effects of intermediate principal stress parameter on cyclic behavior of sand

Soils have an anisotropic response, and changing the inclination () and magnitude of the major principal stress will aect collapse potential and brittleness, as well as shear strength and shear stiness. In this paper, the eect of the stress path, with changes in intermediate principal stress, on the dynamic behavior of Babolsar sand, is studied. A series of undrained monotonic and cyclic tests on loose sand with induced anisotropy were conducted by using automatic hollow cylinder apparatus. Special attention was paid to the signicant role of the intermediate principal stress parameter (b) in the deformation behavior of the sand during cyclic loading. Results show that at constant , conning stress and fabric, variation in b has a signicant eect on strain amplitudes, but will not change the contractive or dilative behavior of specimens. Variation of b has a great eect on liquefaction resistance but has no eect on the mobilized friction angle at steady state. It is shown that conning stress has a signicant eect on soil response (strain development, excess pore water pressure generation and shear modulus and damping ratio). Moreover, by increasing the conning stress, the eect of b value on cyclic behavior is more pronounced.