Hydrological and mechanical behavior of granular materials subjected to internal erosion: A review

Internal erosion is the phenomenon in which the fine particles located in the voids formed by the primary fabric are washed out by the seepage flow. In most cases, internal erosion continues for several years until the earthen structures collapse. In this study, the initiation of internal erosion, the process of internal erosion and post erosion behavior are summarized to provide the overview on the study of internal erosion. Different criteria (i.e., grading criterion, the stress criterion and the hydraulic criterion) for soil stability are investigated. The shape of grading curves could directly determine the soil stability. The rearrangement of the eroded fine particles significantly influences the hydraulic conductivity. If the eroded fine particles are washed out, the hydraulic conductivity increases; if the eroded fine particles clog the pores, the hydraulic conductivity decreases. The rearrangement of the fine particles, the increased void ratio and the seepage flow influence the mechanical behavior of the eroded soil. Triaxial shearing has shown that the mechanical behavior of eroded soils depends on the fine particles in the primary fabric and can be determined on the basis of erosion phenomena (suffosion or suffusion).