Analysis and Treatment of Shallow Pit Accident in Deep Soft Soil Areas in Reclamation Area

Taking a shallow foundation pit in deep and soft soil in Shenzhen as an example, the support type, uplift accident, accident cause analysis and treatments of the foundation pit were introduced. Compared with the third-party monitoring results, the conclusions are as follows: (1) When the deep soft soil shallow foundation pit is supported by slope, the soil stability within the range of at least twice the depth of the foundation pit below the base should be calculated, and the load on the slope top should be limited strictly, otherwise the pit bottom is prone to uplift failure. (2) When the cantilever pile is used to support the shallow foundation pit in deep and soft soil, the supporting pile shall penetrate the silt layer to ensure sufficient effective embedded depth. (3) Strengthening the passive area of shallow foundation pit in deep soft soil with mixing pile can improve the mechanical properties of soil, effectively control the deformation of supporting structure and avoid the uplift deformation of pit bottom. The engineering experience and analysis conclusion have reference significance for similar projects.