Multiphysics Modeling and Simulation of Strength Development and Distribution in Cemented Tailings Backfill Structures

Cemented paste backfill structures are complex underground cementitious structures. After fresh cemented paste backfill (CPB; a mix of tailings, binder and water) is poured into underground stopes (mined-out voids), its strength which is a key mechanical design criterion of CPB structures, gradually develops with time. The development of CPB strength is governed by the coupled thermo-hydro-mechanical-chemical (THMC) processes in the CPB mass. Therefore, to assess and predict the changes to CPB strength and its distribution within the CPB mass, a multiphysics model on CPB strength is proposed in this study, and has been successfully validated against a series of experimental data. Then, the validated model is used to investigate the changes in the strength of CPB structure under various influential factors in the field (e.g., backfilling strategy, inclination angle of stope, and filling rate). The obtained results provide better insight into the process of the strength increase and spatial distribution in CPB structures as well as contribute to more cost-effective engineering designs of CPB structures.