Pore pressure response of composite foundation in interactive marine and terrestrial deposit of Yangtze River Estuary

To learn the pore pressure response characteristics of PHC pipe pile composite foundation in interactive marine and terrestrial deposit of Yangtze River Estuary, a test site is selected at the northern connection project of Chongming—Qidong Bridge, and then field tests are conducted to study the variation of pore pressure at different depths during embankment loading. At the same time, the meteorology and hydrogeololgy of the local area are investigated. The test results indicate that the water table is greatly influenced by local precipitation and seasonal fluctuations of groundwater. The variation of the water table in one year may reach 1.6 m, which must be considered in the pore pressure analysis of foundation soils. The excessive pore pressure of shallow soils fluctuates sharply and dissipates quickly due to their good permeability. While the excessive pore pressure of deep soils may be accumulated and gradually increase owing to their low permeability and embankment loading. The excessive pore pressure in the reinforced zone of the pipe pile composite foundation is low and dissipates quickly, but that in the underlying soft layer is relatively high and dissipates slowly. Therefore, the consolidation property of the underlying soft layer in the interactive marine and terrestrial deposit of Yangtze River Estuary should be paid attention to.