Experimental Study on Briquette Coal Sample Mechanics and Acoustic Emission Characteristics under Different Binder Ratios

[Image: see text] In order to find briquette coal with mechanical characteristics close to those of raw coal samples, we conducted triaxial compression experiments on raw coal and briquette coal samples with different proportions of cement contents. The mechanical characteristics and acoustic emission (AE) characteristics of the coal samples in the triaxial compression process were analyzed in detail. The test results show that the evolution of deformation and strength characteristics of the briquette coal and raw coal samples follow certain common laws. The confining pressure can improve the mechanical properties of both types of coal samples: as the confining pressure continues to increases according to the set values, the elastic modulus, peak strain, and peak strength of both samples show an increasing linear trend. When the value of the confining pressure setting was the same, the compressive strength of the raw coal samples exceeded that of briquette ones, but the deformation and shape variations of the latter exceeded those of the former. When performing triaxial compression experiments on both kinds of coal samples, the AE amplitude and counts showed a close correlation with the stress evolution curves. When the confining pressure was set to 5 MPa, 20% cement content briquette coal was seen to be the closest to raw coal samples regarding mechanical and AE characteristics.