A distinctive feature of granular material such as sand, beside frictional strength is stress-dilatancy: a change in volume as grain particles override one another when sheared. Stress dilatancy plays a crucial role in the behavior of granular material in both monotonic and cyclic loading conditions, as well as the behavior within strain localization which is a precursor to failure.

Several studies on the stress dilatancy behavior of sand in the drained cyclic torsional shear tests have been reported by numerous researchers such as Pradhan et al. (1989), Shahnazari and Towhata (2002), De Silva (2008) and Seto et al. (2010). However, the effect of strain amplitude on stress-dilatancy properties of dense sand is not well addressed; therefore, in this study, stress-dilatancy behavior of sand was investigated by conducting strain and stress controlled tests.