结合杭州解放路延伸隧道工程，针对饱和粉细砂土层，介绍了为保证施工安全及工程质量，采取的分步分层降水技术，主要介绍了管井及井点的设计、降水参数的确定及施工工艺,同时分析了降水效果。

Taking Jiefang Road Extension Tunnel Project in Hangzhou, China as project case, the author presents the stepbystep and layerbylayer dewatering technology adopted for saturated fine silty sand ground so as to ensure the construction safety and the works quality, with the emphasis being placed on the description of the design of the pipe wells and well points, the determination of the dewatering parameters, the dewatering process and the dewatering effect.