First MTR caverns in 25 years open on West Island Line
12 January 2015HONG KONG – The West Island Line (WIL) has opened. The 3.3km-long extension to the Island Line connects three new stations: Sai Ying Pun, Hong Kong University, and Kennedy Town, to the existing route at Sheung Wan Station. Kennedy Town is a cut and cover station, while Sai Ying Pun and Hong Kong University are deep cavern stations.
These were the first station caverns built for an MTR project in over 25 years. The densely populated western district leant weight to the cavern option, as there was limited surface space available. Atkins China and Geodesign Consulting Engineers worked out concept designs with very little local precedent.
The Sai Ying Pun Station is 225m long and comprises a 187m long cavern and a 38m long platform tunnel. The cavern is located approximately 40 to 65m below ground. It has an excavation span of 22.8m and a height of 16m, and will be built with a moderate rock cover of 50m at the western end and a rock cover of only 10m at the eastern end.
The Hong Kong University Station comprises a 240m long cavern with an excavation span of 22.4m and a height of 16m. The overall depth of the cavern is similar to that of Sai Ying Pun Station and varies between 48 and 80m below ground level. However, the rock cover is greater and is anticipated to be around 65m at the western end and 25m at the eastern end of the cavern.
Modifications at Sheung Wan were carried out by Sun Fook Kong Construction; Sheung Wan to Sai Ying Pung tunnels by a Dragages-Maeda-BSG joint venture; Sai Ying Pun and Hong Kong University Stations, and Sai Ying Pun to Kennedy Town tunnels by a Gammon-Nishimatsu joint venture. Kennedy Town Station and overrun tunnel construction was awarded to Gammon Construction.
