开挖扰动对露天矿边坡稳定性影响分析

Analysis of the Impact of Excavation Disturbance on Open-Pit Mining Slope Stability

对西藏某露天矿边坡的稳定性进行深入研究,在综合分析工程地质条件的基础上,运用FLAC3D软件对开挖扰动作用下岩质边坡的位移场和应力场的变化规律进行了数值模拟研究。研究结果表明:采用分步开挖能真实模拟开挖扰动对边坡稳定性的影响;在开挖扰动作用下,岩体的卸荷量和回弹变形量随开挖深度的增大而增加,水平位移量最大值位于坡面岩体的中下部;在坡面及坡肩附近岩体形成拉应力区,坡脚处剪应力显著增高;随着开挖的进行,位移场和应力场还分别表现出"位移陡升"和"应力跌落"的现象。

A thorough study on stability of an open-pit mining slope in Tibet is made. Based on the comprehensive analysis on the engineering geological conditions,and with the use of FLAC^3D numerical simulation software,the variation of displacement field and stress field in the rock slope under the excavation disturbance was studied. Research results show that the stepped excavation can truly simulate the impact of excavation disturbance on the slope stability; Under the effect of excavation disturbance,the rock mass unloading quantity and rebound deformation increases with the excavation depth added; The maximum displacement is situated in the middle-lower part of slope rock mass; The tension stress zone was formed in the vicinity of slope surface and the slope shoulder,and the slope toe shear stress increased significantly; The displacement field and stress field also exhibit＂displacement steep rise＂and＂stress drop＂phenomenon with the excavation proceeding.