Abstract: Aiming at the situation that the surrounding-rock of the tunnel cannot meet the requirements for normal production after being repaired for several times, with No.86 return airway of Haizi colliery affected by mining as the background, the mechanical model of a special point in the floor mining- affected zone was established. It is concluded that the tunnel was in the asymmetric pressure force state, thus elastic-plastic model of the tunnel stress was established in the asymmetric pressure force state, the plastic zone width calculation formula of the tunnel surrounding rock was deduced and reinforcement schemes taking thread steel grouting bolt as the core were made. The results showed that after the floor tunnel was reinforced with supporting system taking the grouting blot as the core, the deformation of surrounding rock, caused by mining in the overlying working face, could be effectively controlled and the plastic zone width calculation of the tunnel surrounding rock was rational.

Key words: mining circumstances, failure evolution mechanisms, control technology