Numerical study of dewatering in a large deep foundation pit

Springer Science and Business Media LLC - Tập 69 - Trang 863-872 - 2012
Jianxiu Wang1,2, Bo Feng2, Haipeng Yu2, Taiping Guo2, Guangyun Yang3, Junwu Tang3
1Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai, China
2Department of Geotechnical Engineering, Tongji University, Shanghai, China
3Shanghai Geological Construction Co., Ltd., Shanghai, China

Tóm tắt

During foundation pit excavation, groundwater is often the most important factor that affects pit stability. Dewatering is widely used in pit excavation to avoid uplift of excavation floors due to high water pressure. The characteristics of seepage in small-scale deep foundation pits of high-rise buildings or in the long narrow foundation pits of subway stations have been extensively investigated. However, the characteristics of seepage in large-scale deep excavations have not been studied. This paper investigates the large deep excavation of the buildings in Oriental Fisherman’s Wharf. The total area of the construction site is 33,917 m2. Single-well and group-well field pumping tests were performed and a numerical simulation by 3D finite difference method (FDM) was carried out. The simulation used results from the field pumping tests. The permeability parameters of the confined aquifer were then revised, based upon comparisons of simulation and observation results. Subsequently, dewatering schemes were simulated by FDM forward analysis. The simulation results show that dewatering schemes can minimize seepage and uplift in large excavation pits, though settlement outside the pit may need treatment measures.

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