Comparative Analysis of Drained Triaxial Compression Behavior of Railway Ballast Materials Using NorSand and SANISAND04 Models

This study investigates the performance of Gabbro and Electric Arc Furnace (EAF) slag aggregates as potential railway ballast materials. The stress-strain behavior of these materials was modeled using two distinct constitutive models: NorSand and SANISAND04, based on triaxial drained compression tests under varying confining pressures. The findings indicate that both models capture the typical stress-strain behavior of two different ballast aggregates adequately. However, NorSand shows superior accuracy in predicting volumetric strain, effectively capturing the contraction and dilation phases observed experimentally. SANISAND04 tends to overestimate both the deviatoric peak stresses and peak friction angles, particularly at lower confining pressures, while NorSand demonstrates a closer match to the experimental results for both Gabbro and EAF Slag ballast aggregates. NorSand’s ability to accurately predict both volumetric strain behavior and peak friction angles, especially at lower confining pressures, makes it a more reliable model for capturing the overall behavior of ballast materials. These results emphasize the critical importance of selecting the appropriate constitutive model for accurate finite element analysis in railway engineering, as the choice of model can significantly impact the reliability of predictions related to ballast material performance under stress.