Railways provide an efficient and economic transport mode in many parts of the developed countries including Australia, China, South Korea and the USA. Ballast layer is designed as a load bearing layer for rail tracks and to be free draining, but when the ballast voids are wholly or partially impeded due to the intrusion of fine particles or ballast breakage, the ballast can be considered to be fouled. Ballast degradation causes a reduction in the drainage capacity of ballast, thereby reducing the track resiliency and triggering high maintenance costs. Geosynthetics are commonly used in railway construction for reinforcement and stabilisation purposes. When railway ballast becomes degraded, the beneficial effect of geosynthetics could significantly decrease. A series of drop-weight impact tests and direct shear tests for ballast with and without the inclusion of geosynthetics are carried out in the laboratory. Discrete element modelling (DEM) is also carried out on ballast with and without the inclusion of geogrids. Load-deformation and ballast breakage responses obtained from the DEM simulations are in reasonable comparison with those measured experimentally. The research outcomes of this study can provide a fundamental laboratory and computational framework to assist practicing engineers in track design considering the role of geosynthetic inclusions.
Menu