Dynamics of Submarine Liquefied Sediment Flows: Theory, Experiments and Analysis of Field Behavior

Abstract

This paper describes an extension of the computational code LIQSEDFLOW. The salient features of the code lie in the capabilities to describe the multi-phased physics of subaqueous sediment gravity flows. Specifically, it combines Navier-Stokes/continuity equations and equations for advection and hindered settling of grains for a liquefied soil domain, with a consolidation equation for the underlying, progressively solidifying soil domain, via a transition layer that is characterized by zero effective stress and a small yet discernable stiffness. Evolutions of the flow and solidification surfaces are traced as part of solution by using a volume-of-fluid (VOF) technique. The predicted features of gravity flows of initially fluidized sediments with different concentrations conform to the observed performances in two-dimensional flume tests. The submarine flow slide that occurred in 1980 on the Klamath River delta, California is also discussed. The present results demonstrate the crucial role of two-phase physics, particularly solidification, in reproducing the concurrent processes of flow stratification, deceleration, and redeposition, as well as in the formation of scarps and terrace in submarine liquefied sediment flows.