Stability of the pipe-liner system with a grouting void surrounded by the saturated soil

Abstract

The rehabilitation of the deteriorated pipe is most commonly undertaken by installing a thin-walled close-fitting cured-in-place pipe (CIPP) polymer liner. The lining procedure results in a small shrinkage gap between the liner and its surrounding pipe. Such a small gap is expected to be eliminated by the grouting technique. However, a small crown grouting void is inevitable between the liner and its host pipe due to the bubbles in the grout and the gravity effect. This grouting void may result in different buckling behavior from the perfectly-confined liner. Therefore, this paper studies the confined liner with a grouting void under water pressure. Firstly, the analytical solutions are derived to predict the buckling pressure of the confined liner with a grouting void. Then, a two-dimensional (2D) simulated model is developed to trace the buckling and post-buckling pressure-displacement equilibrium path, from which the maximum pressure (critical buckling pressure) is obtained. After that, the numerical buckling pressure is compared and shows excellent agreement with the analytical solution, as well as other available experimental data. Finally, the parametric study indicates that the grouting void reduces the pressure capacity dramatically and should be avoided in engineering applications.