Velocity of sand particles transported during sand boiling

Abstract

Thus far, previous studies on seepage failure, known as sand boil, have been mainly focused on the critical hydraulic gradient or critical seepage velocity at which the seepage failure occurs. However, in order to understand how the stability of soil structures changes after seepage failure starts, it is necessary to figure out the transport of soil particles during seepage failure. Herein, laboratory experiments were conducted to investigate the behavior of sand transported by seepage flow during the seepage failure of a sand due to vertical upward seepage flow. The experimental results have shown that the relative velocity between seepage water and soil skeleton follows the Darcy law, and the velocity of sand particles can be well estimated by the equilibrium of forces exerting onto the sand particles, in which the seepage force is given by a function of the hydraulic conductivity.