A method to determine hydraulic conductivity of clayey material under low hydraulic gradients

Based on the column tracer test, we develop a new method to determine the hydraulic conductivity of saturated bentonite under low hydraulic gradient or low flow rate. Derived from Darcy's law and one-dimensional solute transport equation, this method further evaluates hydraulic conductivity through measuring solute concentrations, rather than through flow rates. In order to examine the proposed method, two types of experimental data drawn from a review of the literature are adopted, and four sorts of accuracy-test data are employed. The results of accuracy-tests indicate a good consistency with an error margin of 5.5%. Our experimental results also show that hydraulic conductivities from the tracer method are more precise than those from the flow rate method.