Assessing Interface Friction in Sand Treated Clayey Soil-Concrete Composites

Abstract Understanding the fundamental mechanisms governing friction mobilization at the interface between construction materials and soil is crucial for the design and performance assessment of conventional underground structures like footing, piles, and anchors. This research investigates the interface friction behavior between concrete construction materials and clayey soil, treated with varying sand content of (0%, 20%, 30%, and 40%). Additionally, two levels of water content were examined for each sand content: 8.5% and 17%. The friction angle generated between the solid surface and soil was calculated through experimental tests conducted by using shear test, with three different normal stresses that have been applied at a rate of 0.25 mm/min. The results indicate showed that created friction resistance between the clayey soil and concrete construction material is influenced by both sand and water contents. The increase in the percentages of the interface friction angle when the soil is treated with sand at a water content of 8.5% varied. It was approximately 4, 11, and 15% for sand contents of 20, 30, and 40%, respectively. Similarly, when the clayey soil was treated with the same sand dosages at a water content of 17%, the percentage increase in the interface friction angle differed. It amounted to 5%, 13%, and 27% for sand contents of 20, 30, and 40%, respectively.