Properties and Geotechnical Behaviour of Cemented Tailings Backfills with Additive-Enhanced Performance under Different Thermal and Mechanical Loading Conditions

加拿大是世界上最大的矿业国家之一。然而，这个行业伴随着大量固体废物的产生，尤其是尾矿。尾矿的可持续管理对加拿大来说是一个巨大的挑战。最成功和创新的尾矿管理策略之一是开发胶结膏体回填技术（CPB，一种尾矿、水和粘合剂的混合物）。CPB是地下矿山作业的重要组成部分，其主要功能是实现地下矿山开口的机械稳定，实现矿山安全经济回收的最大化。此外，最大限度地下处置尾矿具有显著的环境效益。任何类型的CPB的关键性能特征包括：静态加载条件下的机械稳定性，动态加载条件下早期的机械稳定性（液化潜力），流动性和成本。CPB技术的关键优先事项之一是开发新型CPB，这些CPB具有高机械稳定性，固化时间短（提高矿山生产率），并且在可接受的成本下改善和/或优异的流动性。为了实现这一目标，近年来矿业和矿山回填工程师一直非常重视在CPB中使用新型添加剂（化学外加剂、纳米颗粒）来开发新型CPB。然而，由于缺乏对含有此类添加剂的cpb的行为和性能的充分和基本的了解，以及缺乏对这些cpb在现场所承受的耦合热-机械（TM）加载条件的考虑，许多先前开发这些新型cpb及其现场应用的尝试都产生了令人失望的结果或失败。长期以来，缺乏对这些耦合TM过程的考虑一直被认为是很难这样做的。然而，这并不意味着这些问题不重要。需要创新思维来面对这些挑战，从而解决这一技术缺陷。因此，研究反应的新方法和工具(如…（g，机械稳定性，液化潜力）这些新型CPB （CH-CPB或含有化学外加剂的CPB；纳米CPB或含有纳米颗粒的CPB）在静态和动态加载条件下对TM载荷的影响，以及在矿山各种热条件下评估这些类型的CPB的流动性，并制定最佳回填配方。这些工具以及对这些新型CPBs在各种现场TM加载条件下的行为和性能的全面了解对于经济原因，矿工的安全以及经济和环境可持续采矿战略的发展是必不可少的。

Canada is one of the largest mining nations in the world. However, this industry is associated with the production of a large quantity of solid waste, especially tailings. The sustainable management of tailings is a great challenge for Canada. One of the most successful and innovative tailings management strategies is the development of cemented paste backfill technology (CPB, a mix of tailings, water and binder). The key functions of CPB, a vital component of underground mine operations, are the mechanical stabilization of underground mine openings, and the maximization of safe and economic ore recovery. In addition, the maximum underground disposal of tailings represents significant environmental benefits. The key performance characteristics of any type of CPB include: mechanical stability under static loading conditions, mechanical stability at the early ages under dynamic loading conditions (liquefaction potential), flowability and cost. One of the key priorities in CPB technology is the development of new types of CPBs that have high mechanical stability with a shorter curing time (increase mine productivity), and improved and/or excellent flowability at an acceptable cost. To achieve this goal, the mining industry and mine backfill engineers have been placing strong emphasis on the use of novel types of additives (chemical admixtures, nanoparticles) in CPB in recent years to develop new types of CPB. However, many previous attempts to develop these new types of CPBs and their field applications have produced disappointing results or failed due the lack of a sufficient and basic understanding of the behaviour and performance of CPBs that contain such additives as well as due to the lack of consideration of the coupled thermo-mechanical (TM) loading conditions to which these CPBs are subjected in the field. The lack of consideration given to these coupled TM processes has long been defended on the basis that it is difficult to do so. However, this does not mean that these issues are not essential. Innovative thinking is needed to face these challenges and thus address this deficiency in technology. Therefore, novel methods and tools for studying the response (e..g, mechanical stability, liquefaction potential) of these new types of CPBs: (CH-CPB or CPB with chemical admixtures; nano-CPB or CPB that contains nanoparticles) to TM loads in static and dynamic loading conditions as well as for assessing the flowability of these types of CPBs under various thermal conditions in mines, and for preparing optimal backfill recipes are identified and proposed in this research program. These tools and a thorough understanding of the behaviour and performance of these new types of CPBs under various field TM loading conditions are imperative and essential for economic reasons, mine worker safety and the development of economically and environmentally sustainable mining strategies.