Abstract

The micro heterogeneities have a significant effect on the mechanical behaviour and failure mode of brittle rocks. In order to study the influence of microstructure and micro-mechanical properties on rock fracturing under blast loadings, a hybrid LS-DYNA and UDEC grain-based discrete element method (UDEC-GBM) is developed in this study. The LS-DYNA code is used to simulate the explosive detonation process, while the UDEC code focuses on the simulation of the rock fracturing process induced by the shock wave. First, the fracturing process of Barre granite under blasting is reproduced by the developed method. The fracture patterns simulated by the coupled LS-DYNA/UDEC-GBM method show a good agreement with experimental results. Then, using the coupled method, the effects of the grain size distribution, the average grain size, the mineral composition, and the contact tensile strength between minerals on the blast-induced fractures are systematically investigated. Numerical results show that intergranular tensile cracks dominate the rock fracturing under blast loadings. The number of microcracks is affected by all these four factors. However, only the mineral composition has a significant influence on the proportion of transgranular cracks to intergranular cracks. In addition, compared with the grain size distribution and mineral composition, the average grain size and contact tensile strength have a more significant influence on fracture patterns.

Article Highlights

• A hybrid LS-DYNA and UDEC grain-based discrete element method (UDEC-GBM) was developed to evaluate blast-induced rock fractures.

• The influence of microstructures (e.g., average grain size, grain size distribution and mineral composition) and micro-mechanical properties on rock fracturing under blast loadings were investigated.

• The micro mechanism of granite fracturing under blast loadings was revealed.

中文翻译：

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花岗岩中爆破裂缝的数值研究：基于LS-DYNA和UDEC的基于离散元素的混合方法的见解

摘要

微观异质性对脆性岩石的力学行为和破坏模式有重要影响。为了研究爆炸载荷下岩石的微观结构和微机械性能对岩石破裂的影响，本研究开发了一种混合的LS-DYNA和UDEC基于颗粒的离散元方法（UDEC-GBM）。LS-DYNA代码用于模拟爆炸的爆炸过程，而UDEC代码则专注于模拟冲击波引起的岩石破裂过程。首先，通过改进的方法再现了巴雷花岗岩在爆破作用下的压裂过程。LS-DYNA / UDEC-GBM耦合方法模拟的断裂模式与实验结果吻合良好。然后，使用耦合方法，对晶粒尺寸分布，平均晶粒尺寸，矿物成分的影响，并系统地研究了矿物之间在爆炸引起的裂缝上的接触抗拉强度。数值结果表明，在爆炸载荷下，晶间拉伸裂纹占主导地位。微裂纹的数量受所有这四个因素影响。但是，只有矿物成分对跨晶裂纹与晶间裂纹的比例有显着影响。另外，与晶粒尺寸分布和矿物成分相比，平均晶粒尺寸和接触抗拉强度对断裂形态有更大的影响。微裂纹的数量受所有这四个因素影响。但是，只有矿物成分对跨晶裂纹与晶间裂纹的比例有显着影响。另外，与晶粒尺寸分布和矿物成分相比，平均晶粒尺寸和接触抗拉强度对断裂形态有更大的影响。微裂纹的数量受所有这四个因素影响。但是，只有矿物成分对跨晶裂纹与晶间裂纹的比例有显着影响。另外，与晶粒尺寸分布和矿物成分相比，平均晶粒尺寸和接触抗拉强度对断裂形态有更大的影响。

文章重点

• 建立了一种混合的LS-DYNA和UDEC基于颗粒的离散元方法（UDEC-GBM），以评估爆炸引起的岩石破裂。

• 研究了爆炸载荷下岩石的微观结构（例如平均晶粒尺寸，晶粒尺寸分布和矿物成分）和微观力学性能对岩石破裂的影响。

• 揭示了爆炸载荷作用下花岗岩破裂的微观机理。