Effective stress response of clay to undrained cyclic loading

The effective stress response of a natural marine clay to slow undrained symmetrical cyclic reversal in shear stress is presented. The effects of cyclic principal stress difference amplitude, cyclic principal effective stress ratio amplitude, initial direction of loading, and step increase in cyclic stress level on the clay stress-strain response are studied under stress conditions of the triaxial test. Characteristic behaviour patterns are identified in terms of effective stresses. Key words : clay, cyclic loading, effective stress, hysteretic work, loading direction, step loading.