ show that serious thaw settlement has be found in the transition section between embankment and bridge. Based on the thaw settlement characteristics and analysis of engineering geological conditions,it is found that thermal erosion of subsurface and supra permafrost water lead artificial permafrost table lower and permafrost with high ice content thawing,resulting in extensive thaw settlement of embankment.To transact this damage,measures of keeping cool of permafrost should be taken to strengthen the freeze of roadbed. While,engineering conditions in subsurface water and waterproofing and drainage should be improved to decrease thaw settlement caused by thermal erosion of subsurface and supra permafrost water. This study provides a scientific basis for stabilizing and maintaining the transition section between embankment and bridge.