Effects of cyclic loading on mechanical properties of slity clay

A series of consolidated undrained static triaxial tests and cyclic triaxial tests were carried out on undisturbed marine silty clay of Bohai Bay;the cyclic triaxial tests consist of cyclic load and post-cyclic undrained shear 2 stages.It was shown that with the increase of cyclic stress ratio,the average axial strain and single amplitude axial strain become large;when cyclic stress ratio large than 0.4,average axial strain and single amplitude axial strain increase fast with number of cycles;average axial strain increase with confining stress,while single amplitude axial strain decrease with confining stress.Under large cyclic stress ratio,normalized average pore pressure and normalized single amplitude pore pressure come to a stabilization with number of cycles;with large cyclic stress ratio normalized average pore pressure and normalized single amplitude pore pressure become large;with large confining stress normalized average pore pressure become small,while the effect of confining stress on normalized single amplitude pore pressure was unapparent.In post-cyclic undrained shear stage,the effective stress path in q-p' plane and pore pressure exhibit the properties of over consolidation clay.