Slope stability is one of the fundamental problems faced on a consistent basis by the
majority of practicing geotechnical engineers. The studied slope may be a cut slope
(excavation), or a formed slope (embankment). The objective of the current paper is
to evaluate and assess the effect of many parameters affecting the stability of slopes
and to produce a general equation for calculating the safety factors in simple and
easy way. The finite element method is a very effective and versatile numerical tool,
especially in nonlinear analysis, and consequently, a finite element code for soil and
rock analysis (PLAXIS) is chosen for this paper. Results indicated that the slope
height is probably the most effective parameter in the safety factors of slopes,
followed by the effect of the presence of water beside or within the slope. Shear
strength parameters and slope angle also affect the safety factor value, as indicated
in the developed general equation for calculating the factor of safety in homogeneous
soil slopes. The proposed equation is verified by comparing the calculated values
obtained from that equation with PLAXIS results, and the maximum difference was
about ±4%. Moreover, the results obtained from the proposed equation are
compared with the results from Michalowski Charts (2002) and the maximum
difference was about 7% in the conservative side, despite employing different
analysis approaches.