Characterization of Static Liquefaction in Tailings through the Critical State Framework

通过临界状态框架表征尾矿静态液化

• 批准号: 556818-2020
• 负责人: Ghafghazi, Mohsen
• 金额: $ 2.08万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Alliance Grants
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=719196
• 关键词: Characterization; Static; Liquefaction; Tailings; through

Tailings storage facilities (TSF) are man-made earth structures used for storing mining waste, comprised of fine minerals and water left behind during the extraction process. They exist at the intersection of economics, safety, and sustainability. The mining industry needs better engineering practices for assessing and improving existing TSFs, designing new TSFs, and disposal processes motivated by: recent catastrophic failures of TSFs; economic challenges demanding reductions in tailings disposal costs; and evolving regulatory and social pressures to improve the safety and sustainability of tailings storage. Granular soils, such as tailings, can lose all or part of their strength in a process called liquefaction. Liquefaction is the phenomenon that happens when loosely compacted particles "want" to form a denser structure, but presense of water in the voids prevents that, at the cost of increasing pressure in the water. The result is obvious: if the water pressure sufficiently increases, the whole mixture will turn into a "liquid". Soils' resistance to liquefaction mainly depends on how densely-packed its particles are. Liquefaction potential is assessed by estimating soil density from its resistance to a penetrating probe. The Cone Penetration Test (CPT) is the predominant site characterisation tool since it provides a wealth of information with fast and inexpensive application. Assessing the potential threat of liquefaction to a TSF involves three steps: How the CPT estimates the density of tailings, if liquefaction will occur given the density of tailings, and how much strength the tailings will retain should liquefaction occur. A consultant (Golder) and a specialty contractor (ConeTec) who often collaborate on TSF projects in Canada and around the world have come together with University of Toronto to pool their expertise and answer these pressing questions. The proposed partnership will produce a new tailings-specific liquefaction assessment framework. Consequently, Canadian consultants, contractors, and mining companies will obtain a competitive edge leading to added work and employment, reduced cost of operation, and most importantly safer designs.

尾矿储存设施 (TSF) 是用于储存采矿废物的人造土结构，由提取过程中留下的细矿物和水组成。它们存在于经济、安全和可持续性的交叉点。采矿业需要更好的工程实践来评估和改进现有的 TSF、设计新的 TSF 以及处置流程，其动机是： 最近 TSF 的灾难性故障；经济挑战要求降低尾矿处置成本；不断变化的监管和社会压力，以提高尾矿储存的安全性和可持续性。粒状土壤（例如尾矿）可能会在液化过程中失去全部或部分强度。液化是当松散压实的颗粒“想要”形成更致密的结构时发生的现象，但空隙中存在水阻止了这种情况，代价是增加了水中的压力。结果很明显：如果水压充分增加，整个混合物就会变成“液体”。土壤的抗液化能力主要取决于其颗粒的密集程度。通过根据土壤对穿透探针的抵抗力估算土壤密度来评估液化潜力。锥入度测试 (CPT) 是主要的场地表征工具，因为它通过快速且廉价的应用提供了丰富的信息。评估液化对 TSF 的潜在威胁涉及三个步骤：CPT 如何估计尾矿密度、给定尾矿密度是否会发生液化，以及发生液化时尾矿将保留多少强度。经常在加拿大和世界各地合作开展 TSF 项目的顾问 (Golder) 和专业承包商 (ConeTec) 与多伦多大学齐聚一堂，汇集他们的专业知识并回答这些紧迫的问题。拟议的合作伙伴关系将产生一个新的尾矿专用液化评估框架。因此，加拿大顾问、承包商和采矿公司将获得竞争优势，从而增加工作和就业、降低运营成本，以及最重要的是更安全的设计。