Potencialidades e limitações do uso da técnica InSAR para avaliação do monitoramento de talude em faixa de dutos em área de vegetação

Abstract

In Brazil, pipes are an important part of oil, gas and derivatives transportation. A significant portion of these structures pass through rugged terrain in the most diverse geomorphological sites and are susceptible to mass movements. Geotechnical monitoring of slopes along pipelines is crucial for continuous safety assessment and decision-making regarding risk reduction measures. The objective of this study is to evaluate the use of synthetic aperture radar interferometry (InSAR) as a complementary tool to conventional geotechnical monitoring methods. The analysis was conducted on a slope subject to slow mass movements (creeping), located in a pipeline in the state of Bahia. The application of InSAR technology involved two approaches. Initially, the classical differential interferometry (DInSAR) technique was used to identify surface displacements from pairs of SAR images. Next, the advanced technique (A-DInSAR) was used, employing persistent scatterer interferometry (PSI) to detect targets that are stable over time. Twenty Sentinel-1 SAR images were used for this purpose. The DInSAR results indicated limitations due to the low interferometric coherence in the study area due to vegetation, which compromised the reliability of the results. Alternatively, the PSI technique allowed for more accurate identification of displacements. However, the low density of persistent scatterers in some sections limited the spatial coverage of the measurements and may represent a limitation for its application. The InSAR technique revealed limitations in areas with vegetation cover, particularly due to temporal decorrelation and a scarcity of coherent targets. The option of integrating analysis with topographic survey and geotechnical inspection data enabled its application in geotechnical contexts. The correspondence between remotely detected displacements and field observations confirmed the results obtained. Even in environments with natural restrictions, the technique has demonstrated the capacity to contribute to slope monitoring and has established itself as a complementary tool in stability studies and risk management