复杂条件下土体的自身性质对边坡稳定性影响很大，且边坡的破坏表现为非线性和渐变性等特征，然而，现有极限平衡计算方法对其考虑不足，已不能满足实际工程的需要。本项目构建三维边坡任意曲线滑动面的生成模型，并在极限平衡理论的基础上，融入非线性强度准则，建立不同强度折减策略下综合安全系数计算模式，且结合剪应力应变关系曲线推导滑动面位移理论解，进而获得综合安全系数和边坡位移双向控制的土质边坡稳定性分析方法，用于揭示土质边坡的非线性失稳灾变机理和内在本质，以及得到边坡的渐进式破坏规律。同时，考虑土的工程特性，引入合理的数学模型，提出蠕变和应变软化条件下土质边坡稳定性极限平衡计算方法。另外，模型试验和数值模拟方法被采用去对比验证理论结果，并开发相应的计算机软件。本项目研究的开展可实现复杂条件下土质边坡稳定性分析的模块化、程序化和可视化，其成果可便于指导现行土质边坡的安全评估与加固防护。

The soil properties have important influence on stability of slope under the complex conditions, and the slope destruction exhibits the non-linear and gradual characteristics. However, the existing limit equilibrium methods (LEM) have inadequate consideration on these characteristics, so they can not satisfy the need of actual projects. In this research project, the generation model for arbitrary curved slip surface of three-dimensional (3D) slope is constructed. Then, through incorporating non-linear strength criterion, establishing the calculation model of comprehensive safety factor under different strength reduction strategy, and deducing the theory solution of slip surface displacement in combination with shear stress – strain curve on the basic of limit equilibrium theory, the stability analysis method for soil slope, which is controlled by the comprehensive safety factor and slope displacement, is obtained. By applying this method, the non-linear instability disaster mechanism and internal essence of soil slope is revealed, and the gradual destruction law of slope is obtained. Meanwhile, introducing the reasonable mathematical model with consideration of soil engineering characteristic, the limit equilibrium calculation methods for slope stability under creep and strain softening condition are proposed. In addition, the model test and numerical simulation methods are used to verify the theoretical results, and the corresponding computer software is also developed. The development of this research project can realize the modular, program, and visualization of soil slope stability analysis under the complex conditions, and these results can be convenient to guide the existing soil slope safety assessment and reinforcement protection.