Abstract: The Geotechnical and Tunnel analysis System was used to simulate the detailed process of foundation pit excavation. The soil displacement, internal force and displacement of supporting structure under the conditions of considering or without considering seepage caused by foundation pit excavation were compared and analyzed. Meanwhile, the effects on the mechanical properties of deep foundation pit caused by waterproof curtain, the permeability coefficient and the depth of precipitation were analyzed. The results show that the impact of seepage on foundation pit should not be ignored, and in the deep foundation pit stability analysis,  the role of groundwater seepage should be fully considered. Setting water curtain can effectively reduce the deformation of soil around the foundation pit, and enlarging permeability coefficient and precipitation depth will increase the surface subsidence.

Key words: deep foundation pits; dewatering; numerical simulation; coupling effect