The Role of Seepage Flow Rate and Deviatoric Stress on the Onset and Progression of Internal Stability in a Gap-Graded Soil

Abstract

The potential for seepage induced internal erosion in a soil depends on a combination of both geometric and hydromechanical criteria, with the complex stress states that the soil is subject to being one of the determinant factors. This preliminary study investigates under small-scale laboratory conditions, the influence of seepage flow under complex stress states on the behaviour of a gap-graded soil including change in volume, permeability, stress-strain response and particle size distribution. The study uses a stress path triaxial permeameter capable of assessing gap-graded soils under complex triaxial stress states undergoing internal erosion via downward seepage. The results obtained from the preliminary analysis of seepage flow testing under constant stress condition indicate that erosion of fines reduces the permeability of gap-graded samples and may also reduce its shear strength. Limitations of this research and future plans are also discussed.