AE source location considering the stress induced velocity anisotropy in rock

In this study investigated was the variation of elastic wave velocities during the uniaxial compression tests, and its location analysis program was modified considering anisotropy. Then, the real fracture plane in the rock specimens were compared with those from A.E. source by qualified program. As the stress level increased under uniaxial compressive test, the wave velolcity immediately before the failure increased 17% in parallel and decreased 26% in normal to the loading direction, respectively. As the stress level increased A.E. source from the modified program coincided nearly with the fracture locations observed in the test specimens for the anisotropic analysis, but not isotropic analysis owing to velocity variation. It was found out from the analysis of A.E. source that at each different stress level the shear microcracks initiated from the center of specimen and propagated upward and downward.