为研究既有隧道结构在新建隧道盾构下穿过程中沉降变化规律及与施工控制方法之间的关系，依托深圳前海—南山排水隧道盾构下穿既有11号线工程开展既有结构变形监测，结合现场监测数据及工程实际情况，进行对重要施工因素的相关性分析，分析得到既有结构在下穿过程中沉降变化规律及与下穿施工控制方法间的关系。研究表明： 1）排水深隧穿越过程中既有11号线隧道竖向变形规律与相应施工阶段、施工措施间存在明显对应关系； 2）既有11号线隧道结构的沉降特点表现为在横向上不同部位沉降存在差异，但道床处未发生明显不均匀沉降，纵向上由于施工原因沉降曲线可表现为“V”形或“W”形； 3）通过选取合理的土舱压力、注浆压力以及采取二次注浆、多次补注浆增强注浆效果的施工措施对控制结构沉降具有重要作用。

To explore the settlement patterns of the existing tunnel structure inducted by underneath crossing of deep drainage shield tunnel and its relationship with construction control methods, a case study is conducted on the Shenzhen Qianhai-Nanshan drainage tunnel crossing underneath the existing Line 11. The essential construction factors affecting the settlement of the existing tunnel are analyzed based on field monitoring data and site conditions. The results reveal the following: (1) The settlement and deformation of the existing Line 11 tunnel is prominently correlated to construction stages and methods. (2) The unenven settlement occurs on the horizontal direction of the existing tunnel, whereas it cannot be found on roadbed. The settlement curve on the longitudinal direction presents a V shape or W shape. (3) Selecting rational soil chamber and grouting pressures and using secondary grouting and frequent supplementary grouting is conductive to settlement control of the existing structure.