1. Senior Project Engineer, 3S Consult GmbH, 80333 Munich, Germany (corresponding author).
2. Professor, School of Civil, Environmental, and Mining Engineering, Univ. of Adelaide, Adelaide, SA 5005, Australia.
3. Professor, Institute for Numerical Mathematics and Optimization, Dept. of Mathematics and Computer Science, Technical Univ. Bergakademie Freiberg, 09596 Freiberg, Germany.