Rheological model of viscoelastic–plastic geogrid-reinforced tailings

A non-linear, four-parameter viscoelastic–plastic model is proposed to characterise the mechanical properties of geogrids under long-term and low-stress load. In this study, a simplified rheological model of viscoelastic–plastic geogrid-reinforced tailings was established. The stress analysis of the whole reinforced tailings complex was divided into two stages. The time for the tailings to produce plastic deformation (plastic arrival time) was the cut-off point for the two stages. The first stage (E-VP model) corresponded to the elastic state of tailings during which the stress of geogrids decreased with time, causing the recombination of microstress in tailings until they reached the yield condition. The second stage (P-VP model) corresponded to the plastic state during which the stress of geogrids remained constant, whereas the overall strain of the reinforced complex increased as a result of the geogrid creep. The force of the reinforced complex changed rapidly from the first to the second stage. Owing to the small deformation in the first stage, the overall strain of the complex was mainly caused during the second stage. The plastic arrival time t _p of the reinforced tailings complex was significantly influenced by the plastic strain ϵ _p and viscosity coefficient η of geogrids and internal friction angle φ of tailings.