急斜放顶煤开采顶板卸载拱结构分析

运用弹性薄板理论对急斜煤层水平分段放顶煤开采基本顶岩层进行拉应力分析,得出了顶板破断的判别准则.依据判别准则实例验证了分段开采后暴露岩板所受荷载只是整个上覆岩层中的一部分,指出上覆层中存在卸载拱结构,正是结构体的存在承担了大部分上覆岩层荷载,直接影响了开采过程的矿压显现.通过对卸载拱影响因素的研究,指出卸载拱是顶板岩层中的一种动态扩展结构,当原有的拱式平衡被打破,拱结构朝顶板侧上移,并达到一种新的平衡态,因此其范围是不断扩展的一个"平衡-失稳-再平衡-再失稳"的动态扩展过程,也是造成工作面矿压显现的原因.

Analysis on unloaded arch structure of roof in mining steep seams using horizontal section top-coal caving

Surrounding rock structures of steep seams and gently inclined seams are different. Basic roof and immediate roof of horizontal section top coal caving were beside the working face in steep seams. A judgment criterion of roof destruction was attained by analyzing tension to basic roof. According to the judgment criterion, it was verified that only one part of overlying strata was loaded to exposed rock board. There is unloaded arch structure in overlying strata. The unloaded arch structure bears most weigh of overlying strata and effects later strata behavior of the working face. It is pointed out that the unloaded arch structure is a dynamic expansion structure. It will move towards roof as original balance of arch was broken and keeps a new balance. The scope of arch is a process constantly to expand from balance to instability.