A foundation pit’s excavation area, which is determined by its radius in a circular foundation pit, exerts a considerable influence on the pit’s behavior. Using a full-scale experiment on a circular foundation pit retained by a prefabricated recyclable supporting structure (PRSS), this study develops a series of axisymmetric numerical models to systematically investigate the influence of excavation radius on the pit’s deformation, stress, and stability. Furthermore, simulation results from axisymmetric models are compared with those from plane strain models to illustrate the influence mechanism. The results show that at a given excavation depth, the deflection and bending moments of the supporting piles, the earth pressure on the non-excavation side, and ground surface settlement increase with the enlarged excavation radius, but the increase rate progressively decreases. However, the foundation pit’s safety factor decreases with an increasing excavation radius and gradually stabilizes. When the excavation radius exceeds 50 m, its influence on the foundation pit’s behavior significantly diminishes. The axisymmetric model results closely approximate those from the plane strain models, suggesting that the spatial arching effects of the circular foundation pit can be disregarded.

Excavations for underground structures, such as working shafts, underground grain silos, and parking garages, are characterized by uniformity, consistent dimensions, large quantities, and strict timelines. Prefabricated recyclable supporting structures (PRSS) are gaining attention over traditional retaining structures due to their standardized design, efficient construction, and reusability, which suit such excavations better. To validate their performance, full-scale tests are conducted to analyze the deformation and stress characteristics of PRSS. The results show that the average maximum lateral displacement of supporting pile is 0.07% of the excavation depth (H_e), roughly half that of steel plate. Differences in ground surface settlement behind steel plates and the supporting piles are not as significant as those in their lateral displacements. While the displacement of the supporting piles is insufficient to induce soil movement into the active limit state on the non-excavation side, the circular excavation’s arching effect reduces the earth pressure on this side of the supporting piles below the active earth pressure limit. Furthermore, the earth pressure acting on the steel plates is lower than that acting on the supporting piles, suggesting the presence of a soil arching effect between two adjacent piles. These findings offer valuable insights for guiding the construction of PRSS.

The prefabricated recyclable supporting structure (PRSS) is an innovative support system that integrates a steel skeleton with polymer waterproof technology. Earth berms are extensively adopted to support the PRSS, but there is limited understanding on the factors influencing their behavior in circular excavations. In this paper, a numerical model is first validated with a case history in Henan, China. Afterwards, the geometric parameters of the earth berms, including the height (H), the top width (B₁), and the bottom width (B₂), on the behavior of the PRSS, are investigated. It is shown that, by increasing the height, top width and bottom width of earth berms, the lateral deflections, and bending moments of supporting piles, as well as the ground surface settlements, tend to decrease. However, the reduction effect of these parameters diminishes as well. Moreover, the raised effective formation level considering the effect of the earth berms on stability and deformation analyses is discussed. The factor of the safety of the excavation is almost doubled when axisymmetric conditions are considered compared to plane strain conditions. In deformation analysis, the raised effective formation level increases with the height of the earth berms until a steady value is reached.