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

Abstract

We investigated the mechanical properties and damage modes of an ultra-high-performance concrete (UHPC) jacked pipe system through full-scale trilateral loading tests and numerical simulations. Key data, including crack load, damage load, and load–displacement curves, were obtained from the trilateral load tests. The results indicated that the crack load of the tested pipe was 232 kN/m, the damage load was 452 kN/m, the maximum horizontal displacement was 64.3 mm, and the maximum vertical displacement was 71.6 mm. During the radial loading phase, four primary cracks developed at both the top and bottom of the pipe, located on the inner and outer left and right sides, with numerous secondary cracks continuously forming around them, resulting in a complex network of extending, expanding, and intersecting cracks. Initially, the concrete at the top and bottom of the pipe spalled due to crack propagation, ultimately leading to the yielding and deformation of the reinforcement, which caused the pipe to fail. A model for the crack load and ultimate bearing capacity of the UHPC pipeline was established according to the test results and considering the tensile properties of the UHPC and the damage mechanisms inherent in pipelines. The model was found to be applicable. ABAQUS numerical software was employed to create a finite element model of the three-edge bearing test for the UHPC pipeline, and the simulation results were compared and analyzed alongside the experimental data, showing that the numerical simulation accurately predicted the macroscopic damage behavior of the UHPC jacked pipe. Furthermore, the results revealed that the radial loading bearing capacity of the UHPC pipe was 2.55 times higher than that of a comparable C50 concrete pipe.