Study on the Alleviation of Mining-Induced Surface Deformation via Goaf Solid Waste Backfill Mining in a Deep Coal Mine

The deep mining of coal resources can lead to surface subsidence, thereby damaging the stability of buildings on the surface; however, this issue can be effectively mitigated through goaf backfilling with coal gangue and other solid wastes. In this study, the technical principles of goaf solid waste backfill mining are illustrated, and the surface movement and deformation patterns under different burial depths and compression rates are examined. Additionally, the monitoring and analysis of the roof subsidence and surface building conditions after goaf solid waste backfill mining are described. The results show that as the burial depth and compression rate increase, the maximum values of the surface subsidence and horizontal deformation gradually decrease. When the burial depth is between 800 and 1200 m, the design value of the compression rate for the goaf should be higher than 79%. The actual measurement results show that the maximum subsidence value of the roof after goaf backfilling is 635 mm, and the compression rate is about 80.8%, which is consistent with the theoretical design value. Hence, surface buildings are little affected by mining activities and are within the safe range for use.