Thermal impact on damaged argillaceous rocks: Permeameter test and Isostatic test on Boom Clay and Opalinus Clay from the TIMODAZ project

SCK•CEN performed two types of laboratory tests in the EC-funded TIMODAZ project. The specific objectives of these laboratory tests are to assess the thermal impact on hydraulic properties of Boom Clay and Opalinus Clay with main single default by monitoring the evolution of the hydraulic conductivities; to test the influence of the pore water compositions injected through the clay samples on their sealing properties under different temperatures; to establish a correlation among the flow properties, stress states, and temperatures for both damaged samples; to visually observe the evolution of the sealing process with a microCT technique. From all the Permeameter tests and Isostatic tests, sealing phenomena for both Boom Clay and Opalinus Clay have been clearly demonstrated. The degree of sealing in terms of hydraulic conductivity differs under different test conditions. The speed of sealing is very fast for Boom Clay, while it is much slower for Opalinus Clay. Except the Permeameter test on Opalinus Clay, all the other test results do not show influence of heating cycle on the sealing behavior. Under the Permeameter test condition, the heating shows positive and significant impact on the sealing behavior of Opalinus Clay. A heating cycle does not seem to enhance healing.