黄土填方区地表沉降时序InSAR监测分析

“削山填沟造地”等岩土工程在湿陷性黄土沟壑地区屡见不鲜，掌握填方区沉降情况具有重要意义。本文收集了2017年11月—2020年12月获取的56景TerraSAR-X StripMap模式影像，利用时序InSAR技术监测了陕北某湿陷性黄土填方地基工程的沉降信息，并与2017年11月—2020年12月期间监测区3个水准点的沉降测量结果比对。结果表明，在填方区地表以沉降为主，在挖方区地表以抬升为主，研究区存在有1处较为明显的地表沉降情况，位于填挖边界线附近填方区内，形变速率范围为-40~-20 mm/a，最大形变速率达-49.9 mm/a，累计量为-151.6 mm，时序InSAR形变结果和实地水准结果吻合性较好，垂直方向形变速率中误差为1.8 mm/a，表明时序InSAR技术在湿陷性黄土填挖方区变形监测中具有较好的应用价值。

Research on land subsidence using time-series InSAR technology in loess fill area

Geotechnical engineering such as “cutting hills and filling ditches to build land” is not uncommon in collapsible loess gully areas. It is a great significance to known the subsidence of the fill area. 56 scenes of TerraSAR-X StripMap mode images were collected from November 2017 to December 2020. The time series InSAR technology is used to monitor the subsidence of a collapsible loess fill foundation project in northern Shaanxi. The subsidence measurement results of 3 benchmarking points are compared to verify the monitoring accuracy of the InSAR results. The results show that the surface of the fill area is dominated by subsidence, and the surface of the excavation area is dominated by uplift. There is a relatively obvious surface subsidence in the study area, which is located in the fill area near the fill-excavation boundary line. The subsidence rate range is -40~-20 mm/a. The maximum subsidence rate is -49.9 mm/a, and the cumulative subsidence is 151.6 mm. the time series InSAR subsidence results are in good agreement with the field leveling results. The error in the vertical subsidence rate is 1.8 mm/a, indicating InSAR technology has good application value in deformation monitoring of collapsible loess fill and excavation area.