Design of the Safe Model of Landfill Dikes for Developing Countries

This article is a dimensioning study of the landfill locker dike of the city of Casablanca, where the geotechnical parameters of waste have particular limitations, theses limitation are a common characteristic for most developing countries. Considering the very small available land area in general, the objective is to achieve an optimal dimensioning of the locker to maximize the volume to be buried, while respecting the requirements of stability of the structure; namely, the model whose safety factor will be greater than 1.5. The Factor of Safety (FoS) was calculated by the Finite Element Method (FEM) using “PLAXIS 2D” software. The results show that, for both cases (with and without final cover), FoS, as obtained from both the analysis, show a similar pattern, with the maximum FoS for low inclinations, especially those lower than 15.95°. The critical FoS (< 1), was obtained for slopes strictly greater than 21.80°. The study also demonstrated that the 3.5H 1V model could be considered as the optimal one that satisfies the structural stability requirements (FoS> 1.5) and maximizes the volume to be buried. Nevertheless, the validation of this model is conditioned by a geometric modification (weakening the lateral slope of the landfill, by moving the dikes by 3 m) and the improvement of the mechanical characteristics of the soil of the peripheral dike, through replacing the material with the compacted clay. This model was validated by PLAXIS, which showed that the FoS for the phase preceding the anchoring of the final cover is 1.577, which reaches 1.604 after anchoring.