Strength Reduction Slope Stability Analyses Using the Curved Mohr-Coulomb Model

The conventional Mohr-Coulomb model assumes a linear shear failure criterion. However, extensive experimental studies reveal that geomaterials, particularly at low confining stresses, exhibit a nonlinear failure envelope, suggesting a curved strength model more representative of material behavior across a broader stress range. This linear assumption can introduce significant inaccuracies in safety assessments, particularly when evaluating shallow slip surfaces in slope stability analyses. This study examines the numerical slope stability analysis using the strength reduction method by adopting a newly implemented curved Mohr-Coulomb strength model in FLAC3D, emphasizing the impacts of a nonlinear failure envelope, stress-dependent dilation, and three-dimensional conditions on factor of stability. This curved Mohr-Coulomb model can define the curved (nonlinear) failure envelope by a pre-defined power law or user-defined piecewise curve, either in either shear stress versus normal stress space, or principal maximum stress versus principle minimum stress space. The findings provide insights into optimizing model parameters for realistic slope stability assessments.