Assessment of liquefaction potential of unsaturated oil sand tailings subjected to future saturation

油砂尾矿是从油砂提取沥青过程的副产物，其包括水、砂、细颗粒、残余沥青或其它烃。加拿大采矿业生产了大量油砂尾矿，永久储存在大型尾矿坝后面。矿山尾矿坝的液化流动失效和尾矿的不受控制的释放将对生产、环境、公众感知和生命损失产生灾难性影响。对这些尾矿进行安全和负责任的管理需要正确了解其抗剪强度和抗液化性。然而，油砂尾矿的液化行为和强度损失，无论是通过地震荷载或其他触发机制，如降雨，饱和，施工荷载，或坝坡过陡没有得到很好的理解。特别是，部分饱和对现场测试测量和解释尾矿的不排水剪切强度的影响是未知的。拟议的研究将校准一个广泛使用的原位测试工具，锥贯入试验（CPT），强度，刚度，单位重量，和饱和和不饱和油砂尾矿的细粒含量。将对油砂样品进行实验室CPT模型实验、剪切波速测量和直接简单剪切试验的综合方案。研究结果将为油砂尾矿的剪切响应和液化行为提供新的认识。将建立一个强大的方法来预测原位强度，并在动态和静态载荷下的CPT测量的油砂尾矿的液化敏感性。然后，采矿工程师可以在不饱和油砂尾矿中使用这种方法来评估尾矿坝的液化潜力和稳定性，如果它们变得饱和。这将使矿山运营商和工程师能够设计更安全的尾矿处理坝，并更好地了解现有坝的风险。这将进一步有利于加拿大，特别是阿尔伯塔省，通过确保矿山存款最终与周围地区融为一体，并回收到一个环境友好和安全的生态系统中，最大限度地减少采矿的环境风险。

Oil sand tailings are by-products of the bitumen extraction process from oil sands, which include water, sand, fine particles, residual bitumen or other hydrocarbons. Large amounts of oil sand tailings are produced by the Canadian mining industry which are stored permanently behind large tailings dams. Liquefaction flow failure of a mine tailings dam and uncontrolled release of tailings would have a catastrophic impact on production, the environment, public perception, and loss of life. Safe and responsible management of these tailings requires proper understanding of their shear strength and resistance to liquefaction. However, liquefaction behavior and strength loss of oil sand tailings, either through earthquake loading or other triggering mechanisms such as rainfall, saturation, construction loads, or oversteepening of dam slopes are not well understood. In particular, the effect of partial saturation on in-situ test measurements and interpreting undrained shear strength of tailings is unknown. The proposed research will calibrate a widely used in-situ testing tool, the Cone Penetration Test (CPT), with strength, stiffness, unit weight, and fines content of saturated and unsaturated oil sand tailings. A comprehensive program of laboratory CPT model experiments, shear wave velocity measurements, and direct simple shear tests will be carried out on oil sand samples. The results will produce new knowledge in shear response and liquefaction behavior of oil sand tailings. A robust method will be established to predict in-situ strength, and liquefaction susceptibility of oil sand tailings under dynamic and static loads from CPT measurements. Mining engineers can then use this method in unsaturated oil sand tailings to assess the liquefaction potential and stability of tailings dams if they become saturated. This will allow mine operators and engineers to design safer tailings disposal dams and have a better understanding of the risks to existing dams. It will further benefit Canada, and particularly Alberta to minimize environmental risks of mining by ensuring that the mine deposit is ultimately integrated with the surrounding area and reclaimed into an environmentally-friendly and safe ecosystem.