1. Engineer, Geotechnical Research Institute, Hohai Univ., Nanjing 210098, China.
2. Professor, Highway and Railway Engineering Institute, Hohai Univ., Nanjing 210098, China (corresponding author).
3. Professor, Faculty of Infrastructure Engineering, Dalian Univ. of Technology, Dalian 116023, China.
4. Professor, Guangdong Province Expressway Co. Ltd., Guangzhou 510100, China.
5. Associate Professor, Highway and Railway Engineering Institute, Hohai Univ., Nanjing 210098, China.
6. Ph.D. Candidate, Geotechnical Research Institute, Hohai Univ., Nanjing 210098, China.