Low-Frequency Vibration Isolation Performance of Floating Slab Track System

In order to attenuate low frequency vibration induced by metro train and reduce the influence on inhabitants and sensitive equipment nearby the traffic line, it becomes more important to improve the dynamic characteristics and vibration isolation performance of floating slab track system under the low frequency excitation. A detailed derivation of vibration differential equations is given to analyze the vibration responses by monitoring the modal parameters and dynamics characteristics of floating slab track system. Based on the theoretical analysis, a 3D finite element model is employed to assess mode interactions and vibration isolation ranges of floating slab system with various parameters. Two kinds of key parameters were evaluated, which include structural parameters (such as length and thickness of slab, etc.) and dynamic parameters (such as railpad stiffness and bearing stiffness, etc.). The result demonstrates that adjusting special parameters can conspicuously improve the vibration isolation performance of floating slab track under low frequency excitation. For vertical vibration and bending vibration, both the dynamic parameters and structural parameters can effect conspicuously. The length should be in the range of 20~50 m for a desirable vibration isolation range and reasonable cost, while the thickness should be selected more than 0.4 m.