(GRS 234) ADDIGAS - Advective and Diffuse Gas Transport in Rock Salt Formations

Beside granite and clay formations also rock salt is investigated as potential host rock for the disposal of radioactive waste. As a result of the mining activities the stress and strain state is changed which leads to dilatancy (i. e., volume increase, mainly causedby microfracturing) in the vicinity of the excavations. The affected area is termed as Excavation Disturbed Zone (EDZ) and is characterized by an increased porosity and permeability with micro- and potential macrofractures.For the radioactive waste disposal in a geologic formation the properties of the EDZ with its permeability, extent, and evolution with time is of importance especially for the construction and building of geotechnical barriers. In the recent years the EDZ in rocksalt formations was investigated at GRS in the frame of various projects. Main subjects of these projects were the characterisation of the EDZ with regard to its extent, hydraulic behaviour and possible healing at the in-situ stress conditions.