Hydraulic conductivity of fly ash - bentonite mixture exposed to salt solutions: ann model and sensitivity analysis

Abstract

Leachate from the landfills contains toxic chemicals which will penetrate through the soil and ultimately pollutes the groundwater. The low permeable liner layer provided below the landfills will prevent the groundwater from being contaminated by the leachate. Generally, owing to its low permeability, a mixture of soil-bentonite is used as liner. Fly ash being locally available and as an alternative for its disposal, it is used to replace the soil in liner material. This study presents a neural network model to predict the influence of chemical solu-tions viz. NaCl, NaOH, HCl, H2SO4, CaCl2 and FeCl3 on the hydraulic conduc-tivity of fly ash-bentonite mixture. The data set is generated with the help of la-boratory model tests which is further processed to develop the numerical ANN model equation. At last, sensitivity analysis is performed to evaluate importance of influencing parameters. The statistical analysis confirms that the hydraulic conductivity is primarily controlled by the concentration of bentonite in the mixture.