迎采动工作面沿空掘巷预拉力支护及工程应用

迎采动工作面留小煤柱沿空掘巷受邻近工作面侧向顶板破断、转动及稳定的全过程动压影响后，顶板煤体离层，小煤柱破裂，围岩稳定性急剧恶化。为了保持巷道形状，防止大变形状态下的支护结构失效成为支护的关键。常规锚杆支护、锚杆与锚索联合支护等不能维持其稳定；而预拉力钢绞线桁架系统是控制顶板离层的有效支护方式，结合高性能预拉力锚杆、M型钢带、小孔径预拉力短锚索等，形成预拉力组合支护技术，可以较好地解决该类问题。针对三河尖矿的典型试验对此作了详细说明。

PRETENSIONED SUPPORT OF ROADWAY DRIVEN ALONG NEXT GOB AND HEADING ADAJACENT ADVANCING COAL FACE AND ITS APPLICATION

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.