1. Lecturer, School of Civil and Architectural Engineering, Beijing Engineering and Technology Research, Center of Rail Transit Line Safety and Disaster Prevention, Beijing Jiaotong Univ., No. 3 Shangyuancun, Haidian District, Beijing 100044, P.R. China.
2. Professor, School of Civil and Architectural Engineering, Beijing Engineering and Technology Research, Center of Rail Transit Line Safety and Disaster Prevention, Beijing Jiaotong Univ., No. 3 Shangyuancun, Haidian District, Beijing 100044, P.R. China (corresponding author).
3. Beijing Mass Transit Railway Operation Corporation Limited, Subway Plaza, No. 2 Xizhimenwaidajie, Xicheng District, Beijing 100044, P.R. China.