Erosional Creep of Fluid-Saturated Granular Medium

Abstract

Erosional creep of grains attributable to the gradient of fluid pressure is considered. Drag forces arising from viscous fluid flux may dislodge grains from the skeleton and initiate solid flux, which can lead to systematic erosional creep of granular fabric as a whole. The probability of local jumps of grains is stipulated by kinematic and local yield conditions that must be met at the same time. Average grain velocity is obtained as a function of the local fluid pressure gradient. Enhancement of fluid flux attributable to simultaneous granular creep is also estimated. The rate of erosional creep is calculated both for the water– and the heavy-oil–saturated granular fabric. Slow and moderate movements of silty slopes can be explained by the erosional creep caused by water flow. Flow of heavy oil can cause erosional creeps of sand fabric with the rates of the same order of magnitude as the heavy oil ones.