Hydraulic barrier performance of soil bentonite mixture cutoff wall

Soil-bentonite mixture (SBM) is one of the materials with a hydraulic conductivity low enough to be used as a containment barrier for contaminated soil. The main concern regarding in-situ containment barriers is the assurance of their high hydraulic barrier performance which is the result of the coupled phenomena of physical and chemical factors. This paper addresses the results of laboratory tests that focused on the hydraulic barrier performance of SBM. Based on the results, hydraulic conductivity decreased when the bentonite powder content is reduced and the chemical concentration increased. The cation in pore water led to a more significant increase in the hydraulic conductivity of SBM than that in the permeant. Piezocone tests (CPTU) were employed to a large-scale soil tank to evaluate the vertically homogeneity. CPTU has the potential to be used for the evaluation of vertical homogeneity of constructed wall, since the profiles of physical properties change with the bentonite powder content and the hydraulic conductivity could be estimated briefly by pore pressure dissipation test.