A technical visit to MTRC Shatin Central Link Contract 1103 organized by the IOM3 Hong Kong Branch was successfully held on 11 July 2015 with 22 participants joining the visit. We were received by the Project Director, Mr. Francois Dudouit, and Construction Director, Mr. Emmanuel Clech of the Contract 1103 Contractor, Vinci Construction Grands Project, who gave a detailed presentation in varies aspects, from innovative proposal to technical detail.
Contract 1103 comprises the design and construction of 2,475 m of drill and blast tunnel and 1,400 m of twin running tunnels being constructed by the Tunnel Boring Machine TBM, connecting Hik Keng and Diamond Hill. This is the first tunnel passing through the Lion Rock since Construction of Lion Rock Road Tunnels 40 years ago.
The participants were introduced how the Contractor proposed innovative ideas of rearranging the TBM drives to mitigate the programme risk and suit the project geographical constraints. The directions of TBM drives were reversed and changed from U-turn after first drive, to both drives launching from same shaft. Also, the Contractor initialed an idea of splitting the TBM launching shaft from the station shaft to minimize the work and allow earlier TBM launching.
The tunnel alignment under the Contract 1103 unavoidably has certain overlap on plan with existing MTRC Tsuen Wan Line tunnels. The Contractor managed to complete first drive successfully with vertical separation to existing tunnels under mixed ground condition. Afterward, the group was given a tour to three of the works sites - Diamond Hill, Ma Chai Hang and Hik Keng. In Diamond Hill, the participants visited a TBM Launching Shaft where a 7.2 m diameter Slurry type TBM was being reassembled after its first drive. The TBM is capable to excavate in varies condition with strength of taking up to 6.25 bar pressure.
In Ma Chai Hang, the group visited a large circular Diaphragm Wall shaft. The Contractor revised the design of 260 m long tunnel from this shaft, by splitting ventilation ducts from an original bigger profile. A separated smaller ventilation adit was then planned with an extension the TBM drives in mixed ground condition. It facilitates significantly the excavation in soft ground condition.
The group also visited an excavated tunnel from Hik Keng where concreting and excavation was conducted concurrently. The Hik Keng site located closed to a residential area. With environmental protective measures including noise enclosure, the Contractor managed to carry out 2 numbers of blasts per day with maximum pull length of 5.5 m. An approval was also obtained from the Water Supplies Department for blasting adjacent to WSD tunnel. Competent granitic rock was revealed in the tunnel and thus pre-excavation grouting works were seldom applied.
All in all, the Vinci Construction Grands Project demonstrated to us state-of-art technology in tunneling method in their return to Hong Kong, since their participation in construction of MTRC tunnels between 1998 and 2002. We would highly appreciated Mr. Francois Dudouit and Mr. Emmanuel Clech who gave a fruitful morning to the participants.
Author: Kelvin Choi, Hong Kong Branch, 21 July 2015
Council Members and Project Director of the Project: Left to Right: Mr. Tim Leung, Mr. Alberto Dias, Mr. Francois Dudouit, Mr. Kelvin Choi, and Mr. Guy Bridges
IOM3 HK President, Mr. Guy Bridges present a souvenir To Mr. Francois Dudouit
Hik Keng: Undrained lining under construction
Diamond Hill: Group Photo in front of TBM Launching Face with the Project Director, Mr. Francois Dudouit and Safety Manager, Mr. Carlos Yau.
Diamond Hill: TBM Launching Face Ready
Diamond Hill: TBM being reassembled