1. School of Transportation Science and Engineering, Beihang University, Beijing 100191, China.
2. School of Civil, Environmental and Chemical Engineering, Royal Melbourne Institute of Technology (RMIT), Melbourne VIC 3001, Australia.
3. State Key Laboratory of Geohazards Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, Sichuan 610059, China.
4. National Engineering Laboratory for High-Speed Railway Construction, Central South University, Changsha, Hunan 410075, China.