为解决粉细砂地层注浆施工过程中浆液难以扩散的问题，依托郑州地铁2号线紫荆山站—东大街站区间联络线暗挖段注浆工程，试验应用偏铝酸钠改性水玻璃浆液与超细水泥单液浆的复合注浆方案。实践表明： 1）偏铝酸钠改性水玻璃浆液扩散半径超过1 m，可注性好，使注浆总量达到了设计的92%； 2）先行注入偏铝酸钠改性水玻璃浆液，待其凝固并形成化学浆脉后，在相邻孔注入超细水泥浆液，使其沿化学浆脉劈裂扩散，形成复合浆脉，充分提升加固区域的围岩强度，在注浆及开挖全过程中，周边建（构）筑物和地层累计变形小于4 mm。此外，汇总分析了近年来多个粉细砂地层注浆施工案例，在与磷酸和硫酸改性水玻璃浆液对比后指出，偏铝酸钠改性水玻璃浆液具有安全性好、凝结时间短、扩散半径大的优势，且来源日趋广泛，能大幅度降低成本，具有良好的经济性和推广应用前景。

To solve the problem of slurry being difficult to diffuse during grouting construction in silty fine sand stratum, a case study is conducted on the grouting project of the mining excavation section of the connecting line between Zijingshan and Dongda Street stations of Zhengzhou metro line 2, and the composite grouting scheme of sodium metaaluminate modified sodium silicate slurry and ultrafine cement single slurry is tested and applied. The practical results show the following: (1) The diffusion radius of sodium metaaluminate modified sodium silicate slurry is more than 1 m, the injectability is good, and the total amount of grouting reaches 92% of the design. (2) The sodium aluminatemodified sodium silicate slurry is injected first. Then, it solidifies and forms a chemical slurry vein. Furthermore, the ultrafine cement slurry is injected into adjacent holes to split and diffuse along the chemical slurry vein to form a composite slurry vein, to fully improve the strength of the surrounding rocks in the reinforcement area. In the whole process of grouting and excavation, the cumulative deformation of surrounding buildings (structures) and strata is less than 4 mm. Recently, several grouting construction cases in silty fine sand stratum are summarized and analyzed. After comparison with phosphoric and sulfuric acids modified sodium silicate slurry, it is pointed out that sodium metaaluminate modified sodium silicate slurry has the advantages of good safety, short setting time, and large diffusion radius. The sodium metaaluminate modified sodium silicate slurry can be obtained from various sources at a greatly reduced cost, thereby reaching good economic and applicable benefits.