Numerical Insights into Shallow Foundation Settlement on Silty Soil Stabilized with Granular Material

Silty soils are fine-grained materials that typically exhibit low strength, low hydraulic conductivity, and high compressibility, which contributes to their minimal bearing capacity. As a result, foundation failures can occur due to the insufficient strength and stiffness of silty soils. Buildings constructed on these types of soil may experience excessive settlement, which can significantly reduce their design lifespan. This excessive settlement can lead to cracks in walls and roof slabs, as well as the misalignment of doors and windows. In severe cases, it may even result in the collapse of the structure. To address these issues, this study proposes a method to enhance the bearing capacity of the existing ground by blending the silty soil with granular material at replacement rates of 20%, 30%, and 40%. Three different footing sizes were tested: (1.83 × 1.83 m²), (1.22 × 1.22 m²), and (1.22 × 1.83 m²). A three-dimensional finite element analysis was conducted to calculate the bearing capacity of the shallow foundations on the original soil, and the performance of the footings on improved ground was compared. To model soil behavior, a linear elastic perfectly plastic model utilizing the Mohr-Coulomb failure criterion was employed. The results indicated that as the size of the footing increases, the yield point also rises. The percentage improvement in ultimate bearing capacity for footings with dimensions of (1.22 × 1.22 m²), (1.83 × 1.83 m²), and (1.22 × 1.83 m²) founded on 40% blended silty clay and granular material was found to be 91%, 89%, and 83%, respectively. This study demonstrates the effectiveness of soil improvement techniques in enhancing the structural integrity of foundations situated on silty soils.