横采内排追踪压帮高度对端帮稳定性影响研究

Influence of the covering height on the stability of the end slope in the condition of the criss-cross-way exploitation with inner dumping

为揭示横采内排追踪条件下压帮至不同高度时端帮稳定性变化规律及力学成因机制,明确端帮的滑坡模式与滑坡机理,以平庄西露天煤矿端帮边坡为工程背景,应用有限差分软件FLAC3D,基于强度折减理论,对压帮不同高度时的端帮稳定性进行了三维数值模拟。结果表明:平庄西露天煤矿端帮滑坡模式为以椭球面为侧界面、以弱层为底界面的切层-顺层滑动;滑坡的力学成因机制类型为牵引式;横采内排追踪压帮高度至少为81 m端帮才能满足安全储备系数的要求;端帮稳定性系数Fs随压帮高度增大呈线性增大。

The present paper is inclined to reveal the law of stability and the mechanical genesis mechanism of the end slope under the condition of the criss-cross exploitation with the inner dumping.At the same time,it has also to identify and determinate the landslide mode and the instability evolutionary mechanism.As is known,the covering height may have a direct impact on the end slope stability and the secure economic production of the open-cast mines.Therefore,it has become a hot topic for the experts and scholars both at home and abroad to make efforts to judge and determine the reasonable covering heights of the mineral resources.For the above said research purpose,we have managed to make a 3-D numerical simulation to pursue the influence of the different covering heights on the stability of the end slope under the condition of the criss-cross exploitation and the inner dumping by taking the Pingzhuang West Open-cast Mine as the typical engineering background sample by using a finite difference software named FLAC3D based on the strength reduction theory.In so doing,we have made a detailed analysis of the 3-D displacement contours of the space and the displacement contour of the principal slip line,which has enabled us to disclose the entire internal movement and deformation regularity of the slope rocks,thus,finding and confirming the potential failure mode,the position and the shape of the sliding surface from the point of view of the geographical configurational spatial construction.The study results demonstrate that the landslide model of the end slope of the said Pingzhuang West Open-pit Mine may have been formulated and evolutionized into a cutting-bed slip along the side surface with the ellipsoid as a lateral boundary and slight layer on its bottom limit.The mechanical feature of the landslide turns to be in a traction.Its covering height can be predicted at least of 81 m if it has to meet the demands of the safety reserve coefficient.What is more,the rising slope stability end factor should also follow and obey the linear rule with the increase of the covering height.Thus,it can be said that we have disclosed a theoretical formula,which can be taken as the foundation for the slope engineering design and stability analysis.