Railway train induced ground vibrations in a low V_S soil layer overlying a high V_S bedrock in eastern Canada

摘要

Railway trains were used as a seismic source to observe the differences in behavior of seismic ground motions at different types of soil and rock sites. Observations indicate that the durations and amplitudes of the train induced seismic waves at the soil sites increased dramatically compared to the reference bedrock site. The very high site effect for railway train induced vibration may be due to the fact that the speed of train was close to the Rayleigh wave velocity of the soil. On the other hand, very large soil amplifications have been observed based on local earthquakes recordings, with a very different source mechanism than train induced seismic waves. Combining these two effects may lead to unusual soil amplification, at least for weak motion, especially when a train is moving at a speed close to the velocity of Rayleigh waves. These findings can be utilized in early warning systems in eastern Canada by mapping the potential railway train induced vibrations and the velocity of Rayleigh waves along railway transportation corridors.