Abstract
Electrokinetic treatment uses low intensity direct electric current or a low electric potential difference, to improve the engineering properties of subsurface soils while having minimum disturbance to the surface. This study aims to investigate the effects of chemical-electrokinetic treatment on properties of two types of clay soils at different intervals under the coupled Chemical, Hydraulic and Electrical (CHE) gradient. “Chemical-electrokinetic treatment” refers to improvement of soil with electrokinetic together with addition of chemical enhancement solution. The enhancement solutions used in this study are hydrated lime and saline solution. The combined effects of these processes together with various electrochemical and geochemical reactions would change the chemical composition of the soil porous medium, hence modifies the properties of the soil. The experiments were conducted in the laboratory using stainless steel electrodes under total applied voltage of 30 V for period of 15 days. Two types of fine-grained soils, kaolinite and bentonite, were used as they possess different mineralogy and geotechnical properties. The cumulative electro-osmotic flow and electric current flow through the soil samples were measured for period of 15 treatment days. Subsequently the specimens were tested for moisture content, pH and Atterberg Limit variations and the results have been reported. Test results revealed that there is a potential of developing this technique to improve engineering properties of finegrained soils, in particular to stabilise and improve soft soils for infrastructure management and constructions.
Highlights
The electrokinetic technology, which is an alternative method to the conventional ground improvement methods, involves electrochemical electro-osmosis stabilization in fine-grained soils
Upon the application of Direct Current (DC) electric potential through the soil across the electrodes, the soil-liquid medium undergoes several physicochemical, hydrological and mechanical changes due to several complex electrochemical processes that take place within the soil porous media. Some of these processes are initiated immediately after the DC electric potential was applied, whereas several other progressions develop with time
With the increase of treatment durations, some of these modifications appear to continue but with a gradually decreasing rate. This is due to the several other system complications, which develop within the porous media hindering the continuation of chemical-electrokinetic processes
Summary
The electrokinetic technology, which is an alternative method to the conventional ground improvement methods, involves electrochemical electro-osmosis stabilization in fine-grained soils. This method has been chosen in this study because it is cost-effective, applicable to insitu and ex-situ testings, rapid installation and easy to operate, having silent operation, having relatively short treatment duration, and can be implement in some existing structures. In this study, investigations are carried out at laboratory scale to identify the effects of chemical-electrokinetic processing on physical and chemical characteristics of two types of fine-grained soils. This study aims to investigate the potential application of this technique as a viable in situ soil treatment method in particular to improve soil physical properties
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