CAREER: Stress Redistribution Imaging for Rock Failure Prediction

CMS-0134034 PI：Erik Westman机构：弗吉尼亚理工学院和州立大学标题：“职业生涯：岩石破坏预测的应力再分布成像“这一教师早期职业发展（CAREER）研究和教育项目使用高分辨率三维断层成像来更好地理解和沟通岩石破坏的过程。 实现预测岩体破坏的最终目标将大大减少死亡人数，降低施工成本，并增加环境保护。 故障预测扩展到岩石力学的所有方面，包括隧道、矿山、岩石边坡、地震、废物库以及桥梁和坝肩。 为了预测岩石破坏，监测岩石内部的应力重新分布是非常有帮助的。 计算能力的最新进展已经允许使用声波和断层成像来完成这一点。 监测应力重新分布的基本原理是岩石内的微裂缝在增加的载荷下闭合，从而允许声波以更大的速度传播，并且衰减更小。 这种方法已成功地应用于实验室，并在现场得到了越来越多的应用，但缺乏基础。 本项目将通过1）标准化方法和2）将先前研究的结果扩展到实验室和现场规模研究之间的差距，将岩石中应力重分布成像技术置于坚实的理论和实践基础之上。 与教育和研究相关的具体任务包括：1）生成三维断层图像，以观察加载到破坏的岩石样品的结构的相关变化，以及2）使用这些图像校准数值模拟结果。 通过收集岩石样本加载时的数据，将开发延时动画，这将有助于向本科生传达应力分析。 额外的教育工作的重点是从表象教学方法过渡到建构主义模型的两个提议者的本科课程，并开发一个研究生水平的课程，通过成像和数值建模结果的耦合分析理解失败。

CMS-0134034PI: Erik WestmanInstitution: Virginia Polytechnic Institute and State UniversityTitle: "CAREER: Stress Redistribution Imaging for Rock Failure Prediction"This Faculty Early Career Development (CAREER) research and education project uses high-resolution, three-dimensional tomographic imaging to better understand and communicate the process of failure in rock. Accomplishing the ultimate goal of predicting rock mass failure will result in significantly reduced fatalities, lowered construction costs, and increased environmental protection. Failure prediction extends to all aspects of rock mechanics including tunnels, mines, rock slopes, earthquakes, waste repositories, and bridge and dam abutments. To predict rock failure, it is quite helpful to monitor the redistribution of stresses within the rock. Recent advances in computational power have allowed this to be done using acoustic waves and tomographic imaging. The basic principal behind monitoring the redistribution of stresses is that microfractures within the rock are closed under increased loading, allowing the acoustic wave to travel at a greater velocity and with less attenuation. This method has been used successfully in the laboratory and has had growing, but poorly founded, application in the field. This project will put the technique of imaging stress redistribution in rock on a sound theoretical and practical foundation by 1) standardizing methods and 2) extending results of prior studies into the gap between laboratory- and field-scale studies. Educational efforts related to rock failure prediction will also be enhanced.Specific tasks associated with both education and research include 1) generating three-dimensional tomographic images to observe relevant alterations to the fabric of rock samples loaded to failure, and 2) using those images to calibrate numerical modeling results. By collecting data as rock samples are loaded, time-lapse animations will be developed which will assist in the communication of stress-analysis to undergraduates. Additional educational efforts focus on transitioning from a presentational teaching method to a constructivist model for two of the proposer's undergraduate courses and developing a graduate-level course for understanding failure through coupled analysis of imaging and numerical modeling results.