Experimental and Computational Investigation of Fracture Propagation in Rocks

透彻地了解岩石裂缝为何、何时、何地开始、扩展和合并，对于岩石结构（如斜坡、基础和隧道）的稳定性以及涉及爆破和水力破裂的过程至关重要。该项目将包括对岩石样品进行断裂的先进实验室测试，为计算模型提供材料行为数据，用于预测能力。该项目的成果将使土木和岩土工程师能够进行更安全、更经济的设计，从而在广泛的应用中造福社会。这项研究将与教育和外联活动结合起来。该项目的跨学科性质，包括实验岩石力学和计算地质力学，将为科罗拉多矿业学院（CSM）的本科生和研究生提供优秀的教育和培训机会。研究人员将鼓励代表性不足的群体参与该项目，例如通过CSM校园内的女工程师协会（SWE）和多元文化工程计划（MEP）学生组织。他们还将开发、实施和评估在研讨会期间交付的材料行为的教学实践模块。研究结果将纳入研究生和本科生课程，并通过会议和期刊文章传播。本研究项目的目的是发现具有不同预先存在缺陷几何形状的天然岩石的压裂特征。研究目标是建立新的经实验验证的裂纹起裂和扩展准则，该准则可适用于具有不同裂纹几何形状的不同岩石，并在先进的数值代码中实现。该项目的一个关键创新是对天然岩石中压裂过程的力学-地球物理-数值联合研究。一套全面的单轴压缩实验将在花岗岩、石灰石和砂岩上进行，并使用声发射和主动地球物理（超声波）监测技术的协同使用。基于实验观察，新的裂缝起裂标准将在扩展有限元法（XFEM）代码中开发和实施，为各向异性岩层的压裂评估和预测提供一种全新的、具有潜在变革意义的数值工具。

A thorough understanding of why, when and where rock fractures initiate, propagate and coalesce is of critical importance in the stability of rock structures such as slopes, foundations, and tunnels, as well as processes involving blasting and hydraulic fracture. This project will involve advanced laboratory testing of fracture in rock samples that will provide data on material behavior for use in computational models that can be used in a predictive capacity. The deliverables of this project will allow civil and geotechnical engineers to perform safer and more economical designs that will benefit society across a broad range of applications. The research will be integrated with educational and outreach activities. The interdisciplinary nature of this project, including experimental rock mechanics and computational geomechanics, will provide outstanding educational and training opportunities for undergraduate and graduate students at the Colorado School of Mines (CSM). The researchers will encourage the participation of underrepresented groups on this project, e.g. through the Society of Women Engineers (SWE) and Multicultural Engineering Program (MEP) student organizations on the CSM campus. They will also develop, implement, and assess instructional hands-on modules on materials behavior to be delivered during workshops. The research findings will be incorporated into graduate and undergraduate courses and disseminated through conference and journal articles. The goal of this research project is to discover the fracturing characteristics of natural rocks with different pre-existing flaw geometries. The research objective is to formulate new experimentally verified crack initiation and propagation criteria that can be applied to different rocks with different flaw geometries for implementation in advanced numerical codes. A key innovation in this project is the combined mechanical-geophysical-numerical investigation of the fracturing processes in natural rocks. A comprehensive suite of uniaxial compression experiments will be conducted on granite, limestone, and sandstone with pre-existing flaws, with synergistic use of acoustic emission and active geophysical (ultrasonic) monitoring techniques. Based on experimental observations, new fracture initiation criteria will be developed and implemented in an eXtended Finite Element Method (XFEM) code to provide an entirely novel and potentially transformative numerical tool for assessment and prediction of fracturing in anisotropic rock formations.