Contribution to the study of landslides in Dir-El Ksiba (Atlas of Beni Mellal, Morocco) using the geological, geotechnical, and geochemical approaches

Landslides present major problems in the mountains and hills of the Atlas of Beni Mellal, Morocco. Therefore, the main objective of the present work is to study the relationship between the geological, geotechnical, and geochemical data of the red layers at risk of landslides and to propose adequate solutions to limit the risk of these landslides. Atterberg limits were made to classify soil samples into swelling or non-swelling. Liquidity and plasticity limits ranged from 38 to 41 and 16 to 21, respectively, favoring the instability of the slopes along these hills, especially during the rainy period. The physicochemical and mineralogical analysis showed that the studied soil is alkaline, strongly rich in carbonates with higher levels of Ca, Si, Al, and Fe, with a clayey texture characteristic of the geological formations of the study area. From the geological point of view, this area shows the dominance of marl–limestone and marl–clayey formations and altered basaltic intrusions in some places. The results also showed that these hills present corners of gravity instability due to the geotechnical behavior of the materials during the rainy periods. These results provide decision-makers with valuable data to limit the risks of landslides in this region.