Use of fine-grained soil for improvement of density and bearing capacity of aeolian sand

The existence of vast areas covered with aeolian sand in many regions of Iran has made the use of this type of soil inevitable in engineering projects. Considering the abundance of fine-grained soil in Khuzestan plain along with the aeolian sand, it is important to investigate the effect of the addition of fine-grained soil to aeolian sand to improve its dry density and bearing capacity. In the present research, different percentages of fine-grained soil were added to aeolian sand from Khuzestan plain to determine its effect on the maximum dry density (gamma dmax), optimum water content (omega opt) and California bearing ratio (CBR) of the aeolian sand and fine-grained soil mixture. It was found that an increase in the percentage of fine-grained soil increased the gamma dmax and decreased the omega opt. The CBR of the soil increased under tests performed at the optimum water content and decreased under saturated conditions. The highest CBR for penetrations of 2.5 and 5 mm (CBR (2.5) and CBR (5)) when the samples were tested at an optimum water content was for the sample where the ratio of the dry weight of the fine-grained soil (WS(F)) to dry weight of the aeolian sand (WS(S)) is equal 40%. Comparison of the results of the current and previous research showed that, in areas such as the Khuzestan plain in which fine-grained soil is available, the use of such soil for improvement of aeolian sand is appropriate.