Ground-based synthetic aperture radar interferometry for deformation monitoring: a case study at Geheyan Dam, China

Full coverage and continuous deformation information retrieval are key aspects for dam health diagnosis. Ground-based synthetic aperture radar (GB-SAR) interferometry is used for the remote monitoring of the Geheyan Dam, China. Although the monitoring of a dam with ground-based interferometry is not an innovation, specific issues have been found out in the case study discussed due to the large dimension of the monitored structure. More than 400 images were used for interferogram generation. Radar signals reflected from the dam were carefully analyzed: a sort of tunneling effect caused by multireflection is observed, and deformations caused by water level and temperature variations were detected during a six-day monitoring campaign. Radar monitoring results were compared to the data recorded by plummets installed in the dam. The agreement between the displacements retrieved from interferometric data and the plummets demonstrates the capability of GB-SAR for deformation monitoring, with the advantage of large area coverage