Impact Analysis of Arch Vault Rise-span Ratio on Steel Pipe Pile Stress and Land Subsidence in Urban Rail Transit Covered PBA Method Stations

Abstract

Objective The arch vault rise-span ratio not only affects the building height, design rationality, and construction safety of covered PBA (pile-beam-arch) method urban rail transit stations. Therefore, it is necessary to study the impact of arch vault rise-span ratio on the stress of steel pipe pile stresss and land subsidence. Method A mechanical model of urban rail transit station arch vault structure is constructed to analyze the structural internal forces under different arch rise-span ratios. A 3D station-stratum numerical model of the station and surrounding soil is established using numerical simulation analysis software, and the rationality of the model is verified by comparing numerical simulation results of land subsidence and field monitoring data of land subsidence. The study also examines the mechanical properties of steel pipe piles and their impact on land subsidence during covered PBA method construction. Result & Conclusion When the arch rise-span ratio varies from 0.20 to 0.40, the maximum bending moment, maximum axial force, and maximum shear force of the arch vault structure show a decreasing trend. The maximum axial force of the steel pipe piles decreases initially and then increases; the middle pile axial forceit is the minimum with the arch vault rise-span ratio of 0.30. As the arch vault rise-span ratio increases, land subsidence first decreases and then increases. The optimal ratio for controlling land subsidence is 0.30, resulting in a 34% reduction compared to the arch vault rise-spana ratio of 0.20. The stages of pilot tunnel and arch closure construction cause the most significant land subsidence. An appropriate arch rise-span ratio increases the proportion of land subsidence induced during these two stages, thereby reducing the disturbance to the soil layers from the subsequent station main structure excavation.

Keywords

• urban rail transit（urt）
• station
• covered pba method
• steel pipe pile stress
• land subsidence
• arch vault rise-span ratio