Analysis of residual deformation in goaf based on SBAS-InSAR technology

In view of the limitations of traditional measurement technology, such as long observation period and high labor cost, and radar differential interferometry technology is vulnerable to spatio-temporal decorrelation and atmospheric phase delay, this paper uses small baseline set technology (SBAS-InSAR) to process 24 Sentinel-1A images, discusses the feasibility of SBAS-InSAR technology, and analyzes the law of residual deformation in goaf.Comparing the results obtained by SBAS with the cumulative settlement value obtained by leveling, it is found that the results obtained by the two methods are completely consistent in trend, and the average root mean square error and standard deviation of all points are 11.05 mm and 20.22 mm respectively.By analyzing the settlement in the study area, it is found that the 90209 working face has the most obvious settlement, with the maximum cumulative settlement of 32 mm, the maximum cumulative settlement of 90208 working faces and 90207 working faces of 13 mm, and the maximum cumulative settlement of 90105 working face of 8 mm, and the settlement of 9101 working face close to 0.The maximum subsidence rate of working face 90209 is 88 mm/a, and that of working face 90208 is 59 mm/a.Six points with obvious settlement are extracted for time series analysis.It is found that the settlement of points in 90209 working face conforms to the quadratic correlation, while the settlement of points in 90208 working face conforms to the linear relationship.The research show that the settlement rate of residual deformation in goaf is gradually decreasing.More than five years after mining, the residual deformation is close to 0, and the area of residual deformation is basically located in the goaf.By comparing the results of SBAS-InSAR technology and leveling, it show that SBAS-InSAR technology has a good application prospect in the study of residual deformation in mining area.