黄土边坡滑坡侵蚀稳定性计算方法探讨

滑坡是土坡重力侵蚀破坏的主要形式，在目前的工程实践中，土坡稳定性分析最常用的方法是圆弧条分法。但对大量黄土滑坡的观测表明，其滑动面并不是圆弧，一般是后壁陡直，下部接近圆弧，总体形状呈“L”形。因此采用经典的圆弧法计算黄土边坡的稳定性是不准确的。根据Mohr-Coulomb强度理论计算出黄土滑坡后缘拉裂的深度，自拉裂底部至坡脚处假定为圆弧滑动面，在此前提下搜索最危险滑动面的位置。笔者曾提出了搜索最危险滑动面的一种方法，并结合该方法推导出了用圆弧法求解稳定系数的解析式。将黄土边坡具有后缘拉裂这一特点，应用于该解析方法中，进一步推导出用于黄土滑坡侵蚀稳定性的计算公式，通过对泾河南岸一黄土高边坡滑动前地形断面观测和土的物理力学性质指标的测试，计算得出其潜在滑动面，再与其滑动后实测滑动面比较，表明提出的方法比一般的圆弧法有更高的精度。

A Method for Calculation of Loess Slope Stability Under Gravity Erosion

Landslide is the main failure form of earth slope under gravity erosion. In engineering practice, the circle sliced method is popularly used in slope stability assessment. Investigations of many loess slides suggest that the sliding surfaces are not typical circle on section, but that is a high back cliff with an approximate circle in the lower potion. That means it is not suitable to apply the circle slice method in loess slope calculation. The depth of tension crack equivalent to the height of back cliff could be calculated with Mohr-Coulomb strength theory, supposing the bottom of the crack to the toe of the sliding is a potential circle sliding surface, a formula suitable for calculating the factor of safety of loess slope stability is proposed. The method is used to calculate the potential sliding surface of a recent failed high loess slope on the south bank of the Jinhe River, the results detained with this method are more close to the actually surveyed sliding surface than with the circle sliced method.