Mohr-Coulomb and Hoek-Brown yielding criteria in FLAC were compounded to overcome their drawbacks using C++. An elastic-brittle-plastic constitutive model was proposed.Two kinds of rockburst criteria proposed by Xu et al and Russense were used to assess the distribution of rockburst regions in the circular tunnel surrounding rock at different confining pressures after the excavated surrounding rock entering an equilibrium state again.In two rockburst criteria,the ratio of loop stress to uniaxial compressive strength was used to determine the magnitudes of rockbursts,such as serious, moderate and slight rockbursts.The relation among these three kinds of rockbursts was discussed.Qualitative analyses were carried out to find the difference and agreement between the present numerical results and observations in situ.With the increase of confining pressure,the elements having occurred rockbursts of different magnitudes increase,and migrate toward the depth of the surrounding rock.
