EAGER: Exploratory Research on Rock Damage from Geologic and Induced Thermal Loading

EAGER：地质和热载荷引起的岩石损伤的探索性研究

• 批准号: 1550307
• 负责人: Rennie Kaunda
• 金额: $ 30万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1550307&HistoricalAwards=false
• 关键词: EAGER; Exploratory; Research; Rock; Damage

The behavior of rock under short- and long-term thermal excursions is a critical knowledge gap in rock science and engineering disciplines. Such advanced understanding will be important in many applications, including mined and civil excavations, in situ resource extraction or geothermal development for which excavations will be extended into rock masses at elevated temperatures. Most analyses have focused on rock stress as result of tectonics and depth. With insight into how thermal changes influence the fabric and structure of the rock, new excavation methods and technologies may be developed that lead to a truly engineered design of thermally-induced rock breakage. The most relevant questions to be investigated are: How does the PT (Pressure-Thermal) history of intact rock (and a rock mass) induce damage and influence behavior? Which mechanisms are most important in influencing the changes in mechanical structure of heated rock? How do these mechanisms influence excavatability, stability and strength? This EArly-concept Grant for Exploratory Research (EAGER) project involves geology, civil and mining engineering, and extractive metallurgy and mineral processing. This multi-disciplinary approach will help broaden participation of underrepresented groups in research and positively impact engineering education.The assessment of induced damage will involve rocks with well-defined thermal and stress history and composition. Rock samples will be subjected to additional selective heat-treatment (e.g., microwaves) in dry and saturated states, and the resulting damage and changes in properties will be evaluated using thin section petrography, optical cathodoluminescence, scanning electron microscopy and automated mineralogy. Investigations of geologic damage caused by thermal and stress history (e.g., skarns in the contact zone of local metamorphism, pegmatitic intrusions) will study samples from core and mined exposures. The temperature and pressure history will be evaluated using geothermobarometry of mineral pairs and placed in regional context based on existing thermochronology studies (e.g. U-Pb/He thermochronology of apatite and zircon). These results will be compared with those from experiment 1) to identify cracking behavior and generation of stresses and damage at grain boundaries as result of heating. Finally, numerical simulation of thermal loading of will be analyzed numerically and the results will be compared to the experimental observations.

岩石在短期和长期热漂移下的行为是岩石科学和工程学科中的一个关键知识空白。 这种先进的理解在许多应用中将是重要的，包括采矿和民用挖掘，原位资源开采或地热开发，挖掘将延伸到高温岩体中。 大多数分析都集中在构造和深度引起的岩石应力上。 通过深入了解热变化如何影响岩石的结构和结构，可以开发新的挖掘方法和技术，从而实现真正的热致岩石破碎工程设计。 最相关的问题是：完整岩石（和岩体）的PT（压力-温度）历史如何引起损伤和影响行为？ 哪些机制对加热岩石的力学结构变化影响最大？ 这些机制如何影响可挖掘性、稳定性和强度？ 这个早期概念的探索性研究资助（EAGER）项目涉及地质学，土木和采矿工程，以及提取冶金和矿物加工。 这种多学科的方法将有助于扩大研究中代表性不足的群体的参与，并对工程教育产生积极影响。 岩石样品将接受额外的选择性热处理（例如，将使用薄片岩相学、光学阴极射线发光、扫描电子显微镜和自动矿物学来评估干燥和饱和状态下的矿物（微波），以及由此造成的损害和性质变化。 调查由热历史和应力历史引起的地质损害（例如，局部变质作用接触带中的矽卡岩、伟晶岩侵入体）将研究来自岩心和开采暴露的样品。 温度和压力历史将使用矿物对的地质温压法进行评估，并根据现有的热年代学研究（如磷灰石和锆石的U-Pb/He热年代学）置于区域背景中。 将这些结果与实验1）的结果进行比较，以确定由于加热而在晶界处产生的开裂行为和应力和损伤。 最后，对热负荷的数值模拟进行了数值分析，并将结果与实验观测结果进行了比较。