A Discrete Fracture Network approach to rock mass characterization and assessment of rock fragmentation for cave mining.

在采矿和土木工程应用中越来越多地使用离散断裂网络（DFN）模型的基础上，拟议的研究有两个主要的相互关联的主题，可以并行开发。 第一个课题是研究裂隙长度和体积裂隙强度之间的关系，试图定量地确定这些参数与岩体自然破碎度之间的关系。预计这一初步工作将有一个显着的重要性，在帮助定义地质力学合成岩体模型的规模需要进行模拟，以充分捕捉代表性的基本体积（REV）的天然断裂岩体。 第二个主题涉及侧重于崩落前评估，特别是岩体破碎，因为破碎不良或意外破碎对洞穴作业的影响是一个重要的工程和经济因素。迄今为止的研究肯定有助于证明，DFN工具可以有效地协助破碎评估，主要是通过提供更好的描述自然破碎的现场岩体。然而，对初级和次级碎裂的评价仍在使用主要基于实际经验的替代方法进行，试图使用根据经验得出的规则来描述这些过程，而不是直接解决所涉及的过程和机制。据信，综合测试的DFN为基础的岩体模型，通过混合有限元/离散元模拟岩石破碎，可以有效地用于更好地捕捉破碎机制，并开发一种替代方法，以帮助破碎评估在采矿和民用应用。所提出的方法将不仅依赖于充分捕获岩体的更广泛的异质性的能力，但更重要的是依赖于确定临界断裂强度值的能力，在该临界断裂强度值处，发生从完整的块状岩体到运动学上移动的岩体的过渡。

Building on the increasing use of Discrete Fracture Networks (DFN) models in both mining and civil engineering applications, the proposed research has two major inter-related topics, which could be developed in parallel. The first topic includes studying the relationship between fracture length and volumetric fracture intensity in an attempt to quantitatively define the relationship between these parameters and the rock mass natural fragmentation. It is expected that this initial work will have a significant importance in helping defining the scale at which geomechanical synthetic rock mass models need to be simulated to fully capture the Representative Elementary Volume (REV) of a naturally fractured rock mass. The second topic involves focusing on pre caving assessment and in particular on rock mass fragmentation, since the impact of poor or unexpected fragmentation upon cave operations represents a significant engineering and economics factor. Research to date has certainly contributed to demonstrate that DFN tools can effectively assist in the fragmentation assessment, primarily through providing a better description of the natural fragmentation of the in-situ rock mass. However, the evaluation of primary and secondary fragmentation is still being carried out using alternative methods mostly based on practical experience, attempting to describe these processes using empirically derived rules rather than a direct solution of the processes and mechanisms involved. It is believed that synthetic testing of DFN based rock mass models, by means of hybrid Finite/Discrete Element simulation of rock breakage, can be effectively used to better capture fragmentation mechanisms and develop an alternative approach to aid fragmentation assessment in mining and civil applications. The proposed approach would rely not only on the ability to fully capture the broader heterogeneity of the rock mass, but more importantly on the ability of determining a critical fracture intensity value at which the transition from intact massive rock mass to kinematically mobile rock mass occurs.