Static Liquefaction of Mine Tailings under Non-Standard Stress Paths

尾矿的静态液化最近在美国和世界各地造成了许多失败。尾矿储存设施的故障会对环境和民用基础设施造成破坏性后果，并导致人命损失。2008年田纳西州的金斯顿化石燃料发电厂故障是一场环境灾难，相关损失约为12亿美元，这是尾矿储存设施故障可能造成巨大影响的一个主要例子。未来的失败可能会对当地和州的经济、人口和行业产生类似的破坏性后果。因此，在任何采矿活跃的地区，如科罗拉多、内华达州、犹他州、亚利桑那州等，评估尾矿储存设施的安全性至关重要。尾矿是一种中间土壤材料，通常归类为桑迪粉土至几乎纯粉土。这些材料的静态液化条件（即使在没有极端事件如地震的情况下也会突然失去稳定性）无法使用已知的工程程序进行评估。这项研究将创造新的知识，以改善尾矿储存设施的抗静态液化弹性设计，并为创建新的设计协议提供见解，以减轻美国和全球范围内由尾矿静态液化引起的潜在灾害。该研究还将通过格鲁吉亚理工学院的STEM中心建立一个教育和推广计划，重点是为K-12学生开发中间土壤材料的课程。通过一个综合的实验和基于数字的计划，该计划受到最近尾矿储存设施失败的启发，本研究通过研究（1）尾矿在标准和非标准条件下的力学响应，标准应力路径，同时考虑一系列边界条件;（2）排水荷载条件下的静态液化条件，尽管岩土工程师的看法相反，但最近的破坏事件表明缺乏彻底的理解;（3）通过基于图像的实验技术，剪切下尾矿的微观力学;（4）利用新的各向异性临界状态理论，研究了细观结构（组构）和诱导各向异性对静态液化触发的影响。深入了解控制尾矿静态液化触发的关键参数，使用各向异性临界状态理论的校准数值程序将改变岩土工程专业的能力，以更有效地评估和减轻尾矿静态液化的风险。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的学术价值和更广泛的影响评审标准。

Static liquefaction of mine tailings has caused numerous recent failures in the United States and around the world. Failure of tailings storage facilities lead to devastating consequences for the environment and civil infrastructure, and lead to loss of human lives. The 2008 Kingston fossil plant failure in Tennessee, an environmental disaster with associated losses on the order of 1.2 billion dollars, is a prime example of the tremendous impact that a tailings storage facility failure can cause. Future failures could have similar devastating consequences for the local and state economies, populations, and industries. Therefore, evaluating the safety of tailings storage facilities is vitally important in any region where mining is active, such as in Colorado, Nevada, Utah, Arizona, and others. Mine tailings are intermediate soil materials often classified as sandy silt to almost pure silt. Conditions for static liquefaction (sudden loss of stability even in the absence of extreme events such as earthquakes) on these materials cannot be evaluated using known engineering procedures. This research will create new knowledge for improving resilient design of tailings storage facilities against static liquefaction and provide insights into creating new design protocols to mitigate potential disasters in the United States and worldwide that are induced by the static liquefaction of mine tailings. The research will also establish an educational and outreach program focused on curriculum development on intermediate soil materials for K-12 students, through STEM centers at Georgia Tech.Through an integrated experimentally and numerically-based program inspired by recent failures in tailings storage facilities, this research advances liquefaction engineering by investigating (1) the mechanical response of mine tailings under standard and non-standard stress paths, while considering a range of boundary conditions; (2) the conditions for static liquefaction under drained loading conditions, where recent failure events point to a lack of thorough understanding despite the opposite perception among geotechnical engineers; (3) the micromechanics of mine tailings under shearing through image-based experimental techniques; and (4) the effects of micromechanical configurations (i.e. fabric) and induced anisotropy on triggering static liquefaction by using the novel anisotropic critical state theory. Gaining insights into the key parameters that govern the triggering of static liquefaction in mine tailings and developing well-calibrated numerical procedures using the anisotropic critical state theory will transform the ability of geotechnical engineering profession to more effectively evaluate and mitigate the risk of static liquefaction in mine tailings.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.