Experimental study on proportion optimization of gangue-based new solid filling materials

Abstract

In order to develop new solid backfill materials, reduce the cost of backfill mining and improve the efficiency of backfill mining, the compaction characteristics of single material and two or more mixed materials based on gangue were studied in this paper. The macroscopic deformation of the material was analyzed by means of laboratory tests and theoretical calculations, the microstructure and phase composition were characterized by SEM and XRD. In the experiment of gangue particle size gradation optimization, the interaction of maximum particle size and gradation coefficient on compaction deformation was analyzed, and the optimal gradation combination is particle size D=30 mm, grading coefficient n=0.3. In the test of gangue-river sand compaction deformation characteristics, river sand was used to replace the fine gangue, which further improved the anti-deformation ability of the filling aggregate. In the test of solid mixed materials, based on the range and variance analysis in the principle of orthogonal repeated test, the optimal dosage of gangue was 65%, the optimal soil-cement ratio was 2∶3, and the influence of the dosage of gangue on the test results was highly significant. In conclusion, it was determined that the ratio of new solid filling materials was gangue: loess: fly ash =65%∶14%∶21%. In this case, the filling material had the strongest bearing capacity and the lowest filling mining cost.

Keywords

• gangue aggregate
• new solid filling material
• proportion optimization
• green mining
• micro mechanism