Abstract：Research purposes： Chengdu to Chongqing inter-city train Rongchang to Yongchuan section through mudstone shale clip limestone of Jurassic Ziliujing stratum, stone of the mined out area is formed after limestone is a large mining. Stone gob has wide distribution, shallow buried depth, surface easy deformation, cracking, collapse, great harmful to the inter-city train engineering, so it is necessary to find out the engineering geological conditions, and the correct evaluation and treatment.
  Research conclusions：Investigation and evaluation of research through Rongchang to Yongchuan section of Chengdu to Chongqing inter-city train distribution of a large number of stone mined out area, we can draw the following conclusions: (1) The stone mined out area investigation difficulty is big, should carry on the comprehensive investigation in the borehole, verify the air region and interpretation of geophysical exploration of mined out area is arranged a large number of suspected speculation, achievement data should be comprehensive analysis and research. (2) Affecting the stone goaf stability of uncertain factors, we should adhere to the qualitative evaluation and quantitative evaluation method combining with evaluation, conclusions should be mutual authentication. (3) For high-speed ballastless track, it should be selected to calculate the safe distance from boundary angle, and set aside a certain width of protection zone, ensure the safety of the project. (4)The research results of this paper can provide references for survey and design of railway and highway projects through the mined out area.