Abstract Rock masses contain various discontinuities such as flaws, cracks, join sets and more, each significantly affect the crack initiation, propagation and coalescence patterns of new cracks which dominates the ultimate failure of geostructures. The interaction of the pre-existing flaws with each other and with the newly formed cracks is complicated which demands a comprehensive look into the phenomenon. This paper focuses on the applicability of the 3D printing technology coupled with the digital image correlation (DIC) and the bonded particle model (BPM) in replicating real behaviour of natural rocks containing pre-existing flaws. Systematic flaws configurations are considered including single, coplanar, partially overlapped and fully overlapped arrangements to enable a comprehensive coalescence analysis. The results show that the BPM is capable of precisely modelling the crack initiation location, type (tensile, shear or mixed-mode) and coalescence type detected by the DIC. Moreover, it is shown that the 3D printed specimens can reproduce the previously identified cracks and coalescence types. By the analysis of the displacement fields, a new coalescence type is detected and introduced and named as type X, which is a mix of wing crack and quasi coplanar secondary shear crack. The analysis of the displacement vectors revealed five types of cracks: shear opposite slip crack, tensile opposite crack, tensile compliant crack, shear compliant crack, and mixed tensile-shear crack. Furthermore, the comparisons made between the peak loads of the experiments and the simulations show a god agreement in terms of peak load magnitude and flaws inclination angle dependency.

中文翻译：

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具有预先存在缺陷的 3D 打印类岩石试样裂纹发展的实验和数值研究

摘要 岩体包含各种不连续性，如缺陷、裂缝、连接组等，每一个都显着影响新裂缝的裂纹萌生、扩展和合并模式，这些新裂缝主导着地质结构的最终破坏。预先存在的缺陷彼此之间以及与新形成的裂纹之间的相互作用很复杂，需要对这种现象进行全面的研究。本文重点介绍了 3D 打印技术与数字图像相关 (DIC) 和结合粒子模型 (BPM) 在复制包含预先存在缺陷的天然岩石的真实行为方面的适用性。系统缺陷配置被认为包括单一、共面、部分重叠和完全重叠的布置，以实现全面的聚结分析。结果表明，BPM 能够对 DIC 检测到的裂纹萌生位置、类型（拉伸、剪切或混合模式）和聚结类型进行精确建模。此外，还表明 3D 打印的标本可以重现先前确定的裂缝和聚结类型。通过对位移场的分析，发现并引入了一种新的聚结类型，并将其命名为X型，它是翼裂纹和准共面二次剪切裂纹的混合体。位移矢量的分析揭示了五种类型的裂纹：剪切反向滑动裂纹、拉伸反向裂纹、拉伸柔顺裂纹、剪切柔顺裂纹和拉伸-剪切混合裂纹。此外，