Abstract: Through a series of stress-controlled bi-directional cyclic shear tests under different three-dimensional anisotropic consolidation stress conditions on the undisturbed saturated marine soft clay from the yellow river delta area, the effects of the initial orientation angle of the maximum principal stress ?0, the ratio of the two stress components R and the cyclic stress level (expressed by cyclic stress ratio Rc) on the characteristics of residual deformation of the saturated marine clay are examined. The test results show that the ?0 has remarkable effect on the residual axial strain ?r caused by cyclic loading, ?r at failure and the relation between ratio of residual axial strain ?r /?rmax and ratio of number of cycles N/Nf . Both ?r caused by cyclic loading and ?r at failure decrease with a decrease of R. At the same N/Nf , ?r /?rmax increases at first then decreases with a decrease of R. The relation curves of ?r /?rmax -N/Nf with different R concentrate in a narrow strip and can be expressed by a unified expression by normalizing the test data. At ?0 =0° and 90°, the differences of relation curves between residual shear strain ?r and cycle number N with different values of R are not remarkable. While at ?0 =30° and 60°, the R has significant influence on the relation curves between ?r and N. The differences of the variation regularities of ?r and ?r under low stress level and high stress level with an increase of N are obvious. The relational expressions between ?r /?rmax and N/Nf are proposed.

Key words: undisturbed saturated clay, three-directional anisotropic consolidation, bi-directional cyclic shear, continuous rotation in principal stress direction, cyclic stress level, residual deformation