露天转地下开采边坡变形和应力特性研究

STUDY ON DEFORMATION AND STRESS CHARACTERISTICS OF SLOPE IN TRANSITION FROM OPEN-PIT TO UNDERGROUND MINING

露天矿开采的中晚期阶段,当深部还有可采矿体时,要由露天转为地下开采,在地下矿体的开采过程中,露天边坡的变形破坏特征直接影响地下开采的安全。针对这一问题本文通过三维数值分析,详细分析了地下矿体开采过程中边坡岩体的变形和应力变化。获得以下主要结论:边坡不同标高处的竖向位移变化在-60、-90、-135和-165 m水平的开采过程中,上下盘边坡岩体的变形相对较小,在-210、-255 m水平开采的过程中边坡岩体竖向位移变化较大;地下矿体的开采主要影响上盘边坡岩体,其变形值和变形范围都较下盘岩体大;不同开采水平下,上盘边坡深部岩体随着开采水平的延深,最大主应力的集中程度逐渐增加,影响范围也在加大;而最小主应力在开采水平附近出现明显减小现象。

In the later stage of open-pit mining, when there is still orebody minable in deep, a transition from open-pit to underground mining is usually adopted. In the process of exploitation of underground mine, deformation and failure characteristics of open-pit slope directly influence the safety of underground mining. To solve the problem, this paper analyses the deformation and stress variation of open-pit slope in the process of underground mining by three dimensional numerical analysis. Some main research results are as follows： Vertical displacement changes at slope of different elevation is relatively small in the -60, -90, -135 and -165 m levels mining process, but large in the -210 and -255 m levels mining process. Underground mining mainly effects upper slope rock mass, its deformation value and scope are larger than that of lower slope rock mass. Under different mining levels, the concentration degree of maximum principal stress of the upper slope deep rock mass gradually increases along with mining level extension, and its influence scope also increases, while the minimum principal stress near the mining level significantly reduces.