Mulan, the Dragages-Zen Pacific Joint Venture’s 8.75m diameter mixed ground Tunnel Boring Machine, has broken through the second and final tube of the KCR West Rail Kwai Tsing Tunnels in Hong Kong ahead of programme.

It marks the completion of all tunnel excavation in the KCR West Rail project.

The Joint-Venture’s design for the 3.6 kilometre Kwai Tsing Tunnels proposed the use of the TBM for part of the excavation to avoid a cut-and-cover section and with substantially reduced impact on the surrounding urban environment and the community.

Environmental measures taken by the JV included the erection of 6,500 square metres of noise barriers at the main shaft as well as a water treatment plant to ensure clean water discharge.

James Blake, Senior Director, Capital Projects, KCRC, said at the Breakthrough Ceremony on 9 July 2001 that the tunnel had been completed without causing disturbance to residents or any major disruption to road traffic: “By any civil engineering and environmental protection standard, this is a job well done.”

The TBM had performed well said Dragages-Zen Pacific Joint Venture Project Director, Philippe Bouquet: “The tunnel passes through difficult ground conditions with both rock and soft ground from former reclamation, but Mulan has completed this second 1.78 kilometre bore in under 5 months, ahead of programme, with few technical problems and minimal disturbance above the ground.”

Mulan is the largest TBM to have worked in Hong Kong.

Dragages (in joint venture with Nishimatsu) also recently completed excavation of another KCR West Rail project, the 5.5 kilometre Tai Lam Tunnel.

Dragages is part of Bouygues Construction, one of the foremost construction groups in the world and the largest in Europe. Bouygues is responsible for tunnelling projects around the world including the Groene Hart tunnel, currently being carried out in Holland, using a 14.85 m diameter TBM, the largest of its type in the world.