Tunnelling project for China

Sheffield-based DavyMarkham has fabricated and shipped a 320 tonne cutterhead for a 12.4m diameter tunnel-boring machine (TBM) being built by The Robbins Company of Ohio.




Sheffield-based DavyMarkham has fabricated and shipped a 320 tonne cutterhead for a 12.4m diameter tunnel-boring machine (TBM) being built by The Robbins Company of Ohio.



The £1.15m TBM is to be dispatched to the mountains of Sichuan Province, China, where it will be used for the new 4,800MW Jinping II hydropower station on the Yalong River. Once completed in 2010 it will transmit electricity to eastern provinces and cities including Shanghai and Beijing.



Fabricated in six sections and test assembled within the UK, the cutterhead and associated Main Beam TBM are then being assembled by Robbins in a massive underground launch chamber, pre-excavated using drill and blast methods.



In order to improve competitiveness when dealing with such large steel pieces, the company employed a newly developed cutting tool for rough machining, which resulted in a metal removal rate five times faster than normal. It also deployed the latest carbide U-drill technology to cut holes eight times faster.