Displacement Monitoring and Analysis of the Three Gorges Dam Area with Multi-Source Time-Series InSAR Technology

Since the impoundment of the Three Gorges Reservoir (TGR) in 2003, the stabilities of the dam and bank slopes threaten by the significant increases and periodic fluctuation of water levels had drawn great attentions. Interferometric synthetic aperture radar (InSAR) with advantages of wide-coverage and high accuracy displacement detection ability had played important role in infrastructure and geological hazard monitoring. In this paper, the displacement of the Three Gorges dam and its surrounding areas was mapped and analyzed with L-band ALOS2 PALSAR2 (2015−2019) dataset and C-band Sentinel-1 (2015−2022) images based on time-series InSAR technique. Results from both datasets agreed well. The analysis results show that there are periodic displacements at the Three Gorges Dam and Maopingxi Dam with amplitudes of 1.1 and 3.2 mm related with water level fluctuation. There is also an obvious displacement at the left bank of Maopingxi, Guanmendong and Yinxingtuo areas with displacement rate of 28, 40 and 40 mm/a, respectively. It was found that the displacement in the Yinxingtuo area was related with consolidation, thus an exponential decay model was employed to model the time series displacement. The model results indicated the displacement of Yinxingtuo area would reach a steady state around 2040. The results show the InSAR technology can clearly us capture the ground displacement and enrich the understanding of ground process, provide bases for controlling and judging of geological disaster. © 2023 Beijing Institute of Technology. All rights reserved.