Effects of micro-structure on the stress-strain behaviour of two natural clays

The influence of soil structure on the small strain behaviour of two Italian clays (Vallericca and Bologna) is analysed in this paper through the results of cyclic and dynamic tests driven by means of an advanced torsional shear equipment. The dependency of initial shear modulus, G0, and damping ratio, D0, on stress level and history are compared with reference to intact, reconstituted and destructured samples. The results were effectively synthesised in terms of normalised variables and objective parameters to account for the different loading histories. The comparisons between normalised plots relevant to the different sample sets permitted to evaluate the corresponding effects of soil structure on the small strain behaviour of the two clays.