Abstract:
The mining activities have led to the penetration of interconnected roadways in the remaining coal pillars into the goaf, causing stress superposition effect and forming high stress concentration zones. Conventional pressure relief ways are difficult to eliminate large-energy rock burst events. Aiming at this problem, based on the limit equilibrium theory, a fully plastic pressure relief scheme for the roof is proposed: the ultimate stress around the roadway is released through roof drilling, forming a fracture zone around the hole (blocking the accumulation of elastic energy), and a spherical crack network is constructed by combining roof blasting. The on-site application results indicate that the maximum microseismic energy is decreased from 1.16 × 10
4 J to 4.38 × 10
3 J, with a decrease of 62.3%; But the fissures at 15-25 m of the remaining penetration section are not penetrated, with significant stress concentration. The conclusion shows that the roof full plastic pressure relief scheme can effectively reduce the impact risk, and the width of the pressure relief protection zone should not be less than 15 m, providing a technical reference for the penetration problem in similar high stress zone.