Numerical simulation and measured analysis of ground subsidence law caused by repeated mining in multiple coal seams

Aiming at the ground subsidence problem caused by the repeated mining of multiple coal seams in the A'ai Mining Area of Xinjiang, based on the production geological conditions of Lower coal No. 1 and Lower Coal No. 5 in a certain mine of the Ai mining area, this paper adopts the method combining FLAC3D numerical simulation, SBAS-InSAR and GPS monitoring technology to analyze the dynamic evolution law of ground subsidence amount and range under the repeated mining of multiple coal seams. The research results show that: Under the multi-coal seam mining conditions, ground subsidence shows obvious asymmetric distribution characteristics. The mining of lower coal layers further increases the magnitude and range of ground subsidence in the mining area. The FLAC3D simulation results show that the maximum ground subsidence after multi-coal seam mining is −211.8 mm. The SBAS-InSAR monitoring results show that the maximum ground subsidence is −229.69 to −251.17 mm, and the ground subsidence obtained by the two methods has a high degree of fit. The method combining FLAC3D and InSAR technology can accurately and reliably monitor and analyze the ground settlement situation under the repeated mining conditions of multiple coal seams in the mining area, providing effective guidance for the stability analysis of the goaf and the prediction of ground deformation.