Thin Spray-on Liners (TSLs) are a novel rock support technology used in underground projects, which often encounter harsh environments such as high humidity. The mechanical properties of TSLs are affected by the high humidity environment. This study aims to summarize the support mechanisms of TSLs and evaluate the effects of humidity on their performance. Two cement-based TSLs were prepared. They used vinyl acetate-ethylene copolymer emulsion (VAE emulsion) and polyacrylate emulsion as modifying materials, respectively. Specimens were subjected to four different humidity environments for 7 days. The mechanical properties of the specimens were evaluated through compressive, flexural and pull-out tests. The impermeability test was utilized to test the sealing of TSLs. Microscopic observation was conducted using a Lecia microscope. The study also analyzed the interfacial failure modes observed in the pull-out test. The results indicated that increasing humidity hindered the film formation reaction of TSLs, preventing the formation of a continuous three-dimensional spatial polymer mesh structure. Instead, cohesive large particles were formed, negatively impacting the mechanical properties. Additionally, increasing humidity led to the formation of large pores and crack lines within TSLs, further decreasing their mechanical and sealing properties. The increase in humidity also weakened the dry shrinkage effect of TSLs, resulting in increased bond strength. Therefore, analyzing the initial mechanical properties of TSLs under high humidity conditions is crucial for guiding their application in underground projects.

薄喷涂衬管 (TSL) 是一种用于地下工程的新型岩石支护技术，这些工程经常遇到高湿度等恶劣环境。TSL 的机械性能受到高湿度环境的影响。本研究旨在总结 TSL 的支撑机制并评估湿度对其性能的影响。制备了两种水泥基 TSL。他们分别使用醋酸乙烯-乙烯共聚物乳液（VAE乳液）和聚丙烯酸酯乳液作为改性材料。样本在四种不同的湿度环境中放置 7 天。通过压缩、弯曲和拉拔试验评估样品的机械性能。抗渗性测试用于测试TSL的密封性。使用Lecia显微镜进行显微观察。该研究还分析了拉拔试验中观察到的界面失效模式。结果表明，湿度的增加阻碍了 TSL 的成膜反应，阻碍了连续三维空间聚合物网状结构的形成。相反，形成了粘性大颗粒，对机械性能产生负面影响。此外，湿度增加会导致 TSL 内形成大孔和裂纹线，进一步降低其机械和密封性能。湿度的增加也削弱了 TSL 的干燥收缩效应，导致粘合强度增加。因此，分析高湿度条件下 TSL 的初始力学性能对于指导其在地下工程中的应用至关重要。