Abstract: Accurate estimation of the water inflow and the effective monitoring of the environmental effect of the ground subsidence in the deep excavation dewatering are the prerequisites for a successful implementation of deep excavation. A case history of a deep excavation project is presented in this paper. The large well analytical method and the finite difference numerical simulation method are used to estimate and to evaluate the water inflow in the deep excavation area. The change of water level and the ground subsidence around the excavation area caused by different insertion depth of water-stop curtain, and the characteristics of additional water level and ground subsidence caused by the leakage of water-stop curtain are also studied. The results show that: (1) the error of water inflow estimation by the large well method is larger than that of by the numerical simulation, and the values of parameters such as the permeability coefficient and the aquifer thickness have an important influence on the estimation of water inflow, the numerical simulation parameters are taken as subarea refinement. (2) when the insertion depth of the water-stop curtain exceeds 60% of the thickness of the aquifer, it begins to play its role; when the insertion depth exceeds 80% , the clogging effect is obvious; when the insertion depth is equal to the thickness of the aquifer, the change of the water level outside the excavation area and the ground subsidence can be neglected; (3) when the water-stop curtain is leaking, the additional water level drop and ground subsidence around the leakage point due to the leakage appear to be centered on the leakage point; The phenomenon that values decrease with distance from the leak point.

Key words: Water Inflow, Large-Well-Method, Numerical Simulation, Ground Subsidence, Waterproof Curtain