| With the advancement of the urbanization process,including the rapid development of a large number of projects including groundwater extraction,mineral resources mining,and underground space development,deformation,and surface collapse caused by ground subsidence have become common.Inmany urban regions of our country,ground subsidence has caused severe property loss and building collapse.It has a great impact on people’s production and life and the stable development of society.Therefore,it is of great significance to monitor the settlement of ground surface and buildings in urban areas for the harmonious and steady development of urban areas.Inthis paper,a variety of InSAR technologies are applied to monitor surface deformation in Hefei City,and the causes of land subsidence are analyzed in combination with hydrological data such as precipitation.Finally,the research results are applied to the analysis of building collapse.D-InSAR technology and PS-InSAR technology are used to conduct time-series deformation monitoring on the main urban area of Wangcheng District,Changsha City,and analyze the reasons for the building collapse.The research content of this paper is as follows:1.Based on the Sentinel-A data,all three technologies were used to monitor the surface subsidence in the main urban area of Hefei city,and D-InSAR technology was used to quickly obtain the settlement amount of-10mm～10mm every two months in this area in a short time.Combined with time-series PS-InSAR technology and SBAS-InSAR technology to monitor the surface subsidence of the main urban area of Hefei,it is concluded that the deformation of the main urban area of Hefei tends to be stable on the whole in the past five years,with the general subsidence trend in the east part of the central area and the upward trend in the west part of the central area.2.The distribution statistics and the annual average settlement rate histogram analysis of the settlement rate obtained by PS-InSAR and SBAS-InSAR processing are carried out,and the distribution and magnitude of the settlement rate of the two are in good agreement.Combined with the hydrological data,the time series analysis of the four key subsidence areas in the main urban area shows that when the rainfall is sufficient in the spring and summer rainy seasons,the land surface subsidence is relatively slowed down,and when the rainfall is low in the autumn and winter,the land surface subsidence has a tendency to deepen to a certain extent.The accuracy of the results of the two methods is compared and analyzed.When PS is verified as a point target analysis,the position accuracy of building construction is greater than that of SBAS distributed target analysis.3.The D-InSAR and PS-InSAR technologies are integrated to conduct temporal deformation monitoring for the main urban area of Wangcheng District,Changsha City.The D-InSAR technology is used to identify and locate the surface deformation of the building collapse area,and the settlement rate of the building in the past two years is analyzed by PSInSAR.By coupling the sequential settlement amount of PS points on the building with the rainfall data and the urban housing construction data,it is analyzed that the deformation of the building is intensified mainly due to the illegal renovation of the residents,the structural deformation of the structure,and the uneven settlement and rainfall of the building in the past two years have accelerated the speed of its collapse to a certain extent.Figure [60] table [3] reference [92]... |
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