Soil-pipe Interaction Phenomena on Slopes under Asynchronous Earthquake Excitation

The present work focuses on the response of pipelines traversing slopes under asynchronous acceleration time histories induced by earthquakes. To this end, nonlinear generalized mechanical models are developed and used in order to describe the soil-pipe interaction phenomena. More specifically, two basic types of models are used: the first one comprises two elastoplastic generalized spring elements connected in parallel with a trilinear elastic spring (labeled as sub-models 1 and 3), while the second model comprises three elastoplastic elements, all connected in parallel (labeled as sub-models 2 and 4). The purpose of the current study is twofold, firstly to introduce nonlinear mechanical models that enable a smooth transition between the elastic and plastic phases and at the same time control the damping in the soil-pipe interaction, and secondly to investigate the effect of the soil strength and soil damping on the axial force that develop in pipelines on slopes. Results are presented from a real pipeline subjected to asynchronous accelerations along a submarine slope.