Hyundai E&C is busy assembling 14 meter diameter tunnel boring machine to tunnel 6.76 km 2 lane tunnel 20-35 meter under Han river. This is for Section 2 of the Seoul Metropolitan Area 2nd Ring Expressway. Under-water part is 2.9 km.

Tunnel is 2 lane. Tunneling will start in October. Once Hyundai complete boring the tunnel, TBM will be un-assembled and reassembled in other direction. And the same length of tunnel again with two lane will be bored in reverse direction.

http://www.kyeongin.com/main/view.php?key=20220625010004580