Seismic propagation in near-source conditions: effects on large embankments

Starting from the 2009 Abruzzo earthquake which struck L'Aquila city and several villages in the Aterno river valley, the Italian scientific community is devoting particular attention to the seismic response of sites close to the seismogenic fault (near-source conditions). In these conditions, very high accelerations were recorded worldwide, even for seismic events characterized by low-moderate magnitude. The objective of the present study is to investigate numerically on the peculiarities of the near-source seismic propagation and, in particular, to evaluate its effects on the seismic response of large embankments close to active faults. The seismic response of such geotechnical systems may be strongly influenced by the spatial variability of the ground motion (asynchronism). This variability may be dangerous for a soil embankment under seismic loading conditions, due to the higher susceptibility to cracks or instability phenomena. In this study the basic rock formation and the included source are modelled together with the subsoil and the embankment. The source has been simulated by introducing an interface with an elasto-plastic constitutive model, subjected to the motion defined through typical mathematical laws adopted in the seismological field.