Deformation Monitoring of Ring Rockfill Dam in Pumped Storage Power Station Based on Spaceborne InSAR

The deformation monitoring of the ring rockfill dam in pumped storage power stations is of great significance. Traditional monitoring techniques such as geodetic survey, GPS, and multi-point displacement meters have high precision and reliability but are limited by point monitoring in terms of layout density and range. InSAR technology has advantages like high precision, large range, all-weather, non-contact, and low cost, yet faces challenges from factors like spatio-temporal decorrelation, atmospheric delay, and vegetation cover.

 

This research utilized the permanent scatterer InSAR processing technology with multi-reference point baseline network adjustment and high-precision DEM data to monitor the surface deformation of the ring rockfill dam in the upper reservoir of Zhanghewan Pumped Storage Power Station. It analyzed the impact of DEM resolution on PSInSAR monitoring accuracy and verified the accuracy of InSAR deformation monitoring using ground synchronous monitoring data from a high-precision measuring robot.

 

The results indicate that the dam and slope of Zhanghewan Power Station's upper reservoir showed an overall uplift trend during the observation period, which was preliminarily judged to be caused by the temperature rise from winter to summer. The correlation coefficient between the monitoring point deformation rate obtained by the InSAR technology and the ground synchronous observation result was 0.838, with an RMSE of ±7.24mm/yr. The higher the precision of the external DEM, the higher the InSAR monitoring accuracy, with an improvement range of 2 - 3mm.

 

By combining the ground and satellite monitoring results with the water level and temperature observation data, it was found that for the ring rockfill dam, the cumulative displacement of the monitoring points was significantly correlated with the temperature, but the displacement change was not significantly correlated with the temperature change. The influence of temperature on the displacement of monitoring points was slow and nonlinear, and different monitoring points had different responses. The cumulative displacement of monitoring points had a weak correlation with the water level, while the displacement change had a stronger correlation with the water level change. The water level had a greater impact on the upstream and downstream displacement of specific points. This study provides an important reference for the research and application of InSAR deformation monitoring of large-area structures such as ring rockfill dams.