Duxseal as backfill material for subway lining to mitigate railway vibrations: Field experiments

Abstract

Subways are fast, efficient, safe, comfortable and energy-saving transportation modes; however, the vibration generated by trains inevitably causes environmental pollution. In this paper, a new vibration isolation strategy is proposed by using Duxseal as the backfill material for tunnel lining (DX-Lining) to mitigate railway vibrations. DX-Lining was installed on Metro Lines in Qingdao, China. A series of field tests were performed to compare the vibration levels associated with DX-Lining and traditional lining. The results indicate that the DX-Lining installed in the metros decreases vibration accelerations in the vertical / lateral / longitudinal direction (X, Y, and Z directions) by 24.4%, 44.3%, and 46.7%, respectively. In addition, evaluation of the vibration level in the Z direction shows that DX-Lining has different insertion loss values in different frequency bands. The vibration isolation effect at low frequencies of 0–100 Hz is better than that at frequencies above 100 Hz. Moreover, the maximum vibration level in the Z direction before vibration reduction is 76 dB, and there is noise pollution at night. After damping, the maximum vibration level is 71 dB, which meets the national standards and has important potential application value in tunnel vibration isolation.