Influence of soil stiffness on building vibrations due to railway traffic in tunnels: Numerical study

In this paper a numerical study about the influence of soil stiffness on the assessment of vibrations induced by railway traffic in tunnels is presented. A comprehensive numerical model is used to achieve the lumped objective, where the source of vibration (train–track interaction), the propagation of vibrations (tunnel-ground system) and their reception (building close to the railway infrastructure) are simulated by a sub-structuring approach. It was found that soil stiffness plays a relevant role on the mechanisms of propagation of vibrations through the ground as well as on soil–structure interaction. Regarding the last topic, different approaches were made for the inclusion of the SSI effects, namely a detailed boundary elements formulation and a simplified lumped-parameter model. The performed study revealed that the usage of lumped parameter models can be seen as a good option considering the compromise between accuracy of the solution and reduction of the computation effort.