High resolution three-dimensional numerical modelling of rockfalls

Accurate prediction of rockfalls is a major need in mountain areas, both for hazard assessment and the design of countermeasures. In this paper, the performance of an original simulation code, initially developed for regional-scale analysis, is tested at the local scale by using high-resolution input data, in order to show its application to site-specific problems. The code is based on a kinematic algorithm and allows to run detailed, spatially distributed simulations of rockfall on a three-dimensional topography described by a Digital Elevation Model. Two examples from the Central Italian Alps, both characterised by the occurrence of frequent historical events, valuable elements at risk (urban areas, corridors) and countermeasures (barriers and retaining walls) are presented. The suggested approach proves to effectively account for rockfall dynamics when used with high-resolution data. Model calibration issues are discussed and model results are compared to available experimental data. The scale dependency of the results is also discussed.