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，特别是尾矿。尾矿的可持续管理对加拿大来说是一个巨大的挑战。最成功和最创新的尾矿管理策略之一是开发胶结膏体充填技术(CPB，尾矿、水和粘结剂的混合物)。CPB是地下矿山作业的重要组成部分，其关键功能是对地下矿山巷道进行机械稳定，最大限度地实现安全和经济的矿石回收。此外，尾矿的最大地下处置代表着显著的环境效益。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、动态加载条件下的早期机械稳定性(液化势)、流动性和成本。CPB技术的关键优先事项之一是开发具有高机械稳定性和较短固化时间(提高矿山生产率)的新型CPB，并以可接受的成本改善和/或改善流动性。为了实现这一目标，采矿业和矿山充填工程师近年来一直非常重视在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，以前开发这些新型CPB及其现场应用的许多尝试都产生了令人失望的结果或失败了，原因是缺乏对含有这种添加剂的CPB的行为和性能的充分和基本的了解，以及由于没有考虑这些CPB在现场受到的耦合热机械(TM)加载条件。长期以来，缺乏对这些耦合TM过程的考虑一直被辩解为很难这样做。然而，这并不意味着这些问题不重要。需要创新思维来应对这些挑战，从而解决技术方面的这一不足。因此，本研究提出了一种新的方法和工具来研究这些新型CPB(CH-CPB或含化学外加剂的CPB；纳米CPB或含纳米粒子的CPB)在静态和动态加载条件下对TM载荷的响应，以及评估这些类型的CPB在不同热条件下在矿山中的流动性，以及用于制备最佳充填配方的新方法和工具。出于经济原因、矿工安全和制定经济和环境可持续的采矿战略，这些工具以及对这些新型多氯联苯在各种现场TM装载条件下的行为和性能的透彻了解是必要和必要的。

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.