Stability analysis. Retroanalysis. slipping

The city of Recife coexists with the constant landslides that affect, especially, the most vulnerable population residing on irregularly occupied slopes. In recent years, with the occurrence of unusual weather phenomena, hundreds of people have been left homeless and lost their lives. In this sense, aiming to contribute to the mitigation of these negative impacts, the present study aims to present a geotechnical characterization, discussing a stability analysis of the slope of Boleiro, located in the North Zone of Recife, in addition to performing a retroanalysis of the rupture that occurred on the slope in May 2022. The analyzes were developed using the finite element software Slope/W and Seep/W, both from GeoStudio (2023). For this, a campaign of field and laboratory tests was carried out, which helped in the construction of the geotechnical profiles, obtained from the SPT surveys and physical characterization tests. The resistance, compressibility and suction parameters were determined from the collection of information blocks extracted in each study area, with results consistent with those presented in the technical literature. For the stability analysis, the saturated and unsaturated conditions of the soil were considered, in order to verify the flow conditions and understand the behavior and influence of infiltration on the stability of the slope. For this purpose, two analyzes were carried out under transient regime, one considering the precipitation of the rainiest month (May 2022) and the other simulating the rupture of a pipe. For the retroanalysis, the saturated and unsaturated condition of the soil was also considered, analyzing the flow conditions and the influence of the accumulated precipitation in the month in which the event occurred (May/2022). In the stability analyses, the results showed a significant reduction in the safety factor values for the two flow conditions, considering the influence of precipitation and pipe rupture. Meanwhile, the results of the retroanalysis show that the main triggering agent for the heat was the accumulated rainfall that occurred in May 2022, with a safety factor equal to 1.0. In this way, the work presents the slope stability condition at the points studied, contributes to theunderstanding of the accident that occurred and helps in understanding the causes and triggering factors of these events, in addition to helping in the prevention and mitigation of future accidents.