Verification of the Fredlund (2019) Unsaturated Shear Strength Function

There has been a proliferation of equations proposed to describe the unsaturated shear strength envelope going back 1970s. However, there have limited studies verify suitability one equation over another. Most attempted relate an soil some aspect(s) soil–water characteristic curve (SWCC). Estimation procedures generally focused on using that air-entry value (AEV) as defined by drying (or desorption) branch degree saturation SWCC (S-SWCC). This paper two “anchor points” reference points) along S-SWCC estimate function. The anchor points referred are and “residual suction point” in terms S-SWCC. Shear conditions associated with both so-called used “boundary conditions” should be satisfied when estimating function for soils. Past research laboratory measurements published literature part verification process this study.