December 13 saw the successful breakthrough of the 5.65m diameter Herrenknecht Mixshield on the 1.1km long mixed ground Main Tunnel section of Hong Kong’s US$220M, 3.7km long Lai Chi Kok Drainage Tunnel. The previous 2.3km long Branch Tunnel broke through on the 18th January this year after driving prominently through granite.
Speaking at the ceremony, The Director of the client, the Drainage Services Department, Mr Chan Chi-chiu, said, “We have overcome a number of challenges during the construction of the main tunnel including driving the TBM across four overlying operational railway lines and through the foundations of numerous existing infrastructures. Moreover, the work has involved 90 construction operations under hyperbaric pressure up to 4.2 bar, which is unprecedented in Hong Kong. We have taken this opportunity to bring to Hong Kong new hyperbaric technology for tunnel construction.”
The contractor for design and construction of the Lai Chi Kok Drainage Tunnel is Leighton-John Holland Joint Venture, and the supervising consultant is AECOM Asia Company Limited. Construction work commenced in November 2008 and the branch tunnel breakthrough took place in January 2011. Work is scheduled for completion by late 2012.