Mechanical Behavior and Acoustic Emission Characteristics of Cemented Tailings Backfill with Varied Water Loss

Superfine tailings-blast furnace slag backfill (SBB) has been designed for recycling solid waste in mines and decreasing the cost of the overall process. During the mining process, the decrease of adjacent ore rock causes backfills water loss and its exposure to air. The mechanical behavior of SBB was investigated by uniaxial compressive strength (UCS), acoustic emission (AE) characteristics, and numerical simulations. Wavelet transform and fast Fourier transform were used to obtain the frequency components of AE events during the whole loading. The results indicated that the main frequency components of AE signals in SBB were close to 100 kHz, while medium and high-frequency components could be also distinguished for specific specimens with certain water loss. Particle flow code (PFC), a typical discrete element method (DEM), could reproduce the stress–strain curves of SBB specimens with varied water loss and simulate AE events of SBB during the loading. For the whole loading process, both indoor experiments and numerical simulation showed that AE events and simulated AE clusters began in the early stage of loading, which indicated that the crack initiated from a low stress level.