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Soil Air Permeability Modeling and Its Use for Predicting Unsaturated Soil Hydraulic Conductivity
Author(s) -
Rahmati Mehdi,
Neyshaboury Mohammad Reza
Publication year - 2016
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2015.12.0430
Subject(s) - hydraulic conductivity , air permeability specific surface , permeability (electromagnetism) , soil science , water content , calibration , conductivity , soil water , environmental science , materials science , geotechnical engineering , chemistry , mathematics , geology , composite material , statistics , biochemistry , layer (electronics) , membrane
Core Ideas K a (θ) was modeled by considering a similar phenomenon between water and air flows in soil medium. K w (θ) and K a (θ) were theoretically linked by considering a similar intrinsic permeabilities for both water and air. The proposed models were tested with laboratory‐measured data showing reasonable accuracy. Since the direct measurement of soil hydraulic conductivity [ K w (θ)] is time consuming and difficult, several methods have been suggested for its prediction. However, their application still requires some kind of direct or experimental measurement, even after calibration. Considering much easier measurement of the air permeability [ K a (θ)] and the water and air flows in the soil medium, several attempts have been made to link K w (θ) and K a (θ), most of which have used K a (θ) to predict the saturated hydraulic conductivity ( K s ). The current research was aimed to model the air permeability and evaluate its application for K w (θ) prediction. In this regard, laboratory measurements were conducted for K w (θ) and K a (θ) at different soil moisture contents (θ). Then, we introduced a semitheoretical model and evaluated it using measured data. Results showed that the proposed model can predict K w (θ), with an average evaluation error of 3.69% and average R 2 of 0.88. Regarding the fast and nondestructive measurement of K a (θ) compared with K w (θ), the proposed model seems to be more practical to characterize unsaturated soil hydraulic conductivity and can improve the accuracy and efficiency of K w (θ) estimation.