Numerical Simulation Study of ground surface subsidence caused by filling mining on surface buildings and facilities in a mining area: a case study

The filling mining method is planned to be adopted in Chentaigou Iron Mine. There are many significant buildings and facilities in the mining area, making it necessary to evaluate the influences of underground mining on the surface buildings and facilities. The main purpose of this research was to evaluate the extent of the surface subsidence basin and the degree of damage of buildings and facilities after filling mining by numerical simulation. To this end, a three-dimensional numerical model of the whole mining area was established. Secondly, a Discrete Fracture Network (DFN) in 3DEC numerical simulation software was adopted to obtain the strength parameters of each representative elemental volume (REV). Furthermore, FLAC3D numerical simulation software was utilized to evaluate the range of influence of the surface subsidence basin after filling mining. Finally, the maximum major principal strain on the surface was calculated. The results show that the surface subsidence basin of underground mining in this iron mine undergoes slow expansion then rapid expansion. Expansion of the surface subsidence basin is restricted by fault F1. After the mining orebody, the maximum major principal strain of surface meets design requirements, and the surface buildings and facilities are deemed safe.