区段煤柱尺寸对覆岩运移影响研究

Influences of section coal pillar size to overlying strata migration

针对亭南煤矿二盘区区段煤柱宽度达30m的情况,应用物理相似模拟实验,对比模拟区段大煤柱、窄煤柱两种条件下对覆岩运移的影响。模拟实验表明:采用区段大煤柱时,煤柱具有较强的支撑能力,矿压显现剧烈、覆岩导水裂隙带较高且不易闭合;采用窄煤柱,当工作面推过一定距离后区段煤柱随即压垮,上覆岩层发生整体下沉,已形成的裂隙易于闭合,有利于隔水层的再生,阻滞了导水裂隙带继续向上发育,覆岩导水裂隙带高度有所降低,同时有效降低了煤柱支承压力,减缓冲击矿压威胁;受煤柱支撑作用影响,覆岩出现扭曲变形,窄煤柱压垮后,扭曲变形大大减弱,有效减轻了覆岩裂缝扩展与破坏。

Aiming at the 30 m wide section coal pillar in second panel of Tingnan coal mine,physical similar simulation experiment is applied to study the overlying strata migration with large or small pillar.The results show that,with large coal pillar,strong support capacity is obtained,the mine pressure behavior is fierce,the height of fractured water-conducting zone is large and water-conducting fracture is not easy to close; with small coal pillar,it crushes after the face advancement and integral subsidence of overlying strata also occurs,the formed water-conducting fracture can be easily closed,which is helpful for the regeneration of aquifuge,the continuous growing of fractured water-conducting zone is stopped,the height of fractured water-conducting zone is decreased,and the support pressure of coal pillar is reduced neutralizing the threat of rock burst.With the support of section coal pillar,distortion appears in overlying strata,which greatly weakens after the crushing of small pillar,alleviating the cracks expansion and damage of the overlying strata.