Measurements of the resistive and capacitive properties of a bentonite clay/sand mixture

Impedance measurements were made on a bentonite clay/sand mixture, referred to as buffer, at various moisture contents using classical geophysical impedance measurement techniques. They were done to study the potential for electrical impedance-computed tomography for in situ imaging of moisture levels in buffer. Tests were first conducted on laboratory samples at different moisture content and density. In situ tests were then conducted at the Underground Research Laboratory in an emplacement borehole packed with buffer. The results show a clear relationship between moisture and impedance and thus establish potential for applying the technique for in situ monitoring of moisture in buffer. 12 refs., 9 figs., 10 tabs