Abstract: The calculation formulas for water inflow of a circular foundation pit with different insertion depths of waterproof curtain are proposed based on the principle of seepage continuity of groundwater and Darcy’s law. The analytical solution of ground subsidence outside the foundation pit with different insertion depths of waterproof curtain is proposed according to the method of resistance coefficient widely used in ship engineering in China. Finally， an applicable procedure of dewatering of foundation pit with waterproof curtain partially penetrating aquifers was developed， in which water control cost is set as the target， and ground subsidence and groundwater inflow are set as the constraints conditions considering both safety and economy of foundation pit design. The proposed optimization method for water control was applied in a project site in Tongzhou district， Beijing.

Key words: foundation pit dewatering; suspended waterproof curtain; groundwater inflow; ground subsidence; water control; optimal design