Determining and Managing Rockfall Risk in the Road Network of Andorra

Abstract

The overall road network in the Principality of Andorra is affected by continuous rockfall hazards from adjacent slopes. To determine the risk of each section of road and establish a priority for actions to be undertaken, a methodology has been developed based on two variables: the rockfall hazardness and the likelihood of impact in road sections based on the average daily traffic (ADT). The aim of the methodology is to define an objective criterion with a parameterization of variables by assigning numerical values to reflect the estimated risk for each road section. The results obtained allow to establish the order of priority for countermeasures and risk management. In those cases where identical results are obtained for various sections, we have used an expert criterion to prioritize a section over another.