A study of post-peak behaviour of rocks and pillar instability in deep underground mines

随着采矿向深部推进，采矿引起的岩石破坏、地震活动和冲击地压问题显著增加。一个好的矿井设计首先要努力避免冲击地压问题，而要实现这一目标，就需要对岩体的性态有很好的了解，特别是在峰后区域。例如，在矿柱设计中，顶峰后岩石性态的知识在评估矿柱突出潜力时是必不可少的。 研究的目的是发展岩石峰后性态的基本知识，研究加载路径对岩石峰后性态的影响，发展一种新的方法来研究机械刚度对岩石峰后性态的影响，发展一种创新的计算矿山刚度的方法，并发展一种地下矿山预期矿柱失稳的评估方法。在实验室里对所有这些问题进行实验研究将是极其困难的，如果不可能的话。因此，应采用实验观测和数值模拟相结合的方法。这种方法将从过去的实验室测试程序中获取数据，并验证和校准将在本研究中使用的一些先进的数值工具。 本研究的研究成果可以加深我们对岩石峰后强度的认识，有助于更好地理解矿柱与围岩之间的相互作用。研究结果将提高我们更准确地评估支柱是否会剧烈坍塌的能力。最重要的是，拟议研究的结果将有助于加拿大的矿产资源部门以更有成效但风险更低的方式回收资源。此外，两名研究生(一名硕士，一名博士)将在该项目的课程中接受培训。

As mining progresses to deep grounds, mining-induced rock failure, seismicity and rockburst problems increase significantly. A good mine design strives to avoid rockburst problems in the first place, and achieving this objective requires a good knowledge of the rock mass behaviour, especially in the post-peak region. For example in mine pillar design, the knowledge of rock's post-peak behaviour is essential in the assessment of pillar burst potential. The objectives of the research are to develop fundamental knowledge on the post-peak behavior of rocks, to study the influence of loading path on the post-peak behavior of rocks, to develop a novel method to investigate the influence of machine stiffness on post-peak behavior of rocks, to develop an innovative method to calculate mine stiffness, and to develop a methodology for assessing anticipated pillar instability in underground mines. It would be extremely difficult, if not possible, to study all these problems experimentally in laboratory. Hence, the approach to be adopted is a combined application of experimental observation and numerical modeling. This approach will take data from past laboratory test programs and validate and calibrate some of the advanced numerical tools to be used in this study. The research findings from this study can deepen our knowledge of post-peak strength of rocks, and contribute to a better understanding of the interaction between the pillar rock and the surround rocks. The outcome of the research will improve our capability to evaluate more accurately whether a pillar will fail violently or not. Most importantly, the results from the proposed research will contribute to the mineral resource sector in Canada for resource recovery in a more productive but less risky manner. In addition, two graduate students (one MASc, one Ph.D) will be trained in the course of the project.