Three-Dimensional State-Dependent Fractional Plasticity Model for Soils

摘要

To capture the nonassociated state-dependent constitutive behavior of soils subjected to different initial densities and pressures, a novel approach, the fractional-order (alpha) plasticity, was developed, which extends the previous alpha plasticity model for more general loading conditions by using the transformed stress method. The developed model was found to have the following key features: (1) state dependence of the three-dimensional (3D) stress-dilatancy relationship was simulated without using empirical state parameters; (2) 3D nonassociated plastic flow rule was captured without using additional plastic potentials; and (3) state-dependent plastic hardening and softening was characterized without using state parameters and plastic potentials. To validate the extended 3D model, a series of laboratory test results of different soils, for example, rockfill, sand, and clay, under different loading paths were simulated, where a good agreement between the model predictions and the corresponding test results can be found. (C) 2019 American Society of Civil Engineers.