ABSTRACT
Soils and rocks are by nature heterogeneous materials whose properties are strongly dependent on the existent variability. In the case of rock massifs the influence of such variability is usually higher and more evident due to the tectonic movements that are associated with their formation. These processes often originate a preferential direction of the rock mass variability, which frequently does not correspond to the traditional horizontal layering observed in soils. In this paper, the impact of the orientation of rock variability is assessed by analysing the excavation of a circular tunnel in a rock mass characterised by a uniform and isotropic stress state. The variability is introduced in the analyses by considering multiple random fields, generated using the Local Average Subdivision (LAS) method. The impact of the orientation of variability is evaluated both in terms of displacements around the excavation and forces in the tunnel lining. The results show that both displacements and forces are affected by the orientation of the variability and that such effect depends on the parameters employed in the generation of the random fields, particularly on the ratio of anisotropy considered for the rock mass.
