The Shatin-to-Central Link (SCL) is a 17km-long strategic railway extension in Hong Kong. By connecting the existing West Rail Line and Ma On Shan Line from East-to-West (EWL) through new stations and extending the East Rail Line across the harbour from North-to-South (NSL), it will serve the New Territories, Kowloon and Hong Kong Island, significantly improving the connectivity, coverage and convenience of the entire rail network.
For the SCL(EWL), Arup was awarded a number of contracts including the SCL consultancy agreement C1105, where we were the appointed designer and Lead Consultant for the detailed design for Sung Wong Toi to Ho Man Tin; and Contract 1103, one of our award-winning civil works contracts which comprises 4km running tunnels from Hin Keng to Diamond Hill, serving as designer for the Contractor VINCI Construction Grands Projects (VCGP).
Deeply engaged in these SCL contracts, Arup provided multidisciplinary detailed engineering design services for stations, tunnelling works and associated infrastructure, significantly improving cost and time savings, sustainability, safety performance and quality of works.
17km strategic railway extension connecting several existing lines
~1.1millionpassengers per day
Linking up the existing and future railway lines
Arup was the Lead Consultant for the detailed design of two new underground stations, Sung Wong Toi and To Kwa Wan, and undertook the reference design of twin 1.7km tunnel boring machine (TBM) running tunnels from Ho Man Tin station to Sung Wong Toi station. Our multidisciplinary design work included architecture, civil, structural, geotechnics, tunnelling, building services, fire, traffic, environmental, construction planning and system assurance.
Ho Man Tin station, another Arup project on the Kwun Tong Line Extension (KTE) serves as an interchange station between the Kwun Tong Line and Tuen Ma Line. Arup were again the Lead Consultant for the station and associated running tunnels.
Traversing the city’s densely-populated urban areas
Our design for Sung Wong Toi station has considered the loading allowance for future major redevelopment at the former Kai Tak Airport and Sung Wong Toi Park with planned topside development. The station comprises a rectangular box with two levels – the platform level is some 35m wide × 285m long whilst the concourse level is 54m wide × 285m long.
In response to the tight physical constraints along the line, the To Kwa Wan station box has a stacked platform configuration to reduce the station footprint and hence the excavation width as the box is very close to a number of old buildings with shallow and deep foundations. Mixed ground TBM and cut-and-cover methods were used for the running tunnels and pedestrian subways.
Engineering an alternative solution
Arup was also involved in tunnel and shaft design for the tender and detailed design of the section between Hin Keng Estate and Diamond Hill station, comprising 1.4km twin TBM tunnels, 2.2km drill-and-blast tunnels, a 40m diameter ventilation shaft, an emergency access shaft, a 100m cut-and-cover tunnel at Hin Keng, and parts of the proposed extension to Diamond Hill station, making concerted multidisciplinary input from our tunnelling, rail, structures, and E&M disciplines.
To overcome difficult geological conditions and mitigate the risks associated with large span mined tunnel excavation, we replaced the original design of a large span mined section of Lion Rock Tunnel with three smaller tunnels, making the underground structures easier and safer to build.
Bringing in multi-fold values
Due to the relatively light weight of the underground ventilation building, flotation of the structure was a major safety consideration. Arup devised an alternative solution by reconfiguring the conforming permanent structure and introducing an underslab drainage system below the base slab to relieve the uplift groundwater pressure, thereby eliminating the need for tension piles and thick slabs. The solution has reduced the risk of adverse ground movement to the buildings nearby and minimised the difficulties and time for constructing diaphragm walls into hard rock.
It has also significantly reduced the volume of excavated materials (approximately 15,000m3) for the ventilation building and the Lion Rock Tunnel, while achieving a carbon emission reduction of about 1,000 tonnes.
Protecting Song Dynasty Culture
Sung Wong Toi station is located partly within the historical footprint of Sacred Hill which is also known as Hill of the King of Song. During station excavation a large number of archaeological relics were found within the original station footprint, some of them are large in size that need to be protected in-situ while some were temporarily relocated. Arup was then requested to re-design the station to protect the large relics in-situ, allow reinstatement of the relics at the original level and orientation, and accommodate two big display cabinets inside the station concourse for education purposes.Learn more about our metro rail experience