The cutting length of the short arm working face is 75 m,the pushing mining length is 240 m,and the working face is covered with hard top plate in a coal mine of Shenmu,Shaanxi.In response to the phenomenon of delayed roof caving in the goaf during the initial mining period of the short wall working face,hydraulic fracturing technology is used to effective-ly weaken the overlying roof of the working face.The effect of hydraulic fracturing on weakening the roof of the ST5201 working face is analyzed.It is concluded that the crack propagation radius can reach about 30 m when the deep hole hydrau-lic fracturing is forced to top off,and the initial weighting step distance of the working face after fracturing is about 20.5 m;The safety and reliability of hydraulic fracturing during the mining period of short wall working faces have been verified from the aspects of the effect of roof caving in the goaf during mining,manual labor intensity during construction,and operational safety.Our study provides a new and effective way for the treatment of hard roof on short arm working faces.
关键词
短壁工作面/坚硬顶板/水力压裂/顶板弱化/强制放顶
Key words
short-wall working face/hard roof/hydraulic fracturing/roof weakening/forced caving
维普
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