The in-situ stress situation is much more complex than assumed during usual underground excavation design. Even when utilizing more sophisticated, three-dimensional numerical models it is general practice to assume parallel alignment of one of the stress tensor's primary stress components and vertical orientation of one of the other two, hence leading to the usual description of the stress conditions with the K0 value. These assumptions are somewhat conflicting with current knowledge and assumptions about the influence of the terrain and tectonic regime on the primary stress state. This paper represents the summary of a parametric study, based on results of numerical calculations conducted under assumption of a primary stress state featuring both arbitrary magnitudes of principal stresses and arbitrary spatial orientations. The patterns found in the relationship between displacement behaviour of the tunnel cross section and the primary stress orientations are presented in this paper.

This content is only available via PDF.
You can access this article if you purchase or spend a download.