China Railway Engineering Equipment Group Co. Ltd. said it has rolled off the tunnel boring machine (TBM), which will be exported to Italy for a high-speed railway building project linking Milan and Verona, Xinhua reported.
The machine, finished Saturday at its workshop in Zhengzhou, capital of central China’s Henan Province, has a diameter of 10.03 meters and an overall length of 155 meters, and weighs 1,800 tonnes.
Franco Lombardi, president of the Italian Cepav Due joint venture, said that the construction project undertaker chose the CREG from a number of bidders for purchasing the TBM, as the Chinese firm was willing to provide customized solutions, the report said.
Zhang Zhiguo, deputy general manager of CREG, said that the export to Italy marked the company’s entry into the European market, a milestone for CREG’s exports.
CREG has participated in urban rail and drinking water projects in 19 countries and regions including Malaysia, Singapore, Algeria and the United Arab Emirates.
TBMs must stand up to tremendous stress, making them difficult to design and build — and that difficulty increases with the machine’s size.
“As the face (of the borer) gets bigger it gets more dangerous,” Ning Haoson, commercial manager for CREG, told Vice.com. “Stabilizing is hard,” Ning added. “All of it is a challenge.”
Operated by a crew of ten, the US$14.5-million machines can chew through 1,300 feet of soil and stone per month, laboring for as many as 10,000 hours before they wear out, Vice.com reported.
The high-voltage powered boring machines boast a flat, toothed cutting head made of super-hard chromium attached to a propulsion system by a spinning bearing: Imagine a locomotive with a huge, jagged, spinning dinner plate attached to the front.
As the TBM grinds forward, a huge, spinning screw pushes debris back and away from the machine. Meanwhile, automated gantries —supportive frames — place concrete wall segments just behind the cutting head, Vice.com reported.