Innovative excavation and support techniques for deep large foundations in soft ground

The Suzhou Taihu New City major underground space development was one of the largest and most complex foundation projects in China. It had a footprint area of 93 000 m² with a depth of 18 m into soft ground. The complexity was increased further by its proximity to existing sensitive assets, which include a metro station and flood defence structure. These challenges were overcome by using multiple innovative excavation and support techniques, including mini-pits, reserved soil berms, compartmentalised excavations, composite slope stabilisation, the observational method and a ‘time–space effect’.