1. Associate Professor, Dept. of Civil Engineering, Central South Univ., Changsha 410075, China; and Researcher, National Engineering Lab for High Speed Railway Construction, Changsha 410075, China (corresponding author).
2. Postgraduate, Dept. of Civil Engineering, Central South Univ., Changsha 410075, China.
3. Professor, Dept. of Civil Engineering, Central South Univ., Changsha 410075, China; and Researcher, National Engineering Lab for High Speed Railway Construction, Changsha 410075, China.