基于时序InSAR的城市形变监测和水准网稳定性评估——以佛山市为例

Urban deformation monitoring and leveling network stability evaluation based on MT-InSAR:A case study of Foshan City

佛山市在粤港澳大湾区经济建设与交通运输中都占据着举足轻重的地位,但由于其特殊的地质条件与频繁的人类活动,导致该地区不均匀沉降突出并常年受地灾危害影响,给当地居民生活及城市建设活动带来了严重威胁。因此,本文以佛山市2015年6月至2019年12月期间Sentinel-1影像为基础开展该地区地表形变监测分析及应用。结果表明,佛山市地表形变区域主要分布在围垦区、建筑施工地和绿植覆盖区等,且近年来有形变特征的区域总面积逐渐增加,占比从0.6%增加至4.48%。局部形变漏斗年平均形变速率超过35mm/yr,部分监测点5年累计年沉降量超过20cm,推断其产生原因主要与频繁的人类基建活动有关。之后通过外部水准监测数据和InSAR结果的对比分析,精度验正结果为3.70 mm/yr,并探测出5个不稳定的水准点。本文研究表明了时序InSAR技术在广域城市地表形变监测、地质灾害防控以及水准网稳定性评估中的明显优势。

Foshan City occupies a pivotal position in the economic construction and transportation of the Guangdong-Hong Kong-Macao Greater Bay Area.However,due to its special geological conditions and frequent human activities,the uneven subsidence of the area is prominent and the area is affected by geological disasters all the year round,posing a serious threat to local residents’lives and urban construction activities.Therefore,this article uses the Sentinel-1 image of Foshan City from June 2015 to December 2019 as the basis to carry out the analysis and application of surface deformation monitoring in this area.The results show that the surface deformation areas in Foshan City are mainly distributed in paddy field breeding areas,construction sites and green plant coverage areas.In recent years,the total area with deformation characteristics has gradually increased from 0.6%to 4.48%.In some areas,the regional average annual deformation rate exceeds 35 mm/yr,and the cumulative annual subsidence of some monitoring points exceeds 20 cm in 5 years.It is inferred that the cause is mainly related to frequent human infrastructure activities.After comparing and analyzing the external leveling monitoring data and InSAR results,the accuracy verification result was 3.70 mm/yr,and 5 unstable leveling points were detected.This paper indicates that time-series MT-InSAR technology has obvious advantages in wide-area urban surface deformation monitoring,geological disaster prevention and control,and leveling network stability evaluation.