Shear Modulus and Damping Ratio Model for Cement Treated Clay

A hyperbolic model-based normalized shear modulus reduction (G/G(max)) formulation for cement treated clay is presented. This three-parameter normalized shear modulus reduction model can be constructed using maximum shear modulus and isotropic compression experiments. The model assumes that cemented clay follows the failure pattern of a modified structured Cam-clay model. The effects of cement content and confining pressures on G/G(max) are modeled and validated with experimental results from resonant column and cyclic triaxial testing. In addition, the damping ratio is calculated based on the Masing rule; however, for cement treated clays, this rule overestimates the damping ratio at all ranges of shear strain. In this study, correction factors are established to propose a reliable damping ratio model. The newly proposed G/G(max) and damping formulations provide reasonable estimates that match well with the experimental results. These formulations can be used in the seismic response analysis of cement treated ground.