双切顶沿空留巷条件下切顶参数对围岩稳定性的影响

The influence of cutting roof parameters on stability of surrounding rocks under the condition of double cutting roof

以沙曲一矿4502工作面为例,利用理论分析、数值模拟及现场实测等手段对切顶参数对围岩稳定性的影响进行研究。结果表明:双切顶措施能减弱实体煤帮内部应力集中现象,有利于巷道围岩稳定,但切顶高度越大,巷道顶板垂直位移越大,不利于控制顶板变形量;一定的切缝角度有利于采空区顶板垮落,但切顶角度越大,应力集中峰值与巷道顶板下沉值越大,增大了锚索加固的难度;切顶高度与角度的选取应适中,最佳值分别为13 m和15°,切缝斜长13.5 m,现场实测与数值模拟结果具有较好的一致性。

Taking 4502 working face of Shaqu No.1 Coal Mine as an example,the influence of roof cutting parameters on the stability of surrounding rock is studied by means of theoretical analysis,numerical simulation and field measurement.The results show that:the double roof cutting can weaken the stress concentration phenomenon inside the solid coal wall,which is beneficial to the stability of the surrounding rock of the roadway,but the larger the height of the roof cutting,the larger the vertical displacement of the roadway roof,which is not conducive to the control of the roof deformation.A certain angle of the roof cutting is beneficial to the collapse of the roof in the mining area,but the larger the angle of the cut roof,the larger the peak stress concentration and the value of the sinking of the roadway roof,which increases the difficulty of the anchor cable reinforcement.The height and angle of the roof cutting should be selected moderately,and the optimum value is 13 m and 15°respectively,when the oblique length of slit is 13.5 m,the results of field measurement and numerical simulation are in good consistency.