Microscopic and Acoustic Interpretations of the Physics of Rock Burst and the Difference in Fracturing Patterns in Class I and Class II Rocks

Abstract The progressive microcracking processes in a burst-prone Class II rock, Kuru granite, and non-burst-prone I Fauske marble were investigated, aiming to reveal the physics of rock burst difference burst-proneness rocks. cylindrical specimens granite uniaxially loaded various levels both pre- post-peak stages, which was monitored by Acoustic emission technique. After that, thin sections parallel perpendicular loading direction prepared from each unloaded specimen. observed intergranular intragranular cracks quantitatively analyzed their length, width orientation as well fracturing modes. It found that extensional cracking dominated damaging process pre-peak stage. In stage, increased abruptly. specimen finally failed splitting. Intragranular shear calcite marble. A number fractures formed along fracture zone. deduced under low confining stress, σ 1 , dissipated relatively small portion strain energy remaining released for ejection. cracking, entire energy.