Rock fall hazard assessment: from qualitative to quantitative failure probability

Didier Hantz (1) , Carine Dussauge-Peisser (1) , Mathieu Jeannin (1) , Jean-Marc Vengeon (1)

1 LIRIGM - Laboratoire Interdisciplinaire de Recherche Impliquant la Géologie et la Mécanique

A new method (HGP) is proposed to estimate the failure probability of potentially unstable rock masses in a homogenous area, as a function of time. It is based on both geomechanical and historical approaches: the first one is aimed to classify the rock masses according to their relative failure probability, but the time factor can not be approached by a mechanical analysis; the second one to estimate the mean expected rock fall number in the studied area, for the considered period and for different volume classes. This rock fall frequency can be estimated from a rock fall inventory, directly or indirectly using a power law for the volume distribution. A relation between these frequencies and the erosion rate is established, which allows to approach the former from a paleogeographical study. The failure probabilities can be calculated from the expected total rock fall number in the area, and the numbers of potential rock falls with different relative probabilities. The method is applied to the case of the Grenoble area. Development of rock fall data basis is needed to improve both geomechanical and historical approaches.

Mots clés: failure probability; rock fall; hazard assessment; failure probability.

Domaines: Géologie appliquée

Didier Hantz, Carine Dussauge-Peisser, Mathieu Jeannin, Jean-Marc Vengeon. Rock fall hazard assessment: from qualitative to quantitative failure probability. Int. Conf. on Fast Slope Movements, Prediction and Prevention for Risk Mitigation, May 2003, Naples, Italy. pp.263-267. ⟨hal-00337780⟩