Three-dimensional Deformation Monitoring Of Mining Area With GNSS And InSAR

The nickel reserve of Jinchang in Gansu Province ranks the first in China,which has an extremely important strategic position.With the continuous mining of the mining area,in June2016,the second mining area of the west of Jinchuan Longshou Mine was stopped due to a large area of surface collapse.In April 2019,the industrialization experiment of sublevel caving without pillar was carried out for the first time in the second mining area of West China.In order to monitor the surface deformation,the current deformation monitoring in this area is mainly carried out by laying GNSS network,but the single points monitoring,time-consuming,laborious and other shortcomings can not reflect the real surface deformation situation in time.InSAR technology has been widely used in various deformation monitoring fields due to its advantages of wide area and high efficiency.However,due to the influence of satellite orbits and image resolution,InSAR technology is difficult to monitor the three-dimensional surface deformation.In order to solve the above problems,this paper proposes to use the interpolation technique to interpolate the GNSS discrete points data into the surface,and then fuse it with the LOS deformation data of the ascending and descending orbits obtained by SBAS-InSAR.The main research contents and achievements are as follows:(1)Through the GNSS discrete points data obtained from April 2019 to June 2020 on the surface of the study area,the GNSS data were interpolated by the Ordinary Kriging method and the Empirical Bayesian Kriging method respectively,and the 3D deformation fields based on the GNSS data obtained by the two methods were obtained.Through comparison with GNSS points data,it is verified that the accuracy of the Empirical Bayesian Kriging method in the North-South,East-West and Up-Down directions are significantly improved compared with that of the three-dimensional deformation fields interpolated by the Ordinary Kriging method,and the three-dimensional deformation fields interpolated by the Empirical Bayesian Kriging method is applied to the fusion of GNSS and InSAR.(2)SBAS-InSAR technology is used to process Sentinel-1A data of 38 scenes ascending orbit and 29 scene descending orbit.In this paper,through multiple experiments on the above67 scenes SAR images,appropriate baseline thresholds and filtering methods are set to obtain the line-of-sight deformation rate,-20mm/a contour line and time-series cumulative shape variables of 2019.3.22-2020.6.8 in the study area.By comparing the deformation results of ascending and descending orbits,the surface deformation of the study area is analyzed,and the reasons for the difference of deformation of different orbits are summarized.(3)According to the posterior weight determination requirements,the EWE-HVCE model is established.By extracting the azimuth and incident Angle of satellite imaging,the GNSS 3D deformation data and InSAR data of ascending orbit and descending orbit are used to calculate the cumulative 3D surface deformation from April 2019 to June 2020 in the study area.In order to verify the effectiveness of the method presented in this paper,three schemes are designed with GNSS monitoring points data as the real value and the precision was compared and analyzed.The results show that the accuracy of 3D surface deformation fields obtained by the EWE-HVCE model is significantly improved compared with the other two methods,and the RMSE of the North-South,East-West and Up-Down deformation are6.26 mm,14.01 mm and 33.04 mm,respectively.