Moduli and Damping Factors of Soft Marine Clays

This paper presents a compilation of resonant‐column and cyclic simple‐shear test results on dynamic moduli and damping factors of soft marine clays. These tests were conducted on 38 undisturbed samples of soft marine clays recovered from five offshore sites. Sample depths ranged from 17 to over 300 ft below seafloor. The test clays had water content ranging from 36 to 86% and plasticity index ranging typically from 30 to 50%. Small‐strain moduli of the test clays were found proportional to consolidation stress and they also depend on void ratio and plasticity index. Normalized shear‐modulus curves and damping curves of the test clays were very similar to those for various onshore and offshore clays. The results of this study may be used to make a preliminary estimate of the dynamic properties of marine clays and to confirm field and laboratory tests on such clays.