On acoustic emission characteristics, initiation crack intensity, and damage evolution of cement-paste backfill under uniaxial compression

Abstract

The objectives of this study are as follows: To establish the relationship between the acoustic-emission (AE) parameters and mechanical-failure mechanism of tantalum-niobium tailings cemented paste backfill (CPB), to better understand the damage-evolution trend of CPB, to investigate the damage-evolution process of the CPB and AE time-effect mechanism, using an AE monitoring system combined with the stress–strain relationship, and to experimental study the damage-evolution and AE characteristics of tantalum–niobium tailing CPB under uniaxial compression. First, we discussed the crack-initiation and damage strengths, and then analyzed the AE characteristics of the CPB. Then, we proposed a damage variable based on the modified AE energy rate. We developed a CPB damage model based on the AE characteristics under uniaxial compression. The damage-evolution curve and equation of the CPB were obtained. Our results show: that the AE information reflects the damage to the CPB, which is closely related to the evolution of the internal microcracks and initiation, propagation, and penetration of new microcracks. The AE characteristics of the CPB can better describe its deformation and damage-evolution trend. The rationality of the damage model based on the AE characteristics is verified. The evolution process of the damaged CPB under uniaxial compression can be divided into three stages: initial damage stage, stable evolution of the damage and damage development stage, accelerated damages stage. The deformation to destruction of the CPB can be regarded as a gradual process. The entire process consists of the initiation and development of deformation and damage to the occurrence of macrocracks, and finally to failure.