[Bid Design for Lot 3 of Jungnyeong Tunnel on Jungang Expressway]
1996.06~1996.07 / Korea Expressway Corporation, Kolon Engineering

Jungnyeong Tunnel, with a length of 4.5 km, is the longest tunnel in Korea, and was built using a TBM+NATM method, the first time this method was used in conjuction with expressway construction in Korea. Both TBM and NATM methods have their advantages, and using them in combination allowed for an efficient and safe construction process.

The use of TBM in an expressway tunnel was the first time in Korea. After the initial excavation using the TBM, the tunnel was expanded using NATM. As the tunnel was long, ventilation and vertical shafts were also installed. Another first in Korea was the application of raise climber (RC) construction method for these shafts. The shafts were first excavated upwards, and then expanded downwards.