Chinese firm's self-made machine boring tunnel under Yangtze River

CCCC Tianhe Mechanical Equipment Manufacturing Co Ltd, a subsidiary of China Communications Construction Co, announced that it had excavated 1,642 meters of tunnels via using its self-developed tunnel-boring machine, or TBM, underneath the river channel in an eastern Chinese city by the end of last week.

The company said it had completed 55 percent of the construction work conducted by TBM for Heyan Road Yangtze River Express in Nanjing, Jiangsu province, by last week. The project is expected to be operational in the first half of 2021.

TBMs are used to excavate tunnels, subway tubes and sewer lines. In comparison with traditional tunnel boring methods like rock drilling, blasting and hand mining in soil, the use of such giant TBMs could minimize the impact on the surrounding ground and produce a smooth tunnel wall, helping certain tunnel projects run through unstable geological conditions.

By using a giant machine measuring 15.03 meters in diameter and 135 meters long and weighing 4,000 metric tons, the company said its excavation work has entered the critical period of the project, as it will dig toward the deepest point within the rock and soil parts underneath the Yangtze River.

It marks a fresh breakthrough in the country's push for high-end machinery production in a world that has been dominated by developed countries, said Zhou Jun, chief engineer of CCCC Tianhe.

As many Chinese and global cities have increasingly deployed resources to improve their transportation infrastructure to boost coordinated regional development, commercial and service activities, Zhou said the company will be building more large-diameter TBMs to meet the market demand.