在稳定性分析中采用了直接法和广义法。简布的简化方法是基于复合非圆的，安全系数是由水平力平衡决定的。该方法考虑了正常的夹层力，但不包括剪切力。一般的基力是确定的，它和安全系数是一样的。毕夏普的简化方法是: 安全系数的推导是建立在力矩和力平衡的基础上的。P= w/b =总垂直应力。B=切片的宽度。
The direct method and generalized method is introduced by Janbu that is used in the stability analysis. The simplified method of Janbu is based on the composite noncircular and the factor of safety is determined by the horizontal force equilibrium. The method considers the normal interslice forces, but it does not include the shear forces. The normal base force is determined, and it is the same as the factor of safety. Bishop’s simplified method is computed by:
The derivations of a factor of safety are based on moment and force equilibrium.
P= w/b = total vertical stress
B= width of the slice
The general limit equilibrium procedures consist of assumptions and developments made by the limit equilibrium methods. This is the extension of Morgenstern-Price and Spencer methods where the interslice slope is assigned to evaluate the interslice forces. The general limit equilibrium is appropriate to compare the common methods in the factor of safety. The most inclinations of moment equilibrium and force equilibrium have been particularly likely for the circular SS analysis. The position of Fm and Ff has been reversed by the plane SS analysis.