Robbins Slurry TBM will delve below Zhanjiang Bay

Below the waters of China's Zhanjiang Bay, a new Slurry TBM is ramping up for excavation. An acceptance ceremony for the 6.26 m (20.5 ft) diameter Robbins TBM was held in Shanghai, China in June 28, 2011. The machine, for contractor Guangdong No. 2 Hydropower Engineering Co., Ltd, will be launched in mid-September 2011.

 

The Slurry TBM will be shipped to the jobsite and lowered down a 28 m (92 ft) deep shaft to excavate the 2.7 km (1.6 mi) long Zhanjiang Bay Cross-Sea Tunnel. The tunnel, with up to 60 m (200 ft) of overburden, is part of a larger fresh water transfer project that will draw from the nearby Jianjiang River to supply a new steel plant on Dong Hai Island. An abbreviated back-up system will be used during launch due to limited site space, allowing the machine to begin boring with umbilical cables connected to gantries at the surface.

 

"This machine has been designed by MHI-MS, and assembled by us with some Robbins components. It is our entry into the Slurry market-- the first machine of this type manufactured by Robbins," said David Han, Project Manager. Mitsubishi Heavy Industries Mechatronics Systems, Ltd. (MHI-MS) has provided key components and engineering for both the TBM and back-up, while Robbins, in addition to component supply and assembly, will provide local support throughout excavation.

 

The high-powered Robbins machine features 20 thrust cylinders for a total thrust of 46,000 kN (10.3 million lb)-a feature needed due to the 6 bar of water pressure expected in the bay. A mixed ground cutterhead with hard facing will be fitted with interchangeable knife-edge bits that can be switched out for disc cutters in geology including coarse, abrasive sand, gravel, and silt.

 

Once complete, twin pipelines will provide fresh water to the Baosteel Plant, a large company with 20,000 employees. The water supply project is part of a plan by the Chinese government to improve the quality and output of steel in Guangdong Province.