安全系数的计算和临界滑动面的确定是边坡稳定性分析的两个组成部分，强度折减法可以得到合理的安全系数，但却不能准确刻画临界滑动面的位置。基于对滑动现象的认识，提出了一种基于位移场分析的临界滑动面确定方法，认为当边坡处于临界状态时，其潜在滑动面附近的位移等值线最为密集，潜在滑动面上的点往往是在深度方向上沿垂直滑面的位移变化率达到最大值的位置。将本文方法与Spencer法、岩质边坡模型试验进行了对比，验证了该方法在曲线和折线滑动面搜索方面的适用性和可靠性。同时，探讨了单元形状、疏密程度、离散点间距等因素对滑动面的影响。

In slope stability analysis, one needs to calculate the factor of safety and determine the slip surface. The strength reduction method can yield reasonable value of the safety factor, but it cannot depict correctly the critical slip surface. This paper proposes an approach to determining the critical slip surface based on the displacement filed analysis during the sliding movement. It is shown that the displacement contours near the slip surface are the densest at the critical state of slope. The points along the potential slip surface represent those points at which the change rate of displacement along the direction perpendicular to the critical slip surface reaches the maximum in the vertical direction. By comparing the proposed method with the Spencer method and physical model test of rock slopes, it is shown that the proposed method yields good results in searching the slip surfaces. In addition, the effects of some other factors such as geometrical shape, degree of density and discrete point spacing on the slip surface are discussed.