Modal Analysis and Parameter Assessment of Floating Slab Track

Assessment of dynamic characteristics and properties of floating slab is crucial for track design to mitigate ground-borne vibration induced by metro trains. Dynamic analysis in combination with numerical simulation presents an efficient strategy for identifying the parameters effect on vibration isolation performance of floating slab track system. Therefore, structural parameters (length and thickness) and dynamic parameters (railpad stiffness and bearing stiffness) of the floating slab track system are evaluated by modal analysis method and finite element model in this paper. It is shown that the modal shapes mainly included vertical vibration and lateral vibration at the length below 6m. Bending vibration and twisting vibration gradually become the controlling shapes with length increasing. The length should be in the appropriate range for a desirable vibration isolation range and avoid resonance, while the thickness should be chosen as large as possible. Compared with the parameters of length and thickness, railpad stiffness can not conspicuously reduce the natural frequency to expand vibration isolation range. Slab bearing stiffness is a major factor in dynamic parameters, producing a greater influence than railpads stiffness.