To take into consideration the effect of mineral microstructure on crack growth and mechanical properties of heterogeneous rocks containing a single pre-existing flaw under uniaxial compression, the discrete-element method in combination with the grain-based model was adopted in this study. The results indicate that the characteristic stresses – that is, crack initiation stress, crack damage stress and peak strength, generally increase with respect to the inclination angle. The normalised crack initiation stress increases with the increasing angle, while the normalised crack damage stress has no pronounced change. Additionally, the variation of inclination angles has little influence on the grain-scale crack growth. The initiation of intergranular cracks is prior to the intragranular cracks, and the proportion of intragranular cracks is slightly greater than intergranular cracks at the peak failure moment. The ultimate failure patterns obtained by numerical simulations agree well with the experimental results, revealing the cracks generated from the pre-existing flaw consist of intragranular and intergranular cracks at the grain scale.

中文翻译：

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基于颗粒离散元方法的含裂纹非均质岩石模拟

考虑到矿物微结构对单轴压缩下存在单个缺陷的非均质岩石裂纹扩展和力学性能的影响，本研究采用离散元法结合颗粒模型。结果表明，特征应力（即裂纹萌生应力，裂纹破坏应力和峰值强度）通常随倾角而增加。归一化的裂纹萌生应力随着角度的增加而增加，而归一化的裂纹损伤应力没有明显的变化。另外，倾斜角的变化对晶粒尺寸裂纹的扩展影响很小。晶间裂纹的产生先于晶内裂纹，在峰值破坏时刻，晶内裂纹的比例略大于晶间裂纹。通过数值模拟获得的最终破坏模式与实验结果非常吻合，表明由预先存在的缺陷产生的裂纹由晶粒内的晶粒内和晶粒间裂纹组成。