Residual deformation model for rock-fill materials

Large scale triaxial shear tests on rock-fill materials are performed to study the residual deformation behaviors of rock-fill materials by using the large-scale triaxial apparatus. The characteristics of residual deformation of cushion material, excavated material and main rock-fill with two different densities are the focuses of this study. Based on enough test results, it is revealed that the generated shear strain after the application of the first cycle of loading is the main part of the residual shear strain, and its development relates to the accumulation rate of the residual shear strain as the loading cycle increases. In the set test vibration times, the convergence trend does not appear. In contrast, the rock-fill materials have asymptotic volumetric behaviors under cyclic loading. On the basis of test data, a residual deformation model with eight parameters is proposed, which can well reflect the development of the residual strain. And the parameters can be calibrated by dynamic triaxial tests.