Abstract: The saturated sandy stratum has the characteristics of high groundwater level, large permeability coefficient, no cohesion, and well connected between the phreatic water and artesian water supply. The surrounding sensitive buildings will be easily affected during the deep excavations in this stratum, inducing with the differential settlement and even building structural damage. As an effective groundwater separation measure, the cut-off wall is widely used in soft soil stratum, but it is rarely used in saturated sandy strata. To explore the control effect of cut-off wall in the building deformation induced by the deep excavation in the saturated sandy stratum, combined with an engineering case history, a refined three-dimensional finite element model was established to study the building deformation under the two working conditions with and without the construction of the cutoff wall. The results show that: the cut-off wall can effectively isolate the area affected by the deep excavation and has a water-proof effect, can maintain the stability of water level at the building, reduce the impact of the deep excavation and discharging of the deep artesian water on buildings, and control the deformation of surrounding buildings within a safe range.

Key words: saturated sandy strata, deep excavations, building, cut-off wall, finite element numerical simulation