Landslide forecasting: mapping risks in Morocco’s middle Rif—BOUALMA LANDSLIDE

This work is situated within the context of a major geotechnical project aimed at delineating high-risk landslide zones in the Middle Rif region of Morocco, particularly between Al Jebha and Al Hoceima. The purpose of this article is to address an example of slope instability identified in the Boualma area using the Limit Equilibrium Method (LEM) methodology and validating it with the Finite Element Method (FEM). The main results of this work are the stabilization solutions for a 150 m high slope, consisting, in Phase 1, of re-profiling the slope to reduce the mass of soil set in motion by the seismic activity known in the study region, complemented by Phase 2, which involves introducing 16 nails that mobilize the friction of the substratum to ensure a highly secure safety factor. Additionally, we demonstrated the superior performance of the FEM compared to the LEM by considering the soil’s rheological behavior and the soil-structure interaction of the stabilizing nails with the supporting soil. Finally, we conducted an economic analysis of the stabilization solution over a 100 m length of the slope to quantify its financial estimate, which amounts to almost 1.3 million USD. Moreover, the conclusion drawn is a recommendation for professionals in the management of road and rail infrastructure to initially invest in durable stabilization solutions, although costly, to ensure the viability of strategic roads and avoid disruptions and their impact on passenger and freight transport.