Abstract We employed a cohesive grain-based model (GBM) to investigate the mechanical behaviour and micro-cracking response of Neuhauser granite under direct tensile loading. The microstructural properties of Neuhauser granite were incorporated into the numerical model, and hourglass-shaped specimens were generated based on the geometrical configuration of specimens. We proposed an alternative calibration procedure, and the numerical observations revealed that the cohesive GBM could accurately reproduce the failure behaviour of physical specimen. At the same time, the conventional GBM failed to return a reliable output. The calibration procedure was augmented by examining the impacts of the random distribution of minerals and tensile loading rate on the fracture behaviour of GBM specimens. Besides, pre-cracked granite was generated to investigate the influence of pre-existing cracks on mechanical and fracture behaviour. By increasing the flaw inclination angle, the peak tensile strength of both single and double flaw specimens was increased. The micro-cracks initiated from flaw tips and extended horizontally towards the side of specimens. At low flaw inclination angles, the macroscopic tensile fracture was almost identical to that of intact rock while the fracture pattern was different at high flaw angles.

中文翻译：

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使用内聚 GBM 方法模拟花岗岩在直接拉伸试验中的微裂纹行为

摘要 我们采用基于内聚颗粒的模型 (GBM) 来研究 Neuhauser 花岗岩在直接拉伸载荷下的力学行为和微裂纹响应。Neuhauser 花岗岩的微观结构特性被纳入数值模型，并根据试样的几何构型生成沙漏形试样。我们提出了一种替代校准程序，数值观察表明，内聚 GBM 可以准确地再现物理试样的破坏行为。同时，传统的 GBM 未能返回可靠的输出。通过检查矿物的随机分布和拉伸加载速率对 GBM 试样断裂行为的影响，增强了校准程序。除了，生成预裂花岗岩是为了研究预先存在的裂纹对机械和断裂行为的影响。通过增加裂纹倾角，单裂纹和双裂纹试样的峰值抗拉强度均增加。微裂纹从裂纹尖端开始并向试样侧面水平延伸。在低缺陷倾角下，宏观拉伸断裂与完整岩石的宏观拉伸断裂几乎相同，而在高缺陷角下断裂模式不同。