极软厚煤层大采高台阶式综采端面煤岩稳定性控制研究

Study on Tip-to-Face Coal and Rock Stability Control of Fully Mechanized Stepped Large Cutting Height Mining in Extremely Soft Thick Seam

基于对极软突出厚煤层大采高综采工作面端面煤岩稳定性的有效控制,提出了台阶式采煤工艺,采用台阶式割煤方式;用数值模拟分析了台阶式割煤的防片帮机理.现场实测分析了大采高开采工作面在采用台阶式回采工艺条件下端面煤岩的失稳特征.研究表明:台阶式割煤工艺改善了煤壁区域的应力状态,减少了工作面煤壁片帮和端面冒顶的发生不同台阶高度比割煤所引起的围岩破坏程度不同,上下台阶高度比为1∶2时煤壁塑性破坏区最小;极软厚煤层大采高开采煤壁片帮主要以剪切滑移引起的三角斜面片帮为主,超高开采是端面顶板冒落的主因.

In order to control the surrounding rock mass stability of fully mechanized large cutting height face in extremely-soft coal-gas burst thick seam effectively, stepped mining technology was presented. Prevention rib spalling mechanics of stepped cutting technology was analyzed by numerical simulation. The instability character of coal or rock in tip-to-face area was analyzed by field observing. The results show that the stepped cutting technology improves the stress state in coal side zone, and reduces the occurrence of sloughing and tip-to-face area roof caving. Surrounding rock mass destroy degree induced by different stepped height ratio is different. Coal side plastic zone of up and down stepped height ratio 1 ： 2 is least. Most rib spalling is triangular slop sloughing caused by shear slipping in high seam mining with extremely soft thick seam. Ultrahigh mining is the major reason top-face area for roof fall.