Stress fields in complex rock masses

深部采矿开挖的稳定性取决于岩体强度和应力条件。估算岩体强度的方法相对成熟，但相比之下，应力条件通常根据整个区域的数据进行估算。虽然有文件证据表明应力会受到当地地质条件的强烈影响，但执行应力测量程序的费用和困难几乎排除了它们在实践中的使用。即使进行了测量，用于设计分析的应力场也总是具有简化的形式.矿山中的某些地面控制问题，包括远离采矿开挖的地震事件，不能用这种简单的方法来解释。申请人最近通过对应力测量的分析表明，某些上地壳断层系统仅是勉强稳定的。进一步的分析表明，在这些系统中，触发远离采矿挖掘的地震事件是自然发生的，应力场的大小和方向的变化也是如此。由于这些结果是新颖的，拟议的研究重点是调查和扩展这一早期工作，以表征应力场在复杂的地质环境中的典型矿山。这项工作将利用连续和非连续数值应力分析代码、分析大型应力测量数据库、矿山的微震数据以及结构地质学文献中提供的关于结构应力场的其他已发表资料来进行。这项研究预计将有助于我们了解应力场在复杂的岩体，如分散在测量，矿山周围的地震活动，断层强度，以及在数值应力分析中的应力场指定的方式。通过改进设计分析，提高矿井安全、布置效率和生产率。研究生水平的预期。

Stability of mining excavations at depth depends on both rock mass strength and stress conditions. Methods of estimating rock mass strength are relatively well developed, but in contrast, stress conditions are generally estimated from data assembled for entire regions. Although there is documented evidence that stresses can be strongly influenced by local geological conditions, the expense and difficulty of carrying out stress measurement programs has all but precluded their use in practice. Even when measurements are made, stress fields used in design analysis invariably have simplified forms. Certain ground control problems in mines, including seismic events located far from mining excavations, cannot be explained using this simple approach. Other less quantifiable design errors are undoubtedly introduced using this simplification.The applicant has recently shown through analysis of stress measurements that certain upper crustal fault systems are only marginally stable. Further analysis has shown that triggering of seismic events remote from mining excavations is a natural occurrence in these systems, as is the variation in magnitude and direction of the stress field. Since these results are novel, the proposed research focuses on investigating and extending this early work in order to characterize stress fields in complex geological settings typical of mines. The work will be carried out using continuum and discontinuum numerical stress analysis codes, analysis of large databases of stress measurements, microseismic data from mines, plus additional published information on stress fields in relation to structures that is available in the structural geology literature. This research is expected to contribute towards our understanding of stress fields in complex rock masses such as scatter in measurements, seismic activity around mines, fault strength, and the way in which stress fields in numerical stress analyses are specified. Through improved design analysis, mine safety,  layout efficiency and productivity will be increased.Through this research, training of two Ph.D. level graduate students is anticipated.