The research presented in this licentiate thesis was carried out during 2012 and 2013 at the Division of Soil and Rock Mechanics, Department of Civil and Architectural Engineering, at KTH Royal Institute of Technology in Stockholm, Sweden.

The work was supervised by Prof Stefan Larsson and Dr Fredrik Johansson. I owe them much gratitude for their constant support and encouragement, not forgetting their valuable comments on my work. The input from my reference group is also gratefully acknowledged. In addition, I would like to thank my colleagues at the Division of Soil and Rock Mechanics for many rewarding discussions, in particular Prof Em Håkan Stille, who initiated my Ph. D. project, and Dr Rasmus Müller, who made me dive far deeper into statistics than I ever intended. Last, but not least, our wonderful administrative staff must be acknowledged for guiding through the university bureaucracy and helping out with all practical issues.