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Ground Deformation Monitoring of Hefei Subway Line 2 Based on SBAS-InSAR

The stability of urban rail transit lines plays an important role in the operation of urban traffic system, and it must be monitored regularly during urban development and construction. In this paper, 25 Sentinel-1A images are processed using Small Baseline Subset InSAR (SBAS-InSAR) technology to study the ground stability of Hefei subway line 2, revealing the spatial distribution and the temporal evolution of the ground deformation from January 2016 to April 2018. The results show that most sections of the subway are stable during construction and operation, with average deformation rate between −4∼2 mm/year. The sections with larger deformation rate are mainly distributed in the eastern part of the line, with the maximum deformation rate reaching −8 mm/year, and the results of time series analysis indicate that the deformation evolution in these sections show a significant correlation with the subway construction process.