工作面末采段深孔预裂切顶护巷技术研究

针对工作面进入末采阶段后,由回采作业引起的采区大巷围岩变形失稳现象,基于超前支承压力分布力学模型,运用极限平衡理论及半平面解法,理论计算得出超前支承压力峰值位置、影响范围及采区大巷处应力大小,分析大巷处应力增高主要是由于工作面上覆岩层较为完整,加剧了超前支承压力的向前传递而引起的.因此,提出采用深孔预裂爆破技术,利用爆...

Research on the technology of deep hole pre-crack cutting roof and roadway protection in the final section of isolated working face

In view of the deformation and instability phenomenon of the surrounding rock in the main roadway in the mining area caused by the mining operation after the working face enters the final mining stage, based on the mechanical model of the distribution of the advanced bearing pressure, the limit equilibrium theory and the half-plane solution method are used to theoretically calculate the peak value of the advanced bearing pressure. The location, the influence range and the stress at the main road in the mining area are analyzed. The main reason for the stress increase in the main road is that the overlying stratum on the working face is relatively complete, which intensifies the forward transmission of the advanced bearing pressure. Therefore, it is proposed to use deep hole pre-split blasting technology, and use the penetration of blasting cracks to form structural weak planes, thereby destroying the transmission path of the advanced bearing pressure, so as to reduce the impact range of working face mining and improve the stability of the surrounding rock in the roadway. ;According to the engineering geological conditions, quantitative analysis selects the key parameters of blasting roof cutting, and uses numerical simulation to verify the rationality of the plan; through on-site industrial test and mine pressure monitoring data analysis shows that: under blasting roof cutting conditions, 5#, 8# The approaching amount of the roof and floor of the measuring point is reduced by 41% and 55.5% respectively, and the moving amount of the two sides is reduced by 68.1% and 74.8% respectively, indicating that this scheme can improve the stress environment of the main roadway in the mining area and reduce the influence range of the advanced bearing pressure.