Quantitative analysis of ultra-close fault dynamic rupture and seismic risks in deep roadway excavation

This study presents a comprehensive numerical analysis of dynamic rupture and fault-induced seismic risks in deep roadway excavation environments, focusing on near-fault conditions. A quantitative assessment was conducted for faults within 5 m of the roadway, a critical range for evaluating heightened seismic risks. Our results demonstrate that within this proximity, fault slip and seismic moment increase significantly, with peak fault slip reaching 17.1 mm and seismic moment exceeding 3.9 × 10¹⁰ Nm. One of the key findings is the amplification effect of wave reflections along the exposed roadway surfaces, particularly in areas near the roof and sidewall. The peak particle velocity (PPV) on the roof reached 0.40 m/s, while the right sidewall recorded 0.49 m/s, highlighting elevated seismic impacts in these critical regions. The study also validated the linear slip weakening model, confirming its effectiveness in capturing the transition from static to dynamic friction during rupture and providing theoretical grounding for observed fault behavior. This research contributes novel insights into the fault-induced dynamic rupture process, particularly in ultra-close fault conditions, and emphasizes the need to account for fault proximity, frictional properties, and wave reflection in seismic hazard assessments. Our findings offer a foundation for improving seismic-resistant design in deep excavation operations, particularly in faulted geological settings.