Advanced tools for analyzing and predicting the performance and durability of paste backfill under different thermal conditions

胶结膏体充填体（CPB）是一种由尾矿、粘结剂和水混合而成的充填体，在采矿业中得到了广泛的应用。其主要目的是确保地下开孔的稳定性、安全、最大限度地回收矿石，并为潜在产酸尾矿的地下处置提供一种环境友好的手段。然而，许多基本方面，如温度对CPB性能（机械稳定性、质量）和耐久性（抗硫酸盐侵蚀：硫酸盐侵蚀粘合剂并破坏其结合效果）的影响仍然知之甚少。此外，众所周知，在广泛的工程问题中，材料性能的变化和损伤的积累不仅是由机械载荷引起的，而且还由温度和湿度引起的载荷以及化学侵蚀因素（例如硫酸盐）或这些过程的各种组合引起的。然而，关于CPB中热、化学、水力和机械过程之间相互作用的知识水平仍然非常有限。因此，要准确预测CPB的性能和耐久性，需要深入了解温度对这些性能的影响，以及CPB中发生的热-化学-液压-机械耦合（TCHM）机制，并开发预测这些特性的工具。因此，通过实验和建模技术的结合，本研究项目将集中在以下目标上：(i)了解温度和耦合TCHM载荷对CPB性能和耐久性的影响；（ii）开发并验证先进的优化工具，使在任何固化温度下制备最佳CPB配方成为可能；（iii）开发并验证先进的TCHM模型，以预测CPB在各种TCHM加载条件下的机械稳定性和耐久性。这项拟议的研究将通过提供可持续和安全采矿的基本知识和先进工具或技术，使研究界、采矿业、教育机构、土木工程公司和加拿大社区受益。

Cemented paste backfill (CPB), a mix of tailings, binder and water, is extensively used in the mining industry. Its main purpose is to ensure the stability of underground openings, safe and maximum ore recovery, and also to provide an environmental-friendly means of underground disposal of potential acid generating tailings. However, many fundamental aspects, such as the impact of temperature on the performance (mechanical stability, quality of the CPB) and durability (resistance to sulphate attack: sulphate attacks the binder and destroys its binding effect) properties are still poorly understood. Furthermore, it is well known that in a broad range of engineering problems the change of material properties and accumulation of damage are not only caused by mechanical loads, but also by temperature and moisture induced loading as well as chemically aggressive factors (e.g., sulphate) or various combinations of these processes. However, the level of knowledge on these interactions between thermal, chemical, hydric and mechanical processes in CPB is still very limited. Thus, an accurate prediction of the performance and durability properties of CPB needs a deep understanding of the effect of temperature on these properties and of the coupled thermo-chemo-hydric-mechanical (TCHM) mechanisms that occur in CPB, and the development of tools that will predict them. Hence, through the combination of experimental and modeling techniques, this research program will focus on the following objectives: (i) understand the impact of temperature and coupled TCHM loadings on the performance and durability properties of CPB; (ii) develop and validate advanced optimization tools that will make it possible to prepare optimal CPB recipes for any curing temperature; and (iii) develop and validate advanced TCHM models to predict the mechanical stability and the durability of CPB under various TCHM loading conditions. This proposed research will benefit the research community, mining industry, educational institutions, civil engineering firms, and Canadian community by providing of fundamental knowledge and advanced tools or techniques for sustainable and safe mining.