The off-shore immersed tunnel is placed at a varying level and consequently has to accommodate complicated foundation condition. The segmental type of tunnel is sensitive to the differential longitudinal settlement. Therefore, a number of ground improvement methods are considered in order to provide an appropriate foundation for the type of immersed tunnel in soft ground. The composite foundation method is one of techniques which can reduce settlement, increase bearing capacity and slope stability. The composite foundation methods included sand compaction pile (SCP), cement deep mixing (CDM), and jet grouting pile, etc. Based on the Island and Tunnel Project of Hong Kong-Zhuhai-Macao Bridge in China and the Busan-Geoje Fixed Link Project in South Korea, this paper describes design and construction in soft ground by the SCP method mainly for off-shore immersed tunnel foundation.
展开▼
