基于MPGA的复杂应力状态边坡稳定性分析

极限平衡法在边坡稳定性分析中处于主导地位,该算法通常建立在一定的假设之上,没有考虑边坡土体的非线性应力-应变关系,不能用于未达到极限状态以及加固后边坡的稳定性分析。为了解决以上问题,将有限元计算与多种群遗传算法(MPGA)相结合,建立一种基于MPGA的复杂应力状态边坡稳定性分析通用模型,通过数值应力场求解安全系数,并为多种群遗传算法构建适应度函数;再利用多种群遗传算法为安全系数的计算提供滑移面。为了保证分析的高效、合理,根据滑移面发展趋势,动态产生初始滑移面,并增加一个滑移面约束条件。最后,通过均质边坡和软弱夹层边坡两个典型算例分析验证了该方法的合理性;通过分析土钉加固的软弱夹层边坡,证明了该方法可用于加固等复杂应力状态边坡的稳定性分析。

Stability analysis of slope under complex stress conditions based on multi-population genetic algorithm

The limit equilibrium method plays a dominate role in the slope stability analysis, but the method is usually based on certain hypotheses, without considering the nonlinear stress-strain relationship of soil, so it can’t be used to analyze the stability of slopes which fail to reach the limit state or are reinforced. To solve the problem, combining the finite element analysis with multi-population genetic algorithm (MPGA), a general numerical model about the stability analysis of slope under complex stress conditions is proposed. The model can solve safety factor by numerical stress field, and construct fitness function for MPGA, and then use MPGA to provide the slip surface for the safety factor calculation. To ensure the analysis efficiency and rationality, the initial slip surface is generated dynamically according to its development trend and a constraint condition is also added to the slip surface. Finally, by the stability analysis of the homogeneous slope and the slope with weak interlayers, the method is verified to be rational. It’s also proved that the method can be applied in reinforced slopes under complex stress conditions by analyzing the stability of soil-nailed slope.