1. Distinguished Professor, Research Director and Foundation Director, Dept. of Civil Engineering, Centre for Geomechanics and Railway Engineering, Faculty of Engineering, Univ. of Wollongong, Wollongong, NSW 2522, Australia (corresponding author).
2. Ph.D. Candidate, Centre for Geomechanics and Railway Engineering, Faculty of Engineering, Univ. of Wollongong, Wollongong, NSW 2522, Australia.
3. Lecturer, Centre for Geomechanics and Railway Engineering, Faculty of Engineering, Univ. of Wollongong, Wollongong, NSW 2522, Australia.