Comparison of Different Procedures to Predict Unsaturated Soil Shear Strength

Several procedures have been proposed in the recent years to predict the shear strength of an unsaturated soil. The soil-water characteristic curve has been used as a tool either directly or indirectly in the prediction of the shear strength along with the saturated shear strength parameters in these procedures. This paper provides comparisons between the measured and predicted values of unsaturated shear strength using these procedures for three soils both for limited and large suction ranges. The three soils used in the study for comparisons have different gradation properties, percentages of clay and plasticity index, Ip values. The advantages and limitations associated with predicting the shear strength of unsaturated soils using the procedures is discussed in the paper.