Monitoramento da integridade e estabilidade de uma barragem de terra através de métodos geofísicos

Abstract

Geotechnical engineering and water management are essential for the preservation of dam integrity. This study addresses the monitoring of the integrity and stability of an earth dam in Caçapava do Sul (RS) through the application of geophysical methods, with an emphasis on resistivity and GPR (Ground Penetrating Radar) methods. The central objective is to evaluate the integrity of the dam using non-invasive techniques to investigate the subsurface characteristics of the soil. Resistivity is employed to map the distribution of electrical resistivity, allowing for the identification of saturated zones and the assessment of soil uniformity. In parallel, the Ground Penetrating Radar maps the subsurface layers, detecting anomalies and providing information on the geometry and internal structure. The assessment was carried out through geophysical investigation and stability analysis. Technical visits were conducted at the dam site, and investigative geophysical profiles were executed using the resistivity and Ground Penetrating Radar methods. The slope stability analysis was produced using the Simplified Bishop and Simplified Janbu methods through the Hyrcan software. The parameters used in the modeling were based on the most critical results, under natural conditions, obtained from geotechnical soil tests and technical parameters of the massif geometry, creating two other conditions for analysis. Thus, the results obtained showed that the proposed methodology is satisfactory. Geophysical analyses revealed significant anomalies, such as low resistivity zones indicating saturated soil or clays, and high resistivity areas suggesting rocky substrate. Fractures, heterogeneities, and high moisture zones were identified, which are critical for the dam's integrity due to the potential for water infiltration and internal erosion. Regarding the safety factor, none of the models generated from the Bishop and Janbu methods presented the minimum value required by current standards. For this reason, it is advised that studies continue to be conducted on site.