| InSAR is a new type of surface deformation monitoring technology,which can obtain surface deformation information through satellite image analysis of the same study area in different time periods,and is widely used in land subsidence monitoring.In recent years,the rapid development of urban modernization in Changde City has improved people’s lives,and also made the safety monitoring of urban construction more and more important.Time series InSAR monitoring technology has the characteristics of all-weather,high precision,and wide coverage,which is in line with the characteristics of urban time span and slow deformation.In this paper,the urban area of Changde City,Hunan Province is taken as the research area,and the PS-InSAR technology and SBAS-InSAR technology are used to monitor the surface deformation to obtain the spatiotemporal characteristics of the surface deformation in the study area.The research contents and experimental results are as follows:(1)The reliability and applicability of the two timing InSAR techniques are verified.The monitoring results were obtained by using the two time-series InSAR methods,and their reliability was verified by joint analysis.The results show that PS-InSAR technology can obtain denser monitoring points in high-coherence areas such as main urban areas and highways,while SBAS-InSAR technology is used in large areas.It has better adaptability in range monitoring.(2)According to the time series analysis of the deformation monitoring of the building area,the surface deformation of the main urban area was obtained.The results showed that during the study period,the subsidence areas were mainly distributed in the northern part of the southern part of Dingcheng District and the northern part of the northern part of Dingcheng District.Most notably,the settling rates were concentrated from-7.4 mm/y to-21.3 mm/y.Combined with the monitoring results,it is found that there is no obvious subsidence area in the center of Wuling District,while the industrial area and highway show obvious subsidence,indicating that industrial activities and transportation have an important impact on the urban land subsidence.A detailed analysis was carried out on the establishment of buffer zones for important highway sections,and the temporal and spatial characteristics of settlement were obtained.The results showed that during the study period,obvious settlement funnels appeared on the Shi-Chang Railway and G207。(3)Through the analysis of monitoring results,it can be seen that the main influencing factor of urban surface deformation in Changde City is urbanization development,including industrial production and road construction.For the better development of the city,industrial production is essential.It is recommended to do a good job of disaster warning and prevention while developing the economy,and try to separate the industrial area from the residential buildings;for the settlement of suburban roads,it is recommended to do a good job of mountain protection engineering. |
