Strength, deformation and crack evolution behaviour of cemented tailings backfill composite structures with different strength ratios

This work comprehensively investigated cemented tailings backfill composite structures (BCS) mechanics and crack evolution mechanisms. A new crack classification method combining Gaussian Mixture Modeling (GMM) and Moving Average Filtering is proposed for the BCS acoustic emission RA-AF dataset. The findings indicate that the upper CTB did not incur significant damage following BCS destruction, enabling BCS to maintain a certain bearing capacity post-failure. The compressive strength of BCS often approximates that of CTB monomers with a lower cement-tailings ratio (this trend diminishes as the upper CTB’s strength increases), and the loss of bearing capacity in BCS is attributed to the failure of CTB monomers with lower strength. The deformation damage in the upper and lower CTB displays a cooperative characteristic throughout the loading-induced damage process, with the axial and transverse strains in the lower CTB surpassing those in the upper CTB. Analysis results from GMM reveal that the compression failure process of BCS is predominantly characterized by tensile failure, with minimal shear failure. The propagation of cracks in the lower CTB exerts a certain influence on the crack evolution of the upper CTB. The findings offer a novel perspective on discerning the fracture evolution behavior of materials.