Influences of initial static shear stress on the cyclic behaviour of over consolidated soft marine clay

In offshore engineering, soft marine clays which are overconsolidated due to surcharge pre-loading beneath embankments may be subjected to initial static shear stress. To experimentally investigate the influences of the initial static shear stress on the cyclic behaviour of overconsolidated soft marine clay, a series of triaxial tests are performed covering various values of the initial static shear stress ratio (SSR) and overconsolidated ratio (OCR). Several useful conclusions are obtained. First, the total axial strain increases as the SSR increases, whereas an increase in the OCR reduces the rate of increase in axial strain. Second, the area encompassed by the stress-strain loop decreases with an increasing OCR, whereas it increases with an increasing SSR. Third, a threshold SSR is proposed. Two quantitative relationships between the permanent axial strain and SSR are then established based on the proposed threshold and verified against the experimental results.Y