VERTICAL FORCE PROPERTIES FOR LONGITUDINAL COUPLED BALLASTLESS TRACK WITH HEAVY GRADE

This paper establishes a calculation model of rail-longitudinal coupled track slab in accordance with Finite Element theory in order to analyze the vertical force properties for the longitudinal coupled ballastless track with heavy grade in vertical curve section under the action of longitudinal forces. A general calculation program is compiled by using the function of the secondary development of ANSYS Parametric Design Language (APDL). The influence of type and size of initial irregularity on rail vertical curve and increasing extent of temperature on vertical displacement of rail structure is researched by the utilization of the general calculation program. The calculation results indicate that (1) the temperature force and the vertical initial irregularity are main factors affecting the vertical force properties for longitudinal coupled ballastless track with heavy grade in vertical curve section; (2) some measures like the dowel should be applied to the longitudinal coupled ballastless track with heavy grade in convex vertical curve section, especially in the area where the temperature changes greatly, to reinforce the connection between the track slab and sub-supporting layer so that the degeneration of track geometry caused by great upward displacement adverse to train operation safety is prevented.