Study on reasonable pillar width and control technology of gob-side roadway driving in fully mechanized caving in Wangjialing coal mine

Aiming at the problem of reasonable width of coal pillars in high-strength fully mechanized caving face, taking Wangjialing coal mine as the engineering background, the asymmetric failure characteristics of surrounding rock of roadway are clarified by peeping the position of basic roof fracture line in borehole exploration, the lateral basic roof fracture structure model of fully mechanized caving face is established, and the expression of bending moment in the roof range of roadway along goaf side is deduced using FLAC^3D numerical model.The simulation software analyzes the evolution characteristics of stress and yield zone of roadway surrounding rock under different pillar widths, and determines that the reasonable pillar width is 8 m.Based on the variation law of roof bending moment when 8 m pillar is retained in N2103 return air drift, the asymmetric control technology of roadway surrounding rock is put forward and applied in the field.The results show that the displacement of the roof, coal pillar and solid coal is 216 mm, 198 mm and 121 mm during the picks period, and the roadway control effect is obvious.