The 4.3-mile (7-kilometer) South Island Line is a medium-capacity railway with five stations. The five stations are: South Horizons, a two-level underground station, constructed by the cut-and-cover method; Lei Tung (a two-level, 40-metre-deep cavern station) constructed by drill-and-blast method with the upper level serving as the concourse with two entrances and the lower level comprising an island platform; Wong Chuk Hang and Ocean Park, both elevated stations with viaducts totaling 2.3 miles (3.7 kilometers) in length; and a depot located at Wong Chuk Hang. The project also included the 2-mile (3.3-kilometer) Nam Fung Tunnel, a drill-and-blast twin-track tunnel; and a cut-and-cover tunnel at Ap Lei Chau Drive.
WSP served as the detailed design consultant, responsible for detailed designs of Lei Tung Cavern Station, associated tunnels, the mined tunnel at Nam Fung, and mined and cut-and-cover tunnels at Lei Tung. All design activities on this major undertaking were performed in collaboration with the MTR’s in-house design and management team from a dedicated project office in Kwun Tong.
The design work was exceptionally challenging due to the tunnels running beneath numerous property developments. The temporary and permanent lining of the tunnel were designed to withstand the loads from the above ground developments and to minimize the settlement of the structures.