Vibration responses of the metro station induced by various train operations under unilateral deep excavation

Field noise tests found that the noise induced by train operation under unilateral excavation is more obvious than that without excavation. Therefore, it is necessary to explore the dynamic response characteristics of metro stations under unilateral deep excavation. Based on the Jincheng Plaza Station in China, this study simulates the impact of train vibration on the structure through a 3-D numerical model and verifies its reliability through field-measured results. Considering various train operations, the analysis is carried out from three perspectives, including time-domain analysis, frequency-domain analysis, and vibration acceleration level (VAL) analysis. The results show that unilateral excavation causes the instability of the station structure, which leads to an 80-140% amplification effect on the peak vibration velocity of the station caused by the train load. Secondly, at the location within the excavation area, the longer the train passes, the more significant the vibration amplification effect is. Thirdly, the station vibration induced by the double-sided train operation is the most significant, which makes the amplitude of frequency domain vibration enlarged by 100-140%. Notably, based on the VAL analysis, it shows that the vibration response of the metro station under excavation is the most significant when the center frequency is 40 Hz. In addition, the VAL under unilateral excavation is 4-7 dB larger than that without exca-vation, and the increase ratio is about 8-13%. Finally, the maximum VAL under excavation reaches 65.8 dB, which exceeds the specified threshold (52.5 dB). For metro stations with both unilateral excavation and train operation, vibration reduction measures and the lateral structural support in the excavation area should be taken to reduce the vibration response, to improve the comfort of passengers and staff.