Master crack types and typical acoustic emission characteristics during rock failure

Abstract Acoustic emission (AE) signals contain substantial information about the internal fracture characteristics of rocks and are useful for revealing laws governing release energy stored therein. Reported here is evolution rock failure with different master crack types as investigated using Brazilian splitting tests (BSTs), direct shear (DSTs), uniaxial compression (UCTs). The AE parameters typical modes each type were obtained, mechanism discussed. From observed changes in parameters, process exhibits staged intensification. scale level activity BSTs significantly lower than those DSTs UCTs. proportion tensile cracks was 65%–75%, while proportions UCTs 75%–85% 70%–75%, respectively. During loading under conditions, accompanied by an increased number cracks. amplitude, duration, rise time signal from larger when dominated rather ones, most medium- high-energy had medium to low frequencies. After calculating proposed amplitude ratio, found exceed that at same scale.