Assessment of the Dynamic Properties of Soils from Triaxial Tests

A detailed laboratory testing programme was conducted on undisturbed sensitive Leda clay samples and on uniform sands under triaxial loading mode. Monotonic and cyclic behavior of sensitive Leda clay are studied by performing large strain tests at various consolidation conditions. Small strain stress controlled quasi-cyclic tests were conducted on clay and sand to establish site-specific modulus reduction and damping ratio curves at small strain amplitudes. The shear strength and cyclic resistance of Leda clay under triaxial testing mode is noted to be significantly higher than the previously reported values under simple shear loading conditions. Further consolidation stress and OCR influence the monotonic shear strength of clay. Site specific modulus reduction and damping ratio curves are proposed for Leda clay, Fraser River sand and Ottawa sand. The proposed dynamic curves indicate that the behavior of sensitive clays does not follow any particular curve proposed in the literature for non-sensitive clays.