NUMERICAL STUDY ON THE EFFECTIVENESS OF STABILIZATION TECHNIQUES OF OFFSHORE PIPELINES AGAINST LIQUEFACTION

Designing a offshore pipeline for installation in an area subjected to earthquake activity requires an investigation of potential effects of seismic shocks. If the seabed or the filling material along a pipeline route consists of cohesionless soils likely to liquefy under the influence of seismic shocks, a pipeline buried in such soils may lose stability and float to the surface of the seabed. This paper describes the effectiveness of three types of stabilization techniques, 1) Anchoring the pipeline, 2) Increasing the weight of the pipeline, and 3) New stabilization technique which has been proposed by the authors. In order to simulate the behavior of pipeline under liquefaction, we used finite element model which was proposed by Minami, Kiyomiya and Tsuchida.