Highway cutting slopes with high rainfall erosion in Morocco: Evaluation of soil losses and erosion control using concrete arches

Highways in northern and northeastern Morocco through mountainous areas generate a series of high cut slopes and embankments. Highway cuttings are generally established in pelitic and marly soils, which are very vulnerable to rainfall erosion. Because of climate change, precipitation is very irregular and often characterized by aggressive showers. This precipitation generates significant soil losses that can compromise the security and durability of highway structures. The Moroccan National Highway Company deploys an important research program and fieldwork to combat the rainfall erosion of cutting slopes. This study concerns the evaluation of soil losses affecting these slopes in the Tangier-Port Tangier Med and Fez-Taza highway sections. It highlights the factors governing soil erosion and proposes a method for the protection of highway cutting slopes by concrete arches. The stability of the cutting slopes several years after the installation of these arches testifies to the efficiency of this protection system.