Test on mechanical properties of solid backfill materials

Abstract

In this paper, characteristics that the overlying strata movement is controlled by solid backfill materials are illustrated in the coal mining with solid backfilling method. In addition, the mineral and chemical composition, density and moisture content of waste rock and fly ash are tested and analysed by physical–chemical treatment. By investigating the compaction deformation and time-dependence characteristics under different ratios of waste rock to fly ash, the optimal ratio of the mixture is obtained to achieve the smallest deformation, and results show that deformation mainly occurs in the initial period of loading. Combining the results of density test on site backfill materials, it indicates that the mass ratio of backfill materials to coal mining is 0·83 in order to ensure the effective of controlling the overlying strata in the coal mining with solid backfill method. The findings of the research provide references for the selection of solid backfill materials in coal mining.