Towards improved design of rock reinforcement systems in burst-prone rock masses

Increased understanding of the amount of released energy rock support systems are subjected to allows for more convenient excavation design and risk mitigation. As it is often not practicable to prevent the occurrence of strain bursts mitigation measures are required so that the consequences can be kept at an acceptable level. Therefore, the energy released with the failing rock must be dissipated by a rock reinforcement system to obtain a stable situation after a burst. To date quantification of the released kinetic energy (E-tot) is assessed based on the kinetic energy of the ejected rock. However, the derivation of required input parameters for this approach has shown to be inconvenient. This paper introduces a concept methodology to quantify the energy release associated with strain bursting in underground excavations based on the size of the failure zone and the elastic strain energy stored in the rock mass prior to failure.