Microstructural analysis of inherent and induced anisotropy in clay

The aim of this study was to relate the mechanical behaviour of saturated clays to their structural characteristics. Two clays were studied: a kaolinite and a bentonite. The evolution of the shape, the size, the concentration and the orientation of the elements which constitute the clay structure was examined by means of scanning and transmission electron microscopes. Particular care was taken to avoid as far as possible disturbing the micro-structure during observation. The results showed the existence of particle breakage and the creation of structural anisotropy during loading. We can conclude from this work that the mechanical behaviour to clayed materials is largely dependent on the changes which occur at the scale of the particles.