Analysis and prevention measures of roof cutting in shallow deep and large mining height working face

In order to solve the problems of unstable pressure intensity, inconsistent roof cutting step distance and repeated roof cutting of 7 m large mining height fully mechanized mining face under the condition of shallow buried thin bedrock and thick loose layer in Haojialiang Coal Mine, the characteristics, causes and prevention strategies of repeated roof cutting of large mining height working face are studied by means of field measurement and theoretical analysis.The research shows that the basic characteristics of the roof cutting are large scope, high strength and fast sinking speed.The cutting of working face has square effect.The topping is advanced and integrated, and the subsidence trace of surface steps is close to the topping line in front of the scaffold.The small margin coefficient of support strength and the conditions of thin bedrock and thick loose layer are the important factors causing the roof cutting in front of the support.From the perspective of actively changing the form of roof collapse, “overall roof cutting” is changed into “sub local breaking” “large breaking step” is changed into “small breaking step”, improving the support capacity of the support, monitoring and early warning of roof cutting and pressing frame, and strengthening the daily management of the roof, the prevention strategy of roof cutting is put forward, and the field test verification is carried out.The research results show that after taking corresponding prevention measures, the roof cutting frequency of the working face is significantly reduced, the ground pressure apparent intensity is reduced, and no frame pressing accident occurs.