ABSTRACT
Clay formations are one of the possible geological host materials for the disposal of radioactive waste. During the construction of underground excavations, fractures may be induced around the opening. As part of the feasibility study on clay as a natural barrier for radioactive waste disposal, this fracturing process has to be better understood and the possibility of the sealing and/or healing of these fractures is studied. Self-healing of clays is investigated by recording acoustic activity during cyclic loading of clay samples in the laboratory. It appears that after longer time delays between loading cycles, the acoustic emissions occur at lower load levels. This could imply that micro-cracks are re-activated at lower load levels after a time delay.
