An elasto-plastic model for pipe-soil interaction of unburied pipelines

Current pipe-soil interaction models for unburied offshore pipelines have generally been developed empirically on the basis of experimental data with little theoretical basis. Hence there are difficulties in transferring these models to conditions other than those from which they were derived. In an attempt to improve this situation, a series of pipe-soil interaction tests was performed using calcareous soil an the beam centrifuge at The University of Western Australia. An elasto-plastic model for pipe-soil interaction has been derived from these tests, comprising: a linear relationship between pipe vertical resistance and penetration depth; a parabolic shaped yield surface in vertical-horizontal load space; and a plastic potential with similar form to the yield surface. This model has been calibrated using the centrifuge test data. Predicted results from the new model show good agreement with the experimental data.