Permeation of Compacted Clay with Organic Chemicals

Abstract

Hydraulic conductivities were measured on three compacted clays that were permeated with water, methanol, and heptane in rigid‐wall and flexible‐wall permeameters. The type of permeameter had little effect when the soils were permeated with water. However, rigid‐wall permeameters generally yielded much higher hydraulic conductivities than flexible‐wall cells when the soils were permeated with organic compounds. Differences in effective stress and confinement along the sidewall of the test specimen are thought to be responsible for the different patterns noted. Permeation of water‐saturated clay with heptane caused the hydraulic conductivity to drop to practically zero because of surface tension effects at the water‐heptane interface. There appeared to be a threshold hydraulic gradient below which the hydraulic conductivity to heptane was zero. The results of this study show order‐of‐magnitude differences in hydraulic conductivity depending on testing apparatus and procedures.