ABSTRACT
This paper discusses the experimental findings pertaining to the flotation of buried pipeline in association with wave-induced liquefaction in sand beds. Centrifuge wave testing with viscous scaling was applied to reproducing the build-up of residual pore pressures in sand beds leading up to liquefaction. The emphasis of the experiments was placed on investigating the relation between the occurrence/propagation of liquefaction and the start of floatation of pipeline to the soil surface. A series of wave tests using a drum centrifuge was performed under a centrifugal acceleration of 70 gravities. The characteristics of liquefaction under irregular waves were investigated as well as under regular waves. It was found that the buried pipe started moving upward upon the onset of liquefaction and reached to the soil surface in association with the significant liquefied soil motion under progressive liquefaction. Under an irregular-waves condition, liquefaction occurred and propagated in the sand bed similar to regular wave tests, and pipeline floated to the bed surface.
