Hengshan Weiqiang Coal Industry Company, Shannxi Yanchang Petroleum Co., Ltd.,Yulin ,China

In order to solve the problem that the basic top of the fully mechanized mining face is difficult to fall and the step size is large, this paper used the hydraulic fracturing technology to carry out the hydraulic fracturing field test research according to the geological conditions of NO.1307 working face of the Weiqiang Coal Mine. This paper discussed the collapse of the top surface of the working face and the initial pressure step. The results showed that after fracture, the fracture degree and crack development of the surrounding rock of the roof were obviously expanded, and the fracturing destroyed the integrity of the surrounding rock of the roof and effectively weakened the roof rock. The continued monitoring of the powered support working resistance showed that after the fracturing operation, the primary falling span of the main roof in the coal mining face was 44.5 m and 8.0 m was reduced compared with the prefabricated blasting forced roof caving. The primary roof falling technology of the fully-mechanized top coal caving mining face with the hydraulic fracturing control would have a small engineering workload, high safety, fast construction speed, good roof control effect and other features and could effectively solve the long primary falling span of the main roof and the high powered support pressure of the fully mechanized top coal caving mining face with the hard roof. It can realize the effective and safe mining.

国家自然科学资助项目（51809033）；陕西延长石油集团科技支撑资助项目（SXYC-2017-0832）