Mechanical properties and energy evolution of cemented tailings-rock powder backfill under uniaxial compression: effect of rock powder type and content

Economic investment and mechanical characteristics represent primary limitations to the widespread adoption of cemented tailings backfill. This study introduces an approach of using quarry waste to generate rock powder, which is subsequently mixed with tailings to produce cemented tailings-rock powder backfill (CTRPB). This method achieves cost efficiency while facilitating synergistic waste management. Through uniaxial compression testing, the influences of rock powder type and content on the mechanical behavior, failure modes, and energy transformation of CTRPB were examined. A piecewise damage constitutive model was developed to explore damage progression mechanisms. Findings demonstrate that the incorporation of rock powder markedly improves the deformation resistance of CTRPB. Both uniaxial compressive strength (UCS) and elastic modulus exhibit an initial increase followed by a decline as content rises, with optimal levels and enhancement effects differing across various rock powders. The failure process of CTRPB encompassed four distinct phases, where rock powder amplified post-peak energy release and fragmentation behaviors. Energy assessment indicated that rock powder significantly boosted energy storage and dissipation capacities, elevating total energy density, elastic energy density, and dissipated energy density by 252.17%, 213.87%, and 478.99%, respectively. The formulated piecewise damage constitutive model correlated well with experimental data in the pre-peak regime. Damage evolution may be categorized into four stages, and damage values can act as indicators for assessing failure conditions in the resource utilization of mining waste and rock powder-tailings backfill technology. This research offers a theoretical foundation for the resource-oriented use of mine waste and rock powder-tailings backfill technology.