Numerical Simulation of Double-Row Retaining System with Different Piers

Abstract

With the rapid expansion of foundation pit excavation areas due to the burgeoning underground transportation networks in large cities, spatial combined double-row retaining structures have become indispensable for ensuring stability and minimizing deformation. Integrating piers into these structures enhances stiffness; however, the research on this topic is limited. This study investigates the Chisha Metro project, which utilizes a double-row support structure with added support piers to improve overall stiffness. Numerical simulations are employed to model the foundation pit and analyze the stress distribution and deformation of double-row retaining systems with T-shaped, cross-shaped, or square-shaped piers. The results demonstrate that the retaining system, after the introduction of piers, exhibits reduced maximum horizontal displacement and surface settlement of soil, and indicates spatial characteristics and the transformation from a planar problem to a spatial problem. Furthermore, in specific geological conditions, the T-shaped support pier proves to be more effective in connecting the front and rear support structures compared to the cross-shaped and square-shaped support piers, which mainly reinforce the soil without connecting the support structures. This research provides valuable insights for improving design and construction practices in foundation pit engineering.