Modeling washboard patterns on unpaved roads through transport dynamics

Washboard patterns are a common feature of unpaved roads. In developing countries, unpaved roads represent a significant portion of the national road infrastructure system. To ensure efficient use of resources, it is crucial to explore new strategies to extend the lifespan of these roads. Despite this importance, the mechanical behaviour that leads to the formation of undulations remains uncertain. This research aims to address this gap by investigating the washboard formation using the granular transport model developed by Nishimori and Ouchi (1993). Originally designed to explain the sand dune formation, this model attributes dune development to shear forces exerted by wind on sand. A similarity was identified with the washboard phenomenon, where waves emerge due to shear forces generated by vehicle wheels. To evaluate this process, the dune transport model is applied to analyse washboard experimental data collected by Ibagón et al. (2023). The findings suggest that the theoretical model captures corrugation development and demonstrates that washboard can also be analysed from the perspective of dynamic particle transport.