SBAS identification of surface abnormal deformation in mining area and revealing of damage causes

With the large-scale mining of underground coal resources, the surface deformation phenomenon different from the conventional law of subsidence continues to appear. It is of great theoretical and practical significance for the development and improvement of subsidence control theory and the formulation of protection measures against abnormal damage in subsidence areas to carry out the research work of identifying and extracting abnormal surface deformation and revealing of damage causes. In this paper, the abnormal damage of a town in Hebei Province was studied as the research object. Based on short baseline set differential interferometry (SBAS-InSAR), the spatial distribution and temporal evolution of surface deformation in the target area from 2019-07-14 to 2020-04-27 were obtained by using 25 sentinel-1A radar images. Compared with the monitoring data of 48 benchmarks in the same period, the mean error between InSAR and leveling is 5.32 mm. Finally, combined with the geological data in the study area, the causes of abnormal damage were revealed. Through the study, the main conclusions are as follows:① The abnormal damage area have been deformed since September 24, 2019, and the abnormal surface deformation continued to develop with the advance of the working face, and its termination position was approximately linear.② From the perspective of the dynamic development process of surface deformation, the initial development position of abnormal deformation was relatively independent of the conventional subsidence basin in space, and then gradually developed into one with the continuous expansion of the underground mining range. ③ The surface abnormal damage was the result of “activation” of fault F15, and surface deformation was transmitted across faults. The research results shows that SBAS technology can effectively identify and extract the surface abnormal deformation, and provide data support for the study of abnormal damage law and the disclosure of causes. The relevant conclusions also have reference significance for the development and improvement of the subsequent subsidence control theory.