Approche chimique et isotopique de l'origine des eaux en transit dans un grand mouvement de terrain: Exemple du glissement de La Clapière (Alpes-Maritimes, France)

Study of large-scale deformation induced by gravity on the La Clapière landslide (Saint-Etienne de Tinée, France) using numerical and geophysical approaches

“…Moreover, these measurements reveal a seasonal response of the landslide characterised by an acceleration of movements correlated to snow melting (Follacci, 1987(Follacci, , 1999. For a few years, this distance monitoring has been combined with other types of investigations: hydrogeological studies (Compagnon et al, 1997;Guglielmi et al, 2000;Cappa et al, 2004), remote sensing (Casson et al, 2003;Squarzoni et al, 2003) and subsurface geophysical investigations (Lebourg et al, 2005;Jomard et al, 2007a,b). Different types of geometric, mechanic or hydromechanic models have been derived from these data sets (Merrien-Soukatchoff et al, 2001;Cappa et al, 2004) but none of them visualise the morphology of the main slip surface geometry.…”

“…Indeed, while numerous studies have been carried out on this site (hydrological, geologic, tectonic, topographic, etc. ) (Follacci, 1987;Ivaldi et al, 1991;Compagnon et al, 1997;Guglielmi et al, 2000Guglielmi et al, , 2002Gunzburger and Laumonier, 2002), very few numerical studies have been conducted (Quenot, 2000;Merrien-Soukatchoff et al, 2001;Cappa et al, 2004) and, to our knowledge, no study has been devoted to the localisation of the deformation as a function of the geomechanical parameters and their relation to the gravitational destabilisation of the slope. In the second part of this contribution, we present the comparison between our numerical data and an electrical survey that we have conducted on the La Clapière landslide and previous results obtained by our team (Lebourg et al, 2005;Jomard et al, 2007a).…”

Identification of the gravitational boundary in weathered gneiss by geophysical survey: La Clapière landslide (France)

“…Moreover, these measurements reveal a seasonal response of the landslide characterised by an acceleration of movements correlated to snow melting (Follacci, 1987(Follacci, , 1999. For a few years, this distance monitoring has been combined with other types of investigations: hydrogeological studies (Compagnon et al, 1997;Guglielmi et al, 2000), remote sensing (Casson et al, 2003;Squarzoni et al, 2003) and subsurface geophysical investigations (Lebourg et al, 2003). Different types of geometric, mechanic or hydromechanic models have been derived from these data sets (Merrien-Soukatchoff et al, 2001;Cappa et al, 2004) but none of them visualise the morphology of the main slip surface geometry.…”

“…Although numerous studies have been carried out on this landslide (hydrological, geologic, tectonic, topographic) (Follacci, 1987;Ivaldi et al, 1991;Compagnon et al, 1997;Guglielmi et al, 2000;Cappa et al, 2004)), only one geophysical survey has been performed at the foot of this landslide (Lebourg et al, 2005). For this reason, we decided to undertake, for the first time, such a study by applying the geophysical approach to the La Clapière landslide and more precisely to the more unstable part located at the top.…”

Hydromechanical modeling of a large moving rock slope inferred from slope levelling coupled to spring long-term hydrochemical monitoring: example of the La Clapière landslide (Southern Alps, France)

“…Indirect methods based on the study of natural hydrogeochemistry of water -rock interactions (Compagnon et al, 1997;Guglielmi et al, 2000) and on artificial tracing experiments (Bonnard et al, 1987) were developed in order to locate water flow paths through the rock mass and to estimate pore pressures at the scale of the LMRM. Tested on French and Swiss landslides, these methods confirm that it is possible to define water infiltration areas, to determine groundwater flow paths, and to estimate water transit and renewal times (Guglielmi et al, 2002).…”