Length 220 meters, weight 3,500 tons: China has created a giant tunnel boring machine
In China, the world's largest double-shield tunnel boring machine in terms of excavation diameter has been manufactured. The 3,500-ton complex, named Yuexi, will be used to construct an 18.4-kilometer highway tunnel in Sichuan Province.
Length 220 meters, weight 3,500 tons: China has created a giant tunnel boring machine
The machine rolled off the production line at the end of September in Chengdu, the administrative center of Sichuan Province. Its total length is 220 meters, and its excavation diameter is 13.01 meters.
Yuexi was jointly developed by the infrastructure company Shudao Investment Group and the tunnel boring equipment manufacturer China Railway Engineering Equipment Group. This record does not apply to all tunnel boring machines, but specifically to the category of double-shield complexes.
Such machines excavate tunnels by crushing rock using a rotating cutterhead. The double-shield design is adapted to operate in various geological conditions, including stable and fractured rock.
At the front of Yuexi, 83 disc cutters, each with a diameter of nearly 48 centimeters, are installed. They crush the rock, while a hydraulic system pushes the machine forward.
The complex can perform several tasks simultaneously: excavating rock, installing precast concrete segments on the tunnel walls, reinforcing the surrounding rock, and transporting the excavated material outside.
The machine is also equipped with drilling and geological exploration systems. They allow for the assessment of the condition of the rock ahead before the complex reaches that point. An automatic laser guidance system serves to maintain the excavation direction with high precision.
Yuexi will be used in the construction of the Yuesi tunnel on the Jinkouhe - Xichang expressway in Sichuan Province. It is reported that it can excavate more than 380 meters per month.
This method is expected to be three to five times more efficient compared to traditional construction based solely on drilling and blasting.
The project will be the first time in China that a large-diameter double-shield machine is used to excavate the main part of a highway tunnel. Previously, such complexes were mostly used in the construction of railway and subway tunnels.