Exploring cracking behavior from mineral-scale do good help to understand the failure mechanism of rock materials. The present study proposes a realistic three-dimensional grain-based modeling (3D-GBM) method considering the actual distribution, geometry and mesoscopic mechanical properties of different minerals in granite samples. The geometrical characteristic and distribution were captured based on high-precision computed tomography (CT) scanning and polarized microscopy. The mesoscopic mechanical properties were measured using nanoindentation combined with the scanning electron microscope-energy dispersive spectroscopy scanning (SEM-EDS). The results indicate that the established model can realistically reproduce the mechanical and failure behavior of granite subjected to unconfined compression in terms of stress-strain curves, failure mode, crack evolution, and force transmission. Investigating crack propagation at mineral-scale shows that the relative damage degree is greater at weak boundaries (i.e., boundary related to mica) and relatively soft minerals (i.e., mica) than that of strong boundaries (i.e., quartz-quartz and quartz-feldspar) and stiffer minerals (i.e., quartz and feldspar). Grain boundaries and soft mica minerals play an important role in guiding and deflecting the crack propagation path due to the mismatch in elasticity and strength compared with the stiffer and harder minerals (i.e., quartz and feldspar).

中文翻译：

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一种逼真的基于 3D 晶粒的建模方法，用于再现脆性花岗岩的力学和失效行为


从矿物尺度上探索开裂行为有助于理解岩石材料的破坏机制。本研究提出了一种现实的基于晶粒的建模 （3D-GBM） 方法，该方法考虑了花岗岩样品中不同矿物的实际分布、几何形状和细观力学性能。基于高精度计算机断层扫描 （CT） 扫描和偏振显微镜捕获几何特征和分布。采用纳米压痕结合扫描电子显微镜-能量色散能谱扫描 （SEM-EDS） 测量细观力学性能。结果表明，所建立的模型能够真实地再现花岗岩在无侧限压缩下的应力-应变曲线、破坏模式、裂纹演化和力传递方面的力学和破坏行为。研究矿物尺度的裂纹扩展表明，弱边界（即与云母相关的边界）和相对较软的矿物（即云母）的相对损伤程度大于强边界（即石英和石英-长石）和较硬的矿物（即石英和长石）。晶界和软云母矿物在引导和偏转裂纹扩展路径方面起着重要作用，因为与较硬和较硬的矿物（即石英和长石）相比，弹性和强度不匹配。