Abstract: The numerical analysis models in the conventional stability analysis of mined-out area have over-simplified the shape of mined-out area, leading to too simple models and a poor reliability of the stability analysis results.CMS (Cavity Monitoring System) was used to make a 3D scanning of the mined-out area in underground mine and accurately get the distance from the laser head to the boundary of mined-out area.The positioning point coordinates of total station survey were entered into the CMSPosProcess software and the generated data into 3Dmine software to build the real occurrence model of mined-out area.A study was made to use VC++ to program an application for a direct input of the block centroid coordinates output from the 3Dmine into FLAC3D so as to establish a mechanical model of mined-out area, forming a new method from a practically measurement model to a mechanical calculation model, greatly improving the accuracy and reliability of the stability analysis of mined-out area.Good results were achieved in the static calculation and the stability analysis of the mined-out area in the south branch mining area at -60 m level in Shirengou Iron Mine.

Key words: CMS, Practical measurement of mined-out area, 3Dmine modeling, Stability of mined-out area, Numerical simulation calculation