1. Professor, College of Civil Engineering and Mechanics, Central South Univ. of Forestry and Technology, Shaoshan Road, 410004, China.
2. Ph.D. Candidate, Geotechnical Engineering Center, Sydney Univ., Darlington, NSW, 2006, Australia.
3. Professor, School of Civil Engineering and Architecture, Central South Univ., Shaoshan Road, Changsha, 41007, China.
4. Lecturer, School of Civil Engineering and Architecture, Central South Univ., Shaoshan Road, Changsha, 41007, China (corresponding author).