The Effect of Initial Water Content on Swelling Behavior of Fine Grained Soils

The variation in water content is known as one of the most important factors for swelling behavior of soils, especially found in arid and semi-arid regions. Swelling soils found in such regions are subjected to volume increase and decrease cycles during rainy and dry periods and thus low-rise buildings constructed in these soils are exposed to damages. Although the relationship between swelling parameters (swelling pressure and swelling percent) and soils' physical-index properties have been investigated in details in previous researches, the effect of variation in water content on swelling mechanism of soils is not yet sufficiently studied. For achieving accurate understanding of swelling behavior at field condition, soils should be subjected to swelling tests at different initial water content conditions. Considering current limitation related to this subject, investigation the effect of initial water content on swelling behavior of soils was aimed within the scope of this research. In accordance with this purpose, soil samples were collected from different locations in Turkey to study on soils having wide range in terms of grain size distributions, mineralogical composition and consistency limits. To minimize the effect of dry unit weight on swelling behavior of soils, samples prepared at the same dry unit weight (14.6 kN/m3) and different initial water content conditions were subjected to swelling tests. It was determined that there is a linear relationship between initial water content and swelling parameters and swelling parameters decrease with increasing initial water content conditions. A simple and multiple regression analyses were performed between grain size distributions and consistency limits of soils and swelling parameters, and equations with high coefficient of determination are obtained. In addition, a general model and a new approach called as "Soil Swelling Designation" were recommended to be used for prediction the effect of water content on swelling pressure and percentage of soils.