Coupled discrete element-finite difference method for analyzing subsidence control in fully mechanized solid backfilling mining

Fully mechanized solid backfilling mining is a green mining'' approach recently developed to control strata movement and reduce solid waste in China. In this mining technology, compaction characteristics of backfill materials and strata movement mechanism are the key factors to achieve effective ground control. In this study, the granular characteristic of backfill gauge and the continuous rock movement process are simulated by discrete element and finite difference methods, respectively. The dynamic process of coal extraction, strata movement, and backfill body compaction is simulated by a coupled method. The coupled method successfully simulates and assists in the analysis of the interaction among gangue backfill, overlying strata, and coal pillar, as well as the effect of the backfilling quality on subsidence control.