This paper examines shear modulus degradation and damping ratio for offshore clays. The work is based on an extensive database of direct measurements obtained from advanced laboratory tests (resonant columns) on undisturbed fine-grained samples from offshore sites worldwide. The effects of soil properties such as plasticity index (PI) and over-consolidation ratio (OCR) on shear modulus degradation and damping ratio are described. A new calibrated hybrid model for marine clays is proposed to evaluate normalized shear modulus reduction and damping ratio curves as a function of shear strain. The proposed relationship can be used for a wide range of cohesive soil conditions for direct use in offshore geotechnical engineering such as non-linear seismic site response analysis or soil-structure interaction assessments for fixed offshore structures including wind turbines.
Lorenzo Zuccarino, Luca Ottonello and Omar Zanoli
Keywords: offshore clays, shear modulus, damping ratio
Publisher: DFI