Development of a New Mechanistic Empirical Rutting Model for Unbound Granular Material

Abstract

AbstractThis paper proposes a new mechanistic-empirical rutting (MER) model to evaluate the permanent deformation (PD) behavior of unbound granular material (UGM). To characterize the stress dependence of rutting behavior in UGM, the MER model incorporated a softening stress term and a hardening stress term into the Tseng-Lytton model, which is based on the Drucker-Prager plastic yield criterion. Repeated load triaxial tests were performed on two types of UGMs in this study, employing seven stress states to calibrate the model coefficients, and two stress states to validate the accuracy of the model predictions. The correlations of the two incorporated stress terms with the accumulated permanent strains were established based on the triaxial test results. It was found that the correlations are fitted by power functions with 0.97–0.99 R2 values. The proposed MER model was compared with the existing UGM rutting models, including the MEPDG model, Korkiala-Tanttu model, and UIUC model in terms of differences ...