A correction to damping ratio for hyperbolic–hysteretic model for clayey soil

Abstract

For clayey soils, the shear modulus and damping ratio are perhaps the two most common parameters considered in dynamic soil behavior characterization. It is well known that under cyclic loading, soil behaves hysteretically in the stress–strain plane. Several mathematical models were proposed to simulate the soil behavior under the cyclic loading conditions. For most of such models, Masing rule is often used to define the unloading–reloading behavior of stress–strain loops. However, it was also noted by many researchers that the framework of Masing rule tends to overpredict the damping ratio at moderate to high strain range. The present paper deals with a hyperbolic–hysteretic undrained soil model based on Masing rule. First, the efficacy of the model to predict the variation of shear modulus and damping ratio for a wide strain range was examined. Second, a simple correction for the calculation of damping ratio was introduced. Finally, the corrected damping ratios for various types of soils with varying plasticity index were compared with published experimental results. Good agreement was obtained between the computed and experimental results for a wide range of strains and plasticity index.