Abstract：Cyclic triaxial tests are conducted on saturated sand in drained condition with cyclic loading and unloading of deviatoric stress and constant spherical stress. The results of systematic test on deformation characteristics with respect to cyclic number in different dry density and consolidation stress condition are presented and analyzed. It shows that：(1) the volumetric strain takes different physical states，including three types of shear contraction (C1 type under initial loading，C2 type without dilation before unloading，and C3 with dilation before unloading)，dilation P and rigid shear R；(2) the relationship between volumetric strain and the deviatoric stress ratio q/p under every physical states are linear. Their parameters have a linear or exponential relationship with the initial volumetric strain of each physical state；(3) the volumetric strain process can be calculated by using the cyclic deviatoric stress and the above linear relationships of different physical states and the calculation result is consistent with that by experiment.
