Dragages (HK) Joint Venture won from CLP Power Hong Kong Limited (CLP Power) two contracts to design and build four cable tunnels located in Kwai Chung, Tsz Wan Shan, Chi Ma Wan and at Tuen Mun River Channel. The four tunnels have a total length of 5.1 km for installation of high voltage electricity cables. The use of tunnels in the three land locations was preferable to open trench works due to logistic, environmental and public inconvenience considerations.

The first contract involves the construction of a 1,070-m tunnel in north Kwai Chung using the drill and blast method; and a 650-m tunnel under Tsz Wan Shan Road, to be built by pipe jacking using a mixed ground Tunnel Boring Machine (TBM). Both tunnels, after completion, will enable the installation of oil free cables to replace ageing and deteriorating oil filled cables. Tsz Wan Shan Tunnel will also house cables to supply new development in South East Kowloon.

The second contract involves the construction of a 3,200-m tunnel across the Chi Ma Wan Peninsula by hard rock TBM, running from Pui O to Tai Long Wan along the southern coast of Lantau Island. By installing new power cables through this tunnel, some of the old 33kV overhead lines can be retired, and as a result the reliability of supply to Cheung Chau will be improved. The contract also covers the construction of a 190-m tunnel beneath the Tuen Mun River Channel by pipe jacking using a mixed ground TBM. The tunnel will be constructed as part of a network reinforcement scheme for Tuen Mun to ensure sufficient and reliable power supply to over 120,000 customers.

The contracts were awarded based on an alternative solution proposed by Dragages, in which the Tsz Wan Shan Cable Tunnel will be constructed by pipe jacking using a mixed ground TBM, replacing the original cut and cover approach. The same solution will be used to build the Tuen Mun River Cable Tunnel. By using TBM for excavation, the impact on the environment is minimised.

“CLP Power is pleased to award the contracts to Dragages (HK) Joint Venture, which is an industry leader in earthworks. The cable tunnels form an integral part of CLP Power’s ongoing cable network upgrading programme to reinforce supply reliability. The adoption of cable tunnel technologies enables the installation of power cables at critical and environmentally sensitive locations with least disturbance to the environment and the public,” said Mr Ted Woodley, Director of Power Systems, CLP Power.

Mr Ludwig Reichhold, Managing Director of Dragages, expressed commitment to the new business relationship. “We adopted an upstream partnering approach with CLP Power to find out the best solutions that ensure excellent quality in every aspect of a project - its design, on-time delivery, safety and minimal impact to the environment; and we look forward to delivering once again a quality piece of work that all of us will be proud of.”

Mr Luc Messier, Director of Civil Works of Dragages also said that these contracts demonstrated the company’s continuous commitment to bringing in the best solutions to meet the clients’ business needs. “The concept of these tunnels, re-designed jointly with CLP Power through an extensive value engineering exercise, is extremely challenging as it involves three completely different tunneling techniques employed on four sites at the same time. These solutions will not only enhance the production cycles, but also reduce disturbance to the environment.”

Detailed design works are being carried out, and works on all four tunnels will start towards the end of 2002. All tunnels will be completed in three years.

About Dragages (HK) Joint Venture

Dragages (HK) Joint Venture is a joint venture between Dragages et Travaux Publics (HK) Ltd and the French civil works leader, Bouygues Travaux Publics SA. Both are part of the French company Bouygues Construction.

About CLP Power

CLP Power is the largest electric utility in Hong Kong serving the business and domestic communities in Kowloon and the New Territories, including Lantau and most of the other outlying islands. Operating a vertically integrated electricity generation, transmission and distribution business, CLP Power provides a highly reliable supply of electricity and excellent customer services to over two million customers in its supply area.

Pipe-jacking using TBM
Photo credit: © Smet-Tunnelling, Belgium

CLP Power Cable Tunnel contracts signing ceremony. (from left to right) Ludwig Reichhold and Christian Gazaignes, Directors of Dragages (HK) Joint Venture pictured with Ted Woodley (Director of Power Systems) and Paul Poon (Chief Engineer - Asset Management of Power Systems) of CLP Power at the signing ceremony held earlier on 13 May.

A Partnering Statement was also signed by representatives of key project team members to mark the commitment of the companies in achieving a successful project.

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