Assessments of Ground Subsidence and Stability Along G218 Highway at Xinjiang Uygur Autonomous Region, China, between 2022 and 2024 with Sentinel-1 Data
Highway G218, the world’s longest brick-paved road, serves as a vital transportation corridor connecting northern and southern Xinjiang Uygur Autonomous Region. However, it traverses permafrost regions and is exposed to a range of extreme climatic conditions. To ensure the safe and reliable operation of this highway, continuous deformation monitoring is essential. Multi-temporal InSAR (MT-InSAR) can monitor the ground deformation with high-resolution over a large area, thereby overcoming the spatiotemporal limitations of conventional in-situ measurements. In this paper, 82 Sentinel-1A images acquired from January 2022 to September 2024 were utilized, integrating persistent scatterers (PS) and distributed scatterers (DS) to perform MT-InSAR deformation monitoring along the Nalati–Baluntai section of G218. The results indicate that, during the study period, the surface deformation rates along the highway primarily ranged between −2 and 5 mm/yr, with the maximum rate of 16 mm/yr, indicating that the ground surface is relatively stable. Notably, the observed deformation is associated with two environmental factors: precipitation fluctuations and soil frost heave effects induced by changes in surface temperature.