Paper Title
A Dimensionless Approach to Model Hydraulic Conductivity of Soil-Fly Ash Mixtures

This paper is aimed to develop a data based mathematical model for the estimation of hydraulic conductivity of clayey soil-fly ash mixture using dimensionless approach. A locally available soil of class CL-ML from Lambhua, Sutanpur, India. and Fly ash (FA) from thermal power plant, Panki, Kanpur, India were collected and used in the experiments. Different proportions of FA varying from 0% to 100% by weight were added to the soil. The hydraulic conductivity of soilfly ash mixtures was determined using falling head permeability test in the laboratory. Eight variables influencing the hydraulic conductivity of soil-fly ash mixture under permeability test viz. initial head, final head, cross sectional area of stand pipe, cross sectional area of soil specimen, void ratio, specific gravity of the soil, fly ash content and superficial velocity of flow were considered for the development of a dimensionless mathematical function for the estimation of hydraulic conductivity of soil-fly ash mixture. A multiplier function was developed using the various dimensionless groups. The multiplier function was fitted linearly with the experimental results with good R2 value 0.9756. The results indicate that such mathematical function can be effectively used for estimation of hydraulic conductivity of soil-fly ash mixture. The error estimates between the experimental and predicted hydraulic conductivities show that the most of the predicted results are within ± 24% error band with few exceptions. Keywords - Falling Head Permeability Test, Dimensionless Variables, Clayey Soil, Fly Ash, Hydraulic Conductivity, Multiplier Function.