Pipe-Soil Interaction Model

The PIPESTAB Pipe-Soil Interaction Project developed a model that predicts the soil resistance to lateral motions of untrenched submarine pipelines. The model improves upon the typical coulomb friction estimation by including soil strength information and pipe displacement history in the resistance prediction. An extensive data base containing results from monotonic and cyclic tests of full-scale pipe sections on five distinct soil conditions forms the foundation for the model. Pipe-soil resistance is far more complex than simple friction. Test data convincingly shows a marked dependence of lateral resistance on pipe penetration and soil strength. The improved empirical model captures this dependence by estimating the lateral resistance using two terms, a sliding resistance component plus a soil passive resistance component. The empirical model incorporates all significant trends observed in the test results and is suitable for use in pipeline dynamic response predictions. The testing program significantly extends the industry's data base, especially in the areas of cyclic loading and correlation of soil parameters to measured resistance.