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K. Mair am Tinkhof, R. Poisel:
"Brittle rock investigations";
Poster: 62. Geomechanik Kolloquium 2013, Salzburg; 09.10.2013 - 11.10.2013.

Underground excavations in rock are complex structures which can face a lot of engineering problems. Especially deep seated tunnels or excavations in weak or brittle rock (e. g. Gotthard Base Tunnel, Brenner Base Tunnel) still pose new challenges. Brittle failure processes can lead to shallow unravelling or to strain-bursting modes of instability that cause difficult conditions for tunnel constructors (Kaiser & Kim, 2008). The stress and the rock mass strength determination is still a challenge for rock engineers. We still do not know exactly where around the opening and at which stress levels failure will occur and how the resulting deformations would affect construction works. It is very difficult to anticipate the "true" rock behaviour; there are scale and shape effects and other geological complexities involved, which make the use of laboratory parameters for the calculation of underground constructions difficult. Better investigation methods and understanding of the failure mechanisms can increase the security during construction and reduce the cost of tunnelling projects.