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,