Abstract:

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.

Key words: ShenzhenZhongshan link, immersed tunnel, final joint, construction process