Evaluation of Geotextile Effects on Improvement Bearing Capacity of Clay-Gravel Mixtures (Study Area: Barandouz)

Soil improvement is a method used for increasing in quality of materials can be applied in pavement layers. From the standpoint of environmental geotechnics, application of the geotextile in many engineering projects can be effective method for soil improvements. Main aim of this study is laboratory evaluation of geotextile effects on bearing capacity of clay-gravel soil mixtures from Barandouz area for applying in pavement. In this research, gravelly soils was mixed with clay in 25, 50 and 75 percent. Geotextile effects evaluated in two conditions. First, in layers (in one, two and three layer). Second, as mixed pieces with 1×1 and 5×5 cm2 dimensions and weight percent of 1, 2 and 3. For determining bearing capacity of specimens, California Bearing Ratio (CBR) test performed in dry and saturate conditions. Also, in saturated state swelling potential of reinforced samples evaluated. Results of study showed appropriate geotextile layer number is one that is embedded in middle part of specimens or adding one percent by weight geotextile pieces with 1×1 cm2 dimensions randomly to reinforcing for improvement of bearing capacity. These values in saturated state significantly reduces swelling in specimens with clay content.