China manufactures the world’s largest tunnel boring machine

China has completed production of the world’s largest tunnel boring machine (TBM) with a diameter of 16.64 m. The machine is called Giang Hai, weighs 5,000 tons and is 145 m long. This is also the largest tunneling machine designed in China. The machine is manufactured in Hunan province, through cooperation between China Railway Construction Heavy Industry Corporation (CRCHI) and China Railway 14th Bureau Group, Interesting Engineering reported on November 1.

The TBM model has a cutting head diameter equivalent to a 5-6 story building. CRCHI Chairman Zhao Hui said this milestone marks an important achievement in the industrialization of large diameter tunnel boring machine technology over 16 m in China. The design of the machine focuses on operating in fault zones, being able to withstand sudden inflows of muddy water. Its ring-shaped cutting head allows excavation in extreme conditions, while dual operating modes enable simultaneous drilling and blasting, improving speed and performance.

The hollow cutting head makes orientation easier in complex geological conditions. Researchers at Tsinghua University expand the machine’s applications in irrigation, hydropower projects, mining and infrastructure. According to test results, the performance of the hollow cutting head can be increased by 30% after cracking treatment in super hard rock.

The new TBM will be used to build a tunnel across the Yangtze River in Jiangsu province, connecting Nantong and Suzhou. This tunnel is part of a 39 km expressway project expected to be completed in 2028. Stretching about 11.2 km below the Yangtze River, the tunnel will reach a depth of 75 m.

According to You Shaoqiang, chief project engineer at China Railway 14th Bureau Group (CR14G), the tunnel faced many challenges due to underground water sources, soft soil and sludge that made conventional tunneling methods impossible. exam. The advanced TBM model will move at a speed of 12 – 16 m/day, the tunneling process will last about 2.5 years. Because the tunnel is located near the mouth of the Truong Giang River, the accuracy must be within 1 cm to ensure the safety of dams on the river.

Previously, in 2022, CRCHI and CR14G co-produced a 16.07 m diameter TBM for a renovation project in Beijing. According to senior engineer Fan Ruiqiang, it took them more than two years to develop the new, larger TBM. The machine is also smarter with a database of past tunneling problems, allowing it to provide suggestions to the operator when similar challenges arise.