Research methods: Through making analysis of the information of foreign countries，first the analysis was made for the settlement deformation of independent units，then the systematic analysis was made for the integrated settlement deformation of different units according to the concrete conditions of building passenger dedicated line in China and the correlative codes.
Research conclusions: Through the analysis and systematic evaluation of inferences from the difference settlement deformation between the different units such as roadbed，bridge and culvert，tunnel etc.，the impact on the ballastless track by settlement deformation of every unit was determined so as to eliminate the impacts of settlement deformation by each unit and also the time of laying ballastless track was determined to ensure the ballastless's service lifecycle.
2007, Vol. 24 
