成层土质边坡稳定性极限曲线法

滑移线场理论在非均质边坡稳定性分析中的单独应用还未见相关报道,提出了基于该理论以土坡变形情况评价成层土坡稳定性的极限曲线法。该法是求有重边坡极限荷载的逆过程,是强度折减法的对偶过程。以极限稳定状态下坡面曲线与原坡面线相交为变形破坏准则,定义了安全度(DOS)和破坏度(DOF)2个稳定性评价指标。将均质土体的特征线法方程组拓展为成层土体情形,原方程组为其特例;依据将土层分界面看成特殊应力间断面的观点,研究了滑移线在土层分界面发生折射的条件与公式。相对于传统方法,该法不必假定和搜索滑裂面。7个成层土坡实例计算结果证明了变形破坏准则的正确性,DOS,DOF与安全系数的评价结论一致,表明该法对成层土坡具有一定适用性。

Limit Curve Method to Assess the Stability of Layered Soil Slope

The independent application of slip line field theory in slope stability analysis has not been reported yet. On the basis of slip line field theory, we propose a limit curve method of assessing the stability of layered soil slope according to the slope deformation situation. This method is the inverse process for the ultimate load of heavy slope and the dual process of strength reduction method. Considering the intersection of slope surface curve under limit state and the original slope surface as failure criterion, we define two assessment indicators: Degree of Safety (DOS) and Degree of Failure (DOF). Then we extend the characteristic line equation of homogeneous soil to the layered soil condition, with the original equation as its special case, and soil interface as the special surface of discontinuity. On this basis, we obtained the condition and formula of slip line refraction in soil interface. Compared with traditional methods, this method needs not assume and search critical slip surface. Seven calculation examples verified the correctness of the deformation failure criterion. The stability evaluations of DOS/DOF with different theoretical methods are consistent, indicating this method is applicable to analyse the stability of layered soil slope.