Abstract: With the development and utilization of urban construction and underground space in Wuhan, deep excavation engineering has received wider and wider applications. The size, excavation depth and supporting methods of deep excavation are moving towards a larger, deeper and more complex direction. However, in the process of its development, some hazards, such as land subsidence, deep excavation collapse, water and quick sand gushing, are still occasionally encountered during the construction. These hazards pose new challenges to the builders and developers. This paper presents a deep excavation supporting in soft soil case history in Wuhan. Although the excavation supporting system passed the peer review in the design stage, there was still local instability in the construction. This paper comprehensively analyzes the reasons and proposes solutions for the overload on the top of the slope and the impact of excessive rainstorm.

Key words: deep excavation, soft soil area, excavation support failure, stability mitigation