A procurement contract for two rock gripper TBMs was signed between tunnelling contractor CMC of Italy and CREG of China at the TBM manufacturer’s headquarters in Zhengzhou last Friday (17 July 2015). The leading Italian tunnel construction company will use the two machines on its contract for the first phase of the Greater Beirut Water Supply Project, which includes construction of a 24km water tunnel, 10km of pipelines and three reservoirs.

The bored tunnel is 22.45km long and has an outer diameter of 3.53m. The two gripper TBMs will mine through rock strengths of between 50-170MPa and will navigate minimum radius curves of 300m.

CMC Technical Manager Ivano Andreis and CREG Gereral Manager Tan Shunhui sign the contract

The cutterheads of the 3.53m diameter gripper TBMs are equipped with 17in back loading disc cutters. The TBMs are fittered with a probe drilling system and a grouting system for pre-excavation consolidation grouting. A short cutterhead shield also allows first support close to the tunnel face.

“The Greater Beirut Water Supply Project TBM is designed in line with international standard,” said CREG General Manager Tan Shunhui. “We have prepared a detailed build schedule and the two machines will be transported to site next April.”

CREG made an intellectual property acquisition of hard rock TBM and shaft boring machine design from Aker Wirth in December 2013. The Chinese President Xi Jinping praised the innovation ability and the cooperative spirit of CREG staff at his visit to the company’s factory in Zhengzhou in May 2014.

CREG supplied one 8.03m gripper TBM to the Jilin water supply project in China last month, in June 2015. Despite the weak rock mass of the local geology, the maximum advance rate by the rock TBM is up to 46m per day.