Solid coal rib support technology of fully-mechanized mining along gob-side entry driving based on main roof fracture location

In order to solve the difficulty of roadway support along gob in deep fully-mechanized caving mining, the theoretical analysis and field practice methods were used to study the damage characteristics of coal ribs along large-area roadways in deep fully-mechanized caving mining. Based on the working principle of the combined anchor-net support, and a method to determine the location of the fracture line of the main roof and the length of long anchor cable in the coal roadway along the deep gobwas put forward according to the variation of the amount of pulverized coal in the process of drilling, and the effectiveness of this method was verified in No.1306 working face of Dongtan Coal Mine. The research shows that the gob-side groove of the deep fully-mechanized caving has the characteristics of large horizontal deformation and large outburst of both coal sides, especially the serious outburst of solid coal side. The working principle of the combined support of anchor cable and anchor net is as follows:In the shallow part, the extrusion reinforcement wall is formed by the support system of point-to-surface combination of anchor cable group and metal anchor net, which resists the lateral pressure of coal body in the plastic zone and strengthens the roadway; The relationship between the amount of pulverized coal drilled, the pressure of surrounding rock and the fracture of roof was established.Based on this, the control countermeasures of solid coal side-wall along gob of deep fully mechanized enlarged cross-section and the determination method of bolt and cable support length of solid coal side-wall along gobwere put forward; Taking the No.1306 track trench of Dongtan Coal Mine as an example, the borehole pulverized coal test of the solid coal side along the gob trench of the fully-mechanized enlarged section was performed. On this basis, the reinforcement design of solid coal side is carried out. The results show that the horizontal deformation of the solid coal side decreases significantly after reinforcement, which confirms the effectiveness of this reinforcement method.