English：

The deep foundation excavation-induced ground volume losses outside the excavation will severely threaten the safety of adjacent buildings and facilities. However, very few studies have been known about safety-control technologies of deep foundation excavation close to existing stations in soft soil area. Based on a foundation excavation project close to one existing subway station in Shanghai, the major challenges faced throughout implementation of deep foundation excavation were analyzed, including implementation of underground diaphragm walls below high voltage lines, protection of the existing subway station, and risk control of hydraulic failures. Moreover, construction technology of ultra-deep diaphragm walls under low-net-clearance conditions, deformation-control technology of deep foundation excavation close to existing stations, and dewatering impact-control technology of complex confined aquifers were proposed, which effectively ensured the safety of project construction.