Bearing capacity of ultra-high-performance concrete jacked pipe: full-scale test and theoretical calculation model

Abstract Current pipe jacking projects predominantly use C50 concrete pipes, which are prone to cracking and failure under jacking forces during complex construction. This study investigates the mechanical performance and failure mechanisms of C150 ultra-high performance fibre reinforced concrete (UHPFRC) pipes through full-scale trilateral loading test and numerical simulation. Key outcomes include crack load (232 kN/m), damage load (452 kN/m), and maximum displacements (64.3 mm horizontal, 71.6 mm vertical). Radial loading induced four primary cracks along the inner/outer left-right surfaces of the pipe, accompanied by extensive secondary crack networks. Damage progression began with concrete spalling at the top/bottom due to crack propagation, followed by reinforcement yielding and structural collapse. A predictive model for crack load and ultimate bearing capacity was developed, validated by experimental data. ABAQUS finite element simulations demonstrated excellent correlation with experiments, accurately reproducing macroscopic damage patterns. Notably, UHPFRC pipes exhibited 2.55-fold higher radial bearing capacity compared to C50 counterparts. This research establishes UHPFRC as a superior material for pipe jacking applications, offering enhanced structural integrity and reliability.