Some aspects of the dynamic performance of two classes of earth dams

Potential instability of large existing earth dams is a major source of seismic vulnerability of Italy. In fact, most of them were designed before the adoption of modern building codes, without accounting for seismic loads explicitly. Hence, there is an urgent necessity to investigate the response of most existing earth dams to severe earthquake loading. This paper compares some aspects of the seismic performance of a homogeneous and a zoned earth dam. The numerical analyses were carried out using two models which were calibrated on the data available from two existing and well documented earth dams. The geometry of the dams was converted into two simplified schemes characterised by the same height and mechanical properties of the foundation soil but by different schemes of water retention. The seismic response of the dams was evaluated through time-domain dynamic analyses in which the same input ground motion, represented by real-time histories, was applied at the base of the models.