Large Gradient Subsidence Monitoring in Mining Area Based on LuTan-1 SAR Images

Abstract. Large gradient subsidence induced by coal mining generally results in limited applicability of interferometric synthetic aperture radar technique, and even fails to obtain complete and reliable deformation details for mining area. To solve this problem, the LuTan-1 SAR data with L-band and high spatial temporal resolution were employed for coal mining area deformation monitoring. In order to provide feasible technical solutions for monitoring large gradient deformation in mining areas, the research focus on the application capability analysis of LuTan-1 SAR data to monitor large gradient deformation in typical mining areas. Time series LuTan-1 SAR data of Shanxi Datong mining area from January to May 2023 were obtained. In combination with precise and high-timeliness DEM obtained from the Lutan-1 bistatic formation data, time-series deformation of the mining area was derived based on the InSAR technique. Through the qualitative and quantitative analysis and evaluation with the Sentinel-1 data monitoring results and leveling measurements, the following conclusions are obtained: (1) From January to May 2023, there are four obvious subsidence basins within the monitoring area, and the maximum subsidence reach to −4.1m within four months, which show a typical large gradient deformation feature; (2) The complete deformation details of the mining area was obtained based on the multi-temporal LuTan-1 SAR data. The monitoring results obtained by Sentinel-1 data in the same period presented obvious decoherence phenomenon, and only the subsidence basin margin deformation details was obtained. (3) Combined with the synchronous levelling measurements results of the mining area, the LuTan-1 time series deformation monitoring accuracy is better than 40mm, and the maximum relative error is better than 4%. For the large gradient deformation monitoring of mining area, the complete and reliable subsidence information can be obtained by using multi-temporal LuTan-1 SAR data, which provides effective technical support for the mining subsidence law research and the safety monitoring of mining area.