Abstract: This paper presents the slope stability evaluation results using the unified triple shear yield criterion. The Swedish Slicing Method with the unified triple shear yield criterion was used to estimate the factor of safety of the target slope. The results indicate that the stress state, shear strength of the soil as well as the middle principal stress coefficient can, at least some extent, affect the factor of safety. When the Lode Parameter is greater than zero, the resultant factor of safety decreases with the increase of the Lode Parameter. When the Lode Parameter is smaller than zero, the obtained factor of safety of the slope increases with this parameter. The factor of safety also increases with the cohesion, the internal friction angle as well as the middle principal stress coefficient. It is concluded that the factor of safety of the slope can be improved by considering the effect of the middle principal stress coefficient.

Key words: Unified TripleShear Yield Criterion, Slope Stability Evaluation, Intermediate Principal Stress