Study on the dynamic response characteristics of surrounding rock in high stress tunnel under blasting disturbance

Abstract

This research delves into the mechanical response of surrounding rock in deep coal mine roadways under high static and dynamic loads, utilizing similarity simulation experiments. The focus is on the stress and displacement fields during distinct phases: original rock stress mining-induced stress, and blasting disturbance. Integrating fiber-optic technology for circumferential strain field examination, the study characterizes rock failure and investigates the rules governing stress wave propagation post-blasting in different coal rock masses, and the consequent dynamic roadway responses. The research results highlighted substantial stress reduction in roadway roofs and floors post-excavation, accompanied by a 50% expansion in stress concentration during mining. Post-blasting observations revealed extensive roof rock stress relief and increased stress along the roadway's left shoulder. Shallow surrounding rock showed expansion-deformation, with displacements in support structures due to shear slip faulting at the roadway shoulder. Stress wave disturbances induced tensile cracks on the roadway's left, leading to macroscopic fractures exceeding support field heights. The study observed pronounced tensile failures in rock roofs and floors, and combined tensile-shear failures at the shoulders. Stress wave attenuation is fastest from low to high impedance mediums, slower within identical mediums, and peak values escalate when transitioning from high to low impedance mediums, surpassing the roof's tensile strength and causing significant rock deformation and instability. Conclusively, blending the theoretical model of stress wave continuously passing through layered rock mass with static-dynamic load superposition principles, the research suggests blasting parameter optimization for enhanced impact reduction and robust joint support in roadway constructions.

Keywords

• high static load
• strong dynamic load
• tunnel surrounding rock
• blasting disturbance
• high stress