IMPACTS OF SUFFUSION FACTOR ON HETEROGENIZATION OF SOILS

Abstract

In recent years, embankment structures have often failed due to extreme weather events, such as typhoons and torrential rains. Suffusion, in which finer particles within the soils are transported by seepage flow, causes heterogenization of the soils and may lead to deterioration of the embankment. Various suffusion factors, such as material properties and hydraulic conditions, have been confirmed. However, the impact of these factors on the degree of heterogenization is uncertain. In this study, repeated seepage tests on cylindrical specimens with different relative densities were conducted. X-ray CT scans of the specimens during the test were also performed. A greater erosion rate was observed in the first seepage flow experience, and a decreasing trend during seepage was observed to differ depending on the hydraulic gradient. It was confirmed that the relative density had a larger impact on the occurrence of suffusion compared to the hydraulic gradient or the number of seepage events. Investigation of CT images demonstrated that heterogenization of soil had occurred by the formation of lower density zones within the samples.