Abstract
A series of stability analyses of cohesive soil slopes was conducted by means of limit equilibrium method to clarify the effects of three-dimensional shapes of sliding mass and slope on the slope stability. In the analyses, straight and curved slopes consisting of frictionless soil were considered; the curved slopes were defined with concentric circles instead of straight lines, and sliding surfaces were defined with spheroid. Through the analytical investigations some important features of three-dimensional slope stability were found. Even straight slope with finite width has a critical sliding depth with notably higher stability factor than that of with infinite width that shows the lowest stability at infinite depth as in ordinary two-dimensional analysis. Curved slopes have their own critical sliding width depending on its curvature. We updated the stability diagram presented by Terzaghi with three-dimensional effects taken into account.
