Analysis on Deformation Characteristics of Super Large Diameter Ring Bracing Deep Foundation Pit in Soft Soil near Subway

Taking the foundation pit of Minghui Garden (phase II) in Shenzhen reclamation area as the engineering background, the monitoring data of lateral deformation, slope top displacement and support axial force caused by foundation pit construction were analyzed. The temporal and spatial distribution characteristics of deep foundation pit deformation in soft soil were discussed, and the relationship between foundation pit deformation and excavation depth as well as soft soil thickness was discussed. The conclusions were as followed: (1) The maximum deformation of the supporting structure gradually increases with the increase of the excavation depth of the foundation pit. After the foundation pit was excavated to the bottom of the pit, the maximum overall deformation was located at the middle of the long side on both sides of the foundation pit, which was supported by a ring. (2) The application of bite pile + super large diameter ring reinforced concrete support structure with large stiffness in soft soil deep foundation pit was very effective in deformation control and reducing the influence of foundation pit engineering on surrounding deformation. (3) With the continuous excavation of the foundation pit downward, the maximum horizontal displacement of the support structure reflected by the three methods gradually increases, but the variation range was different.