基于时序InSAR的常州市地面沉降时空演变规律及成因分析

采用PS-InSAR时序技术对常州市2018-01~2019-12的24期Sentinel-1A影像数据进行处理，获取常州市地面形变信息。所得结果与同期水准监测数据有较好的一致性，两者较差最大值为6.1 mm、平均值为2.7 mm、均方根误差(RMSE)为1.7 mm。结果显示，抬升区域主要位于城镇，累积抬升量平均值约为7.3 mm；沉降区域主要位于农村，累积沉降量平均值约为7.6 mm；武进区南部等地局部沉降严重，累积沉降量平均值超过15 mm。分析第Ⅱ承压水水位变化对地面沉降的影响显示，两者相关系数为0.55；同时分析某分层基岩标各地层回弹情况发现，深部地层多数处于反弹阶段，而浅部地层是目前土层压缩（沉降）的主要层段。说明近2 a第Ⅱ承压水对常州市地面沉降具有一定的影响，但已不是主要影响因素，浅部地层土层压缩已成为常州市地面沉降的主要影响因素。

Analysis of Characteristics and Causes of Land Subsidence in Changzhou by Time Series InSAR

Using PS-InSAR time series technology to process the Sentinel-1A image data from 2018-01 to 2019-12 in Changzhou city, we obtain the ground deformation information of Changzhou city. The results are consistent with leveling data in the same period; the difference between maximum value and average value of the two methods are 6.1 mm and 2.7 mm respectively, and the root mean square error(RMSE) is 1.7 mm. Analysis of the temporal and spatial evolution of land subsidence in Changzhou city shows that the uplift areas are mainly located in cities and towns, with an average cumulative uplift of about 7.3 mm; the subsidence area is mainly located in rural areas, with an average cumulative subsidence of about 7.6 mm; the ground subsidence in some areas such as the southern part of Wujin district is still severe, and the average cumulative subsidence exceeds 15 mm. Finally, we analyze the influence of the second pore confined water on land subsidence, and the correlation coefficient between the two is 0.55; analyzing the rebound situation of each layer of the layer-wise mark, the results show that most of the deep strata are in the rebound stage, and the shallow strata are currently the main layers of soil compression. This result shows that the second confined water has a certain impact on land subsidence and that the impact of soil compression in shallow strata on land subsidence is becoming more obvious.