Anisotropic Hardening Plasticity Model for Sands

An anisotropic hardening plasticity model based on the concept of bounding‐surface plasticity is formulated for prediction of the three‐dimensional stress‐strain‐volume‐change behavior of sand. The model employs the anisotropic invariants of the second‐order stress and rotational tensors as a formalism to account for the material anisotropy. The rotational tensor is linked to the fabric ellipsoid of particulate sand. The model is shown to satisfy the objectivity requirement from the form‐invariance principle. Twelve material constants required in the model can be determined from triaxial experiments. A study of the three‐dimensional behavior of Hostun sand serves as a basis for evaluating the capability of the model. Overall, the model's predictions are acceptable and can capture the variations of soil behavior with the rotation of principal stress direction and the relative magnitude of intermediate principal stress.