DYNAMIC PERFORMANCE OF LOW VIBRATION SLAB TRACK ON SHARED HIGH-SPEED PASSENGER AND FREIGHT RAILWAY

Abstract

This work investigates dynamic performance of a low vibration slab track on a shared high-speed passenger and freight railway, and an optimal modulus of the isolation layer (rubber pad) is proposed to meet the adaptability of the track system under the dynamic actions of high speed passenger and heavy axle-load freight trains. First, detailed finite element models of the slab track with and without the rubber pad between concrete slab and supporting layer are established by using software ANSYS. Further, coupled dynamic models of passenger/freight vehicle–low vibration/tradition slab track system are developed to calculate the wheel–rail forces, which are utilized as the inputs to the finite element model. Finally, the dynamic characteristics of the low vibration slab track, the specific function of the rubber pad, and the optimal modulus of the rubber pad are studied in detail. Results show that the interaction force between the freight vehicle and low vibration slab track is more significant because of the heavy axle-load, which leads to larger vertical stress amplitudes of each track layer. Whereas the accelerations of track components induced by the passenger vehicle are much larger than those induced by the freight vehicle, due to the much faster speed that can generate high wheel–rail interaction frequency. The rubber pad of the slab track does not play a role in attenuating slab vibration; instead it causes an increase of slab acceleration and its surface tension stress. However, the rubber pad can decrease the supporting layer acceleration and the slab compression stress, which plays a significant role in vibration isolation and buffers the direct impact force on the slab caused by vehicle dynamic load. To ensure a reasonable vibration level and dynamic stress of the slab track, the optimal modulus of the rubber pad is suggested to be 3÷7.5 MPa.