Abstract: This paper presents a case history of a cut-and-cover deep excavation for a DN3500 power project in Xi’an where the pipe jacking initiation working shaft. Through theoretical analysis, the influence of the suspended impervious curtain on the seepage stability in the sandy soil and other highly permeable strata is evaluated. And then, the influence of different groundwater control options, such as, water collection and open drainage, dewatering of pipe well points in the pit and dewatering of tube wells outside, on the deformation of the soldier pile in the deep excavation and the soil outside the excavation area are studied. The lateral earth pressure of the soldier pile can improve the safety of the excavation, but compared with the dewatering inside the excavated area, the use of the dewatering outside the pit will significantly increase the settlement of the surface outside the well. Risk control measures related to “requiring dewatering” provide a basis for the pipe jacking project’s construction and a reference for the construction of related projects.

Key words: Highly Permeable Stratum, Deep Excavation for Vertical Shaft, Suspended Impervious Curtain, Osmotic Stability, Ground Settlement