Prediction of vibrations from underground trains on Beijing metro line 15

The impact of vibrations due to underground trains on Beijing metro line 15 on sensitive equipment in the Institute of Microelectronics of Tsinghua University was discussed to propose a viable solution to mitigate the vibrations. Using the state-of-the-art three-dimensional coupled periodic finite element-boundary element (FE-BE) method, the dynamic track-tunnel-soil interaction model for metro line 15 was used to predict vibrations in the free field at a train speed of 80 km/h. Three types of tracks (direct fixation fasteners, floating slab track and floating ladder track) on the Beijing metro network were considered in the model. For each track, the acceleration response in the free field was obtained. The numerical results show that the influence of vibrations from underground trains on sensitive equipment depends on the track types. At frequencies above 10 Hz, the floating slab track with a natural frequency of 7 Hz can be effective to attenuate the vibrations.