Application Of Time Series InSAR Technology In Surface Deformation Monitoring In Changzhou City

Land subsidence can be developed as a serious geological disaster, it can continue to damage the roads, housing construction, underground pipelines and other damage, And many cities in China have suffered varying degrees of economic losses. Changzhou has a long history of land subsidence, the destruction caused by the land subsidence is very serious. Therefore, it is very important to effectively monitor the land subsidence in Changzhou area, which can not only provide reference data for urban construction, but also provide the key basis for geological hazard assessment and prevention. InSAR technology is good to make up for the traditional GPS, leveling which have the shortcomings of sparse monitoring points, long observation interval. InSAR technology can monitor the large area deformation, has high efficiency and high precision, and it has become one of the main means to monitor land subsidence in urban area.The theory of InSAR technology is introducted in detail in this paper, and different time series InSAR methods and SAR data in Changzhou city are used to monitor land subsidence for deep application research. Groundwater and urban change data are used to analyse the causes of land subsidence in Changzhou city. The main research work and results of this paper are as follows:(1) The domestic and foreign research present situation of InSAR technology have been summarized, and the basic principle of DInSAR, PS-InSAR and SBAS-InSAR have been elaborated in detail, the problems of them have been also introduncted.(2) This paper has used 12 scenes of COSMO-SkyMed X-band and 26 scenes of ALOS PALSAR L-band SAR data, which cover Changzhou area. Both PS-InSAR and SBAS-InSAR technology have been used to process the data, and time series deformation results of Changzhou area have been successfully obtained. The InSAR results turn out that land subsidence mainly occurred in Wujin District, the main of urban area (Zhonglou District, Tianning District, Qishuyan District) exited the phenomenon of a slight rebound.(3) The GPS, leveling observation data have been used to analyse the accuracy of the InSAR results. And InSAR results have a good agreement with GPS, the leveling observation results. The accuracy of InSAR results can reach sub-centimeter level.(4) The groundwater level and urban change data have been used to analyse the land subsidence occurrence reason. It can be found that the rise of groundwater level has a good agreement with the trend of slowly land subsidence and the phenomenon of land rebound; With the rapid development of the city, the water consumption enterprises increase sharply, which lead to excessive exploitation of groundwater in the area, which causes serious land subsidence in the local area. The change of groundwater level is still the main influencing factor of land deformation in Changzhou city.