Abstract: Taking the rainfall infiltration caused by the separation of the track-slab of a certain road and bridge transition section of the Shanghai-Kunming high-speed railway as the research object, the transition section rainfall-seepage finite element analysis model was established, which was according to the topography and geomorphology of the road section, hydrogeological conditions and the data obtained from laboratory tests. The deformation characteristics and laws of the transition section between road and bridge were analyzed. The research results show that the subgrade filling of the transition section of the road and bridge has a certain degree of expansion. Under different rainfall infiltration conditions, the subgrade of the transition section will have corresponding expansion. Generally, the expansion at the near abutment is significantly smaller than that at the far abutment. The main reason for the disease of the transition section is that the infiltration of surface water and rainwater causes the subgrade to expand, and the material difference of the transition section causes uneven expansion of the subgrade along the line direction.

Key words: railway engineering; high speed railway; road and bridge transition section; subgrade; rainfall; expansion; gap

摘要： 以沪昆高速铁路某路桥过渡段轨道板离缝引起的降雨入渗为研究对象，依据该路段地形地貌、水文地质条件和室内试验所得数据，建立过渡段降雨-渗流有限元分析模型，对该路桥过渡段的变形特点及规律进行分析。研究结果表明：该路桥过渡段路基填料具有一定的膨胀性，在不同降雨入渗条件下该过渡段路基会出现相应的膨胀量，总体呈现出近桥台处膨胀量明显小于远桥台处膨胀量的现象；引起该过渡段病害的主要原因是地表水和雨水入渗使路基膨胀，过渡段材料差异使路基沿线路方向产生不均匀膨胀。

关键词: 铁道工程；高速铁路；路桥过渡段；路基；降雨；膨胀；离缝