1. Professor of Civil Engineering and Research Director, Centre for Geomechanics and Railway Engineering, Faculty of Engineering and Information Sciences, Univ. of Wollongong, Wollongong, NSW 2522, Australia (corresponding author).
2. Research Fellow, Centre for Geomechanics and Railway Engineering, Faculty of Engineering and Information Sciences, Univ. of Wollongong, Wollongong City, NSW 2522, Australia.
3. Associate Professor, Centre for Geomechanics and Railway Engineering, Faculty of Engineering and Information Sciences, Univ. of Wollongong, Wollongong City, NSW 2522, Australia.
4. Senior Lecturer, Centre for Geomechanics and Railway Engineering, Faculty of Engineering and Information Sciences, Univ. of Wollongong, Wollongong City, NSW 2522, Australia.