Shear strength behavior of preloaded highly plastic clays

This paper presents the results of a study made to characterize the shear strength behavior of an undisturbed, highly plastic marine clay upon preloading. Undrained shear strength (cu) of preloaded clays is found to be directly proportional to applied preload pressure (p). Correlations reported in the literature between cu/p ratio and plasticity index are not found to be valid for this highly plastic clay. A two parameter model is developed for the prediction of undrained shear strength by a simplified procedure through measurement of water content only. The study also suggests that the undrained shear strength of preloaded highly plastic clays can be expressed as a unique function of the ratio of liquid limit water content to water content under the preload.