Shear Strength Properties of Two Stratified Clays

Owing to their intrinsic structure, the undrained strength of stratified clay is a directional property dependent on the orientation of the applied major principal stress. Results of unconfined compression tests performed on specimens trimmed from block samples showed that for the two clays tested, the minimum strengths are considerably lower than the principal strengths. A comparative study demonstrated that the shear behavior of stratified clays are considerably different from those of homogeneou clays. These observations can be explained by a failure hypothesis for stratified clays. The practical implications of these results are examined. The choice of shear strength in slope stability studies is illustrated by the analysis of several case records.