Acoustic emission analysis of blaxially loaded rock

Strainbursts are common around deep mining and civil engineering underground openings. Few biaxial compression tests have been applied to simulate the peripheral state of stress and strainbursts. The results of acoustic emission monitoring of laboratory norite biaxial tests are outlined in this article. All samples failed suddenly and violently in brittle shear; rock spalling from the free face occurs before failure. This mirrors highly stressed opening conditions. Acoustic event numbers, amplitude, signal frequency and source location obtained in the tests are useful in identifying the various stages of failure mechanisms, the effect of confinement on spalling, and final sample fracturing. With more laboratory work, these parameters can compared to microseismic monitoring at the periphery of underground openings in anticipation of failure.