The Robbins Company, engaged in the design and manufacture of tunnel boring machines (TBMs), has announced completion of the Zhanjiang Bay Sub-Sea Tunnel using Robbins’ Slurry TBM in China.
The Zhanjiang Bay Sub-Sea Tunnel is a 2.7km long tunnel, which has been built 56m below water level. The project was constructed by contractor Guangdong No. 2 Hydropower Engineering Company Limited.
The project used Robbins Slurry machine to excavate under six bars of water pressure in Zhanjiang Bay. The TBM features certain key components and engineering from Mitsubishi Heavy Industries Mechatronics Systems, Ltd. (MHI-MS).
The TBM featured a smooth flow cutterhead, which facilitated easier removal of stones and boulders while avoiding clogging at the face. The machine was a mixed ground TBM that utilized interchangeable knife-edge bits that could be switched out for disc cutters in geology that included abrasive sand, gravel, and silt.
The smooth flow design approach for mixed face conditions is consistent with the Robbins design for mixed face EPB-type machines. The 6.2-diameter machine commenced excavation in September 2011 and excavated at the rate of 27m per day, excavating 392m per month.
The Zhanjiang Bay Sub-Sea Tunnel will source water from the nearby Jianjiang River to the steel plant on Dong Hai Island.