Comparison of lime treatment techniques for deep stabilization of expansive soils

Abstract

ABSTRACT In-situ deep Figure 14stabilization of expansive soil deposits is commonly carried out using lime piles and lime slurry injection. Recent research demonstrated the stabilization of expansive soils using lime column technique, and more recently the lime precipitation technique has emerged as the viable choice for stabilization of expansive soils. Comparison of these techniques in stabilizing the expansive soils provides a better understanding of the stabilization mechanisms and their advantages and limitations. Therefore, this paper brings out the relative efficacy of different lime treatment techniques in stabilizing the expansive soils. To achieve this objective, the laboratory model tests were carried out in expansive soil using lime pile and lime precipitation techniques in a compacted state, and lime slurry technique in a desiccated state from a central hole of diameter, d. The lime precipitation was achieved by sequential permeation of 46.2% calcium chloride and 33.3% sodium hydroxide solutions through a central hole in the compacted expansive soil. After 30 days of curing in the test moulds, the undisturbed soil specimens were collected for evaluation of the changes in physico-chemical, index and engineering properties. The experimental results reveal that the treatment is effective in stabilizing the expansive soil up to a radial distance of 0.8d from the central hole in case of lime pile treatment, whereas the lime slurry treatment up to a radial distance of 1.5d and lime precipitation treatment up to a radial distance of 2.5d. The experimental findings were supported with scanning electron microscopic images and energy dispersive X-ray spectroscopy analysis.