边坡三维临界滑裂面的确定及其安全系数的求解是边坡稳定分析中的关键问题，而现有分析方法尚难以方便、可靠地获得三维滑裂面。在有限元数值应力场的基础上，计算边坡的安全系数。通过构造扩展椭球形滑裂面，利用自适应差分进化（SaDE）算法结合反向移动操作，实现了复杂边坡三维临界滑裂面的搜索。扩展椭球滑裂面构造方便，搜索灵活，比传统的球面或椭球面更能反映实际工程情况。整个求解过程为显式求解，不存在收敛性问题。算例考核结果表明，提出的方法具有良好的搜索效率与全局寻优能力，结果与刚体极限平衡法、有限元强度折减法吻合，计算结果合理可靠。通过实际工程边坡，进一步验证了该方法可方便、有效地应用于具有复杂岩性及环境条件的边坡三维稳定性分析。

The determination of three-dimensional (3D) critical slip surface and its associated factor of safety (FoS) of slopes are essential to their stability analysis. However, it is difficult to obtain 3D slip surface conveniently and reliably by using existing analytical methods. In this paper, the FoS of slopes is calculated based on the stresses from the finite element method (FEM). A new method is developed to search 3D critical slip surface of slope by constructing an extended ellipsoidal slip surface and adopting self-adaptive differential evolution (SaDE) algorithm in combination with the opposite-movement scheme. The extended ellipsoidal slip surface is easy to construct and flexible to search, and meanwhile it is more coincident with the actuals than spherical and ellipsoidal slip surface. In addition, the whole calculating process is explicit without the convergence problem. The application of the developed method is verified by re-analyzing benchmark slope stability examples from the literature. The results obtained in examples prove the SaDE algorithm has high efficiency and global optimization ability, which are also in good agreement with limit equilibrium and strength reduction methods. It is also demonstrated that this method is suitable to be applied in stability analysis of slopes under complex lithology and environmental conditions by analyzing actual engineering slopes.