The Performance Response Study On Design Parameters In Metro Ladder Sleeper Structure

The study in this paper is mainly about ballastless track structure with ladder sleepers, to make research findings specific, there will be some expatiate which about the subway project (phase ii) of No.10Metro Line in Beijing. The research purpose is to raise the modeling and analytical methods by which we can analyze and study this kind of ballastless track system with ladder sleepers particularly in the environment of subway, to summarize the mechanical performance of ballastless track system and propose some projects of improvement on these system for supplement.(1) Combined with the original design of the subway project (phase ii) of No.10Metro Line in Beijing, the conditions and design ideas of metro engineering, those design about the rail track、fastening components and sleepers in ballastless track system are comprehended, the design idea on ladder sleepers are studied; Besides this part provide the modeling thought and relevant parameter.(2) In consideration of the actual situation of ladder sleepers used in No.10Metro Line, the rail track-sleeper models of standard ladder sleeper track structure and particular ladder sleeper track structure are established by using the finite element analysis software ANSYS, they are assumed quasistatic, their structural performance in conditions of different situations are analyzed, the change of vertical displacement of rail track and the ladder sleepers are observed, the maximum bending moment of ladder sleepers’section in different conditions are analyzed, then the laws how damping materials affect the track structure are concluded. After these analysis, fastening components and damping materials are checked to be improved, and then the project of improvement are proposed, systemic verification are finished to ensure the rationality of this project.(3) The ladder sleeper ballastless track system with different damping material spacing in that project of improvement above are analyzed. This topic is substantially in relation to the number and distribution of damping materials below the longitudinal sleepers, so for the principle of saving costs we shall prefer the scheme with less amount of damping materials if we have choices that meet the requirements. After this analysis, the reasonable spacing of damping materials in project of improvement is determined.(4) The effects of sleeper section’s modulus of elasticity on track structure are analyzed, the laws how sleeper section’s modulus of elasticity affect the track structure are summarized and they are compared with those laws how damping materials’stiffness affect the track structure, the characteristics of these two important factors’influence on the performance of track structure are distinguished.In the end of this paper, some deficiencies of work in thesis are pointed out, some prospects for further research and the valuable research direction of ladder sleepers in the subway are proposed.