Evaluation of the Hydraulic Conductivity of Clayey Soil Mixed with Calcium-Bentonite Using Odeometer Tests

Abstract

The hydraulic conductivity of clayey soil/Calcium-bentonite backfills for vertical cutoff wall is evaluated based on a series of oedometer tests. Kaolin is used as the control clayey soil, and the Ca-bentonite content is set at 0, 5%, 10% and 15%. The results reveal that the hydraulic conductivity are significantly affected by the bentonite content, with a hydraulic conductivity that is generally lower than 10⁻⁹ m/s. Three empirical methods are assessed to predict the hydraulic conductivity based on e and e_L (or w_L). The predicted values of hydraulic conductivity are found to fall in the range of 1/3 to 3 times those evaluated values. However, the equation based on the frameworks of the Kozeny-Carman (KC) equation is shown to estimate the hydraulic conductivity for both the kaolin-bentonite backfills in this study and the sandy soil-bentonite backfills from earlier reported study with reasonable accuracy.