Monitoring and preliminary numerical interpretation of the interaction between an unstable rock cliff and the underlying soil deposit

Complex landslide mechanisms involving both rock and soil material characterised by remarkably different stiffnesses are not straightforward to analyse numerically, especially if realistic displacement values are to be evaluated in their interaction with civil infrastructures. In this work, one of such landslides interacting with a viaduct occurring in Northern Italy is analysed. After a description of the landslide and the interpretation of relevant field measurements, the problem is analysed numerically by means of Finite Elements. A preliminary numerical interpretation of the gravitational phenomenon is provided, including the initial rock cliff degradation phase leading to the formation of a debris deposit and the subsequent development of rupture surfaces both in the rock and debris material. Comparison between simulations and field evidence suggests that the proposed numerical interpretation is realistic.