D-Wall Tunnel Segment D-Wall D-Wall Bored Pile W= 1.2 m D= 42 m L= 450 m ID= 6.05 m T= 0.3 m W= 1.0 m D= 36 m L= 560 m W= 1.0 m D= 35 m L= 388 m D= 1.0 m, 0.8 m, 0.6 m L= 27 m ~ 37.5 m Km 1+951 Km 1+826 Km 0+615 Km 2+020 Km 0+805 Box Tunnel Type A Box Tunnel Type B Box Tunnel Type C L= 125 m L= 69 m L= 206 m Box-Type U-Type L= 400 m L= 134 m Opera House Station Bored Tunnel Ba Son Station Cut and Cover Tunnel L= 190 m L= 781 m L= 240 m L= 534 m CP-1b L= 1,745 m Km 2+360 Km 2+226 Km 1+586