有限元极限平衡法在黄土边坡稳定性分析中的应用探讨

对目前边坡稳定分析中的极限平衡和有限元两类方法进行分析阐述,在此基础上,结合黄土边坡工程算例,利用geostudio软件将有限元与极限平衡法相结合进行黄土边坡稳定性分析,并对其计算结果进行比较。算例分析结果表明:极限平衡法在求解过程中作出各种假定来解决超静定问题;有限元法克服了极限平衡法的不足,考虑土体的本构关系,但不能确定可能破裂面,对边坡失稳破坏的判断没有一个定量的标准,将有限元法和极限平衡法相结合,取长补短,既能反映边坡的稳定和变形之间的关系,准确描绘出破坏面的特征,又能得到更精准可靠的安全系数;有限元极限平衡法可自动搜索出坡肩带有垂直裂缝的组合滑动面,比极限平衡法搜索出的单一圆弧滑动面更贴近实际情况,提高了边坡稳定性分析的合理性,为类似边坡稳定性分析方法提供参考。

Application of Finite Element Limit Equilibrium Method in Stability Analysis of Loess Slope

The limit equilibrium and finite element methods for slope stability analysis are analyzed. On the basic of it,the limit equilibrium method based on the finite element stress field is analyzed by using Geo Studio software with reference to the engineering calculation of loess slope. The example analysis results show that the limit equilibrium method in solving process has made various assumptions to solve the statically indeterminate problem; the finite element method can overcome the deficiency of the limit equilibrium method in consideration of the constitutive relationship,but can not determine potential rupture surface. There is no quantitative criterion for judging the failure of slope. The combination of the finite element method with the limit equilibrium method can not only reflect the relationship between slope stability and deformation but also accurately depict the failure surface features with more accurate and reliable safety factor. The limit equilibrium method based on the finite element stress field can automatically search for the combined sliding surface with vertical cracks on the slope shoulder,which is much closer to the actual situation than the single arc sliding surface obtained with the limit equilibrium method. Thus the rationality of the slope stability analysis is improved to provide references for similar slope stability analysis.