Numerical Simulation of Consolidation Behavior of Large Hydrating Fill Mass

Abstract

Abstract Underground mined-out voids need to be backfilled for the stability of the surrounding rock and also to increase ore extraction from adjacent pillars. One of the relatively newer means is cemented paste backfilling, which has been extensively adopted in underground mining operations around the world. During and after the placement of cemented paste backfill (CPB) into stopes, complex multiphysics (thermal, hydraulic, mechanical and chemical) processes take place in the large mass of CPB and could affect its consolidation behavior. An analysis of the consolidation process in CPB mass is essential for the assessment of CPB behavior and cost-effective designs in practice. In this paper, multiphysics simulation of the consolidation behavior of CPB mass is performed under different conditions, including the mixture recipe, and backfilling, drainage, surrounding rock and curing conditions. It is found that the in situ consolidation behavior of CPB structures is a function of the multiphysics processes that occur in the cementing backfill mass. Moreover, the rock mass conditions, including the geometry and rock wall roughness, influence the consolidation process of CPB structures. Cement content, curing time and backfilling rate play a crucial role in the consolidation process of CPB. The obtained results can facilitate a better understanding of the consolidation behaviour of CPB for backfill designers and engineers, and thus contribute to enhance the engineering of CPB structures.