为应对复杂外海建设条件、保障工程建设安全、提高工程可靠性以及降低工程造价，在深中通道沉管隧道工程中首次采用整体预制水下推出式最终接头施工工艺。深中通道沉管隧道水下推出式最终接头由扩大段、推出段和后焊段3部分组成，推出段藏于扩大段内，推出对接后隧道内进行后焊段焊接。根据工艺特点和结构受力规律，研究确定采用水力+千斤顶推出系统控制推出段推出，采用纠偏千斤顶系统控制推出段的姿态，通过高精度自润滑滑道系统减少推出段底部摩擦力，采用充气止水带+M止水带双重施工临时止水系统，管节对接后通过锚拉系统进行临时锁定，提出双向受力端封门、临时压载水箱以及水平钢剪力键等新型构造，形成完整的水下推出式最终接头创新构造形式，并根据构造形式研究确定施工工序。

The fullyprefabricated underwater pushtype final joint construction technology was employed in the ShenzhenZhongshan link immersed tunnel for the first time to cope with the complex construction conditions in the open sea. It was to ensure the construction′s safety, improve reliability, and reduce the project cost. The final joint comprises three parts: expansion, pushout, and postwelding sections. The pushout section is hidden in the expansion section, and the postwelding section is welded in the tunnel after pushout. According to the process characteristics and the structural force law, the hydraulic + jack pushout system is used to control the pushout section. In addition, the correction jack system controls the posture of the pushout section. The friction at the bottom of the pushout section is reduced by using a highprecision selflubricating slide system. The temporary water stop system is applied by the inflatable water stop belt + M water stop belt. The anchoring system conducts the temporary locking after the pipe joint is buttoned. Finally, new structures, such as a bidirectional force end sealing door, temporary ballast water tank, and horizontal steel shear key, are proposed to form a complete innovative construction structure of the underwater pushtype final joint, forming the final construction process.