Deformation Monitoring and Numerical Analysis of Supporting Structure of Open Ring Deep Foundation Pit

There are thicker soft soil layers distributed in the subsoil of Nanjing Yangzi coal storage silo project which deep foundation engineering excavates a pit with the depth of 11.40 m. The row piles were used as retaining structure with cast-in-situ bored pile and ring beams as struts which are 10. 0 m length of open arc. However, the open sections of ring struts have a great influence on the deformation and stability of foundation pit excavation. Based on this practical engineering, a three-dimensional finite element numerical analysis model was established and the soil and the interface elements were modeled as elasto-plastic materials obeying Mohr-Coulomb failure criterion, then staged excavations were simulated and calculated. Compared with monitoring data, the results showed that the difference between calculated values and measured values was negligible, and the variation trend was almost the same. The calculated results of finite element are reliable, which can be references for design and construction improvement of similar engineering.