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。尾矿储存设施的失效会对环境和民用基础设施造成毁灭性的后果，并导致人员的生命损失。2008年田纳西州的金斯顿化石厂发生故障，造成了12亿美元的环境灾难，这是一个典型的例子，说明了尾矿储存设施故障可能造成的巨大影响。未来的失败可能会对地方和州的经济、人口和工业造成类似的毁灭性后果。因此，在任何采矿活跃的地区，如科罗拉多州、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都是至关重要的。尾矿是一种中间土壤物质，常被归类为砂质粉土到近乎纯粉土。这些材料的静态液化条件（即使在没有地震等极端事件的情况下也会突然失去稳定性）无法用已知的工程程序进行评估。这项研究将为改善尾矿储存设施的静态液化弹性设计创造新的知识，并为创建新的设计协议提供见解，以减轻美国和世界范围内由矿山尾矿静态液化引起的潜在灾害。该研究还将通过佐治亚理工学院的STEM中心，为K-12学生建立一个教育和推广项目，重点关注中间土壤材料的课程开发。受最近尾矿储存设施失败的启发，通过一个基于实验和数值的综合项目，该研究通过调查(1)矿山尾矿在标准和非标准应力路径下的机械响应，推进液化工程；在考虑一系列边界条件时；(2)排水荷载条件下的静态液化条件，尽管岩土工程师有相反的看法，但最近的破坏事件表明缺乏透彻的理解；(3)利用基于图像的实验技术研究剪切作用下尾矿的细观力学特性；(4)利用新颖的各向异性临界状态理论，研究了微力学结构（如织物）和诱导各向异性对触发静态液化的影响。深入了解控制尾矿静力液化触发的关键参数，并利用各向异性临界状态理论开发校准良好的数值程序，将改变岩土工程专业更有效地评估和减轻尾矿静力液化风险的能力。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.