An example of a complex rock slope failure investigated by means of Laser Scanner Technique and numerical modelling

On March 12, 2005 a rock slope failure occurred in the Scascoli Gorges (Savena Valley, Northern Apennines, Italy), damming the torrent below. The collapsed rock mass was characterized by a failure surface progressively changing from over-steepened at the top to concave at the bottom. Terrestrial laser scanner technique (TLS) has been applied to obtain high resolution topography of the rock slope. Mechanism and kinematics of the rock slope failure has been investigated by a 2D elasto-plastic finite element program (Phase2) and by a 2D distinct-element code (UDEC), simulating the progressively developing damage of the rock mass by reducing the GSI initial value and using the Hoek & Brown constitutive model. Strength and deformation properties of both intact rock and discontinuities were estimated from laboratory tests and by field surveys as well.