为在以富水砂层为代表的软弱地层顺利施工隧道与地下工程大断面，以兰渝铁路某隧道富水未成岩粉细砂层水平旋喷加固及支护施工为例，对水平旋喷加固机制、旋喷参数选择、机械设备配置及施工关键控制技术进行研究及应用。通过高压水平旋喷在开挖线周遍形成水平咬合桩和开挖面稳定锚固桩，有效避免了开挖过程拱顶流砂、坍塌及工作面失稳的现象，实现了富水砂层隧道大断面开挖，提高了开挖施工综合效率。

The mechanisms of consolidation by horizontal jet grouting, the selection of the jet grouting parameters, the matching of the horizontal jet grouting equipment and the key technologies of horizontal jet grouting are studied on basis of the horizontal jet grouting used in the construction of a tunnel in waterrich immature fine silty sand strata on LanzhouChongqing railway. The study results are applied in the construction of the tunnel, i.e., horizontal interlocking jet grouting piles are installed along the perimeter of the tunnel crosssection and anchoring horizontal jet grouting piles are installed in the tunnel face. In this way, quick sand at the tunnel crown, tunnel collapse and tunnel face instability are avoided, the excavation efficiency is improved and successful tunnel construction is achieved. 