Analysis of the micro to macro response of clays to compression

An investigation of clay microstructure and its evolution under one-dimensional (1D) isotropic compression is presented for different clays. Data from the literature are compared to original results on two Italian clays, obtained using scanning electron microscopy, image processing, mercury intrusion porosimetry on-purpose swelling tests. The effects composition loading history microstructure, as well changes along path (pre- post-gross yielding) analysed a conceptual model proposed clays study. Normally consolidated at early virgin compression, either natural or reconstituted, found possess an open fabric random low orientation, complying with prevailing inter-aggregate smaller intra-aggregate porosity, whose size distribution depend composition. Under 1D in field laboratory, porosity lost, rate dependent history, dominant micropore progressively reduced. Accordingly, perfectly oriented stacks domains recognised which, however, embed preserved particle arrangements even large pressures, resulting increase average orientation up reach steady degree. Isotropic causes faster evolution, although pressures required change 1D-induced orientation.