1. Ph.D. Candidate, School of Civil Engineering, Beijing Jiaotong Univ., No. 3 Shangyuancun Haidian District, Beijing 100044, People’s Republic of China.
2. Assistant Professor, School of Civil Engineering, Xi’an Univ. of Architecture and Technology, No. 13 Yanta Rd., Yanta District, Xi’an, Shaanxi 710055, People’s Republic of China (corresponding author).
3. Professor, School of Civil Engineering, Beijing Jiaotong Univ., No. 3 Shangyuancun Haidian District, Beijing 100044, People’s Republic of China.
4. Lecturer, School of Civil Engineering and Geomatics, Southwest Petroleum Univ., No. 8 Xindu Rd., Xindu District, Chengdu, Sichuan 610500, People’s Republic of China.