Effect of initial shear on cyclic behavior of sand

Drained and undrained cyclic torsional simple shear tests are conducted for saturated Ottawa sand with and without initial static shear applications. It was found from the experiment that when the tests were conducted under uniform cyclic shear strains, both pore water pressure generation in undrained conditions and the volume changes in drained conditions were affected very little by the level of the initial static shear applications. The strain method, which uses shear strain parameters as determinative parameters, has been proven to be very useful for liquefaction and cyclic volume change analyses.