Experimental study on dynamic deformation behavior of rockfill materials

Large-scale cyclic simple shear tests on rockfill materials of limestone are performed to study the characteristics of dynamic moduli, damping ratios and residual deformations. The experimental results show that the curves of G_d/G_dmax~γ_d and λ/λ_max~λ_d are described by the modified nonlinear viscoelastic dynamic constitutive model. When the confining pressure and dynamic stress ratio are higher, the relationship between residual strain and numbers of cycles diverges the semilog rules evidently. Based on the test data, a power function is adopted to describe the development of residual strain. Then a residual strain model is proposed, which is a function of the average main stress, consolidation ratio and dynamic shear strain. By analyzing the collected test results, the feasibility of this model is validated.