Study On Influence Of Open-pit Mine Slope Stability By End-slope Mining

In order to using SHM end-slope mining technology to steep end-slope mining, knowing the mechanism of slope deformation and stress redistribution caused by multi-seams mining and ensure the end-slope stability and safety is the key question. The main consideration of this paper is the influence on slope stability, such as the changing of slope angle, sizes of coal pillar and groundwater.This paper is in an engineering background of an open-pit mine, according to the physical and mechanical parameters of the rock mass and mining situation, establishing slope model by FLAC3D based on finite difference principle to numerical simulation. By this model, first, study on the slope stability of pressed coal of slope with steep end-slope mining, compared with change of before and after mining and the changing of slope angle, analyze the convergence of maximum unbalanced force and displacement of monitoring points. Next, study on multi-seams mining of thick coal seam, analyze the variation law of monitoring point displacement and the change of safety factor. Next, analyze the influence of the coal pillars'size, including height, width and spacing of coal pillars, compared with the displacement variation law of monitoring points with the different coal pillars'size. At last, the effect of groundwater seepage has been simulated, analyze the displacement of monitoring points and the change of shear strain increment, conclusion that effect of water on slope stability.Numerical simulation analysis show that:for pressed coal with steep end-slope mining, compared with before and after mining, the slope stability factor reduced significantly, the convergence time step of maximum unbalanced force is one time higher than before; slope stability factor decreases with the slope angle is greater during the steep end-slope mining. For pressed coal of thick coal, at the same depth, displacement of monitoring points increases and slope stability factor decreases with the excavating layer number increases. At the same depth, displacement of monitoring points increases and slope stability factor decreases with height of a pillar increases, width of the pillar decreases or spacing between pillars increases. Considering groundwater seepage, displacement of monitoring points increases, shear strain increment distributes at the whole slope. The maximum occurs at the bottom of slope. The paper is for getting to know the deformation rationale of surface mine slope caused by extremely thick coal seam mining with SHM technology, preventing landslide, determining the mining process and values of important parameters.