Abstract:Identifying the movement and damage of the roof rock is important to the appropriate support design of a roadway driven along next gob and heading adjacent advancing coal face,which is under strongly dynamic pressure and severely subject to the whole breaking process of lateral main roof strata. A mechanical model of the triangle block structure for the main roof above roadway is established to elucidate that the structure can keep self-stable before and after roadway excavation. Because of the adjacent mining-induced effect,the separation of coal seam or weak rockmass from the roof and collapse of the purposely-left narrow coal pillar will unavoidably occur,the stability of the structure is lowered,and the structure must become instable with decrement of coal strength. So effective support is needed to control the separation of roof and prevent the large deformation of roadway. The conventional reinforcement for the walls and corners of roadway by bolting,metal supporting,resin anchored bolt supporting and the method of bolt combined with cable are not good enough to achieve this goal. A new pretensioned support technology is recently developed,which is a creative combination of pretensioned truss of steel strand,pretensioned cable with small borehole,high-quality bolt and M-shape steel strip. A successful application of this technology to Sanhejian coalmine of Xuzhou mining field is illustrated,and the good behavior of this technology is proved.