A behavioural framework for fibre-reinforced gravel

The mechanical behaviour of granular materials is known to be influenced by the addition of fibres. However, most previous research has been carried out on materials with relatively small grains (sands), and its application to larger grains is not well documented. This paper reports an investigation into the mechanical behaviour of a fibre-reinforced granular material with a relatively large grain size corresponding to one-third and one-fifth scale railway ballast. The investigation was carried out by means of triaxial tests incorporating a full-field, image-based deformation measurement technique; this enabled detailed observations to be made of each triaxial test specimen during shearing. The test data demonstrate the benefits of random fibre reinforcement for aggregates that have a relatively large grain size. Analysis taking into account the effect of fibre tension on the effective stresses experienced by the granular skeleton provides new insights into the mechanisms of reinforcement in larger sized granular materials.