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, MohsenMG
• 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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=748847
• 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制结构，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和处置过程，其动机是：最近tsf的灾难性失败；经济挑战要求降低尾矿处理成本；以及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。颗粒状土壤，如尾矿，会在一个称为液化的过程中失去全部或部分强度。液化是一种现象，当松散的颗粒“想要”形成更致密的结构时，就会发生这种现象，但在空隙中存在的水阻止了这种现象的发生，其代价是水中的压力增加。结果很明显：如果水压足够大，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。液化潜力是通过估算土壤密度来评估其对穿透探针的阻力。锥体穿透测试（CPT）是主要的现场表征工具，因为它提供了丰富的信息，快速和廉价的应用。评估液化对TSF的潜在威胁包括三个步骤：CPT如何估计尾矿的密度，在给定尾矿密度的情况下是否会发生液化，以及如果发生液化，尾矿将保留多少强度。一位顾问（Golder）和一位专业承包商（ConeTec）经常在加拿大和世界各地的TSF项目上合作，他们与多伦多大学一起汇集了他们的专业知识，并回答了这些紧迫的问题。拟议的伙伴关系将产生一个新的针对尾矿的液化评估框架。因此，加拿大的顾问、承包商和矿业公司将获得竞争优势，从而增加工作和就业，降低运营成本，最重要的是更安全的设计。