Observations on internal stability of cohesionless soils Available to Purchase

Internal stability refers to the ability of the coarser fraction of a soil to prevent migration of its finer fraction as a result of seepage flow. Skempton & Brogan (1994) report findings from piping tests on four well-graded to gap-graded sandy gravels. Flow was imposed in an upward direction, without surcharge loading and without vibration. An abrupt transition was noted from stable to unstable states, defined by the ratio D′₁₅/d′₈₅ = 4 as postulated by Kezdi (1979) and attributed to work published in 1969. The latter concept was conceived independently by de Mello (1975)...