Uncertainty analysis of safety factor of embankment built on stone column improved soft soil using fuzzy logic α-cut technique

Abstract Uncertainty in safety factor (FS) of slope stability is a main subject in geotechnical engineering. Uncertainties are associated with shear strength parameters of the soil, their complex nature, numerical analysis methods, etc. The main aim of this research was to improve the model used by other researchers for determination of FS of embankments built on stone column improved soft soils, and compare the results with what was found in literature using α-cut fuzzy technique (FAC). The results showed that the highest and lowest uncertainty occurred at equivalent area with existence of underground water, and for single stone column with no underground water respectively. A reduction factor proposed to amend the FS calculated using the equivalent area method. In the equivalent area model, the equivalent parameters were used. This contribution might have real and more precise behavior in comparison with what was suggested by other researchers in literature. In addition, with applying of membership functions, the height of embankment had the most effect on the values of FS obtained using finite element (FE) and finite difference (FD) methods.