Electrochemical stabilization of soils and other porous media

Abstract

Suitable electrolyte conditioning at the electrodes greatly facilitates the transport of desired ions through soil, enhancing the ability of electrokinetic processes to stabilize the soil through cementing reactions. Cationic species are injected at the anode, and anionic species at the cathode, with suitable electrolyte conditioning. For example, if acid or base formation negatively affects transport, chemical conditioning is used to neutralize the acid or base products of electrolysis. Ionic species can be transported through soil at rates of several centimeters a day, even in soils such as clays having a low hydraulic conductivity. Electroosmotic transport can be minimized by appropriate conditioning of the pore fluid chemistry. For example, placement of chemical conditioners with smaller cations at the anode compartment and larger anions at the cathode compartment, or increasing the ion content of the pore fluid (e.g. by acidification) can help minimize electroosmotic transport and any of its adverse effects on species transport. The cations and anions are preferably selected to form cementatious precipitates in the soil. Thus when cationic species are injected at the anode and anionic species are injected at the cathode, stabilization reactions can prevail in the soil as the result of cross-transport of species, and a homogenous and uniform cementation and stabilization can be achieved in a short time.