Study On Structure Parameters Of Low Vibration Track On 250km/h PDL

Low Vibration Track (LVT) is of good elasticity and great performance at vibration and noise reduction as well as favorable track evenness and less track maintenance work like other unballasted track. So it has been adopted on bridge tracks, tunnel tracks and urban rail transit home and aboard. At the same time, because of high elasticity, larger track deformation and rail rotation are produced, which may badly affect train riding quality and even safety as for high speed railway. Presently the maximum train running speed on LVT is 200km/h, and the 200km/h PDL is put into operation in our courtry. So, in order to meet requirements of higher speed, according to the characteristics of LVT, some analysis and researches about track structure parameters are made as for railways of 250km/h train running speed, which mainly consist of the following contents:From the viewpoints of train safety and vibration reduction, evaluation criterions for choosing reasonable values of LVT structure parameters are put forward, including criterions of train safety, driving comfort, wheel-rail dynamic action, track deformation and track vibration.Vehicle-track coupling dynamic modal is built and by referring to national & international track irregularity spectrum and taking national track irregularity status into consideration, American 6-level track profile irregularity spectrum is chosen as excitation. Effects on track dynamic performance, which are brought by differences of track structure parameters, like track stiffness, track damping and supporting block mass, are studied and then reasonable value range for above-mentioned track structure parameters is proposed for railways of 250km/h train running speed. What's more, a comparison about dynamic performance is made between LVT and ballasted track.Analysis model of track dynamic gauge widening is built and effects on dynamic gauge widening, brought by the differences of embedded depth and rubber coat stiffness of supporting blocks affect, are studied. Based on the analysis, reasonable value range for embedded depth and rubber coat stiffness of supporting blocks is gained in the premise of train safety.