Modified anisotropic generalized plasticity model for rockfills based on spatial mobilized plane

摘要

A modified anisotmpic generalized plasticity model for rockfills is developed by improving the previous version. The improvements include a new anisotmpic variable omega', a new anisotropic state parameter xi', and a modified dilatancy equation. The omega' is constructed on the basis of the angle between the spatial mobilized plane and compaction plane and can degenerate to zero in the case of vertical compaction. The anisotropic state parameter xi', which includes the effects of omega' and mean principal stress, can simulate the initial moduli changing with the direction angles of major principal stress under different confining pressures. The modification of the dilatancy equation including xi' and correction term can reduce the overestimation of the volumetric contraction in the initial shear stage. To verify the modified model, triaxial tests for rockfill materials with different confining pressures and different direction angles are simulated and analyzed. The simulation results are in good agreement with the test values. Compared with the original model, the modified model is more effective in describing the mechanical properties of rockfill materials, especially in the initial shear stage, and more practical.