Objectives The high-fill geotechnical engineering in Yan'an new district has induced large-scale ground settlement, which directly impacts the stability of surface facilities. Therefore, it is essential to monitor and investigate the mechanisms of ground settlement and deformation.
Methods Based on this, we employed a time-series interferometric synthetic aperture radar (InSAR) method that combines measurements from persistent scatterer (PS) and distributed scatterer (DS) (PS-DS-InSAR), to process a total of 181 scenes of Sentinel-1A data from ascending orbits spanning from January 2019 to June 2022. This allowed us to obtain ground deformation data for Yan'an new district. Subsequently, we conducted a two-dimensional decomposition of the time-series results to reveal the mechanism of two-dimensional surface deformation. Additionally, we utilized variational mode decomposition technology to decompose the precipitation and settlement data of Yan'an new district into trend and periodic components, thereby investigating the relationship between the components.
Results Utilizing the aforementioned improved method, the point coverage increased from 42.48% to 85.18%. The primary vertical deformation rate ranges from -40 to 10 mm/a, with the maximum settlement rate of 65.3 mm/a observed in the northeastern part of the new area. The thickness of the fill soil is a direct influencing factor on the settlement scale. Eastward deformation is distributed on the left side of the valleys, while westward deformation is located on the right side, which is highly correlated with the pre-construction terrain.
Conclusions This research can provide scientific references for surface deformation monitoring and engineering construction in gully regions after high fill engineering.
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