MICROMECHANICS MODELING FOR STRESS-STRAIN BEHAVIOR OF GRANULAR SOILS .2. EVALUATION

A micromechanics-based constitutive model for granular material is evaluated. The predicted stress-strain behavior for idealized material is compared with that observed from experiments for sands. Under small strain conditions, the model capability is evaluated for predicting initial moduli, secant moduli, and damping ratio with the material is subjected to low-amplitude loading. Under large strain conditions, the model capability is evaluated for predicting the stress-strain strength behavior when the materia is subjected to various stress paths. In the predictions, three material parameters are used to represent the stiffness and friction of the interparticle contact. Although the predictions are made for idealized spherical particles, the predicted behaviors are found to be remarkably similar to that observed for sands in experiments. The potential capability of the proposed constitutive theory is illustrated, and the model performance is discussed on various aspects of granular material behavior, such as stress-induced anisotropy, path dependency, plastic flow, dilatancy, and noncoaxial behavior under rotation of principal stress.