Record-breaking open-type TBM rolls off production line

An open-type rock tunnel boring machine with a diameter of 11.93 meters, the largest of its kind in China, just rolled off the production line on Friday in Changsha, Central China's Hunan province, China News Service reported.

Named Jianghan Xinshiqi, or Jianghan Neolithic, the machine measures approximately 175 meters in length, weighs around 3,000 metric tons and features a design with a minimum turning radius of 800 meters and a maximum gradient of 10 percent. The machine was jointly developed by China Railway Construction Heavy Industry Corp and Sinohydro Bureau 6 Co Ltd.

It is one of the 10 TBMs to be deployed for a project to channel water from the Yangtze River to the Hanjiang River, part of the middle route of the South-to-North Water Diversion Project. This project presents highly complex geological conditions along its route, characterized by great depths, extended length, large tunnel diameters and numerous fault zones. The project faces multiple construction challenges, including rock bursts and gas poisoning.

Addressing the risks and challenges, the open-type TBM's developing team managed to improve its adaptivity to adverse geological conditions and reduce the need of human labor in its operation. The machine is also more intelligent, equipped with technologies such as smart tunneling system, surrounding rock information gathering and advanced detection.