1. Department of Civil, Construction and Environmental Engineering, Iowa State University, Ames, Iowa, USA
2. School of Mining and Environmental Engineering, Research Director of Centre for Geomechanics and Railway Engineering, University of Wollongong, Wollongong City, NSW, Australia
3. Tianjin University, People's Republic of China
4. Centre for Geomechanics and Railway Engineering, University of Wollongong, Wollongong City, NSW, Australia