Modifications to three well-known methods of slope stability analysis

Abstract

Substantial modifications to three well-known methods of slope stabilility analysis, i.e., the Morgenstern-Price method, the rigorous Janbu method, and the Sarma method, are presented. Based on the basic assumptions used by these methods, formulas for computation of factor of safety are re-derived which are more concise and applicable than their original versions. For the Morgenstern-Price method, according to the force and moment equilibrium conditions of the slice, the expressions in algebric form (instead of differential or integral form) for the factor of safety Fs and for the scaling factor λ, are derived respectively, and only a simple iterative scheme is involved for rapidly obtaining converged solutions. For the rigorous Janbu method, the cause of non-convergence inherently in the original solution process is discovered, which can be eliminated by using smooth interslice moment distribution prescribed at certain locations within the sliding body, leading to stable convergence. For the Sarma method, a more concise process is involved in deriving the implicit expression for the factor of safety and the explicit expressions for critical seismic coefficient and critical reinforcing load factor. On modification, the computation processes associated with the three methods are largely simplified and converged solutions are always obtained. The modified versions of the three methods of slope stability analysis can be used by geotechnical engineers in the design of slopes and treatment of landslides.