Toward Three-Dimensional Slope Stability Analyses?

Fredlund reviews why many real slopes behave in three dimensions and argues for broader adoption of 3D analysis. He compares 2D and 3D factors of safety, showing how geometric constraints, stratigraphic variations and pore-pressure conditions often make 3D models more realistic. The article examines back- and forward-analysis implications, showing that 2D back-analysis can produce unconservative shear-strength parameters when the true failure mass is 3D. Fredlund also describes multi-directional and complex-geometry examples and discusses how advances in computing allow practical 3D limit-equilibrium and shear-strength-reduction modelling.