Compressibility of soils containing kaolinite in acidic environments

Abstract

This paper seeks to understand the effect of acidic fluids on the compressibility of soil. Three natural soils (namely, Kansai clay, Yurakucho silt, and Oumigawa silt) containing kaolinite were leached with solutions of sulphuric acid for various lengths of time. At the end of each time interval, standard compression (oedometer) tests were performed to study the behavior of soil in an acidic environment. It was found that the soil structure had a significant effect on the compressibility of clay at low pH. For the Kansai clay and Yurakucho silt, the undisturbed specimens yielded greater compression indices as pH values decreased. In addition, the data indicated that for all three soils, a decrease in pH correlated with an increase in the compression index. Based on the obtained results and available literature, the mechanisms controlling the compressibility of the studied soils at low pH values were discussed.