Evaluating Hazards of Land Subsidence to the Highway Using PS-InSAR Technique

Inhomogeneous land subsidence will result in road surface dislocation and threaten the normal operation of expressway. Persistent scatterer interferometric synthetic aperture radar (PS-InSAR) technique is effective in monitoring large area surface deformation. By analyzing the TerraSAR-X images, we revealed the land subsidence characteristics by the PS-InSAR technique along the expressway, which was used for evaluating the hazard degrees of land subsidence. Firstly, taking the airport
$\mathbf{2^{nd}}$
highway as the research object, we obtained deformation information by PS-InSAR technique from TerraSAR-X images during 2011~2015. Secondly, the InSAR results were validated using 8 leveling benchmarks. Thirdly, plotting deformation rate profile, we analyzed the temporal and spatial deformation characteristics. Finally, according to grading standards, the hazard induced by land subsidence degrees were assessed along the expressway. The results showed that: (1) the airport
$\mathbf{2^{nd}}$
highway presented uneven settlement during 2011~2015. The annual average deformation rate range was -15 mm/year ~-83 mm/year. The accumulated settlement range was -6.1 cm~ -33.7 cm. (2) The land subsidence presented obvious seasonal patterns along the airport
$\mathbf{2^{nd}}$
highway. (3) The hazard degree of land subsidence along the airport
$\mathbf{2^{nd}}$
highway was x-weak, weak and medium.