大采高开切眼桁架锚索支护参数优化研究

Study on support design and parameter optimization of truss and anchor rope in the large mining height open-off cut

为了研究大采高复合顸板煤巷的桁架锚索组合支护作用机理，采用理论分析、现场试验、数值计算试验等方法，对大采高2—1101大断面开切眼桁架锚索组合支护参数进行优化分析。研究结果显示：桁架锚索倾角在65°～75°范围内对控制围岩变形和塑性区扩展效果最好，倾角偏大或偏小均不利；桁架锚索的锚固点必须位于稳定的受压岩层内，保证桁架锚索支护系统有一个稳定的锚固基点;桁架锚索的长度为9m时对开切眼复合顶板围岩的稳定性最有利；桁架锚索钻孔的孔口至切眼巷帮距离最优值为1．5m；顶锚杆密度为10根／排时，现场观测结果显示：两帮移近量最大值为145mm，顶板下沉量最大值为166mm，切眼围岩的收敛率在有效控制范围内，桁架锚索组合支护对切眼围岩控制有良好效果。

In order to study the truss-cable combination support mechanism in the large mining height and complex roof open-off cut, adopting theoretical analysis, field measurement, numerical simulation test method, the truss-cable support parameters in the open-off cut of large mining height 2-1101 working face were optimized. The results show that if the inclination of anchor cable is too large or too small, these are not conducive to control the deformation and plastic zone of the surrounding rock. The anchor cable inclination angle of 650~75~ is the best for truss-cable support; anchor points in the truss system must be anchored into a stable rock pressured to ensure that the truss system has a stable anchoring basis point. Truss-cable drilling depth is chosen as 9 m to enhance the stability of the roadway. The reasonable distance value of the cable drilling to roadway side is 1.5 m. It is better to control the development of the surrounding rock plastic zone when the roof bolt density is 10 in each row. The results of field measurement show that the convergence rate of roadway section is very small. The largest value of the open-off cut two sides moving closer is 145 mm. The roof subsidence maximum is 166 ram; trussanchor-combined support has a good effect on the controlling of surrounding rock in the open-off cut.