A review of rockfall mechanics and modelling approaches

Models can be useful tools to assess the risk posed by rockfall throughout relatively large mountainous areas (>500 km(2)), in order to improve protection of endangered residential areas and infrastructure. Therefore the purpose of this study was to summarize existing rockfall models and to propose modifications to make them suitable for predicting rockfall at a regional scale. First, the basic mechanics of rockfall are summarized, including knowledge of the main modes of motion: falling, bouncing and rolling. Secondly, existing models are divided in three groups: (1) empirical models, (2) process-based models and (3) Geophysical Information System (GIS)-based models. For each model type its basic principles and ability to predict rockfall runout zones are summarized. The final part is a discussion of how a model for predicting rockfall runout zones at a regional scale should be developed. A GIS-based distribution model is suggested that combines a detailed process-based model and a GIS. Potential rockfall source areas and falltracks, are calculated by the GIS component of the model and the rockfall runout zones are calculated by the process-based component. In addition to this model, methods for the estimation of model parameters values at a regional scale have to be developed.