Acoustic Emission Monitoring Of Layered Sandstone Under Brazilian Test Conditions

Results are presented of an experimental study of layered sandstone blocks under Brazilian test conditions with acoustic emission monitoring. The diagrams of cumulative AE hits of studied layered sandstone can be divided into two successive semi-parabolas; each due to the fracturing of different constitutive minerals. The AE hits registered from the early stage of loading that produce the first semi-parabola are mostly related to the cleavage activation of the weak minerals (carbonate and mica), while the second semi-parabola corresponds to the activation of quartz bonds (and sometimes fracturing of quartz grains). It is observed that in different rock blocks as the weak minerals percentage becomes smaller the first semi-parabola of cumulative AE hits becomes smaller and less pronounced, even disappear.