Mechanical properties, deformation response, energy evolution and failure pattern of stratified cemented tailings backfill under triaxial compression

• Incorporating an enhance layer significantly increases the peak deviatoric stress of stratified cemented tailings backfill (SCTB) by up to 50.4% at a thickness ratio of 0.3 under 50 kPa confining pressure. • The elastic energy storage capacity of SCTB improves by up to 85.2% with increasing enhance layer thickness ratio, indicating enhanced energy absorption and stability. • The presence of an enhance layer alters the failure mode from shear failure to splitting bulging and shear bulging, effectively blocking crack propagation and improving structural integrity. • The cohesion of SCTB is more sensitive to enhance layer position and thickness ratio than the internal friction angle, providing key insights for optimizing backfill design in subsequent stoping mines.