Mechanical Response of Barricade to Coupled THMC Behavior of Cemented Paste Backfill

Abstract

Cemented paste backfill (CPB), which is prepared by mixing tailings, binder and water, is widely used in underground mines for waste management and ground control. Since the CPB is delivered into mined-out areas in the form of fluid, a barricade needs to be constructed for retaining it during the process of its filling and hardening. Therefore, the barricade should have enough mechanical stability to ensure the safety of the backfill operation. The behavior of CPB, which is influenced by the thermal, hydraulic, mechanical and chemical (THMC) coupled processes, acts on the barricade and thus affects its mechanical response. In the present study, a numerical model is developed to predict and analyze the barricade mechanical performance in response to the coupled THMC behavior of CPB. The validity of the proposed model is then verified against two field case studies. Acceptable agreement between the model prediction results and in situ monitoring data proves the capability of the developed model in simulating the barricade pressure and displacement. Then, the validated model is used to investigate the effect of filling strategy on the barricade displacement. The obtained results can contribute to a better understanding of the barricade performance under various backfill conditions.