Abstract: In the aim of obtaining the relationship between microcosmic mechanism of soil slope instability and macroscopic displacement, a method of slope stability evaluation is proposed. The internal correlation between the soil element stress and the whole stability in the process of soil slope sliding was analyzed through shear strength reduction finite element method, and the stress difference of soil unit on the potential sliding surface during progressive failure of slope was defined. In subsequence, the consistency and uniformity among different criteria, including plastic zone penetration, abrupt change of characteristic displacement, and stress difference, were verified through instability evaluation. Furthermore, the influences of geometric and physical parameters on the horizontal displacement of slope top in limit state were analyzed through single-factor sensitivity analysis method. These parameters include slope height, slope ratio, elastic modulus, density, cohesion, internal friction angle, and Poisson ratio. Finally, the normalized failure criterion for soil slope based on deformation in consideration of both geometric and physical factors was established through the method of coefficient of variation.

Key words: soil slope, normalized variables, failure criterion, shear strength reduction FEM, global stability