Numerical analysis of engineered metabarrier effect on ground vibration induced by underground high-speed train

The construction of the underground section of the Chengdu-Zigong High-speed Railway, the fastest under-ground railway worldwide with a design speed of 350 km/h, has attracted extensive attention in the trans-portation and environment communities because it passes through many areas with vibration-sensitive equipment. In this context, an in-situ wheelset-dropping experiment is conducted in the high-speed railway tunnel to probe the vibration transfer characteristics of the tunnel-soil system. Further, an elaborate spatial dynamics model is built based on a hybrid time-frequency domain method to explore the feasibility of an engineered metabarrier for mitigating the ground vibration induced by underground high-speed trains from the perspective of numerical analysis. The bandgap characteristics of the metabarrier and the sensitivity of ground vibration attenuation rate to metabarrier depth are revealed. The results show that the horizontal vibrations cannot be ignored, the metabarrier can effectively suppress the ground vibration at 29.11-80.74 Hz, and the ground vibration attenuation rate first increases and then tends to be stable with the increasing metabarrier depth. The in-situ excitation test fills the experimental gap in the field of environmental vibration caused by underground high-speed trains and the research on the application of metabarrier provides fresh insights for preventing railway induced vibration, specifically in studies where metabarriers are considered as mitigation measures.