Previous studies on the strength and deformability of pillars in hard-rock mines have demonstrated that the influence of natural fractures diminishes with increasing pillar width. Jointing conditions and fracture intensity/intersections play a critical role in the behaviour of slender pillars (width-to-height ratio less than 0.5). An important challenge is the characterization of rock mass damage as a function of the natural fracture network and loading conditions. In this paper, we present advanced pre-processing methodologies to measure fracture intensity and fracture density prior to loading and relate those measures to the evolution of damage (intensity and density) with increasing pillar load. A hybrid finite-discrete element method (FDEM) with fracture mechanics capabilities is used to simulate the mechanical behaviour of synthetic pillar models with different embedded discrete fracture traces of similar total length. Newly developed post-processing methodologies are used to capture the location of damage events, track rock mass damage intensity and density as the simulation progresses and relate those changes to the modelled pillar strength. We believe the results of this study provide useful insights on rock mass damage evolution.

中文翻译：

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细长自然断裂柱体力学行为控制因素的研究

以往对硬岩矿山矿柱强度和变形能力的研究表明，天然裂缝的影响随着矿柱宽度的增加而减小。连接条件和断裂强度/交叉点在细长柱的行为中起着关键作用（宽高比小于 0.5）。一个重要的挑战是将岩体损伤表征为天然裂缝网络和加载条件的函数。在本文中，我们提出了先进的预处理方法来在加载之前测量裂缝强度和裂缝密度，并将这些测量与随着柱荷载增加的损伤（强度和密度）的演变相关联。具有断裂力学功能的混合有限离散元方法 (FDEM) 用于模拟具有相似总长度的不同嵌入式离散断裂轨迹的合成柱模型的力学行为。新开发的后处理方法用于捕捉损伤事件的位置，随着模拟的进行跟踪岩体损伤强度和密度，并将这些变化与建模的支柱强度相关联。我们相信这项研究的结果为岩体损伤演化提供了有用的见解。