Support technology of open-off cut in fully-mechanized mining face of large mining height with shallow buried depth and thin bedrock

In order to solve the problems of unreasonable open-off cut support parameters and insutficient support system efficiency infilly-mechanired top-coal mining face with shallow hurial depth, thin belrock and large mining height， the open-offl cut support systemin No.25206 working face of Hongliulin Mine was used as the engineering bhackground by means of field monitoring,mumerical simulation ,theoretical analysis and field practice and other methods to studly the open-off cut support system.The results show that the oviginal sup-porting parameters of the open-off cut can better control the deformation of surrounmding rock, but the supporting strengh is oo high , andthe bolt ( eable) fails to meet its rated supporting resistance.Based on the bolt ( eable) collaborative support methodl, the anchor rod foun-dation support and cable reinforcement collaborative supporting system was established , reasonable suppot parameters were calculated.Busing numerical analysis to verify the rationality and reliability of the bolt and anchor cable scheme , it was determined that when the pre-tightening force is 5O kN, the roof bolt length is 2.6 m , row spacing is 1 200 mmx1 200 mm , the anchor bolt length is 2.2 m, the rowspacing is 1 200mmx1l 200 mm, the anchor cable diameter is 17.8 mm , and the length is 6.0 m, it can control deformation of the sur-rounmding nock of the roadlway; after the optimization of the support scheme , the maxinmm working resistance of the top bolt is 78 kN, themaxvinmum stablility value of the side bolt is 65 kN, and the maximum stablility value of the top bolt is 118 kN. The suppot resistance ofbolt ( cable) is significanly increased, and the support efficieney is obviously improved. Through the research of mine support optimiza-tion，a set of complete support system has been formed.