Study on influence of advanced deep-hole blasting pre-splitting roof on stability of gob side entry retaining

In order to smoothly implement gob-side entry retaining and mining without coal pillar in 3207 working face of Nanyang Coal Mine, Shanxi Province , this paper proposes to carry out advanced deep-hole blasting pre-splitting roof near gob side supporting wall. 'Through numerical simulation and field industrial test , the influence of deep-hole blasting roof cutting on surrounding rock stability of gob-side retaining roadway is studied.Based on the backdrop of retaining roadway along goaf in 3207 working face of Nanyang coal mine ,a numerical simulation model was established , the displacement of roof and floor ,wall and coal body of retained roadway, the stress distribution and variation of surounding rock of retaining roadway were calculated.The numerical calculation shows that the variation of stress and displacement of surrounding rock in gob-side retaining roadway decreases greatly after roof cutting , and the stability of surrounding rock is improved significantly.The field industrial test results show that deep -hole blasting roof cutting can effectively eliminate the rotational extrusion damage of cantilever beam roof to surounding rock of gob-side retaining roadway , and help to maintain the stability and integrity of gob-side retaining roadway structure. The research results of this paper can be used for reference in the design and construction of gob-side entry retaining project.