InSAR technique applied to the monitoring of the Qinghai–Tibet Railway

Abstract

Abstract. The Qinghai–Tibet Railway is located on the Qinghai–Tibet Plateau and is the highest-altitude railway in the world. With the influence of human activities and geological disasters, it is necessary to monitor ground deformation along the Qinghai–Tibet Railway. In this paper, Advanced Synthetic Aperture Radar (ASAR) (T405 and T133) and TerraSAR-X data were used to monitor the Lhasa–Naqu section of the Qinghai–Tibet Railway from 2003 to 2012. The data period covers the time before and after the opening of the railway (total of 10 years). This study used full rank matrix small baseline subset InSAR (FRAM-SBAS) time-series analysis to analyze the Qinghai–Tibet Railway. Before the opening of the railway (from 2003 to 2005), the Lhasa–Naqu road surface deformation was not obvious, with a maximum deformation of approximately 5 mm yr−1; in 2007, the railway was completed and opened to traffic, and the resulting subsidence of the railway in the district of Damxung was obvious (20 mm yr−1). After the opening of the railway (from 2008 to 2010), the Damxung segment included a considerable area of subsidence, while the northern section of the railway was relatively stable. The results indicate that FRAM-SBAS technology is capable of providing comprehensive and detailed subsidence information regarding railways with millimeter-level accuracy. An analysis of the distribution of geological hazards in the Damxung area revealed that the distribution of the subsidence area coincided with that of the geological hazards, indicating that the occurrence of subsidence in the Damxung area was related to the influence of surrounding geological hazards and faults. Overall, the peripheral surface of the Qinghai–Tibet Railway is relatively stable but still needs to be verified with real-time monitoring to ensure that the safety of the railway is maintained.