| As one of the three regions with the most serious subsidence in China,most of the previous research has focused on Beijing,Tianjin and Cangzhou and other areas with extremely serious ground subsidence,and paid less attention to Ji’nan-Handan and other places.Handan is located in the leading edge of the alluvial fan of the Zhanghe River,due to the strong compressibility of the soft soil layer and the exploitation of underground resources in the territory,the phenomenon of settlement occurs from time to time.Therefore,this thesis takes Handan as the research area,selects and downloads multi-source radar satellite image data including 30 ALOS PALSAR data and 128Sentinel-1A,and uses InSAR technology to obtain nearly 2000km2 of surface deformation information in the two time periods of 2007-2011 and 2016-2020,and combines the changes and geological data of groundwater over the years.and the analysis of the influencing factors of surface deformation based on the urbanization development status of other optical remote sensing satellite data.The main research content and results of this thesis are summarized as follows:(1)The ALOS PALSAR monitoring results of the two paths coincident regions were cross-verified,and the difference between the deformation rates was found to be0-3mm/a.The correlation coefficient of the cumulative morphological variables obtained by comparing the Sentinel-1A monitoring results with the level monitoring values was found to be greater than 0.88,and different degrees of settlement were found during the field investigation of the settlement areas monitored by InSAR.It is shown that the use of InSAR technology for deformation monitoring in Handan area is feasible.(2)The spatio-temporal evolution characteristics of surface deformation were analyzed according to the monitoring results of 2007-2011 and 2016-2020,and it was found that the average deformation rates in the study area were-0.21mm/a and-7.00mm/a,the proportion of the area where settlement occurred was 43.83% and52.02%,respectively,and the proportion of lower,moderate,higher and high areas increased by 8.51%,1.59%,0.20% and 0.30%,respectively.And settlement has a tendency to develop eastward.(3)12 of the 16 scale factors of the annual change rate of water head and the rate of surface deformation are positive,and 11 of the correlation coefficients between 16 head changes and surface shape variables are greater than 0.7,which proves that changes in groundwater level be one of the causes of ground subsidence.(4)The typical deformation rates were extracted from the two disks for cross-sectional line analysis,and it was found that the impact of fractures on ground settlement during the two monitoring periods was not very obvious,and only the Handan fault and the Zishan West fault be active and have an impact on the surface.(5)During the two monitoring periods,the proportion of areas where the land use type was newly changed to construction land accounted for 51.49% and 54.30%,respectively;The proportion of areas where subsidence occurred in areas where human activity increased intensity accounted for 45.49% and 52.36%,respectively,and it was found that with the development of urbanization,ground subsidence occurred to a certain extent. |
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