Suction in shales: consequences on triaxial testing

Significant interest has been devoted to claystones and shales in the context of geological radioactive waste disposal at great depth. The determination their mechanical properties is needed for appropriate design underground galleries tunnels. Given high sensitivity changes water content, special care be taken so as provide characteristics close possible (saturated) insitu ones. Based on hydromechanical path followed by samples from coring trimming lab, that most often lead some degree desaturation resulting evaporation drying samples, procedures aimed minimising perturbations are described. considerations presented based data obtained two (swelling) considered Europe deep disposal, i.e., Callovo-Oxfordian claystone (France) Opalinus Clay (Switzerland).