Mechanical interpretations of the homogeneous nature of bentonite due to swelling

Abstract

AbstractTo achieve the high sealing capability required for the bentonite engineered barriers used in geological disposal facilities for radioactive waste, the bentonite should be highly compacted. Previous investigation of methods to enable such compaction has revealed that the construction methods used have an impact on the density distribution. However, these investigations focused on achieving the required average dry density in the bentonite barriers and little attention has been paid to the distribution of dry density. As a result, there has been a lack of understanding of how the construction method used affects this distribution, which is highly pertinent to the evaluation of the long-term performance of bentonite engineered barriers.This paper first describes the residual density distribution after resaturation and then highlights how swelling behaviour can be studied and evaluated based on elasto-plastic theory. The conceptual understanding is that the buffer does not swell to achieve an entirely homogeneous density, but will reach an equilibrium state with a remaining gradient.