为解决普通喷射混凝土凝结时间长、早期强度低和抗渗性能差等问题，通过外掺纳米水化硅酸钙（calcium-silicate-hydrate, C-S-H）凝胶的方式对其进行性能提升。研究纳米C-S-H凝胶对喷射混凝土凝结时间、抗压强度及抗渗等性能的影响，并采用水化热测试、X射线衍射（X-ray diffraction, XRD）和扫描电子显微镜（scanning electron microscope, SEM）等技术探究纳米C-S-H凝胶提升喷射混凝土性能的机理。结果表明：纳米C-S-H凝胶可明显缩短掺速凝剂水泥净浆的凝结时间，与基准组相比，掺2%纳米C-S-H凝胶的喷射混凝土1 d抗压强度可提高19.0%，渗水深度降低31.4%。机理分析表明，纳米C-S-H凝胶的晶核和填充效应能够促进水泥水化且可以致密混凝土内部结构，从而提升喷射混凝土的各项性能。

In order to address the issues of long setting time, low early strength, and poor impermeability of ordinary shotcrete, performance improvements were made by incorporating nano calcium-silicate-hydrate (C-S-H) gel. The effects of nano C-S-H gel on the setting time, compressive strength, and impermeability of shotcrete were investigated. Techniques such as hydration heat tests, X-ray diffraction(XRD), and scanning electron microscope (SEM) were used to explore the mechanisms by which nano C-S-H gel enhanced shotcrete performance. The results show that nano C-S-H gel significantly reduces the setting time of cement paste with an accelerator. Compared to the control group, shotcrete with 2% nano C-S-H gel exhibits a 19.0% increase in 1-day compressive strength and a 31.4% reduction in water penetration depth. Mechanistic analysis indicates that the nucleation and filling effects of nano C-S-H gel promote cement hydration and densify the internal structure of the concrete, thereby enhancing the overall performance of the shotcrete.