Numerical study of solute transport in deformable soil liners
type: CreativeWork
description: For reasons of simplicity and economics, landfills are the main methods of disposing the solid waste (either household or industrial) and the highly contaminated aqueous sediments due to toxic substances. To protect the surrounding environment and groudwater from pollution, liner system is usually constructed beneath the landfill. In a modern composite basal liner system, preventing the breakthrough of volatile organic contaminants (VOCs) is a core concern to design a effective barrier. Conventional methods of analysis assume that the soil is fully saturated. However, throughout much of the world unsaturation exists in landfill basal liner. Although a few investigations have treated the migration of VOCs in unsaturated soil liner, no deformation of liner due to mechanical consolidation was included and VOCs only move in liquid phase. In reality, landfill compacted clay liner (CCL) is compacted on the optimum water content, where the air phase exists in the form of occluded air bubbles. However, the air phase becomes continuous when the temperature increases and then VOCs will be transported in the gaseous phase. Therefore, it is clear that the traditional approaches to assessing VOCs transport are inadequate to enable reliable assessment of VOCs break through landfill basal soil liner. This thesis attempts to make an investigation into migration of VOCs in partially saturated landfill soil liner using numerical modeling techniques. Firstly, pore fluid storage and solute transport equations suitable for quasi-saturated porous medium were developed. In the frame of small strain, a one-dimension coupling model was non-dimensionlized, whereby relative importance of the terms related to consolidation advection were compared. Based on the non-dimensional analysis, a simplified model was proposed and applied to a hypothetical landfill CCL. Numerical results demonstrated that the longitudinal dispersivity and compressibility of the pore fluid can be significant. Furthermore…
abstract: For reasons of simplicity and economics, landfills are the main methods of disposing the solid waste (either household or industrial) and the highly contaminated aqueous sediments due to toxic substances. To protect the surrounding environment and groudwater from pollution, liner system is usually constructed beneath the landfill. In a modern composite basal liner system, preventing the breakthrough of volatile organic contaminants (VOCs) is a core concern to design a effective barrier. Conventional methods of analysis assume that the soil is fully saturated. However, throughout much of the world unsaturation exists in landfill basal liner. Although a few investigations have treated the migration of VOCs in unsaturated soil liner, no deformation of liner due to mechanical consolidation was included and VOCs only move in liquid phase. In reality, landfill compacted clay liner (CCL) is compacted on the optimum water content, where the air phase exists in the form of occluded air bubbles. However, the air phase becomes continuous when the temperature increases and then VOCs will be transported in the gaseous phase. Therefore, it is clear that the traditional approaches to assessing VOCs transport are inadequate to enable reliable assessment of VOCs break through landfill basal soil liner. This thesis attempts to make an investigation into migration of VOCs in partially saturated landfill soil liner using numerical modeling techniques. Firstly, pore fluid storage and solute transport equations suitable for quasi-saturated porous medium were developed. In the frame of small strain, a one-dimension coupling model was non-dimensionlized, whereby relative importance of the terms related to consolidation advection were compared. Based on the non-dimensional analysis, a simplified model was proposed and applied to a hypothetical landfill CCL. Numerical results demonstrated that the longitudinal dispersivity and compressibility of the pore fluid can be significant. Furthermore…
author: Zhang, Huijie
language: eng
date published: 2012
date modified: 2026-07-24T02:07:39Z
provider: University of Dundee
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Dundee