Analysis on Expansion-Contraction Force and Displacement of CRTS I Type Ballastless Track on Simply Supported Bridge

摘要

The force of ballastless track on bridge is relatively complex. Smooth running and running safety of high-speed train is directly influenced by the stability of CWR. Laws of force and deformation of ballastless track CWR on bridge become a hot issue for scholars both at home and abroad in researches. Based on finite element method, theory of bridge-rail interaction and practical situations, a space coupling model of CRTS I type ballastless track CWR on simply supported bridge with a length of 6×32 m is established. Characteristics of force and deformation of the rail, track slab, and base plate under the effect of temperature load have been researched, and the related influencing parameters have been analyzed. Studies show that the maximum of rail expansion-contraction force appears in the place of abutment, pier, and middle-span under the effect of temperature load, the longitudinal displacement of rail follows the trend of decrease after increase with a maximum in the third and fourth span, and the longitudinal contraction trend of rail and track slab are basically consistent, which indicates that the fastener takes a well restraint effect. And the expansion-contraction force and displacement of track structure on bridge increases with the increasing of the temperature difference between the upper and lower surface of beam body, and the increment is obvious. Small resistance fastener of bridge can improve bridge-rail interaction of CWR on bridge when the relative displacement of the track slab and rail is not oversize so as to ensure effective control of rail running on abutment. Under the consideration of reducing the expansion-contraction force and displacement of track structure on bridge, the longitudinal stiffness of fixed bearing of abutment and pier should not be too excessive.