Reinforcement Scheme and Numerical Simulation for Sequential Excavation of the Deep Foundation Pit

Abstract

The deep foundation pit engineering of Wanda Plaza in Yinchuan city is taken as a case study and the corresponding numerical model has been built. The deformation and stability of the foundation pit during sequential excavation has been analyzed by using of the FLAC3D software. The weak positions which may lose the stability are predicted by the results from the numerical simulation. A soil-nailing reinforcing scheme has been proposed to maintain the stability of the foundation pit. To analyze the support effects of the soil-nailing, the Cable structure elements have been adopted to simulate the interaction between soil and soil-nailing. The calculation results show that the maximum horizontal displacement occurs in the middle part of the pit wall and the minimum occurs in corner part of the pit wall. The soil nailing support significantly decreases the deformation of foundation pit by dispersing internal stress of soil. The reliability of the simulation results has been verified by the comparative analysis between the numerical simulation results and the deformation monitoring data of foundation pit. The proposed reinforcement scheme is not only helpful to ensure the safety of Wanda Plaza foundation pit，but also provides valuable experiences for the reinforcement of similar foundation pit engineering.