Risk Mitigation and Construction Control for Effective Underwater Recovery of an EPB Shield: A Case Study of the First Metro Tunnel in Tel Aviv

Table 3

Underwater recovery schedule of shield.

Step	Process	Duration (d)
1	Sealing ring installation	4
2	Concrete cradle casting	2
3	Steel plate and weld placement	4
4	Receiving bracket installation	3
5	Grouting pipe installation for sealing ring	1
6	Water injection into the shaft	2
7	Underground diaphragm wall excavation	1
8	Bottom concrete examination and clearing by divers	2
9	Cutterhead excavation to the shield tail into the diaphragm wall	2
10	Shield tail sealing	1
11	Secondary grouting	2
12	Shaft drainage	2
13	Shield advancement to the designated position	1