Feasibility of using electrokinetics and nanomaterials to stabilize and improve collapsible soils

Loess as a subcategory of collapsible soils is a well-known aeolian deposit generally characterized as a highly-porous medium with relatively low natural density and water content and a high percentage of fine-grained particles. Such collapsible soil sustains large stresses under a dry condition with natural water content. However, it can experience high and relatively sudden decreases in its volume once it reaches a certain water content under a certain load and therefore, the natural condition of the soil might not be suitable for construction if the possibility of the exposure of the soil to excessive water exists during the lifetime of the project. This research presents the utilization of an innovative method for stabilization and improvement of Gorgan loessial soil. This method uses electrokinetics and nanomaterials to instigate additives to move through soil pores, as an in situ remedial measure. To assess the acceptability of this measure, the deformability and strength characteristics of the improved collapsible soil are measured and compared with those of the unimproved soil, implementing several unsaturated oedometer tests under constant vertical stress and varying matric suction. The result emphasizes the importance of the matric suction on the behavior of both improved and unimproved soils. The test results indicate that the resistance of the soil was highly dependent on the water content and matric suction of the soil. The oedometer tests on samples improved by 3% lime and 5% nanomaterials show considerable improvement of the collapse potential. Results also reveal that stabilized samples experience notably lower volume decrease under the same applied stresses. (C) 2019 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V.