Study on Surface Movement Law of Filling Mining Based on Numerical Simulation
A three-dimensional numerical simulation model was established using FLAC3D software,combined with finite element theory,to study the surface subsidence issue during the transition from open-pit to underground mining in a certain iron mine in Liaoning province.The research results indicate that with an increase in backfilling rate,the maximum principal stress and vertical displacement of the roof exhibit a decreasing trend.In the case of timely backfilling after the first mining stage at a depth of-40 meters,the maximum vertical displacement decreased by 45％for a 100％backfilling rate compared to a 90％backfilling rate.When mining reached the middle section at a depth of 305 meters,the vertical displacement decreased by 22％for a 100％backfilling rate compared to a 90％backfilling rate.Both the vertical and horizontal displacements at the surface monitoring points decrease with an increase in the backfilling rate.With a backfilling rate of 95％guaranteed,the impact of underground mining on surface structures is relatively small,meeting the permissible surface deformation values specified by regulations.These research findings provide valuable references for understanding the surface subsidence patterns during the transition from open-pit to underground mining in this mine.
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