厚覆基岩下煤层开采突水溃砂机理研究

Study on mechanism of water inrush and sand inrush in mining of coal seam with thick overlying bedrock

为了揭示较厚上覆基岩煤层开采顶板突水溃砂灾害的形成机理,以照金煤矿突水溃砂事故为例,结合最新补勘地质资料,从导水通道、充水水源、物源、储水空间、动力源和地质构造等多方面对该类型灾害机制进行综合分析。研究结果表明:在采动条件影响下,富水性弱~中等的洛河组含水层也可能发生破坏极大的水害事故;较厚上覆基岩煤层开采顶板突水溃砂的发生并非单一因素造成,而是由多个因素相互作用最终造成水砂混合流运移和突溃的现象;照金矿202工作面综放开采产生的导水裂隙带导通洛河组含水层,水进入宜君组与直罗组之间的离层空腔,随着积水量增加,渗入煤系含水层和古河床相松散体中形成似泥石流体,并会沿工作面切落形成的集中通道瞬间溃入工作面,导致煤层顶板上覆较厚基岩发生突水溃砂。

To reveal the formation mechanism of water inrush and sand inrush disasters from the roof when mining coal seams with thick overlying bedrock,this paper takes the intrusion accident of water and sand in Zhaojin Coal Mine as an example.Combined with the latest supplementary geological data,a comprehensive analysis was conducted on the mechanism of this disaster from many aspects such as channel,water source,source,water storage space,power source and geological structure.The results show that under the influence of mining conditions,the Luohe Formation aquifers with weak and medium water-rich may also suffer from great water accidents.The intrusion of water and sand from the roof when mining the coal seam with thick overlying bedrock is not caused by a single factor.In fact,it is caused by the interaction of multiple factors,which ultimately leads to movement and collapse of the mixed water and sand flowing.The water flowing fractured zone generated during the fully mechanized caving mining of the No.202 longwall face causes the aquifer water of Luohe Formation to enter the separated cavity between Yijun Formation and Zhiluo Formation.As the amount of accumulated water increases,the water in the separated cavity penetrates into the coal measures aquifer and the ancient riverbed phase loose body to form a mud-like fluid.The mud-like fluid instantaneously breaks into the longwall surface along the concentrated channel generated by cutting the longwall face.This leads to the invasion of water and sand in the coal seam roof with a thick bedrock.