Time-Series InSAR for Stability Monitoring of Ankang Airport with Expansive Soil

  Objectives  The deformation of the high filling area of expansive soil and it's slope stability are key issues in the research related to expansive soil disasters. Ankang Airport's large-scale high-filling project on the expansive soil caused a threat to the stable operation of the airport.

  Methods  Interferometric synthetic aperture radar (InSAR) technique based on elevation correction is used to obtain the surface deformation during the early operation of Ankang Airport. Firstly, we use small baseline subset InSAR (SBAS-InSAR) technology to correct the errors of digital elevation model (DEM) and obtain the time-series of the airport deformation.Secondly, we use persistent scatterer InSAR (PS-InSAR)technology to verify the accuracy of SBAS-InSAR results.Finally, we analyze the deformation trends of the flight area and the area affected by the stability of the expansive soil slope separately.

  Results  The time-series results of the three types of typical regional deformations in Ankang Airport flight area, terminal area and expansive soil slope stability influence area show that Ankang Airport is basically stable, with a small cumulative deformation. The maximum regional deformation is -21.7 mm, and the maximum internal deformation of the airport is -15.9 mm, its deformation is within the requirements of civil airport geotechnical engineering design standards.

  Conclusions  Combined with the analysis of regional precipitation and fill depth data, the existing small surface deformation and its special laws are caused by the combined effect of the post-construction settlement of the expansive soil fill area and the expansion and contraction deformation of the expansive soil.