Anion permeation effects on compacted soil shear strength

The impact of two inorganic anions on the shear strength of a compacted sand-clay mixture were carried out in order to investigate their potential influence on a waste landfill liner. Ammonium chloride and ammonium sulfate solutions were employed as the permeant fluids in this study. Concentrations of SO4- ranged from 100 ppm to 100 x 10(3) ppm, while the concentrations of Cl- ranged from 50 ppm to 50 x 10(3) ppm. Pore volumes replaced ranged from one to as high as eight. Based on consolidated-drained triaxial tests, increases in anion concentration and pore volumes permeated significantly decreased the c' parameter, but had much less influence on phi'. The practical implications of these findings on compacted clay liner stability are discussed.