Electrochemical perspective on the applicability of electroosmosis for clay consolidation

Abstract

Abstract There are three main electrochemical factors affecting the electroosmotic flow in clay soil: the voltage loss at the clay/electrode interface, the type of current carriers in the soil, and the ion composition change in the clay due to voltage application. Appropriate evaluation of these factors is important to cost effectively implement electroosmosis for in situ soil consolidation projects. In this study, three different experimental systems were developed and used to investigate electrochemical reactions occurring in reconstituted and natural marine clay during electroosmotic consolidation. The results of polarization tests show that the voltage loss at the clay/electrode interface is different depending on the combination of the clay material and electrode material. The results of electroosmotic element test also show that electroosmotic dehydration does not increase if large current–voltage value is applied and that an optimal current–voltage value for causing electroosmosis depends on the cohesive soil composition. If the clay contains a lot of oxidizable ions, such as sodium, these ions affect electrophoresis and chemical reactions that occur in the soil. Therefore, the optimal configuration to apply electric current also differs depending on the clay. The results of laboratory-scale electroosmotic dehydration tests, arranged in a realistic in situ layout, are performed to study the relationship between soil dehydration, consolidation, and surface crack generation. Graphical abstract