Study On The Optimization Of The Longitudinal Sleeper Embedded Type Track Structure On Bridge Of Tram

Longitudinal sleeper embedded type track structure on bridge is a new type of tracks for trams which is mainly applied on simply-supported continuous bridges of urban traffic. The major components of this new type of track are rail, PUR filling material, unit rail ditch, cast-in-place concrete. The track structure has no fastening system and is constricted just by PUR filling materials. The stresses in Longitudinal sleeper embedded type track structure on simply-supported continuous bridge are very complicated.This dissertation takes a 32-meter Longitudinal sleeper embedded type track structure on bridge as a research object to analyze the characteristics of this new type track. An integration of mechanical model of line-plane-subgrade was built to analyze the mechanical properties of the track under different loads. The structural parameters based on the norm and mechanical properties of the track are studied and an optimization scheme for 32-meter Longitudinal sleeper embedded type track structure on bridge is presented. This dissertation completed the following main contents:(1) The difference between Longitudinal sleeper embedded type track structure and traditional ballastless track as well as the difference between simply-supported continuous bridge and simply-supported were summarized. The integration mechanical model of line-plane-subgrade was established based on the characteristics of Longitudinal sleeper embedded type track structure on bridge and simply-supported continuous bridge.(2) The case that the Longitudinal sleeper embedded type track structure was directly laid on the 32-meter simply-supported continuous bridge was studied to find out it was unavailable because of the bridge/rail interaction. The effect of isolation layer between rail ditch and cast-in-place concrete on longitudinal forces of track was studied as well. Considering the requirements of track stability and geometry and the characteristics of Longitudinal sleeper embedded type track structure on bridge as well as the experience of high-speed railway ballastless track, a preliminary optimization design was proposed.(3) The mechanical properties of optimized track structure which under bridge expansion, temperature load and train load were analyzed. The effect of different loads on structure was analyzed to provide basis for parameter optimization design.(4) The influence factors of mechanical properties under different loads were concluded and corresponding models were established. These factors are including the stiffness of PUR filling material, the geometry of rail ditch and convex retaining wall and so on. Based on the analysis the final optimization scheme for 32-meter Longitudinal sleeper embedded type track structure on simply-supported continuous fridge was determined.