含断层露天矿逆倾层状边坡稳定性数值模拟

Numerical simulation on the Stability of Anti-dip Layered Slope at Open-pit Mine with Faults

平庄西露天矿西北帮为逆倾层状边坡,受坡体内F3断层及弱层的影响,开采过程中存在滑动风险。为保障采剥作业安全,开展了西北帮边坡稳定性研究工作。选取西北帮断层区的典型工程地质剖面作为研究对象,应用有限差分软件FLAC3D,基于强度折减理论,将D-P准则作为岩体破坏准则,以塑性区贯通作为边坡失稳判据,对平庄西露天矿西北帮F3断层区逆倾层状边坡稳定性进行了数值模拟研究。通过分析断层与边坡空间位置不同以及不含断层条件下西北帮边坡失稳破坏特征,揭示了F3断层对西北帮边坡滑移模式与稳定性的影响。研究结果表明,F3断层的存在及其位置控制了平庄西露天矿西北帮断层区边坡的潜在滑坡模式,进而影响了边坡的稳定性;滑坡的力学成因为岩体在自身重力作用下顺F3断层面滑移,进而挤压下部岩体沿MD弱层向临空面滑移,形成推动式滑坡;断层的存在会加速滑坡的进程,且断层距离边坡面越近,这种作用越明显。

During mining process in Pingzhuang west open-pit coal,there exists a serious sliding risk at northwest slope influenced by the F3 fault and weak bedrock layer. To make sure the security of mining-stripping operation,stability researches on northwestern slope were carried out. Based on the strength reduction theory and the rule of D-P,taking transfixion of plastic zone as the slope instability criterion,FLAC3 Dsoftware was used to make the numerical simulation on the stability of the antidip layered slope at northwest F3 fault in Pingzhuang West open-pit coal. From the analysis of different spatial location of fault and slope,and the unstable failure characteristics of slope which did not have fault in northwest,it is indicated that F3 fault has a great effect on slope slippage pattern and stability in northwest. The potential slide pattern of northwest slope was controlled by F3 fault and its location in Pingzhuang West open-pit coal. Landslide was caused by the rock gravity,as the rock slides along F3 fault. Lower rock was squeezed to slide along MD weak layer to the free face,which formed the pushing landslide. Because the existence of fault,landslide was accelerated. The nearer distance of fault from slope surface,the more obvious the effect is.