About the Shield Machine and its Cutter Face
This is the cutter face of one of the slurry shield machine used to drill the undersea tunnel for the Tokyo-Wan Aqua-Line Highway.
The eight slurry shield machines started drilling tunnels from Ukishima , Kaze-no-To and Umi-Hotaru man-made islands, and the tunnels
were joined in the respective centers under the sea to form two tubes of 9.5 km length.
The 14.14 meters in diameter of the shield machine is the world's largest. The drilling operation was carried out by rotaiting the cutter face during 24 months between August 1994 and August 1996,when the tunnel excavation was completed.
By feeling the worn out surface of the cutter bits, you can tell the difficulties of the drilling operation.