Suffusion of a sand-clay mixture: Impact of the ionic-concentration gradient, clay type, sand-grain size, and hydraulic gradient

Yongjoon Choe, Hangseok Choi, Jongmuk Won

Research output: Contribution to journalArticlepeer-review

Abstract

Internal erosion by suffusion within a sand-clay mixture may occur as detachment of clay particles, which is induced by a decrease in ionic concentration (IC) along with application of a high hydraulic gradient. Through designed laboratory soil-column experiments, this study investigates the impact of the IC gradient (stepwise or gradual decrease), clay mineralogy, sand-particle size, and hydraulic gradient on the suffusion of a sand-clay mixture. The observed breakthrough concentration of clay particles revealed the substantial suffusion of a sand-clay mixture caused by a stepwise decrease in the IC for kaolinite and illite, while similar filtrated quantities of bentonite were observed for stepwise and gradual decreases in IC. In addition, the small-grained sand showed a relatively high susceptibility to suffusion by a stepwise decrease in IC, most likely because of the low reattachment of detached clay particles. The mass of filtrated clay particles evaluated from the area of the observed breakthrough curves in this study provides a clear insight into the need to incorporate the IC gradient when assessing the susceptibility to the suffusion of clay-containing soils.

Original languageEnglish
JournalGeotechnique
DOIs
Publication statusAccepted/In press - 2022

Keywords

  • clay mineralogy
  • hydraulic gradient
  • ionic concentration
  • sand-clay mixture
  • suffusion

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Earth and Planetary Sciences (miscellaneous)

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