Failure mechanism and damage constitutive model of cemented tailings backfill with different cement-tailings ratios under uniaxial compression

• Lower cement-tailings ratios significantly reduce the strength and deformation resistance of cemented tailings backfill (CTB), accompanied by decreased elastic energy accumulation at peak stress and reduced dissipation energy in the post-peak stage. • A modified damage constitutive model incorporating a correction factor accurately simulates the entire uniaxial compression process of CTB across different cement-tailings ratios, outperforming classical models. • Particle size distribution and acoustic emission analyses reveal that lower cement-tailings ratios produce coarser particles, intensifying shear-related acoustic emission signals and leading to more pronounced macroscopic shear failure. • The findings provide theoretical support and practical guidance for optimizing CTB mix ratios to enhance underground goaf stability and mining safety.