Abstract: Based on the probability distribution of the uniaxial compressive strength of the rock, the authors present a parallel-pole model of statistical damage to simulate the brittle rock. The calculated stress-strain relationship based on the statistic damage matches well with test results. The parallel-pole model was then used to simulate the surrounding rockmass of a tunnel. The damage variables were derived for different stress conditions. From the concept of statistic damage, the damage variables represent probability of rockbursting.