Nicolas Sarrasin: Etudes d’instabilités rocheuses dans le Saastal et le Mattertal (Valais, Suisse)

Nicolas Sarrasin
Supervisor: Prof. Michel Jayboyedoff
Assistant: Andrea Pedrazzini

A lot of alpine areas are characterized by ground movements. These may represent a danger for people and infrastructure. These phenomena are described and studied for a long time. However the advent of new technologies can improve these analysis.

LiDAR (Light Detection and Ranging) represents a new technology which modernizes the traditional approach of field measurements. LiDAR is therefore defined as a powerful tool able to take remote measurements through laser technology. It allows an analysis in three dimensions adapted to the characterization of rock instabilities. The processing of information gathered makes possible a multitude of tests. LiDAR is so considered a promising tool for the study of risks and natural hazards.

This Master Thesis will use LiDAR technology to analyze the structure of mountain ranges. This method will also highlight the movements of blocks and it will serve as the calculation basis of susceptibility to fracture in rock walls. The target of this study is to identify rockfalls using semi-automatic approaches based on LiDAR surveys. A kinematic analysis of the structure will also be undertaken to arrive at a definition of the susceptibility of rupture for massive Jegihorn of Gabelhorn and Durlochhorn (Mattertal and Saastal, Valais). All analysis performed will aim to highlight areas prone to failure mechanisms and each of the specific results will be compared to observations made on the ground.