工作面过空巷基本顶超前破断压架机理及控制技术研究

Mechanism and control technology of supports crushing induced by main roof's breaking ahead of workface when crossing abandoned roadway

基本顶超前破断及压架研究对工作面过空巷、进入回撤通道安全保障有重要意义。通过相似模拟得到了工作面过大断面空巷基本顶超前破断前后覆岩破断特征、围岩应力及支架载荷。研究表明:在基于圣华煤业复采工作面围岩条件的相似模拟实验中,工作面通过12 m宽不支护空巷时,基本顶会发生超前破断。导致基本顶上方亚关键层随基本顶破断、滑落,支架上载荷由4 000 kN激增到12 500 kN再到16 200 kN,支承应力升高并前移。从理论上研究了超前程度、围岩条件、开采技术对破断后基本顶稳定性的影响,结果表明:随超前破断距离增大,阻止关键块所需阻力成倍增加;随自由空间高度的增加、块度的增加,基本顶结构稳定性降低;亚关键层破断会导致所需支架阻力激增,单从提高支架阻力来维持超前破断后基本顶结构稳定性不可行,应当从防止基本顶超前破断来预防切顶压架事故。提出了针对此类工作面的控制技术,现场应用效果明显。

It has a safety significance to investigate the advance fracture of main roof and support crushing mechanism when workface crossing abandoned roadway or accessing to removal gateway. Similar simulation experiment was used to study the breaking characteristic of overlying strata, the stress on the surrounding rock and the load on the supports. Result shows that in the similar simulation of Shenhua Coal Mine, when the workface passing though the 12 m-wide roadway, the main roof was broken ahead of workface. Worse yet, the inferior key strata was broken at once and slid soon afterwards. The load exerted on the support increased from 4 000 kN to 12 500 kN then to 16 200 kN. The abutnology on the stability of main roof was studied by mechanical model. Result shows that with the increase of ahead dis- tance,the working resistance increased sharply,with the increase of the height of free space or blockness, the stability of main roof structure decreased. Tire break of inferior key strata also leaded to working resistance increase sharply. It is better to prevent the advance fracture than increase the working resistance when it comes to maintaining the main roof＇ s stability in a similar workface. Above all,the control technology was put forward and the effect of site applica- tion was obvious.