边坡的破坏失稳是一个渐进累积的过程。在外部环境作用下，随着应力的升高，坡体内某些部分达到屈服，滑动面逐渐形成，直至完全贯通，随着塑性应变继续增大，边坡最终发生整体破坏。传统的分析方法无法显示坡体的受力、变形和滑动面贯通与破坏的全过程，而采用有限元强度折减法则可以定量显示变形破坏与滑动面发生发展的全过程。文中根据岩土性质和坡体构造对边坡进行了分类。分析不同边坡安全系数条件下各类边坡的变形图和塑性应变云图，可以看到坡体的变形趋势和坡体内滑动面随稳定安全系数的降低逐渐扩展、贯通，直至破坏的全过程，从而直观地揭示了边（滑）坡的破坏机理，为边（滑）坡的防治提供有效依据。

The failure of slope is a gradual accumulation process. Under the effect of many interior and exterior factors, some parts in the slope reach yield with the increase of stress, and sliding surface forms gradually till complete transfixion. With continuous increase of the plastic strain, overall failure happens on the slope. Traditional analysis method cannot display the mechanic conditions and the whole process of deformation, transfixion of sliding surfaces and failure. Meanwhile, FEM strength reduction can quantitatively show the deformation features and the process of occurrence and development of sliding surface. Based on the previous researches, the paper classifies slopes according to the features of rock and soil and the slope structure. Through analyzing the graphs of deformation and the nephograms of plastic strain under different reduction factors or safety factors, the researchers can directly find the deformation tendency of slopes and the whole process of the extension, transfixion and failure of sliding surface with the reduction of safety factor. So, the failure mechanism of slope can be found intuitively, which can provide effective basis for the prevention and governance of slopes.

科技部“973”项目（2011CB710606）