Bounding-Surface Plasticity Model for Drained Cyclic Behaviors of Cohesionless Soil

To describe the drained behaviors of cohesionless soil through a concise constitutive approach, a single-surface model is constructed on the concept of the bounding surface. Based on observations from tests, the maximum prestress memory surface and the radial mapping rule are adopted to take the effects of loading history into consideration. The state-dependent dilatancy is introduced to reflect the influence of density and stress state on the volumetric change. The accumulated plastic strain involved in the function of the hardening measure is used to evaluate the effects of soil fabric changes on soil stiffness. Applying a simplified nonassociative flow rule, which builds upon the state-dependent dilatancy, enables accurate prediction of the plastic volumetric strain. Then the triaxial formulation is generalized to the multiaxial stress space. Compared with existing models, the present model involves only one surface, thereby avoiding lengthy algebraic operations. In addition to the basic parameters calibrated through monotonic tests, only three additional parameters are required to reproduce the cyclic response. The performance of the model is investigated by simulating both monotonic and cyclic tests. By comparing the model predictions with the experimental data, it is demonstrated that the model is capable of capturing the drained behaviors of cohesionless soil.