Evaluation of Crack Initiation and Damage in Intact Barre Granite Rocks Using Acoustic Emission

Abstract

Understanding of crack initiation and propagation in intact rocks is extremely important in rock engineering. The purpose of this study is to identify the different stages of cracking in intact prismatic rock specimens using the acoustic emission (AE) monitoring technique. The testing program involved uniaxial compression testing of Barre granite specimens with eight AE sensors epoxied on the planar surface as well as sides of the specimen. During the experiments, crack induced due to the uniaxial loading was monitored by AE parameters. The rate and the cumulative plots of the AE hit and energy reflected the various stages of crack initiation and coalescence. The study focused on the determination of crack initiation and crack damage stress thresholds using cumulative AE hit method (CAEH) and cumulative AE energy method (CAEE), respectively, and both methods allowed the identification of several cracking stages, including the crack closure, elastic deformation, crack initiation, microcrack growth (stable growth), crack damage, and unstable crack growth. © 2020 ASCE. .