DOI: 10.1061/jmcee7.mteng-23382 ISSN: 0899-1561
Energy Evolution and Acoustic Emission Characteristics of Tailings Backfill with Different Fly Ash Content
Daotan Wen, Kang Zhao, Qizheng Huang, Yichen Shi, Chao Ma, Yinchen Feng Abstract
In this paper, with the help of acoustic emission (AE) monitoring technology, the mechanical properties of tailings backfill under uniaxial compression with three kinds of fly ash (FA) content, slurry concentration of 70%, and ash-to-sand ratios of
1
∶
6
and
1
∶
8
, as well as the energy evolution law of the failure process and the characteristics of AE response, were investigated. The study shows that the failure process of the three FA content backfills can be divided into four stages based on the stress–strain curves, and the specimen failure forms are all splitting failures. The energy evolution and distribution characteristics of the three FA content specimens all have phase changes. The smaller the FA content, the higher the proportion of elastic strain energy in the total input energy of the specimens, and the opposite is true for the dissipated energy, which has a better energy storage performance and a lower intensity of crack evolution before the stress peak. The ringing count responses of 0% and 40% FA-doped specimens were concentrated after the stress peak, and their localized damage failures were intensified after the stress peak; 100% FA-doped specimens were concentrated before the stress peak, and their localized damage failures were intensified before the stress peak. The Bradley model can well characterize the root-mean square–average signal level (RMS–ASL) curves for each FA doping specimen, and as the FA content increases, the fitting parameter
a
decreases and the rate of growth of the RMS–ASL curves also decreases. The rise time/amplitude (RA)-AF data points of the three fly ash (FA)-doped specimens have a high probability density of clustered regions for tensile cracks, which have a higher percentage of signals than shear cracks. The results of the study can provide a scientific reference for the use of FA cemented backfill in mines and promote the win-win situation for the stabilization of the mining airspace and the recycling of tailings and FA solid waste.