On the geomechanical characterisation of complexities in clays: Experimental studies

This paper presents the main results of an experimental study on the behaviour of heterogeneous fine-grained soils from Southern Italy: Fissured clays, where the heterogeneity is due to the fissures visible to the naked eye, and contaminated submarine sediments, where the heterogeneity is of chemical nature. The results are originally analysed from the perspective of the so-called complexity theory-the key question being whether these materials can be thought of as emblematic examples of truly complex systems in geomechanics. It is shown that this is certainly the case for fissured clays: Despite differences in composition and degree of fissuring, these materials follow common emergent behaviour that can be predicted, both in the short and in the long term, by using traditional models based on Cartesian reductionism. The research on the environmentally complex system of the Mar Piccolo has just started and aims at the mechanical characterisation of contaminated soils as a compulsory step for the selection of potential site remedy strategies. The results suggest that the submarine sediments represent a fascinating example of complex adaptive system, for which long-term predictions can be successful as far as the system remains at the edge of chaos.