Strain-rate effects in deep marine clays from the Gulf of Guinea

Abstract

Current developments in deepwater offshore oil production in the Gulf of Guinea (GoG) make it necessary to characterise the mechanical behaviour of the GoG deepwater sediments better. This paper examines some aspects of the strain-rate-dependent behaviour of intact and reconstituted GoG clay specimens. Results from isotropic compression and undrained shearing laboratory tests with changing rates of stress and strain are presented. They show that the soil generally follows an isotach behaviour, with clear strain-rate dependence of the stress–strain behaviour and pore pressure response in the undrained shear tests. The effects of structure and its degradation on the time-dependent response of the sediments seem to confirm general trends observed in other structured clays.