MODELLING VIBRATIONS INDUCED BY UNDERGROUND RAILWAYS IN URBAN AREAS

Nowadays the problem of annoyance related to vibrations produced by human activity is increasingly felt, especially in residential areas. In addition, recent development of high-speed railways has made evident the disturbance and environmental damages caused by vibrations. In this study a mathematical prediction model, able to evaluate vibration level induced by underground railways, is presented. The model can by split into several sub-models. In the first one, namely the Generation Sub- Model, the dynamic interaction between rolling stock and railway superstructure is analyzed. In the second one, that can be named Propagation Sub-Model, interaction forces provided by the previous model are applied to tunnel invert and propagation of vibration waves is obtained by means of a finite elements method (F.E.M.) approach. The validation of the model passed through the comparison between vibration level provided by numerical simulations and on-site measurement carried out in Naples subway, yielding a fairly good agreement.