关键词: 切顶卸压, 定向爆破, 防隔水煤柱, 不耦合系数, 爆破参数设计

Abstract: Abstract: The directional blasting top cutting and pressure relief technology has played an active role in the prevention and control of coal mine disasters. However, due to the complex and diverse geological conditions of coal mines, a set of completely universal blasting parameter design schemes has not been found to meet the requirements of different environments. In order to achieve the expected goal of directional blasting to protect the anti-separation coal pillars in the 3309 working face of a mine in Hebi, based on the actual geological conditions, two numerical models before and after roof cutting and pressure relief were established using FLAC3D software and ANSYS/LS-DYNA software. Different uncoupling coefficient directional energy-concentrating blasting models, the numerical simulation results show that the stress peak value after roof cutting and pressure relief is about 19% lower than that without roof cutting, and the distance between the peak position and the side of the 3309 coal pillar is obvious compared with that without roof cutting increase, the stress environment in the area near the 3309 upper groove is improved; taking the crack propagation length as the analysis index, considering the cutting effect and improving the utilization rate of explosives, the optimal charge structure with a decoupling coefficient of 1.7 as the normal section is adopted. According to the above numerical analysis results and the distribution of faults, a systematic and differentiated blasting parameter design was carried out for the 3309 upper trench. Industrial experiments showed that the directional blasting effect of roof cutting and pressure relief was good, which could meet the actual engineering requirements. A reference is provided for blasting protection of water-proof coal pillars.