中文摘要：

边坡的失稳判断是有限单元强度折减法的一个重点，对目前经常采用的3种判据分别讨论，结果表明：以点的位移突变作为判据比以塑性区贯通和以解的不收敛作为判据更可靠。依据突变理论，建立起水平方向最大位移和折减系数的尖点突变模型，以此作为边坡临界失稳的判据，将失稳判据量化成一个确定的值，并给出判断的方法，消除了计算中人为因素的影响。算例表明，采用该模型作为判据，能体现边坡失稳过程中的突变性，物理意义明确，与极限平衡法计算结果较一致。

英文摘要：

How to determine the slope loss stability is most important in the strength reduction method. The calculation results show that the displacement of a point mutation as a criterion is better than the connectivity of plastic zone and the non-convergence criterion. The cusp catastrophe model criterion is set up based on catas- trophe theory. This model under the direction of the maximum level displacement and reduction factor has high degree of precision and clear physical meaning. Avoiding human influence factors, the examples present reliability.