Dynamics of Anisotropic Clays Under Large Strains

The dynamic behavior of cross anisotropic clays was often studied in a resonant column device which is limited to strains smaller then ${10}^{-3}\text{,}$ and to high frequencies. Here the experimental study is extended to large strains at low frequency; and an attempt is made to model the behavior covering the whole spectrum of strains from small to large. Axial stresses, torsional stresses and their combinations when applied to thin long hollow cylinders lead to strains that show the influence of tridimensional states of stress on the dynamic response. The modulus degradation pattern is noticeably affected by those combined stresses. The inclinations of principal stresses play an important part in the way a clay responds to cyclic loading. Relations are suggested to predict shear moduli and damping ratios. The Ramberg‐Osgood‐Masing hypothesis is shown to be deficient and reduction factors are proposed to bring its prediction in line with experimental data.