1. Research Fellow, Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, College of Civil and Transportation Engineering, Hohai Univ., Nanjing 210098, China (corresponding author).
2. Professor, Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, College of Civil and Transportation Engineering, Hohai Univ., Nanjing 210098, China.