Laboratory Modeling of the Mechanisms of Piping Erosion Initiation

A laboratory modeling program has been conducted to assess the mechanics of initiating the piping erosion process in sandy soils. The models were performed on several soils, differing in gradation, grain size, grain shape, and specific gravity. Observations and monitoring of pore pressures within the samples during the modeling identified four stages in the development of piping initiation: initial movement, progressive heave, boil formation, and total heave. By linking the observed behavior with the measured pore-pressure regime in the sample, a model for the mechanics of piping development has been developed. Finite-element seepage analyses were performed to model the progression of piping development in the laboratory models and corroborate the developed model of mechanics. The findings of the study identified a new model for the initiation of piping development that can be applied to the assessment of piping in the field.