Shallow landslides of the Souk Ahras region: influence of soil geotechnical properties and rainfall

Abstract

In the Souk Ahras area of northeastern Algeria, shallow landslides typically happen after heavy rain. To investigate these landslides and the circumstances surrounding their occurrence, three sectors Zaarouria, Hammam Tassa, and Mechroha were selected. They have been seen to predominantly impact the transportation system, major supply locations, and agricultural land. The purpose of this research is to determine how soil characteristics, geology, and geomorphology relate to precipitation. A number of field excursions to the research locations were planned, and while there, landslide masses were characterized, mapped, and some field measurements, such sampling and determining the natural moisture content, were made. We measure the density, Atterberg limits, reinforcement size distribution, effective cohesion, and internal friction in the lab. The hydraulic function and the soil water characteristic curve (SWCC) of unsaturated soil were then calculated. GeoStudio 2020 software was used to do the stability calculation, which is a coupled study where Seep/W mimics infiltration and Slope/W the safety factor. According to the findings, the studied sector contains clay sands with gravel (SC), well graded sands with silt and gravel (SW SM), and silt sands (SM), with hydraulic conductivity ranging from 4.5. 10 6 for 4.10 5 and 10 3 m/s. The safety factor ranges from 0.8 to 1.16 and back to 0.8. In conclusion, our research supports field findings that a number of shallow landslides occurred in March 2019 when rainfall totaled 110 mm. additionally, the safety factor progressively declines in the two other less permeable soils, Zaarouria and Hammam Tassa, whereas the high permeability soils in Mechrouha exhibit a bigger reduction at the 100 mm rainfall level.