上跨既有地铁盾构隧道的深基坑开挖支护技术

介绍南京火车站的站前地下广场西出口基坑上跨既有地铁1号线盾构区间隧道的深基坑支护施工方案，为降低基坑开挖的减载效应对盾构隧道管片结构的影响，采用“基坑抽条开挖、钻孔桩抗拔、深搅桩加固地层”的综合施工技术，保证盾构隧道结构的稳定.

Excavation and Support Technology for Deep Foundation Pit with Overhead Shield Tunnel of Existing Metro

The support construction scheme of a shield tunnel of existing metro is introduced. This is a tunnel above the founda-tion pit of the west exit of the underground square located in front of the Nanjing Railway Station. To reduce the influence of load reduction effect due to the excavation of foundation pit on the segment structure of shield tunnel so as to ensure the stability of shield tunnel structure, the integrated construction technology is adopted that combines the excavating foundation pit by core pulling, bored pile against being pulled out, and reinforcing stratum with deep agitation piles.