Extreme weather events. Gravitational mass movements. Recife Metropolitan Region (RMR).

Landslides are often associated with human, economic, and environmental losses, mainly affecting vulnerable populations residing in high-risk areas without adequate basic infrastructure. The city of Recife has a high population density living in landslide prone areas, with several landslide disasters recorded in recent years, mainly influenced by extreme weather events. In light of this, the present study aims to evaluate the geotechnical characteristics of a slope located in the Dois Unidos neighborhood, North Zone of Recife, and assess its stability through flow and stability analyses, using the current topography of the area, as well as understanding the slope failure that occurred in May 2022. Geological-geotechnical field and laboratory investigation campaigns were carried out, including planimetric surveys, SPT borehole tests, disturbed and undisturbed sampling, in-situ permeability testing with the Guelph permeameter, physical characterization tests, soil strength, suction, and compressibility tests. The geotechnical parameters obtained from these tests were input into flow and stability analyses, performed using Slope/W and Seep/W software. In stability analyses considering the pre-failure section, it was observed that the rainfall in May 2022 acted as a triggering factor for the landslide, considering its joint action with other predisposing factors. Considering the current topography of the area and the probability of rainfall conditions similar to those in May 2022, the analyses conducted show that the values of the safety factors (FS) can approach unity, indicating that the slope is susceptible to new landslides. Finally, it is concluded that the study area is densely occupied, in an inadequate manner, undergoing constant changes in its landscape, which can directly affect the value of safety factors in the area, and consequently, lead to landslides.