Rock mass redefined: integrating discrete fracture network models and rock mass classification systems

1963年，现代岩土工程之父卡尔·太沙基（Karl Terzaghi）写道：“我们正在超越我们预测行为后果的能力极限。55年后的今天，岩石工程设计仍然依赖于经验方法，通过观察得出结论并产生理论。岩石工程设计面临的挑战是以节理、层面和断层形式存在的物理不连续性，这些不连续性可能影响边坡、地下开挖和坝基的稳定性。存在几种分类系统来量化岩体的质量并说明这些不连续性的影响。然而，这些分类系统大多是在20世纪60年代至70年代开发的，当时岩石工程项目的规模非常有限。随着大型露天矿作业接近其经济极限，矿山正在更深的地下开发，需要一种新的设计方法，这种方法不受经验表的主观解释和岩体性质的定性评估的限制。我们相信，我们的研究可以通过更好地了解地质变异性以及岩体行为与不连续性强度/性质之间的关系，有助于减少“不可预见”事件的发生程度。将传统的不连续面制图与新的远程遥感技术相结合，用于资源岩土工程和自然灾害调查，离散裂隙网络（DFN）方法已日益成为一种有效的工具，以协助岩石工程设计。结合先进的数值分析，基于DFN的岩石工程可以支持更有效的矿山设计并提高运营安全性。我的研究小组介绍了一种新的方法，分析DFN模型的属性，并提供了一种衡量网络连通性的方法，这是实现基于DFN的岩体分类和设计方法的关键因素。加拿大的几家岩土工程咨询公司现在正在使用DFN方法进行岩石工程设计。在此应用中，我们提出了一个研究计划，以推进和更新岩体分类系统，消除定性测量，并专注于使用新技术来绘制更适合统计分析的关键地质参数（例如断裂频率和块体体积）。这是一个关键的要求，如果我们希望岩石工程发展和支持现代设计框架，如故障概率分析和风险评估。为了实现这些目标，该提案将寻求为5名高素质人员（HQP）提供资金。该研究将对改善工程边坡和地下开挖的设计，以及增加DFN工具和概率方法在岩石工程设计中的使用产生重大影响。

In 1963 Karl Terzaghi, the father of modern geotechnical engineering, wrote "we are overstepping the limits of our ability to predict the consequences of our actions". 55 years later, rock engineering design still depends on empirical methods, whereby observations are used to reach conclusions and generate theories. What makes rock engineering design challenging is the presence of physical discontinuities in the form of joints, bedding planes, and faults, which may affect the stability of slopes, underground excavations, and dam foundations. Several classification systems exist to quantify the quality of the rock mass and account for the effects of those discontinuities. However, most of those classification systems were developed in the 1960s-1970s, at a time when the scale of rock engineering projects was much limited. As large open pit operations are approaching their economic limits and mines are being developed deeper underground, a new approach to design is required that is not limited by a subjective interpretation of empirical tables and qualitative assessments of rock mass properties. We believe our research can contribute to reduce the degree of occurrence of "unforeseeable" events, by providing a better understanding of geological variability and the relationship between rock mass behaviour and intensity/nature of the discontinuities. Integrating conventional discontinuities mapping with new long-range remote sensing techniques for resource geotechnics and natural hazard investigations, discrete fracture network (DFN) methods have increasingly become an effective tool to assist with rock engineering design. Coupled with advanced numerical analyses, DFN-based rock engineering can support more efficient mine design and improve operational safety. My research group has introduced a new method that analyse the properties of DFN models, and provides a measure of the network connectivity, which is the key element for implementing a DFN-based approach to rock mass classification and design. Several geotechnical consulting companies in Canada are now using DFN methods for rock engineering design. In this application, we propose a research program to advance and update rock mass classification systems, removing qualitative measurements, and focusing on the use of new technologies to map key geological parameters that are more appropriate for statistical analysis (e.g. fracture frequency and blocks volumes). This is a key requirement if we want rock engineering to evolve and to support modern design frameworks such as the analysis of probability of failure and risk assessment. To meet these objectives, the proposal will seek funding for 5 Highly Qualified Personnel (HQP). The research will have a significant impact with respect to improving the design of engineered slopes and underground excavations, and increasing the use of DFN tools and probability methods in rock engineering design.