Experiments on suffusion of coarse soils from an ageing British dam

Abstract

Abstract Results of suffusion tests with unidirectional seepage on samples of six coarse soils are evaluated. Samples are from an aging earth fill dam, built at the end of the 18th century, in England, with a driving road at the crest level, in which concerns about the threat of suffusion during major storms existed. Suffusion is a form of internal erosion characterized by the migration of fine particles towards downstream areas along the matrix formed by the soils’ coarser fraction. Seven commonly used geometric criteria are comprehensively evaluated against the experimental data carried out. Experimental data showed that suffusion occurs in most of the tested soil specimens, despite some of the available empirical criteria classifying them as internally stable. Following the studies on suffusion, the dam was subjected to important maintenance works to prevent internal erosion phenomena.