急倾斜大采高俯伪斜综采工作面顶板破坏机理与围岩控制技术OA

Aiming at the unclear roof failure mechanism,poor stability of hydraulic supports and prominent gangue flying risks existing in fully mechanized mining faces of steeply inclined seams with large mining height,No.31111 fully mechanized mining face with oblique downward layout in Shidonggou Mine was taken as the research background.Numerical simulation methods were adopted to reveal the distribution laws of surrounding rock stress and evolution characteristics of plastic zones under seam dip angles of 45°,56° and 65°.On this basis,a fully mechanized mining scheme centered on oblique downward layout was proposed.The matching and type selection design of three key mining machines focusing on support lightweighting were carried out,in which key technologies including advance grouting for faults,precise face conversion and comprehensive gangue flying prevention were integrated.The numerical simulation results showed that the failure depth and vertical stress of the roof at the lower part of the working face were always larger than those at the upper part,and such asymmetric characteristics became more obvious with the increase of dip angle.The maximum roof failure depth at the lower part reached 21.7 m at the dip angle of 56°.Field applications demonstrated that the technical system based on the research findings guaranteed a total advancing distance of 426 m for the working face.The maximum monthly advancing distance was 85 m,and the average daily output exceeded 1 500 tons.No personal injuries caused by flying gangue occurred throughout the operation.Safe and efficient fully mechanized mining was realized under complex geological conditions with an average dip angle of 56°.The research results were provided as theoretical references and practical examples for coal mining under similar geological conditions.