Determination of an intrinsic proneness index for strainburst and its verification by true triaxial compression tests

Abstract

A part of the elastic strain energy stored in Class II rock will be converted into kinetic energy, which results in rock ejection after the peak stress. This part of the strain energy is the intrinsic potential energy for strainburst. Therefore, the strainburst proneness of the rock can be quantitatively estimated by the intrinsic burst energy density or the corresponding intrinsic ejection velocity. This study aims to validate the idea of using the intrinsic ejection velocity as a strainburst proneness index by laboratory true triaxial compression tests. In the study, servo-controlled uniaxial compression tests were conducted on six types of rock. The intrinsic burst energy density of these rocks was determined based on the stress–strain curves of the rocks obtained under uniaxial compression. The strainburst proneness of the rocks was then assessed. The same types of rock were then carried out single-free-face true triaxial compression testing to examine the rationality of the evaluation result.