Study on artificial reinforced concrete roof's thickness for subsequent backfilling method in fragmented rock mass...

In response to issues such as roof collapse during the mining process of fragmented rock mass deposits, the application of artificial reinforced concrete roofs (ARCRs) combined with an effective roof-contact filling (RCF) method is considered for open stope mining with subsequent backfilling. The fragmented ore body in the Jinshandian Iron Mine is taken as the background. The thin plate model and simply supported beam model are combined to calculate the reasonable thickness range of the ARCR. Additionally, FLAC3D numerical simulations are adopted to investigate the stope stability under different thicknesses of ARCRs and various RCF conditions at the optimal ARCR's thickness. The combined theoretical analysis and numerical simulation results indicate that: (1) The safe thickness of the ARCR is 4-5 m, which ensures good stability of the artificial roof. (2) The RCF by expansive backfill (EB) can significantly improve the stability and stress distribution of the stope, reduce stress concentration, and minimize roof settlement and floor heaving. (3) The EB provides reverse support force through expansive stress, effectively controlling the compressive stress on the artificial roof and enhancing overall support performance. The research results could provide a theoretical basis for the safe and efficient mining of deep fragmented rock mass deposits.