Emerging Technology for Determining Unsaturated Soil Shear Strength

In 2019 Fredlund proposed a procedure for the estimation of the unsaturated soil shear strength function. The procedure used the air-entry value, AEV, (as defines by the drying branch of the degree of saturation Soil-Water Characteristic Curve, S-SWCC), and residual conditions to define distinct limits for the unsaturated shear strength function. It was suggested that these points formed two "anchor points" (or reference points), along the drying S-SWCC. The suitability of these two "anchor points" was verified through comparisons with published laboratory data sets. This paper details a protocol that can be adhered to when using the S-SWCC to estimate a suitable unsaturated shear strength function for geotechnical engineering applications.