Modeling pore-pressure evolution in hydrating minefill subjected to coupled thermo-mechanical loading

Despite the long-standing success of waste tailings recycling at shallower lithosphere, heat influx from the stifling environment of deep strata and ground squeezing due to aggravating deposit rheology have posed substantial challenges to traditional mine backfilling. To explore the minefill behavior in difficult geology settings, a new thermo-poroelastic model is developed in this study for characterizing the pore-pressure evolution in hydrating backfill subjected to coupled thermal perturbation and mechanical deformation. By scrutinizing the undrained pressure responses to a hierarchy of thermo-mechanical loading configurations, we investigated the relative contribution of heat exchange and wall convergence to the macroscopic minefill behavior. The result suggests that the backfill response could exhibit unique rate and path-dependence upon thermal loading due to the competing processes that govern the pressure evolution. Moreover, it shows that while rapid wall convergence would always induce significant pressure, thermal straining via heat exchange might still modulate substantially the pressure distribution when the temperature catalyzes considerable water expansivity. These findings could facilitate understanding of the complex backfill behavior in difficult geology settings, and thus have significant implications for adaptive tailings management to deep mining development.