Deformation failure and acoustic emission characteristics of continuous graded waste rock cemented backfill under uniaxial compression

Abstract

In order to study the effect of aggregate particle size on damage and failure of cemented backfill, uniaxial compression tests were carried out on waste rock cemented backfill with different Talbol particle size gradations using YZW-30A rock direct shearing instrument. The characteristic parameters of acoustic emission (AE) of the specimens during loading process were monitored, and the damage evolution and failure mode of waste rock cemented backfill with different particle size gradations were discussed. The results show that：With the increase of Talbol particle size gradation index n, the uniaxial compressive strength of backfill body first increased and then decreased, and the failure mode of backfill body gradually changed from shear failure to tensile failure. The cracks on the surface of specimens are more and damage is more serious with the increase of the gradation index n. With the increase of the Talbol gradation index n, AE energy rate is more active, and the cumulative AE energy rate is higher. The AE energy rate increases rapidly in the plastic development stage, and reaches maximum value before and after the peak stress, which can be used as the precursor to judge the failure of waste rock cemented backfill. According to the test results, the damage model and constitutive equations of waste rock cemented backfill with different Talbol particle size gradations are established, which can provide engineering guidance for filling mined-out areas with waste rock to ensure safe production of mines.