Rockburst processes of a circular tunnel are modeled by use of FLAC at different dilation angles. To model the tunnel excavation, a FISH function is written and used to delete the elements in the tunnel. For rock elements exhibiting linear strain-softening behavior beyond the occurrence of failure and then ideal plastic behavior, the failure criterion is a composite Mohr-Coulomb criterion with tension cut-off. The present calculation is divided into three steps. Firstly, a hydrostatic pressure is applied to the plane strain model until a static equilibrium state is reached. Secondly, a tunnel is excavated using the written FISH function. Thirdly, the calculation renews to achieve a new equilibrium state. Results show that with an increase of the dilation angle, the shear band becomes wider; the dog-ear or V-shaped rockburst notch becomes deeper; the number of failed elements is greater and the plastic zone becomes bigger. At lower dilation angles, the apparent strain localization phenomenon is localized at V-shaped notches, the angle between a shear band and the tangential line of the tunnel surface is higher. However, at higher dilation angles, the angle is lower and the apparent strain localization phenomenon is localized at the tunnel surface. The present numerical results about the shear band inclination are consistent with the Roscoe and Arthur theories.