On uncertainty evaluation of contaminant migration through clayey barriers

Abstract

This paper presents a methodology to estimate parameters and to make predictions with quantified uncertainty for an advective–diffusive transport of nonreactive species and low-concentration reactive species through saturated porous media. The methodology is put in the framework of inverse and forward analyses. The maximum-likelihood method (or the weighted least square method) is employed in the inverse analysis, whereas the first-order second-moment method is used in the forward analysis. The methodology facilitates the quantification of uncertainty in the estimated parameters as well as in the predictions. A case study consisting of sets of laboratory tests and field data taken from the literature is used to demonstrate the capability of the proposed methodologies. It is generally recognized that the advective–diffusive transport of contaminants is a rather uncertain process in prediction; therefore the methodology proposed in this study should be useful for practising geotechnical engineers. Key words : statistical analysis, contaminant migration, diffusion, clay barrier, inverse analysis, waste disposal.