岩石断裂韧度是岩石断裂力学中最为重要的参数和指标,它表征岩石材料抵抗裂纹扩展的能力或产生新裂纹表面所需克服的阻力。本文运用离散元法对含预置裂隙的岩石模型破碎过程进行数值模拟,并从能量平衡角度全面模拟巴西圆盘实验加载过程中岩石模型的各种宏观力学响应和裂隙扩展等情况,进而计算岩石的断裂韧度,得到模拟岩样的平均断裂韧度为1.428MPa·m^1/2,依据试验数据计算得到岩样的平均断裂韧度为1.405MPa·m^1/2。计算结果与实验值能够很好地吻合,从而证明了本文方法的有效性和实用性。

The fracture toughness is the most important indicator in the rock fracture mechanics, which represents the ability to resist the crack propagation or the resistance needed to overcome new formations of crack surfaces. In this paper, based on the particle flow theory, the Particle Flow Code (PFC) model of rock with a pre-existing joint is constructed by using the parallel-bond model and the joint model. The failure process and the crack propagation path during the Brazilian disc(CSTBD) test are numerically simulated by using the particle flow code in two dimensions (PFC^2D), and the fracture toughness of the rock model is measured based on the simulated test data and the energy balance. Comparisons between numerical and experimental results show a good agreement, which indicates the validity and practicality of this method.