A finite element (FE) analysis of the field test excavation in Welland Clay is performed using an anisotropic soil behavior model. This paper describes the model, FE formulation, and transient effective stress stability analysis, and compares FE results with the field measurements. The analysis reflects the postexcavation decrease in the factor of safety with time and predicts the failure of the slope along the observed failure surface. The parametric study shows that the time to failure is a function of the pore pressure boundary conditions at the excavation surface and affects the transient factor of safety.Key words: constitutive relations, excavations, finite element, plasticity models, pore pressure, soil anisotropy, stability.