Centrifuge Model Test for Buried Inner Rehabilitated Pipes Affected by Aging Pipes with Different Damage Levels

This paper discusses an experimental study on the pipe rehabilitation method for the purpose of establishing a fundamental design standard. In this method, as the new pipe is directly inserted into the aging pipe, there are several possibilities in terms of cost reduction. It is not clear how the damaged outer pipe mechanically influences the inner pipe through interaction with the surrounding soil when an external force is applied to the ground. In this study, centrifuge model tests for the buried pipe are carried out. The test results indicated that deformation mode of the new pipe is largely dependent on the damage level of the outer pipe. When the damage state is not serious, the outer pipe protects the inner pipe from deforming and behaves positively. On the other hand, the outer pipe, if at ultimate limit state, has almost no influence on the mechanical behavior of the inner pipe. Additionally, the concentration of stress within the inner pipe tends to occur at the position where there is cracking of the outer pipe in a certain damaged condition.