EROSIONAL CREEP OF FLUID-SATURATED GRANULAR MEDIUM

Erosional creep of grains attributable to the gradient of fluid pressu re is considered. Drag forces arising from viscous fluid flux may disl odge grains from the skeleton and initiate solid flux, which can lead to systematic erosional creep of granular fabric as a whole. The proba bility of local jumps of grains is stipulated by kinematic and local y ield conditions that must be met at the same time. Average grain veloc ity is obtained as a function of the local fluid pressure gradient. En hancement of fluid flux attributable to simultaneous granular creep is also estimated. The rate of erosional creep is calculated both for th e water- and the heavy-oil-saturated granular fabric. Slow and moderat e movements of silty slopes can be explained by the erosional creep ca used by water flow. Flow of heavy oil can cause erosional creeps of sa nd fabric with the rates of the same order of magnitude as the heavy o il ones.