Abstract: To investigate the mechanisms of the prestressed anchor bolts in controlling the slabbing failure of rock mass, laboratory physical model experiments on slabbing failure are conducted and the forming process of slabbing failure in plane strain condition is simulated by using the FLAC simulation technology. On the basis of above work, numerical experiments based on three different applying schemes of prestressed anchor bolts are conducted to reveal the mechanisms of the prestressed anchor bolts in controlling the slabbing failure process. The results show that the effect of the prestressed anchor bolts manifest in weakening the concentration effect of stress near crack tip, restraining the crack propagation, coalescence and the slabbing failure process; when applied on the edge of slabbing failure zone, prestressed anchor bolts can not only effectively restrain the formation of slabbing failure but also control the scope of slabbing failure to some extent; when applied in the slabbing zone, prestressed anchor bolts have significant effect in restricting the displacements of the free surface of rock sample, improving the overall stiffness of the slabbing rock. The research results of this paper are of significant importance in understanding the formation mechanisms of slabbing failure, reasonable support control measures of slabbing failure and also rockburst prevention in deep tunnels.

Key words: slabbing failure, model experiments, prestressed anchor bolt, controlling mechanisms, numerical simulation