南京长江过江隧道江北段明挖段基坑主要为引道和盾构始发井施工做准备,由于该基坑规模大,并且紧邻长江北大堤,地下水丰富,地质条件复杂,该深基坑的降水是整个南京过江隧道众多关键技术之一,也是在盾构机进入始发井开始江底隧道掘进首先面临的难题之一,为查明工程区水文地质条件,工程技术人员做了大量试验研究,包括通过抽水试验、微水试验确定含水层水文地质参数、分析工程区地下水的补给、径流和排泄条件。文中介绍了在此试验基础上提出的基坑降水方案,重点介绍了基坑降水方案的设计要点。 Due to the large scale of the foundation pit and its close proximity to the northern levee of the Yangtze River, the groundwater is abundant and the geological conditions are complex. The deep foundation pit Of the precipitation is one of the key technologies of the entire Nanjing Crossing Tunnel. It is also one of the first problems in the tunneling of the tunnel starting from the starting shaft of the shield machine. In order to find out the hydrogeological conditions in the project area, the engineers and technicians have done a lot of work Experimental studies include the determination of hydrogeological parameters of aquifers by pumping tests and micro-water tests, and the analysis of recharge, runoff and drainage of groundwater in the project area. In this paper, the foundation pit dewatering scheme proposed on the basis of this experiment is introduced, and the design essentials of foundation pit dewatering scheme are introduced emphatically.