Shallow failures triggered by the November 2002 meteoric event in the Albaredo valley (Italian Central Alps): mechanics and stability analyses

In the paper the main morphological features of landslides that affected the Albaredo Valley (Italian Central Alps) during the November 2002 meteoric event are described. The triggering rainfall characteristics are also analysed and compared with the pluviometric thresholds defined for the Italian Central Alps. The evaluation of the potential slope instability during the event is also performed with an analysis of infiltration, seepage, and instability mechanisms. Changes in positive and negative pore pressures during the event are modelled by a finite element analysis of water flow in transient conditions, using as boundary condition for the nodes along the slope surface the computed infiltration rate. The slope stability analyses are conducted applying the limit equilibrium method, using pore water pressure distributions obtained in the different time steps by the seepage analysis as input data for the calculation of the safety factor.