二次抛物线破坏准则下的黄土边坡稳定性分析

Loess Slope Stability Analysis with Quadratic Parabola Failure Criterion

近些年来,极限分析理论在边坡稳定性分析中应用广泛。笔者首先以上限定理为基础,并基于二次抛物线破坏准则,采用外切线法引入了非线性强度参数ct、φt;其次,考虑黄土抗拉强度较小,易出现拉裂缝的特性,推导出裂隙—直线型与对数螺旋线型破坏模式下黄土边坡极限高度与稳定系数的公式;最后,通过SQP(序列二次规划算法)法对陕北均质黄土边坡进行塑性极限分析,并与工程中常用的极限平衡法进行比较。结果表明了该方法的正确性以及在非线性取值方面的优越性。

In the past few years, limit analysis theory has been widely applied in slope stability analysis. First, the nonlinear strength parameters cohesion ct and internal friction angle φt was introduced through the tangent method on the basis of upper bound theorem and quadratic parabola failure criterion. Secondly, considering the characteristics of small tensile strength of loess and prone to tension crack, a limit height formula and stability coefficient formula of loess slope was deduced in the failure mode of fissure-linear and logarithmic spiral. Finally, the Luochuan uniform loess slope stability was calculated with plastic limit analysis method thought SQP （sequential quadratic programming algorithm ） and it was compared with the limit equilibrium method. The results show the correctness of the method and the superiority in the field of nonlinear values.