Prestressed steel wires impact on axial bearing capacity of ultra-large section jacking prestressed concrete cylinder pipe (JPCCP): Field experiment and simulation

Jacking prestressed concrete cylinder pipe (JPCCP) represents an innovative composite structure for pipe jacking applications. As a critical component of the JPCCP, the stress levels and stress loss of the prestressed steel wires significantly influence the axial bearing capacity during the jacking process, subsequently impacting the long-term safety and durability of the pipeline. This study presents a field loading experiment conducted with China's largest JPCCP project. The results reveal tension and relaxation phenomena in the prestressed wires at various positions throughout the jacking process, and the wires' deformation in the pipe's central section was greater than that at the bell-spigot end. Following the initial jacking, the stress loss of the prestressed wires was the highest, with significantly reduced deformation in subsequent jacking stages, culminating in a maximum stress loss of 29.0 MPa. Utilizing ABAQUS, a numerical model of the JPCCP incorporating multiple interlayer relationships was developed and validated against experiment data. The study further analyzes the effects of steel wire spacing, prestress level, and prestress loss across different concrete layers, and examines the damage to key areas of the pipe under ultimate compression jacking. The findings indicate that the inner concrete at the spigot end is more prone to damage and yielding, predominantly due to cross-sectional mutations, additional bending moments, and tensile stresses. Based on these findings, specific design and construction proposals are proposed. This study provides an in-depth analysis of the impact of prestressed steel wires on the axial bearing capacity of ultra-large section JPCCP, offering valuable insights into its design and construction.