Abstract: The rib spalling and roof falling were encountered during tunneling process of the -95m sublevel drifts in 4^# stope of Beiminghe iron mine. Although lots of plastic U-shaped arches was mounted， the large deformation and failure of the drift were not under control. Numerical simulation by flac3D was utilized to study the stress distribution in the stope route under different distressing parameters. Results showed that destressing is effective in different part of the drift.The shear stress in the invert and the maximum principal stress in invert， side walls and bottom angle in the drift are decreased by destressing.While the maximum principal stress in the roof is increased during destressing. Destressing width affect the distress result obviously. The destressing width should exceed the boundary of the drift by 1~2m. The destressing method in this project reduced the stress concentration effectively and 150000 tons of ores were mined safely， which contributed a new idea for mining in high stress rock mass.

Key words: roof fall, support, stress concentration, destressing, numerical simulation