Analysis of the long-term response of a clay slope through the hydro-mechanical approach.

The present paper illustrates the analysis of the long-term stress-strain response of a clay slope affected by a deep weather-induced landslide. The study has been carried out with reference to a prototype slope, the Fontana Monte slope in Volturino (FG), representative of the class of instability mechanisms reactivated at the end of the winter. The impact of the seepage regime, related to the underground water-bearing recharged upslope as an effect of weather conditions, on the evolution of the stress-strain behaviour have been investigated through the hydro-mechanical approach. Both first-time failure and reactivation mechanisms of the landslide have been simulated under steady-state hydraulic conditions, accounting for the partially saturated behaviour of soils above water table. Results showed the impact of the underground hydraulic contact in the reliable formation and progression of the shear strain localization, defining a multiple roto-translation failure mechanism, undergoing an evolution related to the variation of the porewater pressure regime.