This very deep excavation was constructed to get passengers from platform level of Hong Kong’s Island line to ground level. The site was congested which gave very little workspace around the shaft. A high-rise building was to be constructed above the station and thus defined spaces were needed in the plan strutting for the later construction of concrete columns within the shaft.
Layers of props were added as excavation proceeded. The levels of these were partially dictated by soil loading on the shaft sides and partly by floor levels of the new building to be erected within the excavation.