Dynamic properties of offshore sands

Abstract

This paper examines shear modulus degradation and damping for offshore sands. The work is based on an extensive database of dynamic soil properties for undisturbed and reconstituted granular samples from offshore sites worldwide. The data set consists of direct measurements obtained from advanced laboratory tests (resonant columns). Data considered in this paper includes a wide range of granular marine sediments. The effects of soil properties such as confining pressure and fines content on the dynamic parameters are described and guidance on interpretation and applicability is provided. A new calibrated model is proposed to evaluate normalized shear modulus reduction and damping ratio curves as a function of shear strain of marine sands. The proposed relationship can be used for a wide range of granular soil conditions for direct use in routine offshore dynamic engineering analyses and, in particular, in non-linear site response analysis.