Decoupled advection-dispersion method for determining wall thickness of slurry trench cutoff walls

Chen, Guan-Nian, Cleall, Peter ORCID: https://orcid.org/0000-0002-4005-5319, Li, Yu-Chao, Yu, Ze-Xi, Ke, Han and Chen, Yun-Min 2018. Decoupled advection-dispersion method for determining wall thickness of slurry trench cutoff walls. International Journal of Geomechanics 18 (5) , 06018007. 10.1061/(ASCE)GM.1943-5622.0001130

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Abstract

Low-permeability slurry trench cutoff walls are commonly constructed as barriers for containment of subsurface point-source pollution or as part of seepage-control systems on contaminated sites. A method to estimate wall thickness in slurry wall design is proposed based on decoupling the advective and dispersive components of contaminant fluxes through the wall. The relative error of the result obtained by the proposed method compared with that by an analytical solution was found to increase as the ratio of the specified breakthrough exit concentration (c*) to the source concentration (c0) increased. For c*/c0 of less than 0.1, which covers common practical situations, the relative error was not greater than 4% and was always conservative, indicating that the proposed method provides sufficient accuracy for design. For a given breakthrough criterion (i.e., c*/c0), the relative error was low for the scenarios having either a low or high column Peclet number, where either dispersion or advection dominates the contaminant migration, respectively, and the relative error was high for the scenario having an intermediate column Peclet number, in which case the coupling effect of advective and dispersive migrations is relatively high.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Engineering
Publisher:	American Society of Civil Engineers
ISSN:	1532-3641
Date of First Compliant Deposit:	2 November 2017
Date of Acceptance:	2 November 2017
Last Modified:	20 Nov 2024 06:00
URI:	https://orca.cardiff.ac.uk/id/eprint/106149

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