Modeling Resilient Modulus of Unbound Granular Materials under Repeated Loading

Resilient modulus of unbound granular materials is a key design parameter for mechanistic empirical pavement design. But the complexity of the affected factors has made it challenging and difficult for practical designers and researchers to find an appropriate model to describe the entire stress-strain response where the plastic deformation is accumulated during the repeated loading condition. A cyclic plasticity model based on fuzzy sets plasticity theory is presented in this paper to model the resilient modulus and permanent strain behavior of unbound granular materials under repeated loading. The concept of the fuzzy set plasticity is first introduced, followed by its model formulation and numerical simulation. The model was calibrated against a resilient modulus testing data of a typical Missouri soil. The numerical results showed that the fuzzy set model is capable of mimicking and simulating the resilient and permanent responses of unbound granular materials under repeated loading.