Abstract
Debris flow occurring in mountainous areas can cause issues to railway tracks. Debris flow may cause large track deformation and even track breakage and introduce server ballast fouling afterwards. After the flash of a debris flow, the fine particles can be retained in the ballast layer and significantly reduce track drainage, leading to lower bearing capacity and a higher risk of track lateral stability problems. Moreover, these solid particles may deposit on the railway surface and endanger the train directly. Unfortunately, those debris flow introduced track issues have not been thoroughly investigated. This study presents a numerical investigation of the impact of the debris flow on the railway track. Various factors governing the debris flow are considered, including particle size and solid fraction. Besides, those factors affecting the ballast are also discussed, such as fouling condition and initial void ratio. A coupled computational fluid dynamics and discrete element method (CFD-DEM) approach is developed to capture the interactions between particles/particles, water/air, and particles/fluid. The results from this study may help the railway to improve track resilience before the debris flow and to improve maintenance strategy after the debris flow flashing.