Abstract:

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.

Key words: silty clay, dynamic triaxial test, dynamic properties, static properties after cyclic loading