Stability of intact slopes with tensile strength cut-off

Abstract

The Mohr–Coulomb yield criterion, typically used in slope stability analyses, predicts the uniaxial as well as the isotropic (triaxial) tensile strength. In this study, the tensile strength was reduced or eliminated from the yield condition in order to determine whether it has any consequences on the outcome of the stability analyses of slopes. It was discovered that the consequences on the slope stability factor are very significant. Slopes that are most affected by the tension cut-off are steep slopes, particularly in the presence of seepage. The difference in stability factor for steep slopes calculated with the classical Mohr–Coulomb strength envelope and a criterion with tensile strength cut-off can exceed 50% for steep slopes subjected to seepage (70% for vertical slopes). Tension cut-off used in the analysis permits deformation modes with the dilatancy angle exceeding the internal friction angle, and this is the likely cause of producing more critical mechanisms of slope collapse. The novelty of this study is in presenting a new slope stability analysis that accounts for tension cut-off, and in demonstrating the significant impact of reduced tensile strength on the outcome of the stability assessment.