Behavior of Buried RC Pipe Loaded Locally from Inner Surface

Abstract

Internal loading method (ILM) was applied to the buried and the unburied RC pipes, in order to evaluate the effect of restraint by the earth pressure for cross-sectional stiffness of the pipes. As a result, the relationship between load and deformation of the buried RC pipe had strong positive correlation. It was confirmed to be same as the case of earth pressure didn't act. It was verified that ILM deformed the cross section of the buried RC pipe into ellipse and accrued local bulges at loading points, considering vertical and horizontal earth pressure and circumferential strain distributions on outside of the pipe. The circumferential strains at top and bottom on the outside of buried RC pipe at a certain deformation (20μm) increased due to the effect of restraint by earth pressure. Finally, it was shown that the stress from cross-sections of an RC pipe (diameter: 400 mm) was transmitted to less than 40 cm along the longitudinal direction.