A plasticity model for predicting the vertical and lateral behaviour of pipelines in clay soils

A complete theoretical model for predicting the undrained behaviour of a rigid pipe in clay soils when subjected to combined vertical and horizontal loading is described. Physical modelling of a pipe on soft, lightly overconsolidated kaolin clay was conducted, with the experimental test programme specifically designed to establish the model parameters. The testing was conducted within the University of Western Australia's geotechnical drum centrifuge using an element of pipe 10 mm in diameter and 50 mm long, at an acceleration of 50 times the Earth's gravity. The model presented is expressed by the force resultants on the pipe and the corresponding displacements and allows predictions of response to be made for various vertical and horizontal load or displacement combinations. However, it is limited to monotonic loading and does not account for the influence of berms created by repetitive large lateral displacements. The model is verified in this paper by retrospectively simulating a selection of combined loading tests and comparing the output with the experimentally recorded results.