| Because the number of dams that have behaved stable over an extended period, the exterior deformation measurement of embankment dams for the safety management often runs into difficulties due to time-consuming surveying procedures and high labor costs. Moreover, during an emergency such as a large earthquake, it is difficult to secure adequate surveyors in a disaster area to carry out temporary inspections, and taking measurements of exterior deformation in such a state of disaster presents a potential risk on the safety for workers. For these reasons, there is a strong demand for a means of conducting a rapid and safe measurement of the exterior deformation of embankment dams. In this paper, on the basis of data collected by Synthetic Aperture Radar (SAR) satellite, a basic examination was carried out regarding the applicability of Interferometric SAR (InSAR) to the exterior deformation measurement of embankment dams. No measurement facilities are needed for SAR, and it results in cost reduction of data acquisition for exterior deformation measurement of embankment dams. Exterior deformation of a rockfill dam with a height of 66 m was measured by InSAR using single pair analysis and time-series analysis during about four years just after the completion. The results by InSAR were compared with those by GPS, and we confirmed the tendency of settlement of a dam body was well reproduced. |
