Grain-size model for hydraulic conductivity estimation of porous media

Abstract

Hydraulic conductivity (k) is an important hydraulic parameter of porous media, and its accurate prediction plays a vital role in sub-surface flow investigations. The study uses the borehole soil samples to develop a k model using parameters, effective grain-size (d10), and standard deviation (σ). The influence of d10 and σ on the k and evaluation of k values via four empirical models is also assessed in this study. For soil samples, the k increases with the increase in the d10 grain-size and decreases with the increase in the σ value. The evaluation of k via empirical models infers that the Hazen model performs well in the estimation of k values. The evaluation of k using various statistical indicators points towards low error statistics (MAE, RMSE, and BIAS) and high determination coefficient (R2) between the measured and developed model-based k values, which substantiate the efficacy of the developed model as compared to the existing empirical models for estimating the k. To establish the versatility of the developed grain-size model, its validation was done using independent soil samples for estimating k values.