地下水位变化对边坡稳定性影响的模拟分析

Numerical Analysis on the Stability of a Slope behind a Substation Under Varying of Ground Water Level

降雨引起边坡地下水位变化、降低岩土体抗剪强度进而引起边坡失稳产生滑坡是电网工程灾害中最常见的地质灾害之一。文章在现场详细工程地质勘察的基础上,基于恢复山体极限平衡法和强度折减法,利用数值分析方法对降雨引起地下水位变化条件下某电网工程边坡稳定性进行了分析。模拟结果表明,现今地下水位条件下,该边坡整体处于极限平衡状态;在最高洪水位条件下边坡则处于失稳状态。边坡的最大变形位于边坡中上部,并呈现出由上部逐渐向下部扩展的趋势。边坡潜在破坏模式为边坡后缘张拉破坏和中下部剪切破坏的复合破坏模式。最后基于数值分析结果,对该边坡的工程治理提出了建议。

Slope instability induced by rainfall is one of the most common geological disasters in power grid engineering.Rainfall in this disaster plays a role in the variation of ground water level and the reduction in shear strength of rock and soil mass.This paper employed numerical analysis method combined with limit equilibrium method under mountain recovery and strength reduction method to evaluate the stability of a slope in power network engineering based on a deep engineering geological investigation.The results shows that the slope is in limit equilibrium state under present underground water level and unstable under maximum flood level.The maximum deformation of the slope is found to locate on the top and middle and extend to the bottom gradually.The composite failure mode of the slope,which is composed by the tension failure on the top and the shear failure on the middle and bottom,is also verified by the modeling results.At last,some advice is proposed to the treatment against the slope instability according to the analysis above.