Analysis of performance and sensitive parameters of prestressed anchorage system for overwintering safety protection of deep foundation pit in paramos freeze-thaw regions

In this study, we focused on essential parameters derived from the deep foundation pit project of a metro station located in Northeast China. We analyzed the monitoring data pertaining to critical indicators, including the prestressing anchor cable tension, horizontal displacements of pile tops, and deformation displacements of anti-slide piles. A three-dimensional finite element model of a prestressed anchorage system was developed. To assess the reliability of the model, simulations of the system's performance were conducted, with comparisons of the results with field monitoring observations. On this basis, the support performance of the prestressed anchorage system during the overwintering period was investigated. The impacts of key variables, such as prestressing, vertical spacing, anchoring angle, and anchorage length of the anchor cable, on its protective performance were evaluated. Specifically, the impact of these parameters on performance indicators, including the horizontal displacement, internal force within the pile body, and overall stability factor of the pit were assessed. Furthermore, the distribution patterns and trends of these performance indicators under various working conditions were compared and analyzed. Finally, the optimal support strategy was pinpointed utilizing a multifactorial orthogonal test. This study provides valuable insights for simulating and designing prestressed anchorage systems for foundation pits in overwintering conditions, serving as a valuable reference for future pile anchor system construction and design in areas subjected to freeze-thaw cycles.