Numerical analysis of an experimental pipe buried in swelling soil

This paper investigates the pipe–soil interaction for pipes buried in expansive soil when subjected to swelling soil movement due to increase in moisture content. A laboratory experiment has been undertaken on a plastic pipe in a large-scale pipe box. A three dimensional numerical model is developed to analyse the pipe response, using FLAC3D computer program. The pipe is assumed to behave as a linearly elastic material, while the soil is modelled as a nonlinear material with Mohr–Coulomb failure criterion. The water flow and soil/pipe deformations are decoupled, where water flow is calculated using simplified capillary rise theory on the basis of measurements made. A reasonably good agreement between the experimental results and model predictions is reported.

► We develop three-dimensional numerical pipe-expansive soil interaction model in FLAC3D.
► Expansive soil behaviour is modelled using moisture content change as the controlling variable.
► We examine the accuracy of the model prediction against the laboratory experimental results.
► We conclude that the swelling stress induced on a buried object modelled using moisture content change as the controlling variable gives reasonable prediction of stresses and deformation.