基于时序InSAR技术的海塘形变监测研究-以钱塘江嘉兴段海塘为例

Research on seawall deformation monitoring based on time-series InSAR technology: a case study of the Qiantang River seawall in Jiaxing section

中文关键词:  全散射体  Sentinel-1  海塘  形变监测

英文关键词:full Scatterer  Sentinel-1  seawall  deformation monitoring

中文摘要:

      钱塘江海塘是我国东南沿海地带的重要防洪工程。由于其特殊的地理位置、独特的地质条件及复杂的构筑材料等原因，容易发生形变。时序InSAR技术是快速获取海塘形变的有效手段，然而常规时序InSAR技术易受大气延迟效应和地表失相干的影响，其成果在监测点密度及精度上往往存在不足。本文以钱塘江嘉兴段海塘为例，在常规时序InSAR技术基础上利用两次不同尺度时域低频滤波，采用2020年10月至2022年10月期间的56景Sentinel-1 SAR影像，提取全散射体，首次全面展示了监测区地表形变特征，监测点密度高达1492个/km2，基本实现了海塘全覆盖监测。采用42个准同步的二等水准测量数据，验证InSAR形变速率中误差为2.38 mm/year。结果发现，嘉兴段海塘沿线沉降较为严重的区域有4处，其原因主要为回填软土固结以及大型工地基坑排水。

英文摘要:

      The Qiantang River Seawall is an important flood control project in the southeastern coastal area of China.Because of its special geographical location, unique geological conditions and complex construction materials, seawalls are prone to deformation. Satellite InSAR is an effective method to obtain the deformation of seawall. However, conventional time-series InSAR techniques are susceptible to atmospheric delay effects and surface decorrelation, leading to deficiencies in the density and accuracy of points.This paper takes the Qiantang River Seawall in Jiaxing section as an example, and uses two different scale time-domain low filters on the basis of conventional time series InSAR technology, and uses 56 Sentinel-1 SAR images from October 2020 to October 2022 to extract the full scatterer. For the first time, it comprehensively shows the characteristics of surface deformation in the monitoring area, with a monitoring point of up to 1492 points/km2, which basically achieves full coverage monitoring of seawall. The InSAR deformation rate error was verified to be 2.38 mm/year using 42quasi-synchronous second-class leveling measurement.The results show that there were four significant subsidence centers along the seawall in Jiaxing section.The main reasons are the consolidation of backfilled soft soil and the drainage of large construction site foundations.