Recently, the left tube of the Caoguoshan Tunnel, the last barrier in the construction of the Manjin Expressway, was successfully bored through.

The main line of the Manjin Expressway is 50.58 kilometers long, with a total of 127 bridges and 16 tunnels, and a bridge-tunnel ratio of 79.8%. The Caoguoshan Tunnel is a key control project of the entire line, connecting Adebo Township and Jinhe Town in Jinping Miao, Yao and Dai Autonomous County. It is 7,005 meters long with a maximum burial depth of 903.8 meters, making it a deep-buried extra-long tunnel. Since construction began, the construction team has strictly followed the principles of advance forecasting, minimal disturbance, early support, frequent measurement and short advance, and has efficiently and steadily advanced tunnel construction on the basis of ensuring quality, quantity and safety.

Up to now, the Manjin Expressway project has been completed 97% overall, including about 98% of subgrade works, about 99% of bridge works and about 99% of tunnel works. Pavement, electromechanical, traffic safety, greening and building works are all proceeding in an orderly manner.