Protection Technique of Support System for Dynamic Disaster in Deep Underground Engineering: A Case Study

During excavation in a deep tunnel, dynamic disaster is an extremely severe impact failure. The necessity of an energy-absorbing support system is analyzed for different characteristics of dynamic disaster (rockburst) failure. The energy-absorbing support system design includes a combination of early-warning, energy-absorbing bolts, and other components. This support system is designed to meet the energy requirement of a rockburst disaster based on an early warning. The energy-absorbing rockbolt uses the stepwise decoupling technique to realize the brittle-ductile transition of the structure, which is referred to as a stepwise decoupling rockbolt (SD-bolt). The ultimate force, ultimate deformation, and energy were calculated as 241 kN, 442.3 mm, and 95.89 kJ under static pull-out load. Monitored by a microseismic system, the support system was tested by moderate rockburst disaster impact on site. Considering similar rockburst disaster failure cases, this energy-absorbing support system can reduce rockburst disaster damage to a certain extent and improve overall safety during deep engineering construction.