The joint venture between Dragages (HK) and Bouygues Travaux Publics started boring a 3.5km long twin-tube rail tunnel under Long Valley in Hong Kong last month for the Kowloon Canton Railway Corporation (KCRC). The US$359M design and build contract will be constructed using Mulan (pictured), a refurbished 8.75m diameter NFM dual-mode EPBM that was previously used by Dragages to construct the 3.6km long Kwai Tsing tunnels on the West Rail project in Hong Kong. The bored section forms part of a 5.2km long tunnel between Sheung Shui and Chau Tau, as part of the 7.3km long Sheung Shui-Lok Ma Chau spur line. The western and eastern approaches to the bored section will be constructed using cut and cover. The tunnels’ alignment crosses mixed soft ground, transitional mixed face zones and full-face rock. Construction of the first drive should take 11 months. Dragages/Bouygues JV was tipped as early as November 2001 for the contract because of owning Mulan. James Blake, KCRC senior director, said that this section could be confidently tunnelled using the EPBM. He is also an advocate of including the contractor in the design process, as their involvement “enhances the construction process”.
