Footwall slope stability analysis with the numerical manifold method

Abstract

This paper extends the numerical manifold method (NMM) for footwall slope stability analysis. A fracturing algorithm based on the Mohr–Coulomb criterion with a tensile cutoff is implemented into the NMM code. The developed program is first calibrated by simulating four typical crack problems. It is then applied to analyze the potential footwall slope instability. Parametric studies with respect to dip of a bedding plane, orientation of a predominant joint set, the bedding profile, etc., are carried out. Numerical results indicate that the developed program can simulate the opening and sliding along pre-existing discontinuities, fracturing through intact rock, as well as kinematics of the failed slope, and can also reproduce the major failure mechanisms observed in footwall slope collapses. The NMM is promising for such problems and deserves to be further developed to be practically used in natural/excavated rock slope stability analysis and open pit slope design.