DRUM CENTRIFUGE MODEL EXPERIMENTS ON THE IMPACTS OF LIQUEFIED GROUND FLOW ACTING ON SUBSEA STRUCTURES

Abstract

 This paper examines the impacts of liquefied sediment flows on subsea structures through a series of centrifuge model tests. Additionally, a numerical analysis of a high-density liquid flow based on the Navier-Stokes equation was conducted to compare with the experimental results. A series of gravity flow experiments was performed under a centrifugal acceleration of 50 gravities, by varying the initial thickness of collapsed sediment and the distance from the sediment collapse point to the structure. The experimental results showed that immediately after the liquefied sediment flow impacted and acted on a subsea structure, the impact pressure rose rapidly and reached its peak, with the peak increasing with greater thickness and shorter distance. The predicted impact pressures obtained from the analysis considering the density of the liquefied gravity flow quantitatively matched the observed ones from the centrifuge experiments, indicating that the liquefied sediment flow acts on subsea structures as a high-density fluid that has a specific density of the liquefied flow. These results may facilitate the stability assessment of a subsea structure against liquefied sediment flow.