Sediment creep triggered by porous flow

TL;DR

This study investigates how porous flow influences sediment creep through experiments, revealing a new dimensionless parameter that unifies deformation behavior and identifies distinct creep regimes.

Contribution

The paper introduces the dimensionless parameter P* that consolidates porous flow and gravity effects, and characterizes two regimes of sediment creep.

Findings

Deformation decay rates increase with channel tilt and porous flow.

A new parameter P* collapses all data onto a single curve.

Two distinct creep regimes are identified based on void size distribution.

Abstract

Quasi-2D experiments of a submerged sediment layer creeping downward were performed, varying the channel tilt and a porous flow under the respective thresholds for yielding. Logarithmic decay rates of the deformation are observed, with the rate increasing with both control parameters. A new dimensionless parameter, $P^*$, accounting for both mean porous flow and gravity force effects on particle motion, allows a collapse of all the deformation results on a single curve. Two distinct creep regimes are identified, and correspond to a systematic change of the void size distribution as $P^*$ increases.