Propositions pour le développement d'une méthodologie d'évaluation quantitative de l'aléa rocheux A new methodology for quantitative rock fall hazard assessment

Didier Hantz (1) , Denis Jongmans (1) , Laurent Baillet (1)

1 ISTerre - Institut des Sciences de la Terre

An innovative methodology is proposed for assessing rock fall hazard. Diffuse hazard can be assessed from rock fall frequency obtained by laser scanner or photogrammetry. For located hazards, the probability of occurrence is difficult to estimate quantitatively, due to two key problems: (a) the poor knowledge of the internal rock mass structure (or geometry); (b) the poor knowledge of the processes which lead to failure. A new approach is proposed to constraint the geometrical and mechanical model of the rock wall, which is based on the dynamic response of the potentially unstable rock compartments to seismic noise. To describe the temporal evolution of the stability and predict the time to failure, a simple rheological law is suggested. It is proposed to fit the rheological parameter of this law, by taking into account the expected number of rock falls in the studied rock wall, derived from the rock fall frequency. The study of the dynamic response is also suggested as an innovative method for monitoring of unstable rock masses.

Mots clés: Rock fall; hazard assessment

Domaines: Géologie appliquée

Didier Hantz, Denis Jongmans, Laurent Baillet. Propositions pour le développement d'une méthodologie d'évaluation quantitative de l'aléa rocheux A new methodology for quantitative rock fall hazard assessment. 2013. ⟨hal-00808438⟩