1. School of Urban Rail Transportation, Soochow Univ., Soochow 215021, China; formerly, Ph.D. Student, Institute of Geotechnical Engineering, Southeast Univ., Nanjing 210096, China.
2. Professor, Institute of Geotechnical Engineering, Southeast Univ., Nanjing 210096, China (corresponding author).
3. Professor, Institute of Geotechnical Engineering, Southeast Univ., Nanjing 210096, China.
4. Ph.D. Student, Dept. of Engineering, Cambridge Univ., Cambridge CB2 1PZ, UK; formerly, M.S. Candidate, Institute of Geotechnical Engineering, Southeast Univ., Nanjing 210096, China.