Internal erosion: critical hydraulic gradient in 1-D vertical seepage and its relation to soil gradation

A hydromechanical envelope that governs the onset of soil erosion by seepage-induced internal instability is examined with reference to theoretical and laboratory stress-gradient paths for one-dimensional upward downward seepage flow. The method validated from permeameter test results on glass ballotini. Using theory, analysis a database 22 gradations establishes semi-empirical relation between attributes grain size distribution curve stress-reduction factor governing potential erosion. provides screening-tool susceptibility instability.