1. Shandong Hi-Speed Group Innovation Research Institute, Jinan 250014, China
2. Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing 210098, China
3. College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, China
4. School of Civil and Construction Engineering, Oregon State University, Corvallis, OR 97331, USA
5. School of Traffic & Transportation Engineering, Changsha University of Science & Technology, Changsha 410114, China