Evaluation of Empirical Procedures for Predicting the Shear Strength of Unsaturated Soils

This paper provides a summary of nineteen empirical procedures or techniques that are available for predicting or estimating the shear strength of unsaturated soils. While six of these procedures use the soil-water retention curve (SWRC) as a tool; the remainder thirteen procedures are mathematical formulations for the prediction or estimation of the shear strength of an unsaturated soil. A comprehensive analysis is undertaken to predict the variation of shear strength with respect to matric suction of twenty soils using the six prediction equations that use SWRC. The studies presented in this paper highlight the suitability of these equations for successful predictions of the shear strength of the unsaturated soils.