新建隧道近接下穿既有地铁结构施工已经成为城市地铁工程建设中的一种常见情况，由于既有结构沉降控制要求严格，如何有效控制沉降已经成为目前研究的热点问题。以北京地铁6号线东四站—朝阳门站区间下穿既有5号线东四站为例，介绍了超前注浆加固及止水技术、CRD+千斤顶支护法、辅助深孔注浆及背后回填和补偿注浆技术等暗挖隧道下穿既有车站施工技术，通过对既有5号线东四站结构沉降监测可知，采用上述方法有效地控制了既有结构的变形，确保了隧道施工安全和既有地铁的正常运营。

It often happens that a running tunnel has to cross closely underneath existing Metro structures, which have strict settlement limit. Therefore focus has always been placed on how to effectively control the settlement of the existing Metro structures. The running tunnel from Dongsi station to Chaoyangmen station on Line 6 of Beijing Metro crosses closely underneath Dongsi station of Line 5 of Beijing Metro. Key technologies adopted in the construction of the mentioned running tunnel, including reinforcement and waterstopping by advance grouting, CRD+jack support method, grouting through assistant deep holes, and backfill and compensation grouting, are presented in the paper. The monitoring of existing Dongsi station of Line 5 of Beijing Metro shows that, due to the aforementioned technologies, the deformation of the existing structure has been brought under effective control, which guarantees the tunneling safety and the normal operation of the existing Metro line. 