Design of reinforced embankments: Limit equilibrium and numerical methods

Abstract

The aim of this paper is a comparative study of a reinforced embankment using two different design approaches. The first methodology is based on the limit equilibrium approach and the fundamental aspect of achieving equilibrium of forces and/or moments along predefined failure surfaces. The approach is widely used due to its simplicity and leads to an adequate and safe design, considered in many codes, by providing a global safety factor. However, it lacks the ability of predicting the kinematic field and the level of stresses, while a main shortcoming is the incapacity of materials to vary their ultimate strength in relation with the stress path. In the second approach, the powerful tool of numerical analysis is applied, providing the ability of modeling the mechanisms developed and allowing for shear strength variation with regard to stress and displacement field. In addition to estimating the safety factor, numerical analysis provides both displacement and stress field, indicating the areas where failure is to initiate and progress. Several numerical analyses under static and seismic loading have been carried out in order to assess the effect of both the multi-stage modeling and the creep action on the response of a reinforced embankment. Quantitative and qualitative comparison of the results arising from the aforementioned approaches is made and the main advantages and drawbacks are discussed.