Piping Criteria for Hydraulically Stable Anisotropic Slopes

Abstract

Piping has been a documented cause of collapse of multiple tailings dams, hydraulic structures and natural slopes. Important limitation of the existing piping criteria for a sloped ground is that they are treating soils as hydraulically isotropic, which is rarely the case in real life problems. Another obstacle for wider application of these criteria in engineering practice is that they have not been translated into an adequate definition of the safety factor against piping. This paper provides rigorous yet simple piping criteria and safety factors for slopes built of hydraulically stable anisotropic materials, as well as the safety factor against instability of an infinite anisotropic slope with a slope-parallel flow. It has been demonstrated why it is important to account for anisotropy, and how the proposed analytical expressions can be applied to practical problems with calculated flow nets and piezometric field measurements.