Abstract:
The interferometric synthetic aperture radar (InSAR) technique can only acquire deformation along the radar line of sight (LOS), facing challenges in fully characterizing the three-dimensional (3D) surface deformation of mining areas. This study proposes a single-orbit InSAR 3D deformation inversion method based on the characteristics of surface deformation induced by the mining of a near-horizontal coal seam along its rectangular mining face. The core of the method is to derive a calculation model for converting LOS deformation into 3D deformation based on the symmetric distribution patterns of the above-mentioned surface deformation along the strike line. Simulation experiments on a certain mining face in the Chahasu mine field were conducted on the MATLAB platform, with the 3D deformation in the mining face being calculated using ALOS PALSAR-2 data. The experimental results show that the symmetry axis offset along the strike direction was likely to induce significant calculation errors, while the symmetry center offset along the strike exerted relatively weak impacts. The deformation distribution in the LOS direction exhibited asymmetry and thus failed to characterize the actual 3D deformation of the mining area. Verification through engineering measurements reveals that the inversion for subsidence and horizontal movement exhibited root mean square errors (RMSEs) of 0.021 m and 0.035 m, respectively, confirming the applicability of the proposed method. The developed method overcomes the limitation of one-dimensional monitoring based on single-orbit InSAR, providing a reference for high-accuracy 3D deformation monitoring in specific mining areas.