Shield tunneling machines made in China are being well received by global buyers because of the innovative technologies developed for their production and operation.

In Zhengzhou City of central China's Henan Province, a shield tunneling machine has just passed through final tests at the general assembly workshop of the China Railway Engineering Equipment Group before being shipped to Italy.

The shield tunneling machine has a cross section diameter of nearly 14 meters, the largest of any such machine ever exported to Italy, and carries many innovative technologies such as continuous excavation and cast-in-situ inverted arch.

"In view of the gas-rich characteristics of Italy's formation, we adopted the zoning concept and made targeted explosion-proof design for the entire machine, which solved the technical difficulty for conventional shield machines to dig into formations rich in harmful gases. The efficiency of tunnel construction has been raised by 20 or 30 percent," said Yin Yuefeng, an engineer with the technology center of the China Railway Engineering Equipment Group.

Not long ago, the shield tunneling machine for the Jintang Undersea Tunnel of the Ningbo-Zhoushan railway, the world's longest undersea high-speed rail tunnel, finished installation and tests and is about to start boring.

The tunnel, with a total length of over 16 kilometers and a maximum depth of 78 meters, will be built with two shield tunneling machines excavating simultaneously from both ends and then meeting under sea with an error of less than 20 millimeters. The complexity of the construction is rarely seen worldwide.

For the project, the constructors have developed more than 10 new technologies, applied a currently most accurate guidance system in the world, and deployed advanced geological prediction and advanced grouting reinforcement equipment.

"China's tunnel projects are large and widely distributed, and often pass through mountains and seas where the formation is complex and changeable. During the construction, we have continued to innovate and accumulated rich experience, which endows us with very strong advantages in international competition. The ability to solve different problems and customize various kinds of functions is why China's shield tunneling machines and constructors are trusted and popular around the world," said Hu Hao, chief commander of the Ningbo-Zhoushan railway project.