Comparison of slope stability methods of analysis

TLDR

Slope stability analyses use factor‑of‑safety equations that are structurally identical across methods, with the normal‑force equation differing only for the ordinary method. This study compares six slice‑based methods for slope stability analysis. The authors derive a best‑fit regression solution for the Morgenstern–Price method by independently solving force and moment equilibrium factors of safety across λ values, thereby distinguishing interslice‑force handling among the methods. The best‑fit regression solution yields the same factor of safety as the Newton–Raphson method and provides clear insight into how the factor of safety varies with λ.

Abstract

The paper compares six methods of slices commonly used for slope stability analysis. The factor of safety equations are written in the same form, recognizing whether moment and (or) force equilibrium is explicitly satisfied. The normal force equation is of the same form for all methods with the exception of the ordinary method. The method of handling the interslice forces differentiates the normal force equations.A new derivation for the Morgenstern–Price method is presented and is called the 'best-fit regression' solution. It involves the independent solution of the force and moment equilibrium factors of safety for various values of λ. The best-fit regression solution gives the same factor of safety as the 'Newton–Raphson' solution. The best-fit regression solution is readily comprehended, giving a complete understanding of the variation of the factor of safety with λ.