Volume 23, Issue 4 (December 2000)
Tomographic Evaluation of Air and Water Flow Patterns in Soil Column
This paper describes the use of computerized tomography (CT) as a nondestructive method to estimate the three-dimensional spatial distributions of porosity, air, and water saturations during air-water displacement tests in a soil column. Local porosity was found to be a critical factor in controlling the air and water flow patterns. In nonhomogeneous soil, high local porosity promotes early development of isolated air channel breakthrough that maintains a high average water retention saturation. In homogenous soil, micro air channels are established uniformly, resulting in a low water saturation. Interpretation of data based on overall porosity could lead to unreliable flow analysis for water and/or air movement in unsaturated soil. In addition, this paper investigates the use of gas exsolution to enhance the delivery of air within soil media.