EXPERIMENTAL STUDY ON DYNAMIC DEFORMATION CHARACTERISTICS OF ROCKFILL MATERIALS UNDER DIFFERENT STRESS PATHS

Dynamic deformation experiments of rockfill materials were carried out by using the large-scale triaxial apparatus, such as the conventional triaxial cyclic loading, the p=const cyclic loading and the q=const cyclic loading. The influence and deformation mechanisms of confining pressure, consolidation stress ratio and dynamic stress ratio on the volumetric strain and deviatoric strain were discussed. The test results indicated that different stress paths had a great influence on the development pattern of the volumetric strain and deviatoric strain under the cyclic loading. The reciprocating volumetric strain was negative under the p=const cyclic loading, indicating dilatancy with its maximum dilatancy occurring in the axial shearing, while the shear dilatancy did not show in the reverse shearing. The large residual volumetric strain and residual deviatoric strain were produced under the q=const cyclic loading, which were not negligible, and it was mainly related to the anisotropy and particle breakage of the rockfill materials.