Application And Research Of InSAR Technology In Three Gorges Reservoir Area Landslide Measurement

As one of major geological disasters,landslides are prone to cause casualties and property losses.In China's geological disasters,landslides account for a large proportion.The Three Gorges reservoir area is a region with high geological disasters such as landslides and mudslides.Since 2008,the reservoir has been stored for 175 meters in the reservoir area.A large number of new landslides and bank collapses have occurred in the Three Gorges reservoir area.The disaster situation and dangers in some areas have gradually increased.According to investigations by relevant departments,the landslides are concentrated in low areas outside the canyon.In the mountainous areas,these areas are also the main areas for the relocation of urban migrants in the reservoir area.Therefore,it is urgent to carry out pre-identification,key monitoring,timely forecasting and effective control of geological disasters in the Three Gorges reservoir area.As an active remote sensing technology,Synthetic Aperture Radar Interferometry has the ability to pass through clouds and fog,and to detect large-scale deformation.It has been widely used in landslide monitoring.In view of the wide distribution of landslides in the Three Gorges reservoir area,the uneven size of landslides,the long sliding period and the high vegetation coverage,firstly,different data processing methods are used to carry out the identification of landslides in the large area of the Three Gorges reservoir area.Secondly,the research and experiment on the deformation time series from high and low resolution radar data acquisition are carried out for Daping landslide alone,and the accuracy of time series deformation is verified by the Global Positioning System(GPS)observation data of landslide body.Finally,according to the test results combined with other external data the law of landslide motion is explained,The specific research content is as follows;1.Using Stacking-In SAR technology,the surface deformation rate of the large area of Badong-Zigui of the Three Gorges reservoir area between February 2017 and February 2019 was obtained,With the deformation rate greater than 20cm/y as the threshold,combined with other related literatures total of 3 known landslide bodies were identified.The Small Baseline Subset In SAR(SBAS-In SAR)technique was used to identify the known landslide bodies with the same deformation rate threshold.The similarities and differences between the two methods in the landslide body identification in the reservoir area were summarized and analyzed.2.For the identified Daping landslide,SBAS-In SAR technology was used to obtain the time series deformation information of the landslide body using Sentinel-1 data and ALOS-2 data,and the accuracy of In SAR data was verified by using the GPS monitoring data of the Daping landslide.3.The time series deformation information of the leading edge,middle and trailing edge of the landslide on the Daping landslide is analyzed.Correlation analysis is carried out with the rainfall and Yangtze water level data.It is concluded that the settlement of the trailing edge of the landslide body and the change of rainfall have higher correlation,and the sloping front settlement is affected by the water level of the river.The study reveal the deformation mechanism of the Daping landslide.