浅埋深薄基岩高强度开采工作面压架机理分析

Analysis on jammed mechanism of hydraulic powered supports in high intensity coal mining face in shallow depth seam with thin base rock

为解决浅埋深薄基岩高强度开采影响下引起的压架事故,采用数值模拟和理论分析的手段,分析了工作面推进过程中覆岩的破坏过程及压架事故发生机理。结果表明:在煤层开采过程中,不同岩性的岩层中应力分布差异很大,其破断冒落条件也不相同;覆岩中上行裂隙、下行裂隙同时发育贯通是压架事故发生的前提;覆岩载荷传递因子的变化、基本顶破断岩块架后切落、地表厚风积沙的存在以及水沙对基本顶破断岩块运动形式的影响,均增加了顶板沿煤壁大范围切落并导致压架事故发生的概率。通过对乌兰木伦煤矿31402工作面局部压架事故进行分析可知,采高增大而破断岩块长度减小,基本顶结构仅以单关键块形式出现,是基本顶结构容易发生切落的主要原因。

In order to solve the hydraulic powered support jammed difficult problem caused by a large area roof cutting and falling along thecoal mining face under the high intensity mining influences,the numerical simulation and theoretical analysis were applied to analyze the o-verburden strata failure process and disaster occurred mechanism during the coal mining face pushing forward process. The results showedthat during the seam mining and excavation process,the distribution difference of the stresses in different lithology strata would be high andthe breaking and falling conditions also would be different. The upward cracks and downward cracks in the overburden strata were devel-oped at the same time and the run-through were the prerequisite of the catastrophe occurred. The load of the overburden strata could transitthe variation of the factors,the basic roof could break the rock block and then cut the rock block,the thick aeolian sand existed on the sur-face ground and watery sand affected to the broken rock block movement mode of the basic roof would totally increase the probability to thehydraulic powered support jammed disaster occurred by the large area roof cutting and falling down along the coal wall. The mining heightincreased and the length of the broken rock block would be reduced and the basic rock structure would appear in a single key block only.The paper explained the cause the cutting and falling phenomenon easily occurred by the basic roof structure. Finally the paper analyzedthe partial powered supports jammed accident occurred in No. 31402 coal mining face of Wulanmulun Mine.