Soil-steel structures play an important role in the infrastructure of mining industry. The ease to ship and construct in remote locations distinguishes this system comparing to conventional concrete and steel structures. In addition, the ability to dismantle the structural system and restore the site to the initial condition with the least environmental cost at the end of mining projects is considered a great asset to the environment. Soil-steel structures are widely used in supporting heavy haul roads subjected to excessive loadings. This study presents a three-dimensional numerical investigation for soil-steel structures subjected to various heavy weight haul trucks. The numerical technique is validated by the field measurements of a fully monitored 10.0 m span soil-steel structure subjected to tandem axle loading until failure. The numerical simulation succeeded to capture the ultimate capacity of the steel structures under truck loading conditions. The validated numerical technique is then used to investigate the ultimate behavior of the world’s largest-span soil-steel structure with a span exceeding 32 m. The results demonstrated the ability of soil-steel structures in sustaining various haul trucks with gross weight of more than 850 tons.