1. Ph.D. Student, School of Civil Engineering, Southwest Jiaotong Univ., Chengdu, Sichuan 610031, China.
2. Professor, School of Civil Engineering, Chongqing Univ., Chongqing 40044, China; Professor, School of Civil Engineering, Southwest Jiaotong Univ., Chengdu, Sichuan 610031, China (corresponding author).
3. Professor, School of Civil Engineering, Chongqing Univ., Chongqing 40044, China.