Large-Scale Triaxial Experiments on the Creep Behavior of a Saturated Rockfill Material

Large-scale triaxial compression and creep experiments were conducted with a saturated limestone rockfill material. The relationships between dilatancy ratio and stress ratio during loading and creeping were analyzed. It was found that the dilatancy ratio during both loading and creeping decreased nonlinearly when the stress ratio increased. In addition, the positive dilatancy ratio was considerably higher in creep than in vertical loading under the same stress state. Experimental data also showed that creep strains evolve linearly with the logarithm of time after a certain period, and both the final amounts of creep strains at the end of experiments and their rates are influenced by the stress states. A higher confining pressure and higher deviatoric stress lead to larger creep strains and higher strain rates. Empirical equations relating the final amounts of creep strains and their rates to the stress states are suggested.