Análise de estabilidade de uma falésia na região central de Pipa – Tibau do Sul/RN

Abstract

The erosion processes to which the seacliffs are subjected trigger the continuous occurrence of mass movements. Periods of high rainfall and the increasing occupation of areas adjacent to seacliffs enhance the occurrence of these mass movements, which can cause high socioeconomic and environmental damage. Thus, the present study aimed to carry out stability analyzes by methods based on limit equilibrium and stress analysis, when applied to the case of a seacliff located in the central region of Pipa - Tibau do Sul/RN. Associated to the seacliff in question, which is located in an area of high real estate speculation and touristic activity, potentially favorable conditions for the outbreak of mass movements were identified. For this purpose, parameters of mechanical behavior of the soils of the Barreiras Formation under natural moisture content and saturated conditions, derived from studies carried out in the region, were used to support the analyses. Furthermore, slope profiles were drawn considering the geometry of the seacliff and situations observed at the site, such as the presence of accumulations of colluvium adjacent to the slope, incisions at its base and overload at its top. The influence of these factors on the stability of the slope was evaluated for the soils in the natural moisture content and saturated conditions in the stress analyses, in addition to being considered wetting fronts in the limit equilibrium analyses. The results showed that the accumulation of colluvium near the base of the seacliff tends to contribute to an increase in its safety factor on a limit-equilibrium based analysis. On the other hand, the presence of a basal incision has the potential to trigger significant mass movements on the seacliff, and its effect is better evaluated by means of stress analysis. In all situations, the considered overload and the hypotheses with soil saturation of the layers were unfavorable factors for the stability of the slope.