Laboratory investigation of geotextile position on CBR of clayey sand soil under freeze-thaw cycle

In cold regions, soil experiences repetitive freeze–thaw cycles that are considered as one of the most important phenomena in cold region engineering. Approximately 30 percent of soils around the world and a large portion of fertile lands are subjected to daily or seasonal freeze-thaw cycles. These cycles cause considerable changes in water content, solute movement, permeability, strength parameters, erosion rate, and other physical or chemical characteristics of the soil. Nowadays, one of the ways for improvement the physical and mechanical characteristics of the soil is to incorporate geosynthetic material as a layer between the embankment and the ground surface. This paper presents results of some California Bearing Ratio tests a clayey sandy soil. Moreover, effect of freeze–thaw cycles on the compressive strength of geotextile-reinforced soil is investigated. The geotextile layer was placed in five positions in different depths of 1.3, 2.6, 3.9, 5.85 and 7.8 cm beneath the surface of the mold and then the sample was exposed to freeze-thaw cycles. It was found that the optimum depth of the geotextile layer is 3.9 cm. In addition, it could be observed that reinforcing the soil can diminish the weakening effect of freeze-thaw cycles up to 41.7%.