Stand-up Time of Jointed Rock Masses in Underground Excavations

地下开挖节理岩体的挺立时间

• 批准号: RGPIN-2016-04052
• 负责人: Cai, Ming
• 金额: $ 1.97万
• 依托单位: Laurentian University of Sudbury
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=753206
• 关键词: Stand; up; Time; Jointed; Rock

Stand-up time is the time that an un-supported tunnel would remain stable after excavation before it collapses. In underground mining and civil tunneling, the stand-up time is closely related to design and installation of rock support systems near tunnel advancing faces. If the stand-up time can be assessed accurately, it is then possible to optimize the excavation cycle and increase the tunnel advance rate considerably. Unfortunately, the current method of estimating stand-up time is still based on the method proposed by Bieniawski in 1976, which shows a large uncertainty in stand-up time prediction.The challenge in this research is to better understand the behaviour of rock mass and provide solutions to assess stand-up time of tunnels excavated in rock masses more accurately. Based on the need to advance knowledge in rock mechanics and mining science, we propose to study the phenomenon of time-dependent rock failure, understand the mechanisms that govern stand-up time, develop a time-dependent rock failure model and verify the model using laboratory and field data, study how rock support enhances stand-up time, and apply the result to underground mining. The approach to be adopted is a combined application of experimental and field observations and numerical modeling using advanced numerical tools. Stand-up time of tunnels excavated in jointed rock masses will be calculated and new charts for stand-up time estimation considering factors such as excavation span, rock mass quality, overburden depth, and excavation shape will be developed. Many mines apply shotcrete immediately after scaling in an excavation cycle. The effect of shotcrete on stand-up time enhancement will be studied quantitatively in this study.The research findings from this study can contribute to a better understanding of the fundamental problem of time-dependent behaviour of rocks and provide a tool for the mining and civil tunneling industries to estimate stand-up time more accurately. The potential cost-benefits of this investigation are significant because it provides Canadian mining companies a useful tool to make important decisions related to rock support in tunnel development so as to improve safety and productivity.

站立时间是指无支撑隧道在开挖后在倒塌之前保持稳定的时间。在地下采矿和土建隧道中，站立时间与隧道掘进面附近岩石支护系统的设计和安装密切相关。如果能够准确评估站立时间，则可以优化挖掘周期并显着提高隧道掘进速度。不幸的是，目前估计站立时间的方法仍然基于Bieniawski于1976年提出的方法，这在站立时间预测中表现出很大的不确定性。这项研究的挑战是更好地理解岩体的行为和提供更准确地评估在岩体中开挖的隧道的站立时间的解决方案。基于提高岩石力学和采矿科学知识的需要，我们建议研究与时间相关的岩石破坏现象，了解控制站立时间的机制，开发与时间相关的岩石破坏模型，并使用实验室和现场数据，研究岩石支护如何提高站立时间，并将结果应用于地下采矿。所采用的方法是实验和现场观察以及使用先进数值工具的数值建模的结合应用。将计算在节理岩体中开挖的隧道的直立时间，并制定考虑开挖跨度、岩体质量、覆土深度和开挖形状等因素的直立时间估算新图表。许多矿山在挖掘周期中结垢后立即使用喷射混凝土。本研究将定量研究喷射混凝土对增强站立时间的影响。本研究的研究结果有助于更好地理解岩石随时间变化的行为这一基本问题，并为采矿和土木工程提供工具。隧道行业更准确地估计站立时间。这项调查的潜在成本效益非常显着，因为它为加拿大矿业公司提供了一个有用的工具，可以在隧道开发中做出与岩石支护相关的重要决策，从而提高安全性和生产率。