Low-amplitude dynamic properties for compacted sand-clay mixtures

Shear modulus and damping ratio are important input parameters in dynamic analysis. A series of resonant column tests was carried out on pure clays and sand-clay mixtures prepared at different densities to investigate the effects of aggregate content, confining stress, void ratio and clay plasticity on the maximum shear modulus and minimum damping ratio. Test results revealed an increase in the maximum shear modulus of the mixture with the increase in sand content up to 60%, followed by a decrease beyond this value. It was also found that the maximum shear modulus increases with confining stress, and decreases with void ratio. In addition, minimum damping ratio increases with sand content and clay plasticity and decreases with confining stress. Finally, on the basis of the test results, a mathematical model was developed for the maximum shear modulus.