扎哈淖尔露天煤矿南帮压煤回采边坡稳定性分析

针对露天矿边帮普遍存在的压煤问题,基于极限平衡及强度折减理论,从控制边坡稳定性角度出发,结合扎哈淖尔露天煤矿南帮软岩边坡工程实际,通过定量计算与定性分析,提出横采内排压帮开采方式。采用二维刚体极限平衡与三维数值模拟相结合的方法分析了横采深部开挖角度及内排跟踪距离对边坡稳定性的影响及其程度,优化设计了扎哈哈淖尔露天矿横采南帮边坡形态。结果表明:南帮边坡滑坡模式为以IVC煤层底板弱层为底界面的切层-顺层滑动;横采内排压帮开采方式可借助边坡三维效应提高露天矿边坡角度及其自身稳定性,进而达到安全、高效地回收边帮压煤,提高露天矿煤炭资源回收率;扎哈淖尔露天煤矿横采南帮边坡稳定性随内排跟踪距离增大呈负指数降低;最终确定横采开挖位置为+908水平,内排跟踪距离为100 m,深部开挖角度为42°,可累计为扎哈淖尔露天煤矿多采出IV煤4 701.39万t,经济效益显著。

Analysis of the slope stability of the underlying southern slope coal extraction in Zhahanaoer open-pit mine

This paper intends to present an analysis of the slope stability of the underlying southern slope coal recovery in the Zha hanaoer Open-pit Mine,in response to the actual engineering geoconditions of the southern soft-rock slope in the mine.In view of controlling the slope stability,the paper has brought about the horizontal mining and inner dumping mining technology via the quantitative calculation and qualitative analysis based on the limit equilibrium and the strength reduction theory.For this purpose,we have made an exploration of the degree of influence of the different deep slope angles of the cross exploitation and the different tracing distances of the interior dumpingon the slope stability,so as to optimize the southern slope shape of the mine by joining the 2-D rigid limit equilibrium method and the 3-D numerical simulation.The results of our exploration show that the landslide of the southern slope is the consequence of the slip of bedding-cutting due to the weak layer of the floor of IVC coal seam at the bottom interface.The slope angle and the slope stability can be improved with the 3-D effect by using the horizontal mining and inner dumping technology,so as to make the coal of southern slope safely and efficiently recycled at the recovery rate of the coal resources.The 3-D stability of the southern slope in horizontal mining can help to reduce the negative effect exponentially with the increase of the tracing distance.In so doing,we have chosen the final excavation position at the point of 908,with the tracing distance of the inner dumping being 100 meters and the deep slope angle being 42°.What is more,the cumulative coal amount to be excavated should reach 47 million and 13 000.9 tons for the Ⅳ-th coal group of Zhahanaoercoal Mine,with the remarkable economic benefits gained.Therefore,it can be said that it is the scientific research of the perspective of the mining practice that has pushed the development of the mining production in the Zhahanaoer Open-pit Mine.