Constitutive modeling of creep behaviors of coarse-grained materials

The creep empirical model, which is characterized as an exponential function, is proposed for coarse-grained materials (CGMs) based on analyses of their creep evolution, and the final creeps are described by the state-dependent formulations. Within a constitutive framework of coupled breakage and friction dissipation (CBFD), an elasto-visco-plasticity model is developed for CGMs by incorporating the above-mentioned creep formulations into the hardening rules of post CBFD elasto-plasticity model. The reasonability and reliability of this model are preliminarily verified using the test data of a series of triaxial creep tests on CGMs. The numerical simulation about a high embankment (HE) filled with CGMs shows that: (1) The temporal and spatial evolution of stresses predicted by this model in the HE agrees with the measured trend of stress change in the HE projects; (2) Within 3 years of pos construction, the model predictions of settlement in the HE are in good agreement with the in-situ measured results. (3) The creep effect of CGMs is remarkable, and it is a significant factor which results in the long-term post construction settlement of HE filled with CGMs.