Stability Analysis of a Rock Column in Seismic Conditions

Abstract The stability of a rock column located on a high conglomerate cliff in Roverino, near Ventimiglia, in northwestern Italy, has been analysed by continuum and discontinuum modelling, in both static and seismic conditions. The rock column, which is 40 m high and nearly 36,000 m3 in volume, exposes the residential area below the cliff, housing more than 4,000 people, to a high risk level. As the area is located in a seismic region with estimated peak acceleration between 0.24 and 0.28 g, the stability analyses were carried out in both static and seismic conditions. Continuum and discontinuum modelling of the rock mass was carried out by using the finite difference methods and the distinct element methods. It is shown that both methods are effective in describing the modes of instability of the rock column in static conditions. On the contrary, a convincing description of the rock column response induced by earthquake excitation is achieved bydiscontinuum modelling.