Contract 904 involved the construction of tunnels and underground stations located on Ap Lei Chau. The tunnels measured approximately 1.2 km from the connection with the bridge over Aberdeen Channel, to South Horizons Station. The tunnel spans varied from 7 m to 17 m, and a station cavern at Lei Tung was constructed 25 m wide by 22 m high at its largest section.
The section of tunnels was constructed by a combination of drill and blast, mechanical excavation, and cut and cover tunnelling techniques. Apart from the main line tunnels, Contract 904 also included Lei Tung and South Horizons Stations, ancillary buildings, and many access and ventilation adits.
Aurecon acted as the contractor’s designer, performing a review of geotechnical, temporary rock support design for cavern, mainline tunnels and station entrance adits. The design of temporary rock support for the mixed ground tunnels accommodated a station span approaching 25 m. Optimisation of the permanent lining design was also a key requirement.
Aurecon developed the blasting assessment reports, through governmental department approval processes, and predicted grouting quantities and volumes in the design for project planning purposes.
The HK$16.5 billion line, operated with driverless three-carriage trains, will run from South Horizons in Ap Lei Chau to Admiralty via the other three new stations at Lei Tung, Wong Chuk Hang and Ocean Park.
With the new railway line, passengers can travel from South Horizons to Admiralty in approximately nine minutes, as compared with the 25 to 45 minutes taken by using road transport during rush hours.