The Effect of the Consolidation Ratio of Sands on Dynamic Shear Modulus and Response Spectrum of Soil Layer

The dynamic shear modulus (DSM) is the most basic soil parameter in earthquake or other dynamic loading conditions. By using the resonant column tests, the effect of the consolidation ratios on the maximum DSM for two types of sands is investigated and an incremental formula for calculating the maximum DSM for the cases of the anisotropic consolidation is presented. The results indicate that the increase in the maximum DSM due to kc>1.0 is significantly larger than that predicted by Hardin and Black's formula. Also, the nonlinear behavior of DSM due to the anisotropic consolidation is investigated and its effect on the surface response spectrum is presented in the paper. By comparing to the isotropic consolidation, the consideration for the actual anisotropic consolidation makes the earthquake influence factor increase and makes the characteristic period decrease. For the incidence of the strong seismic excitation, the effect of the anisotropic consolidation on earthquake ground motion should be considered.