SALT project: Preliminary physical and mineralogical characterization of Alpine sulphates for geological and geotechnical modeling

The excavation of underground infrastructures in geological sequences containing sulphates may cause swelling, water weakening, creep and karst. All these phenomena have been observed in tunnels for decades, but related technical problems still remain. This is especially true for geologically complex domains as Alpine environments, where the mechanical behviour of sulphates needs to be evaluated in relation to the structural complexity of the fracture network and of the 3D geometries of the orogenic context. This study, that is developed in the framework of the SALT project, a multiscale and interdisciplinary investigation of sulphate salts in the Alpine region, proposes a description of the main features of outcropping sulphates in Western Alps, providing useful preliminary information to afford technical issues related to sulphates during the realization of infrastructures in the Alps.