Study on acoustic emission characteristics of muddy limestone under brazilian splitting tests at various loading rates.

To explore the correlation between Acoustic Emission (AE) and fracture response characteristics and loading rates in the failure and instability of muddy limestone, the borehole near the Baode Coal Mine Power is taken as the research object, Brazilian splitting tests combined with acoustic emission measurements were conducted on muddy limestone specimens at various loading rates, mechanical parameters, AE phenomena, and fracture response features of muddy limestone were analyzed. The results demonstrate the average tensile strength, elastic modulus, peak strain, and residual strength of the rock specimen exhibit stage-dependent loading effects. At low loading rates, ample deformation and damage occur within the rock, resulting in more severe fragmentation, with increasing loading rate, rock specimens gradually evolve from shear-tensile failure dominated by shear-tensile mechanisms to tensile failure.As the loading rate increases, distinct AE signals occur earlier, both cumulative ring count and cumulative energy first increase and then decrease, and the AE energy changes from isolated event type to cluster event type.The AE b-value shows a gradual decreasing trend.