The unsaturated shear strength parameter, ϕb, is usually determined using triaxial of direct shear apparatus that have been modified to allow for the control and (or) measurement of pore-air and pore-water pressures. A fairly high level of expertise is required for the characterization of ϕb using these modified apparatus. A simple procedure for determining ϕb for statically compacted soils at different water contents is presented along with a method of analysis. The tests can be performed on a conventional direct shear apparatus. The unsaturated shear strength parameter, ϕb, obtained using the proposed procedure is shown to be comparable to that obtained using the modified direct shear test. Since the proposed procedure utilizes standard laboratory direct shear equipment and takes a relatively short time to complete, it offers an easy and convenient alternative for the determination of ϕb for statically compacted soils. Key words: shear strength, matric suction, unsaturated soils, statically compacted soils, direct shear test.
Coupled Eulerian-Lagrangian simulation of a modified direct shear apparatus for the measurement of residual shear strengths
