Effects Of Water Retention Curves And Permeability Equations On The Prediction Of Relative Air Permeability

Appropriate simulation of air flow in porous media needs an accurate estimate of relative air permeability (RAP). Combining 2 traditional and 2 fractal water retention curves (WRCs) respectively with 6 permeability equations, we obtained 12 statistical and 12 fractal RAP models. All these models were subsequently tested with 31 experimental datasets of disturbed soils to examine their predictive ability for RAP. Results showed that irrespective of using traditional or fractal WRCs, the six permeability equations exhibit consistent performances for RAP prediction. The modified Burdine (Yang & Mohanty, 2015, https://doi.org/10.1002/2014wr016190) permeability equation best fits the published soil data. In addition, the selection of a proper permeability equation is critical for accurately predicting the RAP, whereas the choice of WRCs has little effect on RAP prediction. This finding suggests that for disturbed soils, air permeability is primarily dictated by the pore tortuosity-connectivity but not the pore size distribution inferred from the WRCs.