Landfill clay barrier subjected to cracking: Multi-scale analysis of bending tests

The behaviour of a clay cover barrier of a site for storing nuclear waste with very low activity is considered in this paper, more particularly, the focus is on the behaviour of clay in the case of differential settlements within underlying waste. For this kind of application, maximum tensile strength is not the goal, but rather the maximum ductility and maximum extension of the clay without cracking. A four points bending test protocol is proposed for the clay material used in the landfill cover to optimise the implementation conditions (water content and compaction energy). Original large scale bursting tests in field conditions are performed for validation: monitoring deformations both for the laboratory and the field tests demonstrates that the initiation of cracks in the clay material occurs for basically the same strain. Therefore, preliminary field tests are not needed.