Continued Monitoring and Modeling of Xingfeng Solid Waste Landfill Settlement, China, Based on Multiplatform SAR Images

Abstract

Continued settlement monitoring and modeling of landfills are critical for land redevelopment and safety assurance. This paper adopts a MTInSAR technique for time-series monitoring of the Xingfeng landfill (XFL) settlement. A major challenge is that the frequent and significant settlement in the initial stage after the closure of landfills can affect the coherence of interferograms, thus hindering the monitoring of settlement by MTInSAR. We analyzed the factors that can directly affect the temporal decorrelation of landfills and adopted a 3D phase unwrapping approach to correct the phase unwrapping errors caused by such deformation gradient. SAR images from four platforms, including 50 Sentinel-1A, 12 Radarsat-2, 4 ALOS-2, and 2 TerraSAR-X/TanDEM-X images, are collected to measure the settlement and thickness of the landfill. The settlement accuracy is evaluated by a cross-evaluation between Radarsat-2 and Sentinel-1A that have similar temporal coverages. We analyzed the spatial characteristics of settlement and the relationship between the settlement and thickness. Further, we modeled the future settlement of the XFL with a hyperbolic function model. The results showed that the coherence in the initial stage after closure of the XFL is primarily affected by temporal decorrelation caused by considerable deformation gradient compared with spatial decorrelation. Settlement occurs primarily in the forward slope of the XFL, and the maximum line-of-sight (LOS) settlement rate reached 0.808 m/year from August 2018 to May 2020. The correlation between the settlement and thickness is 0.62, indicating an obvious relationship between the two. In addition, the settlement of younger areas is usually greater than that of older areas.

Satellite Data Potentialities in Solid Waste Landfill Monitoring: Review and Case Studies

“…They used multi-temporal COSMO-SkyMed interferometric data to mon-itor a low-magnitude landfill settlement with millimetric accuracy. In [35], the authors used the multitemporal InSAR technique for the time-series monitoring of deformation at the Xingfeng landfill in China. Multitemporal InSAR allows for the elimination of the influences of temporal and spatial decorrelation and atmospheric noise.…”

Strength Characteristics of a Smooth HDPE Geomembrane/Nonwoven Geotextile Interface Based on a Novel Ring Shear Apparatus

“…Published experimental data on the smooth geomembrane/geotextile interfacial strength indicate that the maximum normal stress that could be applied using a ring shear apparatus was 480 kPa [13]. However, the normal stress acting on the bottom lining system of the majority of municipal solid waste landfills has exceeded 480 kPa [14][15][16][17][18][19][20][21][22][23][24][25][26]. This normal stress has even exceeded 2 MPa in some leachate ponds [27,28].…”