Enhancing the Soft Clay Bearing Capacity by Using Cement Dust – Lime Columns

Abstract

Soft clay deposits cause a lot of problems to structures due to low shear strength and high deformation. Soft clay properties can be improved by several methods such as; prefabricated vertical drains, sand cushion reinforced with shredded waste tire, geofoam, stabilization with lime silica and silica fume and stabilization with flyash. The proposed research studies the effect of adding encased cement dust and lime mix column to soft clay on the clay properties such as bearing capacity and settlement. Model tests were performed in different diameters (3.5 cm, 4.0 cm, and 5.0 cm) and different lengths (60%, 80%, and 100%) of the clay layer depth. Non-woven geotextile was used to confining the mix. Some laboratory tests were done on the geotextile, lime, cement dust and clay that artificially prepared from kaolinit. The model was performed on soil that has undrained shear strength of 7 kPa. LVDT was installed to measure the corresponding settlement to each load. A series of 9 tests were carried out using columns considering the case of no columns. A relationship between stress and settlement were plotted and finally the improvement percentages were found. It was found that; the increasing in column diameter and length improve the bearing capacity and reduce the settlement, the floating column gives a better improvement than the end bearing column. The cement dust – lime column enhance the soft clay bearing capacity by 353%.