Abstract: Aiming at the stability analysis of multistage homogeneous loess slopes, a systematic analysis method is proposed. Firstly, the possible failure mechanisms such as slope toe circle and midpoint circle under the overall failure mode and local failure mode of multistage loess slopes are established. Then, based on the improved limit equilibrium method, an analytical solution of slope safety factor corresponding to each failure mechanism is derived, and the optimization method is used to determine the minimum value of safety factor corresponding to each failure mechanism under the overall and the local failure modes. Finally, the flowchart of systematically performing multistage loess slope stability analysis is put forward to determine the minimum safety factor and the critical slip surface. The results of numerical examples show that the proposed method are comparative to the traditional stripe method. The relative deviation of the minimum safety factor calculated by the two methods is less than 5%, and the critical slip surfaces determined by the two methods agree to each other very well. The proposed method in this paper can be widely applied to various multistage homogeneous loess slopes and even single-stage slopes, which is promising for engineering applications.

Key words: multistage slope, limit equilibrium method, optimization, safety factor, critical slice surface