“…The direct shear test has been used to determine shear strength properties of various soilstructure interfaces. Such applications of direct shear testing range from fundamental studies on the effects of dilatancy (Simoni and Houlsby, 2006), particle size (Yu et al, 2006) and shear box platen fixities (Jewell, 1986) to field applications including skin friction generated between various construction materials (Potyondy, 1961), geosynthetic-reinforced structures (Anubhav and Basudhar, 2013;Arulrajah et al, 2013), large-scale hydropower projects, and excavations of lunar regoliths (Iai and Luna, 2011). Direct shear tests can be conducted under conditions of constant normal load (CNL), constant normal stiffness (CNS), or constant volume (CV) (Pellet and Keshavarz, 2014).…”