Abstract: The sudden water intrusion in the deep excavation can induce catastrophic consequences to project. The research on deep excavation water intrusion prevention and control system and related technologies is of great significance. Based on engineering case histories, the triggering factors of the sudden water intrusion the deep excavation are analyzed, and the main factors that prevented the water curtain from completely blocking artesian groundwater are the seepage around the bottom and horizontal seepage at the bottom of the mixing column water stop curtain. The permeability coefficient of the confined water layer was obtained through in-situ depressurization well pumping tests. The reasons for the increase in permeability coefficient were analyzed. The design of the deep excavation groundwater intrusion prevention and control should consider the impact of the increase in permeability coefficient of the confined water layer. This article introduces the prevention and the control system for the sudden groundwater intrusion and the pressure reduction in deep excavations, which includes the graded layout of pressure reduction wells, weight sealing bottom, zoning excavation, rapid bottom sealing, and strengthened monitoring. Among them, the graded layout of pressure reduction wells is the key. Developed pressure reducing well sealing technology for the pressurized water and applied it in engineering. Related research can provide reference for similar engineering design and construction.

Key words: Deep Excavation, Water Intrusion, Pressure Reduction Prevention and Control, Pressure Reduction Wells, Pressure Sealing