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<inf>MI-EC</inf> k <inf>u</inf>: A novel methodology for estimating unsaturated hydraulic conductivity of porous media
Journal
Acta Geotechnica
ISSN
18611125
Date Issued
2022-09-01
Author(s)
Joseph, Jeevan
Rakshith, Shetty
Singh, D. N.
Tang, C. S.
Abstract
Numerous applications of hydraulic conductivity of porous media (e.g., soils, clay liners, rocks, concrete, ceramic filters, etc.) in their unsaturated state are well established in the field of geotechnical and agriculture engineering. In recent years, researchers have developed laboratory techniques by resorting to thermal flux sensors, electrical impedance spectroscopy, geotechnical centrifuge, and tensiometers, for determining the unsaturated hydraulic conductivity, ku, of the porous media. However, these methodologies and techniques are susceptible to yield ‘uncertain’, if not ‘erroneous’, results mainly: (i) due to the difficulties associated with maintaining uniform saturation of the specimen and (ii) intricacies in maintaining a pressure gradient along the porous media (having nanometric pore size) to facilitate flow at a constant suction. To overcome these limitations, a novel methodology, MI-ECku (read as, my-easy ku), that employs, (i) ‘modified Kozeny-Carmen relationship’ and the pore-size distribution characteristics (obtained from mercury intrusion porosimetry, MIP) and (ii) the electrical conductivity (obtained from impedance spectroscopy) of the porous media, has been proposed for determining ku. The robustness and ease of utilization of MI-ECku have been demonstrated by employing the standard porous media, SPM, which contains a rigid pore structure and inert mineralogy. It has been noticed that ku of the SPM determined by MI-ECku is in good agreement with those predicted by van Genuchten-Mualem model and hence it can be employed for estimating ku of various porous media such as compacted soils and rocks.
Volume
17
Subjects