ABSTRACT
Circular corrugated steel pipes (CSP) are emerging in utility tunnel construction. Unlike other elliptical, arch, and square sections, circular CSP does not require segment assembly on-site, which can shorten the construction period. Despite this advantage, CSPs installed by the cut-and-cover method can deform with the surrounding soil, with circular CSPs resulting in greater horizontal deformation than other cross sections. Current installation practices show that bedding conditions for corrugated steel utility tunnels (CSUT) are not uniform, which significantly affects this deformation. In this study, a three-dimensional numerical analysis was conducted to investigate the influence of bedding factors on the deformation behavior of CSUT. The model was validated against data from full-scale laboratory tests. The ovaling deformation caused by varying the diameter of the CSP 1.2m, 1.8m, and 3m was evaluated. As the diameter increased, the pipe deformation increased exponentially, appearing as heaving at the ground surface. Further studies into bedding design are required.
