Aurélien Gay-des-Combes: Analyse des processus gravitaires du flanc des Revenettes (Commune de Trient, Valais)

This study focuses on gravitational processes affecting the slope of the Revenettes, located in
the municipality of Trient, in the canton of Valais, within the Swiss Alps. This area is mainly
composed of scree and has been known for over a century to show signs of slope instability.
The most active and concerning sector is the Donna Gremé landslide. Monitored by the
geological and engineering firm Tissières SA in Martigny, the landslide poses a threat to the
inhabitants of the hamlets of Berte and Gremé, located on the valley of the village of Trient. A
rockfall protection dam was built in 2018, and a project to raise it is currently underway.
The study examines the entire Revenettes slope by combining newly collected data with
existing analyses. Fieldwork was conducted to produce a geological phenomenon map and five
geological cross-sections, proposing an interpretation of the internal structure of the slope. Two
terrestrial LiDAR survey campaigns were carried out, and the resulting point clouds were
compared with scans from the Federal Office of Topography (Swisstopo) and airborne LiDAR
data acquired by Tissières SA. Rockfall propagation simulations were also performed using
StnParabel and RockyFor3D, along with an analysis of InSAR satellite data.
The results highlight a deep-seated gravitational slope deformation (DSGSD) affecting a large
portion of the slope, involving a potential mobilized volume of several million cubic meters.
The northern section of the landslide shows more activity than the southern part. This contrast
may be related to the recent glacial history and the erosion of a former ridge (Oulianoff, 1945).
Structural analysis identified major discontinuity families, which are potential sources for
rockfall initiation. Rockfall simulations identified accumulation zones that correlate with field
observations.
This work shows that the regular monitoring of ground movements, combined with an inventory
of rockfall events in the municipality of Trient, could help detect a potential acceleration of
movements and reduce the risks associated with gravitational processes.