Improved Hardin-Drnevich model for the dynamic modulus and damping ratio of frozen soil

The Hardin-Drnevich model is frequently employed in the seismic ground response analysis, but the original model cannot be directly applied to frozen soils, the dynamic properties of which are functions of the soil temperature. Resonant column tests were carried out and empirical correction factors were proposed to revise the model. The improved model was applied to the seismic ground response analysis of a permafrost site, and the influences of the variations of the correction factors were analyzed. The resonant column test results indicated that soil temperature had large influences on the shear modulus and damping ratio, while in the range investigated in this study, the effect of the degree of saturation was not significant. The proposed correction factors properly fitted the test results in the present and previous studies, but the correction factors varied considerably even for the same category of clayey or silty or sandy soils. Compared with the correction factors for the modulus reduction curve and damping curve, the correction factor for the maximum shear modulus had a larger effect on the seismic ground response of a permafrost site. In the seismic response analyses, the response spectral values at the ground surface were generally larger if the investigated site was assumed to be non-frozen.