1. Research Academic (Australian Research Council), Centre for Geomechanics and Railway Engineering, School of Civil, Mining and Environmental Engineering, Univ. of Wollongong, Wollongong, NSW 2522, Australia.
2. Professor of Civil Engineering and Research Director, Centre for Geomechanics and Railway Engineering, Program Leader, ARC Centre of Excellence in Geotechnical Science and Engineering, Faculty of Engineering and Information Sciences, Univ. of Wollongong, Wollongong, NSW 2522, Australia (corresponding author).
3. Associate Professor, Centre for Geomechanics and Railway Engineering, Univ. of Wollongong, Wollongong, NSW 2522, Australia.