Application of the dilatancy concept on the behavior of opalinus clay

Excavating in deep underground alters the state of stress, which causes an excavation damaged zone (EDZ ) or damaged rock zone (DRZ) in the near-field, and an excavation disturbed zone (EdZ) or disturbed rock zone in the far-field. In soft rocks these two zones are separated by the dilatancy boundary. The excavation induced stress differences will reduce with time by creep. To derive a constitutive equation for Opalinus clay we have investigated its creep and dilatancy behaviour. (authors)