In mine cemented backfill, the pipeline transportation and mechanical properties of backfill materials are pivotal for the successful application of the backfill system. This study therefore investigates the self-flowing pipeline transportation and mechanical properties of full-tailings cemented backfill materials through L-pipe and strength tests. The variation patterns and microscopic mechanisms of backfill properties were analyzed and the feasibility of its industrial applications was discussed. Results show that increasing binder content and slurry mass concentration led to decreasing yield stress and increasing pipeline transportation resistance. As the viscosity and strength of backfill body increased, the maximum filling gradient was negatively correlated with pipeline transportation resistance. Intensified interparticle attraction and exacerbated interparticle friction were the intrinsic causes for the rise in yield stress and viscosity, as yield stress exerted a dominant influence on pipeline transportation resistance than viscosity. Individual or simultaneous increase in test factors leads to increased quantity of hydration products, reduced pore area, improved structural compactness and strength. With binder content of 210 kg/m³ and slurry mass concentration of 68 %, the system exhibited both industrial adaptability and economic efficiency, achieving a 4.11 % surplus in maximum filling gradient and 28 d strength of 2.08 %. This study offers references for self-flowing transportation theories and technologies of cemented backfill materials.

To investigate the actual dynamic fracture process and energy dissipation mechanisms of coal under triaxial loading conditions, a visual experimental study was conducted using a self-developed multi-field coupled Split Hopkinson Pressure Bar (SHPB) testing system. This research systematically examined crack evolution characteristics in coal samples under varying water confining pressure conditions. The relationships between dynamic mechanical parameters (impact velocity, strain rate, and water confining pressure) were quantitatively analyzed, along with the influence of water confining pressure on energy absorption, conversion, and release processes during coal failure. The research results show that the dynamic strength of coal shows obvious strain rate effect under water confining pressure environment. There is a good quadratic function relationship between water confining pressure and the dynamic strength of coal mass, and the failure strain of coal samples shows a decreasing trend with the increase of water confining pressure. With the increase of water confining pressure, the fracture mode of coal mass will change from "axial splitting failure" to "compression-shear failure". The greater the impact load, the higher the total energy input to the coal body and the dissipated energy used for damage and deformation, and the more serious the deformation of the coal body. With the increase of water confining pressure, the total input energy shows a trend of gradual increase, and more energy is required from the outside when the coal body is damaged.