Abstract Understanding the dynamic fragmentation of geological materials is important to many fields, but is particularly significant for mining. Here, a series of expanding ring experiments are reported, investigating the dynamic fragmentation of a typical granite from a mining environment. In addition to in-situ diagnostics which measure time-resolved loading characteristics, fragments were soft-captured and analysed. Measured fragment size distributions agree well with existing theory, but show unexpected strain rate variation. Specifically, the reduction in fragment size with rate is shown to be limited as the fragments neared the material grain size, a phenomenon not previously observed. Inter-granular failure was confirmed by fractographic analysis of the recovered material. The phenomenon was hypothesised to be caused by the fragmentation being dominated by an intergranular fracture mechanism which becomes inhibited when fragments near the grain size. More generally, the approach provides a new experimental route through which the fragmentation of geological materials can be understood.

中文翻译：

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典型花岗岩中晶粒尺寸受限动态破坏的观察

摘要 了解地质材料的动态破碎对许多领域都很重要，但对采矿尤其重要。在这里，报告了一系列扩展环实验，研究了来自采矿环境的典型花岗岩的动态破碎。除了测量时间分辨载荷特性的原位诊断外，还对碎片进行了软捕获和分析。测量的碎片大小分布与现有理论非常吻合，但显示出意外的应变率变化。具体而言，随着碎片接近材料晶粒尺寸，碎片尺寸随速率的减小显示出有限，这是以前未观察到的现象。通过回收材料的断口分析证实了晶间破坏。假设这种现象是由晶间断裂机制主导的破碎造成的，当碎片接近晶粒尺寸时，该机制会受到抑制。更一般地说，该方法提供了一种新的实验途径，通过该途径可以了解地质材料的破碎。