Evolution of Mechanical Properties and Acoustic Emission Characteristics in Uniaxial Compression: Raw Coal Simulation...

Simulation of raw coal using briquette coal samples with similar mechanical properties and acoustic emission (AE) characteristics is quite instrumental in various analog models. Uniaxial compression with AE monitoring of raw coal and briquette coal samples with a 7% content of different types of binders was conducted using an RMT-150B electrohydraulic test bench. The compression process could be split into compaction, elastic, plastic (yield), and failure stages, with intrinsic AE features. Except for the MA group briquette coal samples, the AE signal average values of briquette coal samples always exceeded those of the raw ones. The maximal and minimal cumulative values of uniaxial compressive strength, peak strain, and AE signal were observed in briquette coal groups, containing 7% of coal tar or water, respectively. Measurements via the similarity method based on the Euclidean distance were used to construct space vectors, with the peak strength, peak strain, and elastic and deformation moduli of briquette and raw coal samples as characteristic values. The mechanical characteristics and deformation patterns of the briquette coal group with 7% rosin as a binder had the best compliance compared to those of raw coal samples, which makes them lucrative for further analog modeling of the raw coal behavior.