Research On Surface Deformation In The West Of Shenzhen Based On SBAS-InSAR Technology

With the development of a large number of engineering constructions,the catastrophic problems caused by surface deformation in Shenzhen have become increasingly prominent.In order to elimin ate potential safety hazards in time,it is particularly important to conduct deformation monitoring in Shenzhen.Traditional deformation monitoring technology cannot meet the requirements of high-density and large-scale monitoring at the same time.The emergence and development of synthetic aperture radar interferometry technology has greatly broken through the limitations of traditional measurement technology.This technology is mainly based on multiple radar images to obtain large-scale surface deformation information,combined with geographic information spatial analysis technology,to evaluate the dangers caused by surface deformation,which has important practical significance and reference value for preventing urban geological disasters.First,this paper uses 34 Sentinel-1A images from March 2017 to December 2019 as the data source,and uses SBAS-InSAR technology to monitor the surface deformation in the western part of Shenzhen;Secondly,the PS-InSAR results and leveling data are used to compare SBAS-InSAR results are verified;Then the results of surface deformation are analyzed from the three aspects of road traffic,construction density,and reclamation area;Finally,a surface deformation risk evaluation system in the western part of Shenzhen is constructed.The main research contents and conclusions are as follows:(1)In order to verify the reliability of the SBAS-InSAR technology for monitoring the surface deformation,PS-InSAR technology is used to monitor the time series deformation of the study area,and the PS-InSAR results are compared with the SBAS-InSAR results,and the level data is used on this basis Accuracy assessment of SBAS-InSAR results.The results show that the deformation rate range of the western part of Shenzhen obtained by using SBAS-InSAR technology is-50.04?28.18mm/a,and the deformation rate range of the study area obtained by using PS-InSAR technology is-23.37?25.53mm/a.It is found by comparison that SBAS-InSAR results are generally consistent with the PS-InSAR results;The 20 extracted SBAS-InSAR results monitoring points and leveling data are used for accuracy verification,and the error between the two is found to be ±5.5mm,indicating the deformation monitoring of SBAS-InSAR technology the accuracy can reach the millimeter level,and the monitoring results in the western part of Shenzhen are highly reliable.(2)According to the results of SBAS-InSAR,comprehensively analyze the surface deformation characteristics of road traffic,construction density and reclamation area in western part of Shenzhen.The results show that:?Based on the deformation data of Binhai Avenue and the middle section of Metro Line 10,analyze the time-series settlement characteristics of pavement characteristic points and the cumulative settlement of the pavement centerline,obtain the surface deformation characteristics of the road section,and find the road and subway construction it has a greater impact on the surface deformation,especially during the construction of the subway line,the settlement of the subway station is significantly greater than the settlement of the subway line during the construction;?According to the 5 construction density zones divided by Shenzhen,the deformation rate value of the different density zones analyzing the distribution characteristics,it is found that the proportion of settlement coherent points in different construction density zones in western part of Shenzhen is negatively correlated with the corresponding construction density,and the cause of land subsidence is closely related to urban renewal;?Dividing the reclamation area into 1990 Non-reclamation areas,reclamation areas from 1990 to 2000,and reclamation areas from 2000 to 2010.Statistical analysis of the deformation values of each area.Showed that the settlement rate of reclamation areas from 1900 to 2000 was basically the same as that of non-reclamation areas in 1990.From 2000 to 2010,the reclamation area is more prone to subsidence and the settlement rate is higher,indicating that the longer the land consolidation time in the reclamation area,the stronger the land bearing capacity and the more stable geology.(3)Based on the deformation rate and deformation variables obtained by the SBAS-InSAR technology,and using the ground elevation,construction density and rainfall data,combined with the analytic hierarchy process and fuzzy comprehensive evaluation method to build a surface deformation evaluation system in the western part of Shenzhen.The results show that:the area with high risk is about 0.67km~2,accounting for 0.07%of the total area of the study area,mainly distributed in the Qianhai Cooperation Zone in Nanshan District and Shajing Democracy Village in Baoan District;the area with high risk is 15.60km~2,accounting for The total area is 1.59%;the area with medium risk is 123.69 km~2,accounting for 12.60%of the total area;the area with less risk is 737.66 km~2,accounting for 75.14%of the total area;the area with low risk is 104.06 km~2.