Study of acoustic emission during deformation of rocks under conditions of a complex axisymmetric stressed state

Abstract

1. A study of the laws for AE behavior with a complex stressed state has shown that the nature of the dependence for the number of AE signals depends markedly on the ratio of stressed state components for the specimen. 2. Localization is detected for the maximum AE intensity in a specific and quite narrow range of axial strains. The position of this range is almost independent of the level of side pressure and it corresponds to the transition zone from material densification to loosening. 3. The existence of a range for the maximum AE intensity is due to formation of cracks of tensile origin. The range of minumum AE intensity corresponds to the shear mechanism of deformation with a growing residual increase in material volume (quasiplastic deformation). 4. The amount and nature of AE behavior in the range of maximum intensity depends on material structure. For plastic materials the maximum is expressed more weakly than for more brittle materials. Material porosity leads to expansion of the zone of the maximum and to asymmetry of its shape. 5. The dependence of maximum AE intensity on the amount of specimen side pressure has been analyzed. It has been shown that for plastic materials the logarithm of AE intensity falls linearly with an increase in σ3.