本文通过对天津地铁西站(既有站)-洪湖里(新建站)区间新建结构与既有结构相接的研究，详细介绍了接缝处明挖基坑止水帷幕特殊的处理方法、新旧结构接头施工缝的设置、接头处防水及外包防水层的设置与施工、防止新旧结构不均匀沉降的措施等。希望能为同类工程提供一些参考。

This paper introduces a special method to make waterproof retaining at the joint, the setting of construction joint connecting the newly built structure to the pristine structure, the waterproof design and construction technology, the method to prevent from settlement of the newly built structure and the pristine structure, etc. Hope that some references may be obtained for the congeneric engineering.