A review on study of Electrokinetic stabilization of expansive soil

Needless to elaborate the harmful effects of the Expansive soil on the light-weight structures, as it is a very common problem faced by the Structural and Geotechnical engineers all over the world. In INDIA, the site having BlackCotton soil force the local engineers to think differently in order to find a way which can improve the ground condition very efficiently. One solution, which is not used worldwide, is the Electrokinetic Treatment which uses the principle of Electroosmosis, Electromigration and Electrocementation, and has been proved the best for fine grained soil. Till now, inadequate studies have been done to prove its efficiency in using it for the expansive soil. Apparently, there may be some reasons why the researchers don't consider this technique useful in such soils. This paper includes the whole and sole of this treatment reckoned from the past studies and its scope in implementation with Expansive soils. Experimental study, both in field and laboratory, followed by its analysis using available software packages, is required to decide the factors of this treatment influencing expansive soil

Preliminary study on the contribution of osmotic effects for the electrical resistivity of sands

Electrical resistivity of soils can be used to evaluate the level of contamination in soils in geophysical prospection tests. The chemical composition of pore fluid also corresponds to a given water potential, named as osmotic suction. Therefore both electrical resistivity and osmotic suction can be related when soil is saturated. This paper investigates their relationship when the soil is not saturated. The osmotic suction and electrical resistivity were measured for uniform grading size samples of sand prepared with different concentrations of an ionic leachate from a real landfield. Both were measured also for the fluid with the different concentrations. Suction was measured for different degrees of saturation using the ionic fluid for the different concentrations. The soil osmotic suction is similar to the osmotic suction of the pore fluid independently from the degree of saturation, and the differences in electrical resistivity in the saturated samples and pore fluid alone as function of osmotic suction are related by a constant. Although pore fluid composition affects electrical resistivity, when evaluating the electrical resistivity considering the degree of saturation one should pay attention to factors that are related with matric suction instead of osmotic suction

Correspondence between electrical resistivity and total suction in compacted kaolin considering the presence of salt

Prospection techniques based on measuring the electrical resistivity of geomaterials are being used mainly for geophysical characterization, for evaluating soil contamination and the extension of contaminated areas, in addition to the compaction control in geotechnical works. This technique is based on the fact that contrasts in electrical resistivity along the profiles analysed help identifying zones of transition, because this property is affected by the presence of water and dissolved salts in the electrolyte, as well as by soil structure. However, in situ data interpretation has some difficulties because electrical resistivity is affected by changes in the unsaturated state of the soil, as well as by the presence of salt compounds (natural or from contamination). The correspondence between electrical resistivity and total suction in compacted kaolin considering the presence of salt was investigated in the study presented. The samples tested were compacted for the same voids ratio and water content, however one type was prepared with distilled water and the other with a NaCl solution (0.5 M). This is a relatively small concentration of salt, to which there were no significant changes in the liquid and plasticity limits, neither on zeta potential if pH is equal to 7, however the quantity of ions supplied was enough to affect the electrical resistivity of the compacted material. The water retention curve of the two kinds of samples was determined using a water dewpoint device and through vapour equilibrium. The electrical resistivity was measured in samples to which suction was known, allowing to find a relationship between total suction and electrical conductivity, and therefore between water content and electrical resistivity. The results found are commented considering the electrical transport through the liquid phase and its continuity in the porous media, which depends on the conductivity of the electrolyte and on the degree of saturation

Correspondence between electrical resistivity and total suction in compacted kaolin considering the presence of salt

Prospection techniques based on measuring the electrical resistivity of geomaterials are being used mainly for geophysical characterization, for evaluating soil contamination and the extension of contaminated areas, in addition to the compaction control in geotechnical works. This technique is based on the fact that contrasts in electrical resistivity along the profiles analysed help identifying zones of transition, because this property is affected by the presence of water and dissolved salts in the electrolyte, as well as by soil structure. However, in situ data interpretation has some difficulties because electrical resistivity is affected by changes in the unsaturated state of the soil, as well as by the presence of salt compounds (natural or from contamination). The correspondence between electrical resistivity and total suction in compacted kaolin considering the presence of salt was investigated in the study presented. The samples tested were compacted for the same voids ratio and water content, however one type was prepared with distilled water and the other with a NaCl solution (0.5 M). This is a relatively small concentration of salt, to which there were no significant changes in the liquid and plasticity limits, neither on zeta potential if pH is equal to 7, however the quantity of ions supplied was enough to affect the electrical resistivity of the compacted material. The water retention curve of the two kinds of samples was determined using a water dewpoint device and through vapour equilibrium. The electrical resistivity was measured in samples to which suction was known, allowing to find a relationship between total suction and electrical conductivity, and therefore between water content and electrical resistivity. The results found are commented considering the electrical transport through the liquid phase and its continuity in the porous media, which depends on the conductivity of the electrolyte and on the degree of saturation