Assessment and mitigation of railway-induced environmental vibrations over underground comprehensive transportation hub

With the development of railway networks, a new infrastructure integrating the underground comprehensive transportation hub and building complex (UCTH&BC) is constructed in many metropolitan cities. However, there is no relevant research to analyse its railway-induced environmental vibrations and propose an appropriate mitigation measure for such a large structure. To have a comprehensive assessment and satisfying control of the potential environmental vibration problem during the life-cycle of UCTH&BC, a numerical study of a newly-built UCTH&BC was carried out through a time-frequency method based on transfer function theory. The ground and building vibrations were firstly evaluated to have a better understanding of vibration transmission and distribution characteristics. Furthermore, rubber mat floating slab tracks (RMFST) were optimised to propose a suitable mitigation measure. Results show that if adopting ordinary track structures, the ground vibrations in the regions where train-induced vibrations transmit directly through columns exceeded the standard limit seriously by more than 5 dB, while the nearby building vibrations were acceptable. The RMFST with the stiffness of 0.011 N/mm(3) was recommended to efficiently reduce vibrations by more than 10 dB, ensuring environmental vibrations in the UCTH&BC satisfy the relevant standard requirement and provide a sufficient safety margin to deal with worse track conditions.