Abstract: The theory of hypoplasticity provides an effective mean for modeling the nonlinear behavior of granular materials. In particular the CLoE hypoplastic model has salient advantages in modeling the strain localization problems. In simulating the cyclic stress-strain loops with small amplitude, however, the hypoplastic model shows the ratcheting effect. To resolve this issue, the intergranular strain tensor is incorporated into the CLoE hypoplastic model so that it can effectively describe the behavior of dense sand under cyclic loading. In addition, to reserve the consistency of the modified model in describing the sand behavior under monotonic loading conditions, the definitions of intergranular strain rate and the maximum intergranular strain are improved. The numerical results show that (1) the modified model reserves the advantage of overcoming ratcheting effect; (2) the modified model can account for the unloading stiffness of different cyclic amplitudes; (3) for large cyclic amplitudes, the area of the cyclic loop increases with cyclic number; (4) the consistency of the modified CLoE model and CLoE model can also be guaranteed under the same monotonous loading condition; (5) the modified model well represents the mechanism of the fatigue-induced failure of materials.

Key words: cyclic load, CLoE hypoplastic model, ratcheting effect, intergranular strain