Centrifuge Modeling for Mechanical Behavior of Liners in Damaged Host Pipes

Abstract

In Japan, a trenchless rehabilitation method has often been used for replacing aging irrigation pipes because of the economical reason. With the method, damaged host pipes are repaired with new pipes. Namely, the rehabilitated pipeline system comprises two pipes: a damaged host pipe and a liner. The mechanical behavior of liners is influenced by host pipes. In the present study, in order to reveal the mechanical behaviors, centrifuge model tests were carried out under various conditions including the damage levels of the host pipe, the positions of surcharge load, the ring stiffness of the liner, and the stiffness of the backfill. Test results indicate that the deflection of the liner increases with the damage level of the host pipe, and the influence of the host pipe on the liner is negligible when the host pipe reaches the ultimate damaged state. In addition, the strain concentration occurs at the crown of the inner due to the contact between the edge of the damaged host pipe and the liner. The strain concentration is reduced by 20 % with the increase of the ring stiffness of the liner. It is also revealed that the strain concentration appears even if the stiffness of backfills increases.