高位巨厚砾岩对工作面开采地表沉降控制机理

Control mechanism of surface settlement in mining face by high and thick conglomerate

为研究工作面开采后高位巨厚砾岩层对地表沉降的控制机理,以高庄煤矿西十一采区典型工作面为背景,采用理论分析、数值模拟、地表沉降实测等方法开展研究;基于微震事件分布分析了高位巨厚砾岩层工作面覆岩结构特征,高位巨厚砾岩层受采动影响较小,破坏程度较低;通过建立巨厚砾岩层Euler-Bernoulli固支裂缝梁力学模型,推导了裂缝影响下挠曲变形方程,阐明了巨厚砾岩层对地表沉降控制机理。数值模拟结果显示:覆岩垂直位移在巨厚砾岩层底部发生突变,巨厚砾岩层底部易产生离层空间,离层空间经历了“月牙”形、“盘”形形态演化,巨厚砾岩层影响下的模型地表沉降量明显较小。地表沉降实测结果显示:高位巨厚砾岩区工作面开采地表沉降量明显更小,高位巨厚砾岩对地表沉降具有明显的控制作用。

In order to study the control mechanism of surface subsidence by the high and huge thick conglomerate strata after working face mining,the typical working face of west 11th mining area of Gaozhuang Coal Mine is taken as the background,and the research is carried out by using the theoretical analysis,numerical simulation,and the actual measurement of surface subsidence;based on the distribution of micro-seismic events,we analyzed the characteristics of overlying strata structure in the working face of the high level huge-thick conglomerate layer,and the high level huge-thick conglomerate layer is less affected by mining,and the degree of fissure development is lower;a mechanical model of Euler-Bernoulli solid-supported cracked beam in giant conglomerate strata was established,and the deflection control equations under the influence of cracks were deduced,which elucidated the control mechanism of giant conglomerate strata on surface subsidence.Numerical simulation results show that the vertical displacement of overlying strata changes abruptly at the bottom of the giant conglomerate strata,the bottom of the giant conglomerate strata is prone to generating off-stratum space,and the off-stratum space undergoes the morphology evolution of“crescent”and“disk”,and the modeled surface subsidence under the influence of the giant conglomerate strata is significantly smaller than that of the giant conglomerate layer.The amount of modeled surface subsidence under the influence of the giant conglomerate layer is significantly smaller.The measured results of surface subsidence show that the amount of surface subsidence of the working face mining in the high level giant thick conglomerate area is obviously smaller,and the high level giant thick conglomerate has an obvious controlling effect on surface subsidence.