急倾斜煤层水平分段综放顶板“倾倒-滑塌”破坏模式

Toppling-slumping failure mode in horizontal sublevel top-coal caving face in steeply-inclined seam

为揭示顶板破坏与移动规律,以江仓一号井11220工作面为工程背景,进行了顶板破坏相似模拟试验和UDEC数值计算,建立了顶板破断岩块倾倒力学模型,揭示了顶板上分段"倾倒式"和下分段"滑塌式"2种破坏模式,提出了顶板岩块"破坏形态转变点"的判别准则,定义了表征顶板破坏形态的滑-倾系数,讨论了顶板载荷和岩块厚度对"滑-倾"系数的影响.结果表明:随着顶煤的放出,顶板易悬空张裂而发生倾倒-滑塌破坏;随着开采水平的加深,上分段倾倒的顶板岩块作用在下分段顶板上,促进了下分段顶板的折断与倾倒,对采空区产生冲击载荷;随着顶板载荷和岩块厚度的增大,顶板更容易发生"滑塌式"破坏;随着顶板岩块高厚比的增加,顶板更容易发生"倾倒式"破坏.

To reveal the law of roof failure and movement,the Face 11220 in Jiangcang 1#coal mine was investigated by a roof failure physical model,a UDEC numerical model and a roof failure mechanical model.It is revealed that the roof fails in two modes,i.e.toppling in the upper section and slumping in the lower section.Based on the theoretical model,a＂roof failure mode transition criterion＂and a＂slumping-toppling coefficient＂were proposed to represent the roof failure modes.The impacts of overburden stress and roof thickness on slumping-toppling coefficient was analyzed.The results show that as the mining level deepens,the breaking and toppling of the lower section roof are promoted due to the upper section toppling roof blocks,then generating impact loads on the gob;the roof may fail in slumping with the increase of roofthickness and overburden stress,and that toppling failure may occur with the increase of the ratio of roof height over thickness.