Integrating Eurocode 7 (load and resistance factor design) using nonconventional factoring strategies in slope stability analysis

Abstract

In traditional allowable stress design, as known, the safety factor is calculated with respect to shear strength of soil(s) by dividing the available shear strength by the mobilized stresses. The limit-state method, on the other hand, compares — in the form of the inequality Ed≤ Rd— the effects of all the actions, Ed, with the corresponding resistance of the ground, Rd. Although this method considers different loading conditions by using suitable combinations of design values, it is still based on direct comparison of the available shear strength with the mobilized stresses. In the present paper, various factoring strategies (in addition to the traditional one with respect to shear strength of soils) are integrated into a limit-state method framework. Eurocode 7 has been chosen for this purpose. The whole procedure aims at giving a more comprehensive insight into the design of slopes and the sensitivity of safety level of slopes to the various parameters. In addition, the proposed methodology, as shown, may result in a safety level of slopes significantly lower than the respective one obtained using the limit-state method in its traditional form. As man-made slopes that conform to design standards often fail in practice, even though conservative input values are used, these failures must be treated with more skepticism by practitioners adopting supplementary design practices such the one presented herein.