A simplified third-type inlet boundary condition solution for contaminate transport through slurry cut-off walls

Abstract

Low-permeability slurry trench cut-off walls are commonly constructed as barriers for containment of subsurface point source pollution or as part of seepage control systems on contaminated sites. Scholars made achievements on design methods for first-type inlet boundary scenarios, but there are still lacking on third-type inlet method, as the choice of inlet boundary conditions is still controversial. A method to estimate wall thickness in slurry wall design in such boundary condition is proposed based on previous design method for first-type inlet. An error analysis is performed to investigate the impact of this assumption by comparing the results obtained by the proposed method to those from an analytical solution. For breakthrough criterion C* of less than 0.1, which covers common practical situations, the relative error is not greater than 15%, demonstrating that the proposed method is suitable for design. An example is also presented to illustrate the procedure of implementing the proposed method for slurry wall design.