Assessment of Uncertainty of Undrained Shear Strength of Soft Clay Using Ball Penetrometer

Abstract

Nowadays, ball penetrometers are increasingly being used for well-defined full flow failure mechanism to determine in situ undrained shear strength for offshore soft clay soil to overcome the limitations of cone penetrometer. It is observed that the undrained shear strength estimated from ball penetrometer data is highly uncertain due to inherent variability, transformation or model uncertainty and measurement uncertainty. Undrained shear strength is determined from measured penetration resistance using a factor leads to model uncertainty. The ultimate capacity of various foundations, such as suction anchors and spudcan foundations are inherently uncertain as those are designed based on the estimated undrained soil shear strength which also involves uncertainty. This paper examines the degree of total uncertainties involved while determining undrained shear strength for soft clay soil using a probabilistic approach. The variability of soil undrained shear strength is quantified using the ball penetrometer data.