采场覆岩厚硬关键层初次破断的研究

Study on the initial fracture of thick and hard key layer of overlying strata

以某矿12号煤层开采为背景,运用RFPA2D数值模拟软件,通过理论分析与现场实测相结合,研究不同厚度的直接顶条件下,采场上覆厚硬关键层初次破断的形式,以及初次破断步距的预测。结果表明,当直接顶厚度为2m时,厚硬关键层会发生回转失稳,容易造成支架压架或更为严重的冲击矿压事故;当直接顶厚度为5m时,厚硬关键层会形成相互咬合的砌体梁结构;基于厚硬关键层初次破断是非对称的,结合薄板理论公式可预测厚硬关键层的破断步距。

Based on the mining of No. 12 coal seam in a mine, using the RFPA2D numerical simulation software, by combining the theoretical analysis with the on-site measurement, the initial breaking fracture and breaking step pre- diction of the thick and hard key layer on the stope under the direct roof conditions of different thicknesses were studied. The results show that when the direct top thickness is 2m, the thick and hard key layer will be unstable and can easily cause the support destruction or more serious impact pressure accident, when the direct top thickness is 5m, the thick and hard key layer will form the intertwined masonry beam structure. The initial breaking based on the thick and hard key layer is asymmetrical, the breaking step of the thick and hard key layer can be predicted by using the theoretical for- mula of the thin plate.