Albano Lake coastal rock slide (Roma, Italy): Geological constraints and numerical modelling

The aim of this paper is to back analyze the stress-strain conditions that led to an ancient massive rock slope failure occurred in the inner slope of the Albano lake (Rome, Italy), whose scar and accumulation areas are respectively subaerial and submerged. Detailed geological and geomorphological field surveys, DEM-derived topographical reconstructions of the pre-landslide topography and geomechanical data derived from both in situ and laboratory characterizations, allowed to obtain the engineering-geology model of the slope prior to the landslide occurrence. A numerical modelling by the FDM code FLAC 5.0 was then performed in order to analyze the possible landslide trigger; static, hydrostatic and pseudostatic conditions were taken into account. Static and hydrostatic analyses indicate significant displacements, with the lake level close to the actual one; if an horizontal acceleration higher than 0.02 g is applied, a failure occurs according to a rock-slide kinematic mechanism, strongly influenced by the local geologic-structural setting.