ESTIMATION OF SWELLING PRESSURE USING SIMPLE SOIL INDICES

In arid to semiarid regions, damage from expansive soils to light structures in the longterm may be as costly as damage by major natural hazards. Swell characteristics,including swell pressure, of expansive soils have been the subject of numerous studies.Studies examining this property employ almost exclusively the conventional oedometerapparatus, which indirectly measures swell pressure. The results of such studies are oftenspeculative. This investigation covers 1000 swell tests on 124 soil samples, using constantswell and free swell tests. Identical specimens at different initial water contents and drydensities were constituted through static compaction for each soil sample. Atterberg limitswere incorporated into regression analyses along with the water content and dry densitydata. The resulting empirical relationship reasonably predicts the swell pressure. Thecorrelation between the data from constant volume and free swell tests was even moreconclusive. Comparing the empirical form obtained from this investigation and thepreviously published two equations reveals that the other relationships dramaticallyunderestimated the swell pressure, which was attributed to the use of indirect methods.1. Girifl

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