Investigation on the deformation response of submarine pipelines subjected to impact loads by dropped objects

Abstract The response of pipelines to transverse impact loads by dropped objects is investigated experimentally and numerically. A series of experiments are carried out to examine the relevant effects, including the bed conditions (rigid or flexible seabed) and impact energy. A finite element numerical model is established to determine the dynamic response and it is validated against the experimental results, showing good consistency. An extensive parametric study is conducted, to examine the effects from various factors, including the velocity, weight and shape of dropped objects, pipeline wall thickness, concrete coating, internal pressure and free pipe span length. The effects of seabed flexibility, burial depth and soil properties on pipeline response are studied with a coupled Eulerian-Lagrangian method, able to simulate large deformation of the soil. Based on these analyses, the model applicability is validated and the research results give an insight to the effects of the various mechanisms on pipeline response, which provides a considerable reference for engineering design of submarine pipelines.