This paper investigates and analyzes small strain shear modulus (Go) of naturally sedimented undisturbed soft marine clays using field seismic cone tests and laboratory bender element tests. Laboratory bender element tests have been performed at the in situ stress state and also at isotropically normally consolidated stress state. The investigated soils are: Ariake and Hachirogata of Japan, Pusan of Korea, Bangkok of Thailand and Bothkennar of United Kingdom. Various models proposed in predicting Go have been critically examined against the data obtained from the investigation. Finally, based on the present study, an empirical model has been developed to predict Go
Small strain shear stiffness (Go) is a fundamental parameter in characterizing non-linear stress-strain behavior of a soil, both in monotonic and dynamic Ioadings and related shear deformation problems. Particularly, geotechnical works subjected to dynamic loading such as earthquake, wave-loads, traffic-loads and machine foundations demand accurate estimate of small strain shear deformation. When shear strain is smaller than the elastic threshold strain, shear modulus (G) is practically constant and is independent of shear strain level (Hardin, 1978; Jardine et al., 1986; Burland, 1989). However, once the shear strain exceeds the threshold strain, shear stiffness decreases nonlinearly with additional increase in shear strain. Various types of dynamic tests are available in measuring G of a soil. G measured using field seismic cone and bender element test is believed to yield small strain shear modulus (i.e. G=Go). Go of a soil can be measured in field and laboratory by passing elastic shear wave of velocity v,. through soil of density Gt having length L, by recording its travel time t, and using the following relationship. This paper investigates Go from field seismic cone test as well as laboratory bender element tests on the following naturally sedimented undisturbed soft marine clays:
