A rheological model to simulate the shear creep behavior of rockfills considering the influence of stress states

Rockfills have been extensively used in the construction of high-fill embankments and dams, which exhibit complex time-dependent behavior. This paper presents a rheological model to simulate the shear creep behavior of rockfills based on the classic Burgers model, in which a nonlinear elasto-damage unit, a modified Newton unit, and a modified Kelvin unit are connected in series. By analyzing the results of large-scale triaxial creep tests on different rockfills, the influence of stress states (i.e., the deviator stress level and confining pressure) on the shear creep behavior of rockfills is revealed. A method to modify the key model parameters is proposed to consider such influence and is incorporated into the proposed model. Furthermore, the accelerated creep behavior of rockfills is reproduced by a nonlinear elasto-damage unit. Despite its simplicity, the model can simulate the essential aspects of the shear creep behavior of rockfills, and reasonable consistency is found between the simulation results and the large-scale triaxial creep test results.