Vibration Characteristics and Effectiveness of Floating Slab Track System

Ground-borne vibration excited by metro traffic is becoming a more and more important problem for the rapidly developing transport system in urban areas and increasing public concern about environmental problems. In order to attenuate the vibration influence down to an acceptable level, floating slab track have been applied worldwide on metro line. An analytical dynamic model is employed in this paper to assess vibration characteristics and effectiveness of floating slab system. The dispersion equations of floating slab track system are solved by means of Fourier transformation method. The contour integration method is used to convert the vibration responses of the track system. The result demonstrates that the dispersive characteristics of the track system act as a continuous layered wave conductor with an infinite length slab. It will generate same-phase oscillation and infinite wavelengths in track system when excitation frequency is close to the cutoff frequencies. An increase of slab mass is most effective to expand the vibration isolation range, whereas it has no obvious effect to enhance the vibration isolation efficiency. A relatively high slab searing damping and low slab bearing stiffness generally decrease force transmission to improve the vibration isolation effectiveness and decrease resonant response of the track system.