Abstract:Aiming at the stability problem of complex goaf caused by deep mining in Hebian mining area of Nanwenhe Tungsten Mine in Yunnan province, this study builds a refined three-dimensional geomechanical model based on FLAC3D , and systematically analyzes the characteristics of stress redistribution, displacement evolution and plastic zone expansion of surrounding rock in goaf. The results show that the vertical stress in the goaf is concentrated in the middle of the pillar (maximum 40 MPa), the roof stress is low (5 MPa), and the pillar and surrounding rock have no significant plastic failure. The maximum displacement of the roof is 18. 06 mm, the maximum displacement of the bottom heave is 0. 64 mm, and the overall deformation is small and tends to be stable. The plastic zone shows partial tensile failure of the roof, but the stability of the pillar dense area is good. Through continuous simulation monitoring of 10 monitoring points on the roof, it was further confirmed that the roof stress (with stable values all less than 1. 2 MPa) and displacement tended to be stable in the later stage of calculation. Numerical simulation shows that the goaf has high stability under the existing filling conditions, which can provide theoretical support for disaster prevention and control and green mining in hydrologically sensitive mining areas.
