Framework for Simulating Fracture, Ejection, and Restraint of Rock around a Mine Drift Subjected to Seismic Loading

Researchers at the National Institute for Occupational Safety and Health (NIOSH), Spokane Mining Research Division (SMRD) have developed a modeling framework, using commercially available software, for investigating the fracture and ejection of rock into underground mine openings caused by seismic loading and the restraint of this failed rock by the ground support system. The modeling framework presented here establishes the conceptual foundation and demonstrates the required capabilities for a model of a simple two-dimensional cross-section of a deep mine drift. The model has been used to investigate the effects of various wave parameters on the stability of underground excavations, both with and without ground support. Additionally, kinetic energy of ejected rock and energy dissipated by the ground support system are calculated and compared. Finally, the effectiveness of ground support, with and without containment, has been investigated. The main conclusion is that simplified empirical rockburst damage analyses based solely on volume of ejected rock are inadequate. The damage potential of a seismic event should be measured in terms of dynamic energy demand on the ground support. Further, peak specific power may be a better wave parameter to correlate with this demand. This research aids in the understanding of the effects of mining induced seismic loading on underground excavations and support systems, and may lead to improvements in miner safety.